diff options
Diffstat (limited to 'kernel/crypto/asymmetric_keys')
24 files changed, 4040 insertions, 0 deletions
diff --git a/kernel/crypto/asymmetric_keys/.gitignore b/kernel/crypto/asymmetric_keys/.gitignore new file mode 100644 index 000000000..ee328374d --- /dev/null +++ b/kernel/crypto/asymmetric_keys/.gitignore @@ -0,0 +1 @@ +*-asn1.[ch] diff --git a/kernel/crypto/asymmetric_keys/Kconfig b/kernel/crypto/asymmetric_keys/Kconfig new file mode 100644 index 000000000..4870f2840 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/Kconfig @@ -0,0 +1,70 @@ +menuconfig ASYMMETRIC_KEY_TYPE + tristate "Asymmetric (public-key cryptographic) key type" + depends on KEYS + help + This option provides support for a key type that holds the data for + the asymmetric keys used for public key cryptographic operations such + as encryption, decryption, signature generation and signature + verification. + +if ASYMMETRIC_KEY_TYPE + +config ASYMMETRIC_PUBLIC_KEY_SUBTYPE + tristate "Asymmetric public-key crypto algorithm subtype" + select MPILIB + select PUBLIC_KEY_ALGO_RSA + select CRYPTO_HASH_INFO + help + This option provides support for asymmetric public key type handling. + If signature generation and/or verification are to be used, + appropriate hash algorithms (such as SHA-1) must be available. + ENOPKG will be reported if the requisite algorithm is unavailable. + +config PUBLIC_KEY_ALGO_RSA + tristate "RSA public-key algorithm" + select MPILIB + help + This option enables support for the RSA algorithm (PKCS#1, RFC3447). + +config X509_CERTIFICATE_PARSER + tristate "X.509 certificate parser" + depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE + select ASN1 + select OID_REGISTRY + help + This option provides support for parsing X.509 format blobs for key + data and provides the ability to instantiate a crypto key from a + public key packet found inside the certificate. + +config PKCS7_MESSAGE_PARSER + tristate "PKCS#7 message parser" + depends on X509_CERTIFICATE_PARSER + select ASN1 + select OID_REGISTRY + help + This option provides support for parsing PKCS#7 format messages for + signature data and provides the ability to verify the signature. + +config PKCS7_TEST_KEY + tristate "PKCS#7 testing key type" + depends on PKCS7_MESSAGE_PARSER + select SYSTEM_TRUSTED_KEYRING + help + This option provides a type of key that can be loaded up from a + PKCS#7 message - provided the message is signed by a trusted key. If + it is, the PKCS#7 wrapper is discarded and reading the key returns + just the payload. If it isn't, adding the key will fail with an + error. + + This is intended for testing the PKCS#7 parser. + +config SIGNED_PE_FILE_VERIFICATION + bool "Support for PE file signature verification" + depends on PKCS7_MESSAGE_PARSER=y + select ASN1 + select OID_REGISTRY + help + This option provides support for verifying the signature(s) on a + signed PE binary. + +endif # ASYMMETRIC_KEY_TYPE diff --git a/kernel/crypto/asymmetric_keys/Makefile b/kernel/crypto/asymmetric_keys/Makefile new file mode 100644 index 000000000..e47fcd9ac --- /dev/null +++ b/kernel/crypto/asymmetric_keys/Makefile @@ -0,0 +1,64 @@ +# +# Makefile for asymmetric cryptographic keys +# + +obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys.o + +asymmetric_keys-y := asymmetric_type.o signature.o + +obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o +obj-$(CONFIG_PUBLIC_KEY_ALGO_RSA) += rsa.o + +# +# X.509 Certificate handling +# +obj-$(CONFIG_X509_CERTIFICATE_PARSER) += x509_key_parser.o +x509_key_parser-y := \ + x509-asn1.o \ + x509_rsakey-asn1.o \ + x509_cert_parser.o \ + x509_public_key.o + +$(obj)/x509_cert_parser.o: $(obj)/x509-asn1.h $(obj)/x509_rsakey-asn1.h +$(obj)/x509-asn1.o: $(obj)/x509-asn1.c $(obj)/x509-asn1.h +$(obj)/x509_rsakey-asn1.o: $(obj)/x509_rsakey-asn1.c $(obj)/x509_rsakey-asn1.h + +clean-files += x509-asn1.c x509-asn1.h +clean-files += x509_rsakey-asn1.c x509_rsakey-asn1.h + +# +# PKCS#7 message handling +# +obj-$(CONFIG_PKCS7_MESSAGE_PARSER) += pkcs7_message.o +pkcs7_message-y := \ + pkcs7-asn1.o \ + pkcs7_parser.o \ + pkcs7_trust.o \ + pkcs7_verify.o + +$(obj)/pkcs7_parser.o: $(obj)/pkcs7-asn1.h +$(obj)/pkcs7-asn1.o: $(obj)/pkcs7-asn1.c $(obj)/pkcs7-asn1.h + +clean-files += pkcs7-asn1.c pkcs7-asn1.h + +# +# PKCS#7 parser testing key +# +obj-$(CONFIG_PKCS7_TEST_KEY) += pkcs7_test_key.o +pkcs7_test_key-y := \ + pkcs7_key_type.o + +# +# Signed PE binary-wrapped key handling +# +obj-$(CONFIG_SIGNED_PE_FILE_VERIFICATION) += verify_signed_pefile.o + +verify_signed_pefile-y := \ + verify_pefile.o \ + mscode_parser.o \ + mscode-asn1.o + +$(obj)/mscode_parser.o: $(obj)/mscode-asn1.h $(obj)/mscode-asn1.h +$(obj)/mscode-asn1.o: $(obj)/mscode-asn1.c $(obj)/mscode-asn1.h + +clean-files += mscode-asn1.c mscode-asn1.h diff --git a/kernel/crypto/asymmetric_keys/asymmetric_keys.h b/kernel/crypto/asymmetric_keys/asymmetric_keys.h new file mode 100644 index 000000000..f97330886 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/asymmetric_keys.h @@ -0,0 +1,18 @@ +/* Internal definitions for asymmetric key type + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +extern struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id); + +static inline +const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key) +{ + return key->type_data.p[1]; +} diff --git a/kernel/crypto/asymmetric_keys/asymmetric_type.c b/kernel/crypto/asymmetric_keys/asymmetric_type.c new file mode 100644 index 000000000..bcbbbd794 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/asymmetric_type.c @@ -0,0 +1,406 @@ +/* Asymmetric public-key cryptography key type + * + * See Documentation/security/asymmetric-keys.txt + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ +#include <keys/asymmetric-subtype.h> +#include <keys/asymmetric-parser.h> +#include <linux/seq_file.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/ctype.h> +#include "asymmetric_keys.h" + +MODULE_LICENSE("GPL"); + +static LIST_HEAD(asymmetric_key_parsers); +static DECLARE_RWSEM(asymmetric_key_parsers_sem); + +/** + * asymmetric_key_generate_id: Construct an asymmetric key ID + * @val_1: First binary blob + * @len_1: Length of first binary blob + * @val_2: Second binary blob + * @len_2: Length of second binary blob + * + * Construct an asymmetric key ID from a pair of binary blobs. + */ +struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1, + size_t len_1, + const void *val_2, + size_t len_2) +{ + struct asymmetric_key_id *kid; + + kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2, + GFP_KERNEL); + if (!kid) + return ERR_PTR(-ENOMEM); + kid->len = len_1 + len_2; + memcpy(kid->data, val_1, len_1); + memcpy(kid->data + len_1, val_2, len_2); + return kid; +} +EXPORT_SYMBOL_GPL(asymmetric_key_generate_id); + +/** + * asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same. + * @kid_1, @kid_2: The key IDs to compare + */ +bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1, + const struct asymmetric_key_id *kid2) +{ + if (!kid1 || !kid2) + return false; + if (kid1->len != kid2->len) + return false; + return memcmp(kid1->data, kid2->data, kid1->len) == 0; +} +EXPORT_SYMBOL_GPL(asymmetric_key_id_same); + +/** + * asymmetric_key_id_partial - Return true if two asymmetric keys IDs + * partially match + * @kid_1, @kid_2: The key IDs to compare + */ +bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1, + const struct asymmetric_key_id *kid2) +{ + if (!kid1 || !kid2) + return false; + if (kid1->len < kid2->len) + return false; + return memcmp(kid1->data + (kid1->len - kid2->len), + kid2->data, kid2->len) == 0; +} +EXPORT_SYMBOL_GPL(asymmetric_key_id_partial); + +/** + * asymmetric_match_key_ids - Search asymmetric key IDs + * @kids: The list of key IDs to check + * @match_id: The key ID we're looking for + * @match: The match function to use + */ +static bool asymmetric_match_key_ids( + const struct asymmetric_key_ids *kids, + const struct asymmetric_key_id *match_id, + bool (*match)(const struct asymmetric_key_id *kid1, + const struct asymmetric_key_id *kid2)) +{ + int i; + + if (!kids || !match_id) + return false; + for (i = 0; i < ARRAY_SIZE(kids->id); i++) + if (match(kids->id[i], match_id)) + return true; + return false; +} + +/** + * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID. + * @id: The ID as a hex string. + */ +struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id) +{ + struct asymmetric_key_id *match_id; + size_t hexlen; + int ret; + + if (!*id) + return ERR_PTR(-EINVAL); + hexlen = strlen(id); + if (hexlen & 1) + return ERR_PTR(-EINVAL); + + match_id = kmalloc(sizeof(struct asymmetric_key_id) + hexlen / 2, + GFP_KERNEL); + if (!match_id) + return ERR_PTR(-ENOMEM); + match_id->len = hexlen / 2; + ret = hex2bin(match_id->data, id, hexlen / 2); + if (ret < 0) { + kfree(match_id); + return ERR_PTR(-EINVAL); + } + return match_id; +} + +/* + * Match asymmetric keys by an exact match on an ID. + */ +static bool asymmetric_key_cmp(const struct key *key, + const struct key_match_data *match_data) +{ + const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); + const struct asymmetric_key_id *match_id = match_data->preparsed; + + return asymmetric_match_key_ids(kids, match_id, + asymmetric_key_id_same); +} + +/* + * Match asymmetric keys by a partial match on an IDs. + */ +static bool asymmetric_key_cmp_partial(const struct key *key, + const struct key_match_data *match_data) +{ + const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); + const struct asymmetric_key_id *match_id = match_data->preparsed; + + return asymmetric_match_key_ids(kids, match_id, + asymmetric_key_id_partial); +} + +/* + * Preparse the match criterion. If we don't set lookup_type and cmp, + * the default will be an exact match on the key description. + * + * There are some specifiers for matching key IDs rather than by the key + * description: + * + * "id:<id>" - find a key by partial match on any available ID + * "ex:<id>" - find a key by exact match on any available ID + * + * These have to be searched by iteration rather than by direct lookup because + * the key is hashed according to its description. + */ +static int asymmetric_key_match_preparse(struct key_match_data *match_data) +{ + struct asymmetric_key_id *match_id; + const char *spec = match_data->raw_data; + const char *id; + bool (*cmp)(const struct key *, const struct key_match_data *) = + asymmetric_key_cmp; + + if (!spec || !*spec) + return -EINVAL; + if (spec[0] == 'i' && + spec[1] == 'd' && + spec[2] == ':') { + id = spec + 3; + cmp = asymmetric_key_cmp_partial; + } else if (spec[0] == 'e' && + spec[1] == 'x' && + spec[2] == ':') { + id = spec + 3; + } else { + goto default_match; + } + + match_id = asymmetric_key_hex_to_key_id(id); + if (IS_ERR(match_id)) + return PTR_ERR(match_id); + + match_data->preparsed = match_id; + match_data->cmp = cmp; + match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE; + return 0; + +default_match: + return 0; +} + +/* + * Free the preparsed the match criterion. + */ +static void asymmetric_key_match_free(struct key_match_data *match_data) +{ + kfree(match_data->preparsed); +} + +/* + * Describe the asymmetric key + */ +static void asymmetric_key_describe(const struct key *key, struct seq_file *m) +{ + const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key); + const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); + const struct asymmetric_key_id *kid; + const unsigned char *p; + int n; + + seq_puts(m, key->description); + + if (subtype) { + seq_puts(m, ": "); + subtype->describe(key, m); + + if (kids && kids->id[1]) { + kid = kids->id[1]; + seq_putc(m, ' '); + n = kid->len; + p = kid->data; + if (n > 4) { + p += n - 4; + n = 4; + } + seq_printf(m, "%*phN", n, p); + } + + seq_puts(m, " ["); + /* put something here to indicate the key's capabilities */ + seq_putc(m, ']'); + } +} + +/* + * Preparse a asymmetric payload to get format the contents appropriately for the + * internal payload to cut down on the number of scans of the data performed. + * + * We also generate a proposed description from the contents of the key that + * can be used to name the key if the user doesn't want to provide one. + */ +static int asymmetric_key_preparse(struct key_preparsed_payload *prep) +{ + struct asymmetric_key_parser *parser; + int ret; + + pr_devel("==>%s()\n", __func__); + + if (prep->datalen == 0) + return -EINVAL; + + down_read(&asymmetric_key_parsers_sem); + + ret = -EBADMSG; + list_for_each_entry(parser, &asymmetric_key_parsers, link) { + pr_debug("Trying parser '%s'\n", parser->name); + + ret = parser->parse(prep); + if (ret != -EBADMSG) { + pr_debug("Parser recognised the format (ret %d)\n", + ret); + break; + } + } + + up_read(&asymmetric_key_parsers_sem); + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} + +/* + * Clean up the preparse data + */ +static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep) +{ + struct asymmetric_key_subtype *subtype = prep->type_data[0]; + struct asymmetric_key_ids *kids = prep->type_data[1]; + int i; + + pr_devel("==>%s()\n", __func__); + + if (subtype) { + subtype->destroy(prep->payload[0]); + module_put(subtype->owner); + } + if (kids) { + for (i = 0; i < ARRAY_SIZE(kids->id); i++) + kfree(kids->id[i]); + kfree(kids); + } + kfree(prep->description); +} + +/* + * dispose of the data dangling from the corpse of a asymmetric key + */ +static void asymmetric_key_destroy(struct key *key) +{ + struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key); + struct asymmetric_key_ids *kids = key->type_data.p[1]; + + if (subtype) { + subtype->destroy(key->payload.data); + module_put(subtype->owner); + key->type_data.p[0] = NULL; + } + + if (kids) { + kfree(kids->id[0]); + kfree(kids->id[1]); + kfree(kids); + key->type_data.p[1] = NULL; + } +} + +struct key_type key_type_asymmetric = { + .name = "asymmetric", + .preparse = asymmetric_key_preparse, + .free_preparse = asymmetric_key_free_preparse, + .instantiate = generic_key_instantiate, + .match_preparse = asymmetric_key_match_preparse, + .match_free = asymmetric_key_match_free, + .destroy = asymmetric_key_destroy, + .describe = asymmetric_key_describe, +}; +EXPORT_SYMBOL_GPL(key_type_asymmetric); + +/** + * register_asymmetric_key_parser - Register a asymmetric key blob parser + * @parser: The parser to register + */ +int register_asymmetric_key_parser(struct asymmetric_key_parser *parser) +{ + struct asymmetric_key_parser *cursor; + int ret; + + down_write(&asymmetric_key_parsers_sem); + + list_for_each_entry(cursor, &asymmetric_key_parsers, link) { + if (strcmp(cursor->name, parser->name) == 0) { + pr_err("Asymmetric key parser '%s' already registered\n", + parser->name); + ret = -EEXIST; + goto out; + } + } + + list_add_tail(&parser->link, &asymmetric_key_parsers); + + pr_notice("Asymmetric key parser '%s' registered\n", parser->name); + ret = 0; + +out: + up_write(&asymmetric_key_parsers_sem); + return ret; +} +EXPORT_SYMBOL_GPL(register_asymmetric_key_parser); + +/** + * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser + * @parser: The parser to unregister + */ +void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser) +{ + down_write(&asymmetric_key_parsers_sem); + list_del(&parser->link); + up_write(&asymmetric_key_parsers_sem); + + pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name); +} +EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser); + +/* + * Module stuff + */ +static int __init asymmetric_key_init(void) +{ + return register_key_type(&key_type_asymmetric); +} + +static void __exit asymmetric_key_cleanup(void) +{ + unregister_key_type(&key_type_asymmetric); +} + +module_init(asymmetric_key_init); +module_exit(asymmetric_key_cleanup); diff --git a/kernel/crypto/asymmetric_keys/mscode.asn1 b/kernel/crypto/asymmetric_keys/mscode.asn1 new file mode 100644 index 000000000..6d09ba48c --- /dev/null +++ b/kernel/crypto/asymmetric_keys/mscode.asn1 @@ -0,0 +1,28 @@ +--- Microsoft individual code signing data blob parser +--- +--- Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. +--- Written by David Howells (dhowells@redhat.com) +--- +--- This program is free software; you can redistribute it and/or +--- modify it under the terms of the GNU General Public Licence +--- as published by the Free Software Foundation; either version +--- 2 of the Licence, or (at your option) any later version. +--- + +MSCode ::= SEQUENCE { + type SEQUENCE { + contentType ContentType, + parameters ANY + }, + content SEQUENCE { + digestAlgorithm DigestAlgorithmIdentifier, + digest OCTET STRING ({ mscode_note_digest }) + } +} + +ContentType ::= OBJECT IDENTIFIER ({ mscode_note_content_type }) + +DigestAlgorithmIdentifier ::= SEQUENCE { + algorithm OBJECT IDENTIFIER ({ mscode_note_digest_algo }), + parameters ANY OPTIONAL +} diff --git a/kernel/crypto/asymmetric_keys/mscode_parser.c b/kernel/crypto/asymmetric_keys/mscode_parser.c new file mode 100644 index 000000000..214a99212 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/mscode_parser.c @@ -0,0 +1,126 @@ +/* Parse a Microsoft Individual Code Signing blob + * + * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "MSCODE: "fmt +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/oid_registry.h> +#include <crypto/pkcs7.h> +#include "verify_pefile.h" +#include "mscode-asn1.h" + +/* + * Parse a Microsoft Individual Code Signing blob + */ +int mscode_parse(struct pefile_context *ctx) +{ + const void *content_data; + size_t data_len; + int ret; + + ret = pkcs7_get_content_data(ctx->pkcs7, &content_data, &data_len, 1); + + if (ret) { + pr_debug("PKCS#7 message does not contain data\n"); + return ret; + } + + pr_devel("Data: %zu [%*ph]\n", data_len, (unsigned)(data_len), + content_data); + + return asn1_ber_decoder(&mscode_decoder, ctx, content_data, data_len); +} + +/* + * Check the content type OID + */ +int mscode_note_content_type(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + enum OID oid; + + oid = look_up_OID(value, vlen); + if (oid == OID__NR) { + char buffer[50]; + + sprint_oid(value, vlen, buffer, sizeof(buffer)); + pr_err("Unknown OID: %s\n", buffer); + return -EBADMSG; + } + + /* + * pesign utility had a bug where it was putting + * OID_msIndividualSPKeyPurpose instead of OID_msPeImageDataObjId + * So allow both OIDs. + */ + if (oid != OID_msPeImageDataObjId && + oid != OID_msIndividualSPKeyPurpose) { + pr_err("Unexpected content type OID %u\n", oid); + return -EBADMSG; + } + + return 0; +} + +/* + * Note the digest algorithm OID + */ +int mscode_note_digest_algo(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pefile_context *ctx = context; + char buffer[50]; + enum OID oid; + + oid = look_up_OID(value, vlen); + switch (oid) { + case OID_md4: + ctx->digest_algo = HASH_ALGO_MD4; + break; + case OID_md5: + ctx->digest_algo = HASH_ALGO_MD5; + break; + case OID_sha1: + ctx->digest_algo = HASH_ALGO_SHA1; + break; + case OID_sha256: + ctx->digest_algo = HASH_ALGO_SHA256; + break; + + case OID__NR: + sprint_oid(value, vlen, buffer, sizeof(buffer)); + pr_err("Unknown OID: %s\n", buffer); + return -EBADMSG; + + default: + pr_err("Unsupported content type: %u\n", oid); + return -ENOPKG; + } + + return 0; +} + +/* + * Note the digest we're guaranteeing with this certificate + */ +int mscode_note_digest(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pefile_context *ctx = context; + + ctx->digest = value; + ctx->digest_len = vlen; + return 0; +} diff --git a/kernel/crypto/asymmetric_keys/pkcs7.asn1 b/kernel/crypto/asymmetric_keys/pkcs7.asn1 new file mode 100644 index 000000000..a5a14ef28 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/pkcs7.asn1 @@ -0,0 +1,127 @@ +PKCS7ContentInfo ::= SEQUENCE { + contentType ContentType, + content [0] EXPLICIT SignedData OPTIONAL +} + +ContentType ::= OBJECT IDENTIFIER ({ pkcs7_note_OID }) + +SignedData ::= SEQUENCE { + version INTEGER, + digestAlgorithms DigestAlgorithmIdentifiers, + contentInfo ContentInfo, + certificates CHOICE { + certSet [0] IMPLICIT ExtendedCertificatesAndCertificates, + certSequence [2] IMPLICIT Certificates + } OPTIONAL ({ pkcs7_note_certificate_list }), + crls CHOICE { + crlSet [1] IMPLICIT CertificateRevocationLists, + crlSequence [3] IMPLICIT CRLSequence + } OPTIONAL, + signerInfos SignerInfos +} + +ContentInfo ::= SEQUENCE { + contentType ContentType, + content [0] EXPLICIT Data OPTIONAL +} + +Data ::= ANY ({ pkcs7_note_data }) + +DigestAlgorithmIdentifiers ::= CHOICE { + daSet SET OF DigestAlgorithmIdentifier, + daSequence SEQUENCE OF DigestAlgorithmIdentifier +} + +DigestAlgorithmIdentifier ::= SEQUENCE { + algorithm OBJECT IDENTIFIER ({ pkcs7_note_OID }), + parameters ANY OPTIONAL +} + +-- +-- Certificates and certificate lists +-- +ExtendedCertificatesAndCertificates ::= SET OF ExtendedCertificateOrCertificate + +ExtendedCertificateOrCertificate ::= CHOICE { + certificate Certificate, -- X.509 + extendedCertificate [0] IMPLICIT ExtendedCertificate -- PKCS#6 +} + +ExtendedCertificate ::= Certificate -- cheating + +Certificates ::= SEQUENCE OF Certificate + +CertificateRevocationLists ::= SET OF CertificateList + +CertificateList ::= SEQUENCE OF Certificate -- This may be defined incorrectly + +CRLSequence ::= SEQUENCE OF CertificateList + +Certificate ::= ANY ({ pkcs7_extract_cert }) -- X.509 + +-- +-- Signer information +-- +SignerInfos ::= CHOICE { + siSet SET OF SignerInfo, + siSequence SEQUENCE OF SignerInfo +} + +SignerInfo ::= SEQUENCE { + version INTEGER, + issuerAndSerialNumber IssuerAndSerialNumber, + digestAlgorithm DigestAlgorithmIdentifier ({ pkcs7_sig_note_digest_algo }), + authenticatedAttributes CHOICE { + aaSet [0] IMPLICIT SetOfAuthenticatedAttribute + ({ pkcs7_sig_note_set_of_authattrs }), + aaSequence [2] EXPLICIT SEQUENCE OF AuthenticatedAttribute + -- Explicit because easier to compute digest on + -- sequence of attributes and then reuse encoded + -- sequence in aaSequence. + } OPTIONAL, + digestEncryptionAlgorithm + DigestEncryptionAlgorithmIdentifier ({ pkcs7_sig_note_pkey_algo }), + encryptedDigest EncryptedDigest, + unauthenticatedAttributes CHOICE { + uaSet [1] IMPLICIT SET OF UnauthenticatedAttribute, + uaSequence [3] IMPLICIT SEQUENCE OF UnauthenticatedAttribute + } OPTIONAL +} ({ pkcs7_note_signed_info }) + +IssuerAndSerialNumber ::= SEQUENCE { + issuer Name ({ pkcs7_sig_note_issuer }), + serialNumber CertificateSerialNumber ({ pkcs7_sig_note_serial }) +} + +CertificateSerialNumber ::= INTEGER + +SetOfAuthenticatedAttribute ::= SET OF AuthenticatedAttribute + +AuthenticatedAttribute ::= SEQUENCE { + type OBJECT IDENTIFIER ({ pkcs7_note_OID }), + values SET OF ANY ({ pkcs7_sig_note_authenticated_attr }) +} + +UnauthenticatedAttribute ::= SEQUENCE { + type OBJECT IDENTIFIER ({ pkcs7_note_OID }), + values SET OF ANY +} + +DigestEncryptionAlgorithmIdentifier ::= SEQUENCE { + algorithm OBJECT IDENTIFIER ({ pkcs7_note_OID }), + parameters ANY OPTIONAL +} + +EncryptedDigest ::= OCTET STRING ({ pkcs7_sig_note_signature }) + +--- +--- X.500 Name +--- +Name ::= SEQUENCE OF RelativeDistinguishedName + +RelativeDistinguishedName ::= SET OF AttributeValueAssertion + +AttributeValueAssertion ::= SEQUENCE { + attributeType OBJECT IDENTIFIER ({ pkcs7_note_OID }), + attributeValue ANY +} diff --git a/kernel/crypto/asymmetric_keys/pkcs7_key_type.c b/kernel/crypto/asymmetric_keys/pkcs7_key_type.c new file mode 100644 index 000000000..751f8fd73 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/pkcs7_key_type.c @@ -0,0 +1,98 @@ +/* Testing module to load key from trusted PKCS#7 message + * + * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PKCS7key: "fmt +#include <linux/key.h> +#include <linux/err.h> +#include <linux/key-type.h> +#include <crypto/pkcs7.h> +#include <keys/user-type.h> +#include <keys/system_keyring.h> +#include "pkcs7_parser.h" + +/* + * Preparse a PKCS#7 wrapped and validated data blob. + */ +static int pkcs7_preparse(struct key_preparsed_payload *prep) +{ + struct pkcs7_message *pkcs7; + const void *data, *saved_prep_data; + size_t datalen, saved_prep_datalen; + bool trusted; + int ret; + + kenter(""); + + saved_prep_data = prep->data; + saved_prep_datalen = prep->datalen; + pkcs7 = pkcs7_parse_message(saved_prep_data, saved_prep_datalen); + if (IS_ERR(pkcs7)) { + ret = PTR_ERR(pkcs7); + goto error; + } + + ret = pkcs7_verify(pkcs7); + if (ret < 0) + goto error_free; + + ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted); + if (ret < 0) + goto error_free; + if (!trusted) + pr_warn("PKCS#7 message doesn't chain back to a trusted key\n"); + + ret = pkcs7_get_content_data(pkcs7, &data, &datalen, false); + if (ret < 0) + goto error_free; + + prep->data = data; + prep->datalen = datalen; + ret = user_preparse(prep); + prep->data = saved_prep_data; + prep->datalen = saved_prep_datalen; + +error_free: + pkcs7_free_message(pkcs7); +error: + kleave(" = %d", ret); + return ret; +} + +/* + * user defined keys take an arbitrary string as the description and an + * arbitrary blob of data as the payload + */ +static struct key_type key_type_pkcs7 = { + .name = "pkcs7_test", + .preparse = pkcs7_preparse, + .free_preparse = user_free_preparse, + .instantiate = generic_key_instantiate, + .revoke = user_revoke, + .destroy = user_destroy, + .describe = user_describe, + .read = user_read, +}; + +/* + * Module stuff + */ +static int __init pkcs7_key_init(void) +{ + return register_key_type(&key_type_pkcs7); +} + +static void __exit pkcs7_key_cleanup(void) +{ + unregister_key_type(&key_type_pkcs7); +} + +module_init(pkcs7_key_init); +module_exit(pkcs7_key_cleanup); diff --git a/kernel/crypto/asymmetric_keys/pkcs7_parser.c b/kernel/crypto/asymmetric_keys/pkcs7_parser.c new file mode 100644 index 000000000..3bd5a1e4c --- /dev/null +++ b/kernel/crypto/asymmetric_keys/pkcs7_parser.c @@ -0,0 +1,417 @@ +/* PKCS#7 parser + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PKCS7: "fmt +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/oid_registry.h> +#include "public_key.h" +#include "pkcs7_parser.h" +#include "pkcs7-asn1.h" + +struct pkcs7_parse_context { + struct pkcs7_message *msg; /* Message being constructed */ + struct pkcs7_signed_info *sinfo; /* SignedInfo being constructed */ + struct pkcs7_signed_info **ppsinfo; + struct x509_certificate *certs; /* Certificate cache */ + struct x509_certificate **ppcerts; + unsigned long data; /* Start of data */ + enum OID last_oid; /* Last OID encountered */ + unsigned x509_index; + unsigned sinfo_index; + const void *raw_serial; + unsigned raw_serial_size; + unsigned raw_issuer_size; + const void *raw_issuer; +}; + +/* + * Free a signed information block. + */ +static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo) +{ + if (sinfo) { + mpi_free(sinfo->sig.mpi[0]); + kfree(sinfo->sig.digest); + kfree(sinfo->signing_cert_id); + kfree(sinfo); + } +} + +/** + * pkcs7_free_message - Free a PKCS#7 message + * @pkcs7: The PKCS#7 message to free + */ +void pkcs7_free_message(struct pkcs7_message *pkcs7) +{ + struct x509_certificate *cert; + struct pkcs7_signed_info *sinfo; + + if (pkcs7) { + while (pkcs7->certs) { + cert = pkcs7->certs; + pkcs7->certs = cert->next; + x509_free_certificate(cert); + } + while (pkcs7->crl) { + cert = pkcs7->crl; + pkcs7->crl = cert->next; + x509_free_certificate(cert); + } + while (pkcs7->signed_infos) { + sinfo = pkcs7->signed_infos; + pkcs7->signed_infos = sinfo->next; + pkcs7_free_signed_info(sinfo); + } + kfree(pkcs7); + } +} +EXPORT_SYMBOL_GPL(pkcs7_free_message); + +/** + * pkcs7_parse_message - Parse a PKCS#7 message + * @data: The raw binary ASN.1 encoded message to be parsed + * @datalen: The size of the encoded message + */ +struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen) +{ + struct pkcs7_parse_context *ctx; + struct pkcs7_message *msg = ERR_PTR(-ENOMEM); + int ret; + + ctx = kzalloc(sizeof(struct pkcs7_parse_context), GFP_KERNEL); + if (!ctx) + goto out_no_ctx; + ctx->msg = kzalloc(sizeof(struct pkcs7_message), GFP_KERNEL); + if (!ctx->msg) + goto out_no_msg; + ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL); + if (!ctx->sinfo) + goto out_no_sinfo; + + ctx->data = (unsigned long)data; + ctx->ppcerts = &ctx->certs; + ctx->ppsinfo = &ctx->msg->signed_infos; + + /* Attempt to decode the signature */ + ret = asn1_ber_decoder(&pkcs7_decoder, ctx, data, datalen); + if (ret < 0) { + msg = ERR_PTR(ret); + goto out; + } + + msg = ctx->msg; + ctx->msg = NULL; + +out: + while (ctx->certs) { + struct x509_certificate *cert = ctx->certs; + ctx->certs = cert->next; + x509_free_certificate(cert); + } + pkcs7_free_signed_info(ctx->sinfo); +out_no_sinfo: + pkcs7_free_message(ctx->msg); +out_no_msg: + kfree(ctx); +out_no_ctx: + return msg; +} +EXPORT_SYMBOL_GPL(pkcs7_parse_message); + +/** + * pkcs7_get_content_data - Get access to the PKCS#7 content + * @pkcs7: The preparsed PKCS#7 message to access + * @_data: Place to return a pointer to the data + * @_data_len: Place to return the data length + * @want_wrapper: True if the ASN.1 object header should be included in the data + * + * Get access to the data content of the PKCS#7 message, including, optionally, + * the header of the ASN.1 object that contains it. Returns -ENODATA if the + * data object was missing from the message. + */ +int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, + const void **_data, size_t *_data_len, + bool want_wrapper) +{ + size_t wrapper; + + if (!pkcs7->data) + return -ENODATA; + + wrapper = want_wrapper ? pkcs7->data_hdrlen : 0; + *_data = pkcs7->data - wrapper; + *_data_len = pkcs7->data_len + wrapper; + return 0; +} +EXPORT_SYMBOL_GPL(pkcs7_get_content_data); + +/* + * Note an OID when we find one for later processing when we know how + * to interpret it. + */ +int pkcs7_note_OID(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + ctx->last_oid = look_up_OID(value, vlen); + if (ctx->last_oid == OID__NR) { + char buffer[50]; + sprint_oid(value, vlen, buffer, sizeof(buffer)); + printk("PKCS7: Unknown OID: [%lu] %s\n", + (unsigned long)value - ctx->data, buffer); + } + return 0; +} + +/* + * Note the digest algorithm for the signature. + */ +int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + switch (ctx->last_oid) { + case OID_md4: + ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_MD4; + break; + case OID_md5: + ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_MD5; + break; + case OID_sha1: + ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA1; + break; + case OID_sha256: + ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA256; + break; + default: + printk("Unsupported digest algo: %u\n", ctx->last_oid); + return -ENOPKG; + } + return 0; +} + +/* + * Note the public key algorithm for the signature. + */ +int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + switch (ctx->last_oid) { + case OID_rsaEncryption: + ctx->sinfo->sig.pkey_algo = PKEY_ALGO_RSA; + break; + default: + printk("Unsupported pkey algo: %u\n", ctx->last_oid); + return -ENOPKG; + } + return 0; +} + +/* + * Extract a certificate and store it in the context. + */ +int pkcs7_extract_cert(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + struct x509_certificate *x509; + + if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) { + pr_debug("Cert began with tag %02x at %lu\n", + tag, (unsigned long)ctx - ctx->data); + return -EBADMSG; + } + + /* We have to correct for the header so that the X.509 parser can start + * from the beginning. Note that since X.509 stipulates DER, there + * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which + * stipulates BER). + */ + value -= hdrlen; + vlen += hdrlen; + + if (((u8*)value)[1] == 0x80) + vlen += 2; /* Indefinite length - there should be an EOC */ + + x509 = x509_cert_parse(value, vlen); + if (IS_ERR(x509)) + return PTR_ERR(x509); + + x509->index = ++ctx->x509_index; + pr_debug("Got cert %u for %s\n", x509->index, x509->subject); + pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data); + + *ctx->ppcerts = x509; + ctx->ppcerts = &x509->next; + return 0; +} + +/* + * Save the certificate list + */ +int pkcs7_note_certificate_list(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + pr_devel("Got cert list (%02x)\n", tag); + + *ctx->ppcerts = ctx->msg->certs; + ctx->msg->certs = ctx->certs; + ctx->certs = NULL; + ctx->ppcerts = &ctx->certs; + return 0; +} + +/* + * Extract the data from the message and store that and its content type OID in + * the context. + */ +int pkcs7_note_data(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + pr_debug("Got data\n"); + + ctx->msg->data = value; + ctx->msg->data_len = vlen; + ctx->msg->data_hdrlen = hdrlen; + ctx->msg->data_type = ctx->last_oid; + return 0; +} + +/* + * Parse authenticated attributes + */ +int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); + + switch (ctx->last_oid) { + case OID_messageDigest: + if (tag != ASN1_OTS) + return -EBADMSG; + ctx->sinfo->msgdigest = value; + ctx->sinfo->msgdigest_len = vlen; + return 0; + default: + return 0; + } +} + +/* + * Note the set of auth attributes for digestion purposes [RFC2315 9.3] + */ +int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */ + ctx->sinfo->authattrs = value - (hdrlen - 1); + ctx->sinfo->authattrs_len = vlen + (hdrlen - 1); + return 0; +} + +/* + * Note the issuing certificate serial number + */ +int pkcs7_sig_note_serial(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + ctx->raw_serial = value; + ctx->raw_serial_size = vlen; + return 0; +} + +/* + * Note the issuer's name + */ +int pkcs7_sig_note_issuer(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + ctx->raw_issuer = value; + ctx->raw_issuer_size = vlen; + return 0; +} + +/* + * Note the signature data + */ +int pkcs7_sig_note_signature(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + MPI mpi; + + BUG_ON(ctx->sinfo->sig.pkey_algo != PKEY_ALGO_RSA); + + mpi = mpi_read_raw_data(value, vlen); + if (!mpi) + return -ENOMEM; + + ctx->sinfo->sig.mpi[0] = mpi; + ctx->sinfo->sig.nr_mpi = 1; + return 0; +} + +/* + * Note a signature information block + */ +int pkcs7_note_signed_info(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + struct pkcs7_signed_info *sinfo = ctx->sinfo; + struct asymmetric_key_id *kid; + + /* Generate cert issuer + serial number key ID */ + kid = asymmetric_key_generate_id(ctx->raw_serial, + ctx->raw_serial_size, + ctx->raw_issuer, + ctx->raw_issuer_size); + if (IS_ERR(kid)) + return PTR_ERR(kid); + + sinfo->signing_cert_id = kid; + sinfo->index = ++ctx->sinfo_index; + *ctx->ppsinfo = sinfo; + ctx->ppsinfo = &sinfo->next; + ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL); + if (!ctx->sinfo) + return -ENOMEM; + return 0; +} diff --git a/kernel/crypto/asymmetric_keys/pkcs7_parser.h b/kernel/crypto/asymmetric_keys/pkcs7_parser.h new file mode 100644 index 000000000..efc7dc9b8 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/pkcs7_parser.h @@ -0,0 +1,59 @@ +/* PKCS#7 crypto data parser internal definitions + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/oid_registry.h> +#include <crypto/pkcs7.h> +#include "x509_parser.h" + +#define kenter(FMT, ...) \ + pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) \ + pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__) + +struct pkcs7_signed_info { + struct pkcs7_signed_info *next; + struct x509_certificate *signer; /* Signing certificate (in msg->certs) */ + unsigned index; + bool trusted; + bool unsupported_crypto; /* T if not usable due to missing crypto */ + + /* Message digest - the digest of the Content Data (or NULL) */ + const void *msgdigest; + unsigned msgdigest_len; + + /* Authenticated Attribute data (or NULL) */ + unsigned authattrs_len; + const void *authattrs; + + /* Issuing cert serial number and issuer's name */ + struct asymmetric_key_id *signing_cert_id; + + /* Message signature. + * + * This contains the generated digest of _either_ the Content Data or + * the Authenticated Attributes [RFC2315 9.3]. If the latter, one of + * the attributes contains the digest of the the Content Data within + * it. + */ + struct public_key_signature sig; +}; + +struct pkcs7_message { + struct x509_certificate *certs; /* Certificate list */ + struct x509_certificate *crl; /* Revocation list */ + struct pkcs7_signed_info *signed_infos; + + /* Content Data (or NULL) */ + enum OID data_type; /* Type of Data */ + size_t data_len; /* Length of Data */ + size_t data_hdrlen; /* Length of Data ASN.1 header */ + const void *data; /* Content Data (or 0) */ +}; diff --git a/kernel/crypto/asymmetric_keys/pkcs7_trust.c b/kernel/crypto/asymmetric_keys/pkcs7_trust.c new file mode 100644 index 000000000..1d2937607 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/pkcs7_trust.c @@ -0,0 +1,200 @@ +/* Validate the trust chain of a PKCS#7 message. + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PKCS7: "fmt +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/asn1.h> +#include <linux/key.h> +#include <keys/asymmetric-type.h> +#include "public_key.h" +#include "pkcs7_parser.h" + +/** + * Check the trust on one PKCS#7 SignedInfo block. + */ +static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, + struct pkcs7_signed_info *sinfo, + struct key *trust_keyring) +{ + struct public_key_signature *sig = &sinfo->sig; + struct x509_certificate *x509, *last = NULL, *p; + struct key *key; + bool trusted; + int ret; + + kenter(",%u,", sinfo->index); + + if (sinfo->unsupported_crypto) { + kleave(" = -ENOPKG [cached]"); + return -ENOPKG; + } + + for (x509 = sinfo->signer; x509; x509 = x509->signer) { + if (x509->seen) { + if (x509->verified) { + trusted = x509->trusted; + goto verified; + } + kleave(" = -ENOKEY [cached]"); + return -ENOKEY; + } + x509->seen = true; + + /* Look to see if this certificate is present in the trusted + * keys. + */ + key = x509_request_asymmetric_key(trust_keyring, x509->id, + false); + if (!IS_ERR(key)) { + /* One of the X.509 certificates in the PKCS#7 message + * is apparently the same as one we already trust. + * Verify that the trusted variant can also validate + * the signature on the descendant. + */ + pr_devel("sinfo %u: Cert %u as key %x\n", + sinfo->index, x509->index, key_serial(key)); + goto matched; + } + if (key == ERR_PTR(-ENOMEM)) + return -ENOMEM; + + /* Self-signed certificates form roots of their own, and if we + * don't know them, then we can't accept them. + */ + if (x509->next == x509) { + kleave(" = -ENOKEY [unknown self-signed]"); + return -ENOKEY; + } + + might_sleep(); + last = x509; + sig = &last->sig; + } + + /* No match - see if the root certificate has a signer amongst the + * trusted keys. + */ + if (last && last->authority) { + key = x509_request_asymmetric_key(trust_keyring, last->authority, + false); + if (!IS_ERR(key)) { + x509 = last; + pr_devel("sinfo %u: Root cert %u signer is key %x\n", + sinfo->index, x509->index, key_serial(key)); + goto matched; + } + if (PTR_ERR(key) != -ENOKEY) + return PTR_ERR(key); + } + + /* As a last resort, see if we have a trusted public key that matches + * the signed info directly. + */ + key = x509_request_asymmetric_key(trust_keyring, + sinfo->signing_cert_id, + false); + if (!IS_ERR(key)) { + pr_devel("sinfo %u: Direct signer is key %x\n", + sinfo->index, key_serial(key)); + x509 = NULL; + goto matched; + } + if (PTR_ERR(key) != -ENOKEY) + return PTR_ERR(key); + + kleave(" = -ENOKEY [no backref]"); + return -ENOKEY; + +matched: + ret = verify_signature(key, sig); + trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags); + key_put(key); + if (ret < 0) { + if (ret == -ENOMEM) + return ret; + kleave(" = -EKEYREJECTED [verify %d]", ret); + return -EKEYREJECTED; + } + +verified: + if (x509) { + x509->verified = true; + for (p = sinfo->signer; p != x509; p = p->signer) { + p->verified = true; + p->trusted = trusted; + } + } + sinfo->trusted = trusted; + kleave(" = 0"); + return 0; +} + +/** + * pkcs7_validate_trust - Validate PKCS#7 trust chain + * @pkcs7: The PKCS#7 certificate to validate + * @trust_keyring: Signing certificates to use as starting points + * @_trusted: Set to true if trustworth, false otherwise + * + * Validate that the certificate chain inside the PKCS#7 message intersects + * keys we already know and trust. + * + * Returns, in order of descending priority: + * + * (*) -EKEYREJECTED if a signature failed to match for which we have a valid + * key, or: + * + * (*) 0 if at least one signature chain intersects with the keys in the trust + * keyring, or: + * + * (*) -ENOPKG if a suitable crypto module couldn't be found for a check on a + * chain. + * + * (*) -ENOKEY if we couldn't find a match for any of the signature chains in + * the message. + * + * May also return -ENOMEM. + */ +int pkcs7_validate_trust(struct pkcs7_message *pkcs7, + struct key *trust_keyring, + bool *_trusted) +{ + struct pkcs7_signed_info *sinfo; + struct x509_certificate *p; + int cached_ret = -ENOKEY; + int ret; + + for (p = pkcs7->certs; p; p = p->next) + p->seen = false; + + for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) { + ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring); + switch (ret) { + case -ENOKEY: + continue; + case -ENOPKG: + if (cached_ret == -ENOKEY) + cached_ret = -ENOPKG; + continue; + case 0: + *_trusted |= sinfo->trusted; + cached_ret = 0; + continue; + default: + return ret; + } + } + + return cached_ret; +} +EXPORT_SYMBOL_GPL(pkcs7_validate_trust); diff --git a/kernel/crypto/asymmetric_keys/pkcs7_verify.c b/kernel/crypto/asymmetric_keys/pkcs7_verify.c new file mode 100644 index 000000000..cd455450b --- /dev/null +++ b/kernel/crypto/asymmetric_keys/pkcs7_verify.c @@ -0,0 +1,361 @@ +/* Verify the signature on a PKCS#7 message. + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PKCS7: "fmt +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/asn1.h> +#include <crypto/hash.h> +#include "public_key.h" +#include "pkcs7_parser.h" + +/* + * Digest the relevant parts of the PKCS#7 data + */ +static int pkcs7_digest(struct pkcs7_message *pkcs7, + struct pkcs7_signed_info *sinfo) +{ + struct crypto_shash *tfm; + struct shash_desc *desc; + size_t digest_size, desc_size; + void *digest; + int ret; + + kenter(",%u,%u", sinfo->index, sinfo->sig.pkey_hash_algo); + + if (sinfo->sig.pkey_hash_algo >= PKEY_HASH__LAST || + !hash_algo_name[sinfo->sig.pkey_hash_algo]) + return -ENOPKG; + + /* Allocate the hashing algorithm we're going to need and find out how + * big the hash operational data will be. + */ + tfm = crypto_alloc_shash(hash_algo_name[sinfo->sig.pkey_hash_algo], + 0, 0); + if (IS_ERR(tfm)) + return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm); + + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); + sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm); + + ret = -ENOMEM; + digest = kzalloc(digest_size + desc_size, GFP_KERNEL); + if (!digest) + goto error_no_desc; + + desc = digest + digest_size; + desc->tfm = tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + /* Digest the message [RFC2315 9.3] */ + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len, digest); + if (ret < 0) + goto error; + pr_devel("MsgDigest = [%*ph]\n", 8, digest); + + /* However, if there are authenticated attributes, there must be a + * message digest attribute amongst them which corresponds to the + * digest we just calculated. + */ + if (sinfo->msgdigest) { + u8 tag; + + if (sinfo->msgdigest_len != sinfo->sig.digest_size) { + pr_debug("Sig %u: Invalid digest size (%u)\n", + sinfo->index, sinfo->msgdigest_len); + ret = -EBADMSG; + goto error; + } + + if (memcmp(digest, sinfo->msgdigest, sinfo->msgdigest_len) != 0) { + pr_debug("Sig %u: Message digest doesn't match\n", + sinfo->index); + ret = -EKEYREJECTED; + goto error; + } + + /* We then calculate anew, using the authenticated attributes + * as the contents of the digest instead. Note that we need to + * convert the attributes from a CONT.0 into a SET before we + * hash it. + */ + memset(digest, 0, sinfo->sig.digest_size); + + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + tag = ASN1_CONS_BIT | ASN1_SET; + ret = crypto_shash_update(desc, &tag, 1); + if (ret < 0) + goto error; + ret = crypto_shash_finup(desc, sinfo->authattrs, + sinfo->authattrs_len, digest); + if (ret < 0) + goto error; + pr_devel("AADigest = [%*ph]\n", 8, digest); + } + + sinfo->sig.digest = digest; + digest = NULL; + +error: + kfree(digest); +error_no_desc: + crypto_free_shash(tfm); + kleave(" = %d", ret); + return ret; +} + +/* + * Find the key (X.509 certificate) to use to verify a PKCS#7 message. PKCS#7 + * uses the issuer's name and the issuing certificate serial number for + * matching purposes. These must match the certificate issuer's name (not + * subject's name) and the certificate serial number [RFC 2315 6.7]. + */ +static int pkcs7_find_key(struct pkcs7_message *pkcs7, + struct pkcs7_signed_info *sinfo) +{ + struct x509_certificate *x509; + unsigned certix = 1; + + kenter("%u", sinfo->index); + + for (x509 = pkcs7->certs; x509; x509 = x509->next, certix++) { + /* I'm _assuming_ that the generator of the PKCS#7 message will + * encode the fields from the X.509 cert in the same way in the + * PKCS#7 message - but I can't be 100% sure of that. It's + * possible this will need element-by-element comparison. + */ + if (!asymmetric_key_id_same(x509->id, sinfo->signing_cert_id)) + continue; + pr_devel("Sig %u: Found cert serial match X.509[%u]\n", + sinfo->index, certix); + + if (x509->pub->pkey_algo != sinfo->sig.pkey_algo) { + pr_warn("Sig %u: X.509 algo and PKCS#7 sig algo don't match\n", + sinfo->index); + continue; + } + + sinfo->signer = x509; + return 0; + } + + /* The relevant X.509 cert isn't found here, but it might be found in + * the trust keyring. + */ + pr_debug("Sig %u: Issuing X.509 cert not found (#%*phN)\n", + sinfo->index, + sinfo->signing_cert_id->len, sinfo->signing_cert_id->data); + return 0; +} + +/* + * Verify the internal certificate chain as best we can. + */ +static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, + struct pkcs7_signed_info *sinfo) +{ + struct x509_certificate *x509 = sinfo->signer, *p; + int ret; + + kenter(""); + + for (p = pkcs7->certs; p; p = p->next) + p->seen = false; + + for (;;) { + pr_debug("verify %s: %*phN\n", + x509->subject, + x509->raw_serial_size, x509->raw_serial); + x509->seen = true; + ret = x509_get_sig_params(x509); + if (ret < 0) + goto maybe_missing_crypto_in_x509; + + pr_debug("- issuer %s\n", x509->issuer); + if (x509->authority) + pr_debug("- authkeyid %*phN\n", + x509->authority->len, x509->authority->data); + + if (!x509->authority || + strcmp(x509->subject, x509->issuer) == 0) { + /* If there's no authority certificate specified, then + * the certificate must be self-signed and is the root + * of the chain. Likewise if the cert is its own + * authority. + */ + pr_debug("- no auth?\n"); + if (x509->raw_subject_size != x509->raw_issuer_size || + memcmp(x509->raw_subject, x509->raw_issuer, + x509->raw_issuer_size) != 0) + return 0; + + ret = x509_check_signature(x509->pub, x509); + if (ret < 0) + goto maybe_missing_crypto_in_x509; + x509->signer = x509; + pr_debug("- self-signed\n"); + return 0; + } + + /* Look through the X.509 certificates in the PKCS#7 message's + * list to see if the next one is there. + */ + pr_debug("- want %*phN\n", + x509->authority->len, x509->authority->data); + for (p = pkcs7->certs; p; p = p->next) { + if (!p->skid) + continue; + pr_debug("- cmp [%u] %*phN\n", + p->index, p->skid->len, p->skid->data); + if (asymmetric_key_id_same(p->skid, x509->authority)) + goto found_issuer; + } + + /* We didn't find the root of this chain */ + pr_debug("- top\n"); + return 0; + + found_issuer: + pr_debug("- subject %s\n", p->subject); + if (p->seen) { + pr_warn("Sig %u: X.509 chain contains loop\n", + sinfo->index); + return 0; + } + ret = x509_check_signature(p->pub, x509); + if (ret < 0) + return ret; + x509->signer = p; + if (x509 == p) { + pr_debug("- self-signed\n"); + return 0; + } + x509 = p; + might_sleep(); + } + +maybe_missing_crypto_in_x509: + /* Just prune the certificate chain at this point if we lack some + * crypto module to go further. Note, however, we don't want to set + * sinfo->missing_crypto as the signed info block may still be + * validatable against an X.509 cert lower in the chain that we have a + * trusted copy of. + */ + if (ret == -ENOPKG) + return 0; + return ret; +} + +/* + * Verify one signed information block from a PKCS#7 message. + */ +static int pkcs7_verify_one(struct pkcs7_message *pkcs7, + struct pkcs7_signed_info *sinfo) +{ + int ret; + + kenter(",%u", sinfo->index); + + /* First of all, digest the data in the PKCS#7 message and the + * signed information block + */ + ret = pkcs7_digest(pkcs7, sinfo); + if (ret < 0) + return ret; + + /* Find the key for the signature if there is one */ + ret = pkcs7_find_key(pkcs7, sinfo); + if (ret < 0) + return ret; + + if (!sinfo->signer) + return 0; + + pr_devel("Using X.509[%u] for sig %u\n", + sinfo->signer->index, sinfo->index); + + /* Verify the PKCS#7 binary against the key */ + ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig); + if (ret < 0) + return ret; + + pr_devel("Verified signature %u\n", sinfo->index); + + /* Verify the internal certificate chain */ + return pkcs7_verify_sig_chain(pkcs7, sinfo); +} + +/** + * pkcs7_verify - Verify a PKCS#7 message + * @pkcs7: The PKCS#7 message to be verified + * + * Verify a PKCS#7 message is internally consistent - that is, the data digest + * matches the digest in the AuthAttrs and any signature in the message or one + * of the X.509 certificates it carries that matches another X.509 cert in the + * message can be verified. + * + * This does not look to match the contents of the PKCS#7 message against any + * external public keys. + * + * Returns, in order of descending priority: + * + * (*) -EKEYREJECTED if a signature failed to match for which we found an + * appropriate X.509 certificate, or: + * + * (*) -EBADMSG if some part of the message was invalid, or: + * + * (*) -ENOPKG if none of the signature chains are verifiable because suitable + * crypto modules couldn't be found, or: + * + * (*) 0 if all the signature chains that don't incur -ENOPKG can be verified + * (note that a signature chain may be of zero length), or: + */ +int pkcs7_verify(struct pkcs7_message *pkcs7) +{ + struct pkcs7_signed_info *sinfo; + struct x509_certificate *x509; + int enopkg = -ENOPKG; + int ret, n; + + kenter(""); + + for (n = 0, x509 = pkcs7->certs; x509; x509 = x509->next, n++) { + ret = x509_get_sig_params(x509); + if (ret < 0) + return ret; + pr_debug("X.509[%u] %*phN\n", + n, x509->authority->len, x509->authority->data); + } + + for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) { + ret = pkcs7_verify_one(pkcs7, sinfo); + if (ret < 0) { + if (ret == -ENOPKG) { + sinfo->unsupported_crypto = true; + continue; + } + kleave(" = %d", ret); + return ret; + } + enopkg = 0; + } + + kleave(" = %d", enopkg); + return enopkg; +} +EXPORT_SYMBOL_GPL(pkcs7_verify); diff --git a/kernel/crypto/asymmetric_keys/public_key.c b/kernel/crypto/asymmetric_keys/public_key.c new file mode 100644 index 000000000..2f6e4fb1a --- /dev/null +++ b/kernel/crypto/asymmetric_keys/public_key.c @@ -0,0 +1,129 @@ +/* In-software asymmetric public-key crypto subtype + * + * See Documentation/crypto/asymmetric-keys.txt + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PKEY: "fmt +#include <linux/module.h> +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/seq_file.h> +#include <keys/asymmetric-subtype.h> +#include "public_key.h" + +MODULE_LICENSE("GPL"); + +const char *const pkey_algo_name[PKEY_ALGO__LAST] = { + [PKEY_ALGO_DSA] = "DSA", + [PKEY_ALGO_RSA] = "RSA", +}; +EXPORT_SYMBOL_GPL(pkey_algo_name); + +const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST] = { +#if defined(CONFIG_PUBLIC_KEY_ALGO_RSA) || \ + defined(CONFIG_PUBLIC_KEY_ALGO_RSA_MODULE) + [PKEY_ALGO_RSA] = &RSA_public_key_algorithm, +#endif +}; +EXPORT_SYMBOL_GPL(pkey_algo); + +const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST] = { + [PKEY_ID_PGP] = "PGP", + [PKEY_ID_X509] = "X509", +}; +EXPORT_SYMBOL_GPL(pkey_id_type_name); + +/* + * Provide a part of a description of the key for /proc/keys. + */ +static void public_key_describe(const struct key *asymmetric_key, + struct seq_file *m) +{ + struct public_key *key = asymmetric_key->payload.data; + + if (key) + seq_printf(m, "%s.%s", + pkey_id_type_name[key->id_type], key->algo->name); +} + +/* + * Destroy a public key algorithm key. + */ +void public_key_destroy(void *payload) +{ + struct public_key *key = payload; + int i; + + if (key) { + for (i = 0; i < ARRAY_SIZE(key->mpi); i++) + mpi_free(key->mpi[i]); + kfree(key); + } +} +EXPORT_SYMBOL_GPL(public_key_destroy); + +/* + * Verify a signature using a public key. + */ +int public_key_verify_signature(const struct public_key *pk, + const struct public_key_signature *sig) +{ + const struct public_key_algorithm *algo; + + BUG_ON(!pk); + BUG_ON(!pk->mpi[0]); + BUG_ON(!pk->mpi[1]); + BUG_ON(!sig); + BUG_ON(!sig->digest); + BUG_ON(!sig->mpi[0]); + + algo = pk->algo; + if (!algo) { + if (pk->pkey_algo >= PKEY_ALGO__LAST) + return -ENOPKG; + algo = pkey_algo[pk->pkey_algo]; + if (!algo) + return -ENOPKG; + } + + if (!algo->verify_signature) + return -ENOTSUPP; + + if (sig->nr_mpi != algo->n_sig_mpi) { + pr_debug("Signature has %u MPI not %u\n", + sig->nr_mpi, algo->n_sig_mpi); + return -EINVAL; + } + + return algo->verify_signature(pk, sig); +} +EXPORT_SYMBOL_GPL(public_key_verify_signature); + +static int public_key_verify_signature_2(const struct key *key, + const struct public_key_signature *sig) +{ + const struct public_key *pk = key->payload.data; + return public_key_verify_signature(pk, sig); +} + +/* + * Public key algorithm asymmetric key subtype + */ +struct asymmetric_key_subtype public_key_subtype = { + .owner = THIS_MODULE, + .name = "public_key", + .name_len = sizeof("public_key") - 1, + .describe = public_key_describe, + .destroy = public_key_destroy, + .verify_signature = public_key_verify_signature_2, +}; +EXPORT_SYMBOL_GPL(public_key_subtype); diff --git a/kernel/crypto/asymmetric_keys/public_key.h b/kernel/crypto/asymmetric_keys/public_key.h new file mode 100644 index 000000000..5c37a22a0 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/public_key.h @@ -0,0 +1,36 @@ +/* Public key algorithm internals + * + * See Documentation/crypto/asymmetric-keys.txt + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <crypto/public_key.h> + +extern struct asymmetric_key_subtype public_key_subtype; + +/* + * Public key algorithm definition. + */ +struct public_key_algorithm { + const char *name; + u8 n_pub_mpi; /* Number of MPIs in public key */ + u8 n_sec_mpi; /* Number of MPIs in secret key */ + u8 n_sig_mpi; /* Number of MPIs in a signature */ + int (*verify_signature)(const struct public_key *key, + const struct public_key_signature *sig); +}; + +extern const struct public_key_algorithm RSA_public_key_algorithm; + +/* + * public_key.c + */ +extern int public_key_verify_signature(const struct public_key *pk, + const struct public_key_signature *sig); diff --git a/kernel/crypto/asymmetric_keys/rsa.c b/kernel/crypto/asymmetric_keys/rsa.c new file mode 100644 index 000000000..459cf97a7 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/rsa.c @@ -0,0 +1,278 @@ +/* RSA asymmetric public-key algorithm [RFC3447] + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "RSA: "fmt +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <crypto/algapi.h> +#include "public_key.h" + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("RSA Public Key Algorithm"); + +#define kenter(FMT, ...) \ + pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) \ + pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__) + +/* + * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2]. + */ +static const u8 RSA_digest_info_MD5[] = { + 0x30, 0x20, 0x30, 0x0C, 0x06, 0x08, + 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* OID */ + 0x05, 0x00, 0x04, 0x10 +}; + +static const u8 RSA_digest_info_SHA1[] = { + 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, + 0x2B, 0x0E, 0x03, 0x02, 0x1A, + 0x05, 0x00, 0x04, 0x14 +}; + +static const u8 RSA_digest_info_RIPE_MD_160[] = { + 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, + 0x2B, 0x24, 0x03, 0x02, 0x01, + 0x05, 0x00, 0x04, 0x14 +}; + +static const u8 RSA_digest_info_SHA224[] = { + 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, + 0x05, 0x00, 0x04, 0x1C +}; + +static const u8 RSA_digest_info_SHA256[] = { + 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, + 0x05, 0x00, 0x04, 0x20 +}; + +static const u8 RSA_digest_info_SHA384[] = { + 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, + 0x05, 0x00, 0x04, 0x30 +}; + +static const u8 RSA_digest_info_SHA512[] = { + 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, + 0x05, 0x00, 0x04, 0x40 +}; + +static const struct { + const u8 *data; + size_t size; +} RSA_ASN1_templates[PKEY_HASH__LAST] = { +#define _(X) { RSA_digest_info_##X, sizeof(RSA_digest_info_##X) } + [HASH_ALGO_MD5] = _(MD5), + [HASH_ALGO_SHA1] = _(SHA1), + [HASH_ALGO_RIPE_MD_160] = _(RIPE_MD_160), + [HASH_ALGO_SHA256] = _(SHA256), + [HASH_ALGO_SHA384] = _(SHA384), + [HASH_ALGO_SHA512] = _(SHA512), + [HASH_ALGO_SHA224] = _(SHA224), +#undef _ +}; + +/* + * RSAVP1() function [RFC3447 sec 5.2.2] + */ +static int RSAVP1(const struct public_key *key, MPI s, MPI *_m) +{ + MPI m; + int ret; + + /* (1) Validate 0 <= s < n */ + if (mpi_cmp_ui(s, 0) < 0) { + kleave(" = -EBADMSG [s < 0]"); + return -EBADMSG; + } + if (mpi_cmp(s, key->rsa.n) >= 0) { + kleave(" = -EBADMSG [s >= n]"); + return -EBADMSG; + } + + m = mpi_alloc(0); + if (!m) + return -ENOMEM; + + /* (2) m = s^e mod n */ + ret = mpi_powm(m, s, key->rsa.e, key->rsa.n); + if (ret < 0) { + mpi_free(m); + return ret; + } + + *_m = m; + return 0; +} + +/* + * Integer to Octet String conversion [RFC3447 sec 4.1] + */ +static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) +{ + unsigned X_size, x_size; + int X_sign; + u8 *X; + + /* Make sure the string is the right length. The number should begin + * with { 0x00, 0x01, ... } so we have to account for 15 leading zero + * bits not being reported by MPI. + */ + x_size = mpi_get_nbits(x); + pr_devel("size(x)=%u xLen*8=%zu\n", x_size, xLen * 8); + if (x_size != xLen * 8 - 15) + return -ERANGE; + + X = mpi_get_buffer(x, &X_size, &X_sign); + if (!X) + return -ENOMEM; + if (X_sign < 0) { + kfree(X); + return -EBADMSG; + } + if (X_size != xLen - 1) { + kfree(X); + return -EBADMSG; + } + + *_X = X; + return 0; +} + +/* + * Perform the RSA signature verification. + * @H: Value of hash of data and metadata + * @EM: The computed signature value + * @k: The size of EM (EM[0] is an invalid location but should hold 0x00) + * @hash_size: The size of H + * @asn1_template: The DigestInfo ASN.1 template + * @asn1_size: Size of asm1_template[] + */ +static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size, + const u8 *asn1_template, size_t asn1_size) +{ + unsigned PS_end, T_offset, i; + + kenter(",,%zu,%zu,%zu", k, hash_size, asn1_size); + + if (k < 2 + 1 + asn1_size + hash_size) + return -EBADMSG; + + /* Decode the EMSA-PKCS1-v1_5 */ + if (EM[1] != 0x01) { + kleave(" = -EBADMSG [EM[1] == %02u]", EM[1]); + return -EBADMSG; + } + + T_offset = k - (asn1_size + hash_size); + PS_end = T_offset - 1; + if (EM[PS_end] != 0x00) { + kleave(" = -EBADMSG [EM[T-1] == %02u]", EM[PS_end]); + return -EBADMSG; + } + + for (i = 2; i < PS_end; i++) { + if (EM[i] != 0xff) { + kleave(" = -EBADMSG [EM[PS%x] == %02u]", i - 2, EM[i]); + return -EBADMSG; + } + } + + if (crypto_memneq(asn1_template, EM + T_offset, asn1_size) != 0) { + kleave(" = -EBADMSG [EM[T] ASN.1 mismatch]"); + return -EBADMSG; + } + + if (crypto_memneq(H, EM + T_offset + asn1_size, hash_size) != 0) { + kleave(" = -EKEYREJECTED [EM[T] hash mismatch]"); + return -EKEYREJECTED; + } + + kleave(" = 0"); + return 0; +} + +/* + * Perform the verification step [RFC3447 sec 8.2.2]. + */ +static int RSA_verify_signature(const struct public_key *key, + const struct public_key_signature *sig) +{ + size_t tsize; + int ret; + + /* Variables as per RFC3447 sec 8.2.2 */ + const u8 *H = sig->digest; + u8 *EM = NULL; + MPI m = NULL; + size_t k; + + kenter(""); + + if (!RSA_ASN1_templates[sig->pkey_hash_algo].data) + return -ENOTSUPP; + + /* (1) Check the signature size against the public key modulus size */ + k = mpi_get_nbits(key->rsa.n); + tsize = mpi_get_nbits(sig->rsa.s); + + /* According to RFC 4880 sec 3.2, length of MPI is computed starting + * from most significant bit. So the RFC 3447 sec 8.2.2 size check + * must be relaxed to conform with shorter signatures - so we fail here + * only if signature length is longer than modulus size. + */ + pr_devel("step 1: k=%zu size(S)=%zu\n", k, tsize); + if (k < tsize) { + ret = -EBADMSG; + goto error; + } + + /* Round up and convert to octets */ + k = (k + 7) / 8; + + /* (2b) Apply the RSAVP1 verification primitive to the public key */ + ret = RSAVP1(key, sig->rsa.s, &m); + if (ret < 0) + goto error; + + /* (2c) Convert the message representative (m) to an encoded message + * (EM) of length k octets. + * + * NOTE! The leading zero byte is suppressed by MPI, so we pass a + * pointer to the _preceding_ byte to RSA_verify()! + */ + ret = RSA_I2OSP(m, k, &EM); + if (ret < 0) + goto error; + + ret = RSA_verify(H, EM - 1, k, sig->digest_size, + RSA_ASN1_templates[sig->pkey_hash_algo].data, + RSA_ASN1_templates[sig->pkey_hash_algo].size); + +error: + kfree(EM); + mpi_free(m); + kleave(" = %d", ret); + return ret; +} + +const struct public_key_algorithm RSA_public_key_algorithm = { + .name = "RSA", + .n_pub_mpi = 2, + .n_sec_mpi = 3, + .n_sig_mpi = 1, + .verify_signature = RSA_verify_signature, +}; +EXPORT_SYMBOL_GPL(RSA_public_key_algorithm); diff --git a/kernel/crypto/asymmetric_keys/signature.c b/kernel/crypto/asymmetric_keys/signature.c new file mode 100644 index 000000000..7525fd183 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/signature.c @@ -0,0 +1,50 @@ +/* Signature verification with an asymmetric key + * + * See Documentation/security/asymmetric-keys.txt + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "SIG: "fmt +#include <keys/asymmetric-subtype.h> +#include <linux/module.h> +#include <linux/err.h> +#include <crypto/public_key.h> +#include "asymmetric_keys.h" + +/** + * verify_signature - Initiate the use of an asymmetric key to verify a signature + * @key: The asymmetric key to verify against + * @sig: The signature to check + * + * Returns 0 if successful or else an error. + */ +int verify_signature(const struct key *key, + const struct public_key_signature *sig) +{ + const struct asymmetric_key_subtype *subtype; + int ret; + + pr_devel("==>%s()\n", __func__); + + if (key->type != &key_type_asymmetric) + return -EINVAL; + subtype = asymmetric_key_subtype(key); + if (!subtype || + !key->payload.data) + return -EINVAL; + if (!subtype->verify_signature) + return -ENOTSUPP; + + ret = subtype->verify_signature(key, sig); + + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} +EXPORT_SYMBOL_GPL(verify_signature); diff --git a/kernel/crypto/asymmetric_keys/verify_pefile.c b/kernel/crypto/asymmetric_keys/verify_pefile.c new file mode 100644 index 000000000..2421f4618 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/verify_pefile.c @@ -0,0 +1,474 @@ +/* Parse a signed PE binary + * + * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PEFILE: "fmt +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/pe.h> +#include <linux/asn1.h> +#include <crypto/pkcs7.h> +#include <crypto/hash.h> +#include "verify_pefile.h" + +/* + * Parse a PE binary. + */ +static int pefile_parse_binary(const void *pebuf, unsigned int pelen, + struct pefile_context *ctx) +{ + const struct mz_hdr *mz = pebuf; + const struct pe_hdr *pe; + const struct pe32_opt_hdr *pe32; + const struct pe32plus_opt_hdr *pe64; + const struct data_directory *ddir; + const struct data_dirent *dde; + const struct section_header *secs, *sec; + size_t cursor, datalen = pelen; + + kenter(""); + +#define chkaddr(base, x, s) \ + do { \ + if ((x) < base || (s) >= datalen || (x) > datalen - (s)) \ + return -ELIBBAD; \ + } while (0) + + chkaddr(0, 0, sizeof(*mz)); + if (mz->magic != MZ_MAGIC) + return -ELIBBAD; + cursor = sizeof(*mz); + + chkaddr(cursor, mz->peaddr, sizeof(*pe)); + pe = pebuf + mz->peaddr; + if (pe->magic != PE_MAGIC) + return -ELIBBAD; + cursor = mz->peaddr + sizeof(*pe); + + chkaddr(0, cursor, sizeof(pe32->magic)); + pe32 = pebuf + cursor; + pe64 = pebuf + cursor; + + switch (pe32->magic) { + case PE_OPT_MAGIC_PE32: + chkaddr(0, cursor, sizeof(*pe32)); + ctx->image_checksum_offset = + (unsigned long)&pe32->csum - (unsigned long)pebuf; + ctx->header_size = pe32->header_size; + cursor += sizeof(*pe32); + ctx->n_data_dirents = pe32->data_dirs; + break; + + case PE_OPT_MAGIC_PE32PLUS: + chkaddr(0, cursor, sizeof(*pe64)); + ctx->image_checksum_offset = + (unsigned long)&pe64->csum - (unsigned long)pebuf; + ctx->header_size = pe64->header_size; + cursor += sizeof(*pe64); + ctx->n_data_dirents = pe64->data_dirs; + break; + + default: + pr_debug("Unknown PEOPT magic = %04hx\n", pe32->magic); + return -ELIBBAD; + } + + pr_debug("checksum @ %x\n", ctx->image_checksum_offset); + pr_debug("header size = %x\n", ctx->header_size); + + if (cursor >= ctx->header_size || ctx->header_size >= datalen) + return -ELIBBAD; + + if (ctx->n_data_dirents > (ctx->header_size - cursor) / sizeof(*dde)) + return -ELIBBAD; + + ddir = pebuf + cursor; + cursor += sizeof(*dde) * ctx->n_data_dirents; + + ctx->cert_dirent_offset = + (unsigned long)&ddir->certs - (unsigned long)pebuf; + ctx->certs_size = ddir->certs.size; + + if (!ddir->certs.virtual_address || !ddir->certs.size) { + pr_debug("Unsigned PE binary\n"); + return -EKEYREJECTED; + } + + chkaddr(ctx->header_size, ddir->certs.virtual_address, + ddir->certs.size); + ctx->sig_offset = ddir->certs.virtual_address; + ctx->sig_len = ddir->certs.size; + pr_debug("cert = %x @%x [%*ph]\n", + ctx->sig_len, ctx->sig_offset, + ctx->sig_len, pebuf + ctx->sig_offset); + + ctx->n_sections = pe->sections; + if (ctx->n_sections > (ctx->header_size - cursor) / sizeof(*sec)) + return -ELIBBAD; + ctx->secs = secs = pebuf + cursor; + + return 0; +} + +/* + * Check and strip the PE wrapper from around the signature and check that the + * remnant looks something like PKCS#7. + */ +static int pefile_strip_sig_wrapper(const void *pebuf, + struct pefile_context *ctx) +{ + struct win_certificate wrapper; + const u8 *pkcs7; + unsigned len; + + if (ctx->sig_len < sizeof(wrapper)) { + pr_debug("Signature wrapper too short\n"); + return -ELIBBAD; + } + + memcpy(&wrapper, pebuf + ctx->sig_offset, sizeof(wrapper)); + pr_debug("sig wrapper = { %x, %x, %x }\n", + wrapper.length, wrapper.revision, wrapper.cert_type); + + /* Both pesign and sbsign round up the length of certificate table + * (in optional header data directories) to 8 byte alignment. + */ + if (round_up(wrapper.length, 8) != ctx->sig_len) { + pr_debug("Signature wrapper len wrong\n"); + return -ELIBBAD; + } + if (wrapper.revision != WIN_CERT_REVISION_2_0) { + pr_debug("Signature is not revision 2.0\n"); + return -ENOTSUPP; + } + if (wrapper.cert_type != WIN_CERT_TYPE_PKCS_SIGNED_DATA) { + pr_debug("Signature certificate type is not PKCS\n"); + return -ENOTSUPP; + } + + /* It looks like the pkcs signature length in wrapper->length and the + * size obtained from the data dir entries, which lists the total size + * of certificate table, are both aligned to an octaword boundary, so + * we may have to deal with some padding. + */ + ctx->sig_len = wrapper.length; + ctx->sig_offset += sizeof(wrapper); + ctx->sig_len -= sizeof(wrapper); + if (ctx->sig_len < 4) { + pr_debug("Signature data missing\n"); + return -EKEYREJECTED; + } + + /* What's left should be a PKCS#7 cert */ + pkcs7 = pebuf + ctx->sig_offset; + if (pkcs7[0] != (ASN1_CONS_BIT | ASN1_SEQ)) + goto not_pkcs7; + + switch (pkcs7[1]) { + case 0 ... 0x7f: + len = pkcs7[1] + 2; + goto check_len; + case ASN1_INDEFINITE_LENGTH: + return 0; + case 0x81: + len = pkcs7[2] + 3; + goto check_len; + case 0x82: + len = ((pkcs7[2] << 8) | pkcs7[3]) + 4; + goto check_len; + case 0x83 ... 0xff: + return -EMSGSIZE; + default: + goto not_pkcs7; + } + +check_len: + if (len <= ctx->sig_len) { + /* There may be padding */ + ctx->sig_len = len; + return 0; + } +not_pkcs7: + pr_debug("Signature data not PKCS#7\n"); + return -ELIBBAD; +} + +/* + * Compare two sections for canonicalisation. + */ +static int pefile_compare_shdrs(const void *a, const void *b) +{ + const struct section_header *shdra = a; + const struct section_header *shdrb = b; + int rc; + + if (shdra->data_addr > shdrb->data_addr) + return 1; + if (shdrb->data_addr > shdra->data_addr) + return -1; + + if (shdra->virtual_address > shdrb->virtual_address) + return 1; + if (shdrb->virtual_address > shdra->virtual_address) + return -1; + + rc = strcmp(shdra->name, shdrb->name); + if (rc != 0) + return rc; + + if (shdra->virtual_size > shdrb->virtual_size) + return 1; + if (shdrb->virtual_size > shdra->virtual_size) + return -1; + + if (shdra->raw_data_size > shdrb->raw_data_size) + return 1; + if (shdrb->raw_data_size > shdra->raw_data_size) + return -1; + + return 0; +} + +/* + * Load the contents of the PE binary into the digest, leaving out the image + * checksum and the certificate data block. + */ +static int pefile_digest_pe_contents(const void *pebuf, unsigned int pelen, + struct pefile_context *ctx, + struct shash_desc *desc) +{ + unsigned *canon, tmp, loop, i, hashed_bytes; + int ret; + + /* Digest the header and data directory, but leave out the image + * checksum and the data dirent for the signature. + */ + ret = crypto_shash_update(desc, pebuf, ctx->image_checksum_offset); + if (ret < 0) + return ret; + + tmp = ctx->image_checksum_offset + sizeof(uint32_t); + ret = crypto_shash_update(desc, pebuf + tmp, + ctx->cert_dirent_offset - tmp); + if (ret < 0) + return ret; + + tmp = ctx->cert_dirent_offset + sizeof(struct data_dirent); + ret = crypto_shash_update(desc, pebuf + tmp, ctx->header_size - tmp); + if (ret < 0) + return ret; + + canon = kcalloc(ctx->n_sections, sizeof(unsigned), GFP_KERNEL); + if (!canon) + return -ENOMEM; + + /* We have to canonicalise the section table, so we perform an + * insertion sort. + */ + canon[0] = 0; + for (loop = 1; loop < ctx->n_sections; loop++) { + for (i = 0; i < loop; i++) { + if (pefile_compare_shdrs(&ctx->secs[canon[i]], + &ctx->secs[loop]) > 0) { + memmove(&canon[i + 1], &canon[i], + (loop - i) * sizeof(canon[0])); + break; + } + } + canon[i] = loop; + } + + hashed_bytes = ctx->header_size; + for (loop = 0; loop < ctx->n_sections; loop++) { + i = canon[loop]; + if (ctx->secs[i].raw_data_size == 0) + continue; + ret = crypto_shash_update(desc, + pebuf + ctx->secs[i].data_addr, + ctx->secs[i].raw_data_size); + if (ret < 0) { + kfree(canon); + return ret; + } + hashed_bytes += ctx->secs[i].raw_data_size; + } + kfree(canon); + + if (pelen > hashed_bytes) { + tmp = hashed_bytes + ctx->certs_size; + ret = crypto_shash_update(desc, + pebuf + hashed_bytes, + pelen - tmp); + if (ret < 0) + return ret; + } + + return 0; +} + +/* + * Digest the contents of the PE binary, leaving out the image checksum and the + * certificate data block. + */ +static int pefile_digest_pe(const void *pebuf, unsigned int pelen, + struct pefile_context *ctx) +{ + struct crypto_shash *tfm; + struct shash_desc *desc; + size_t digest_size, desc_size; + void *digest; + int ret; + + kenter(",%u", ctx->digest_algo); + + /* Allocate the hashing algorithm we're going to need and find out how + * big the hash operational data will be. + */ + tfm = crypto_alloc_shash(hash_algo_name[ctx->digest_algo], 0, 0); + if (IS_ERR(tfm)) + return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm); + + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); + digest_size = crypto_shash_digestsize(tfm); + + if (digest_size != ctx->digest_len) { + pr_debug("Digest size mismatch (%zx != %x)\n", + digest_size, ctx->digest_len); + ret = -EBADMSG; + goto error_no_desc; + } + pr_debug("Digest: desc=%zu size=%zu\n", desc_size, digest_size); + + ret = -ENOMEM; + desc = kzalloc(desc_size + digest_size, GFP_KERNEL); + if (!desc) + goto error_no_desc; + + desc->tfm = tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + + ret = pefile_digest_pe_contents(pebuf, pelen, ctx, desc); + if (ret < 0) + goto error; + + digest = (void *)desc + desc_size; + ret = crypto_shash_final(desc, digest); + if (ret < 0) + goto error; + + pr_debug("Digest calc = [%*ph]\n", ctx->digest_len, digest); + + /* Check that the PE file digest matches that in the MSCODE part of the + * PKCS#7 certificate. + */ + if (memcmp(digest, ctx->digest, ctx->digest_len) != 0) { + pr_debug("Digest mismatch\n"); + ret = -EKEYREJECTED; + } else { + pr_debug("The digests match!\n"); + } + +error: + kfree(desc); +error_no_desc: + crypto_free_shash(tfm); + kleave(" = %d", ret); + return ret; +} + +/** + * verify_pefile_signature - Verify the signature on a PE binary image + * @pebuf: Buffer containing the PE binary image + * @pelen: Length of the binary image + * @trust_keyring: Signing certificates to use as starting points + * @_trusted: Set to true if trustworth, false otherwise + * + * Validate that the certificate chain inside the PKCS#7 message inside the PE + * binary image intersects keys we already know and trust. + * + * Returns, in order of descending priority: + * + * (*) -ELIBBAD if the image cannot be parsed, or: + * + * (*) -EKEYREJECTED if a signature failed to match for which we have a valid + * key, or: + * + * (*) 0 if at least one signature chain intersects with the keys in the trust + * keyring, or: + * + * (*) -ENOPKG if a suitable crypto module couldn't be found for a check on a + * chain. + * + * (*) -ENOKEY if we couldn't find a match for any of the signature chains in + * the message. + * + * May also return -ENOMEM. + */ +int verify_pefile_signature(const void *pebuf, unsigned pelen, + struct key *trusted_keyring, bool *_trusted) +{ + struct pkcs7_message *pkcs7; + struct pefile_context ctx; + const void *data; + size_t datalen; + int ret; + + kenter(""); + + memset(&ctx, 0, sizeof(ctx)); + ret = pefile_parse_binary(pebuf, pelen, &ctx); + if (ret < 0) + return ret; + + ret = pefile_strip_sig_wrapper(pebuf, &ctx); + if (ret < 0) + return ret; + + pkcs7 = pkcs7_parse_message(pebuf + ctx.sig_offset, ctx.sig_len); + if (IS_ERR(pkcs7)) + return PTR_ERR(pkcs7); + ctx.pkcs7 = pkcs7; + + ret = pkcs7_get_content_data(ctx.pkcs7, &data, &datalen, false); + if (ret < 0 || datalen == 0) { + pr_devel("PKCS#7 message does not contain data\n"); + ret = -EBADMSG; + goto error; + } + + ret = mscode_parse(&ctx); + if (ret < 0) + goto error; + + pr_debug("Digest: %u [%*ph]\n", + ctx.digest_len, ctx.digest_len, ctx.digest); + + /* Generate the digest and check against the PKCS7 certificate + * contents. + */ + ret = pefile_digest_pe(pebuf, pelen, &ctx); + if (ret < 0) + goto error; + + ret = pkcs7_verify(pkcs7); + if (ret < 0) + goto error; + + ret = pkcs7_validate_trust(pkcs7, trusted_keyring, _trusted); + +error: + pkcs7_free_message(ctx.pkcs7); + return ret; +} diff --git a/kernel/crypto/asymmetric_keys/verify_pefile.h b/kernel/crypto/asymmetric_keys/verify_pefile.h new file mode 100644 index 000000000..55d5f7ebc --- /dev/null +++ b/kernel/crypto/asymmetric_keys/verify_pefile.h @@ -0,0 +1,42 @@ +/* PE Binary parser bits + * + * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/verify_pefile.h> +#include <crypto/pkcs7.h> +#include <crypto/hash_info.h> + +struct pefile_context { + unsigned header_size; + unsigned image_checksum_offset; + unsigned cert_dirent_offset; + unsigned n_data_dirents; + unsigned n_sections; + unsigned certs_size; + unsigned sig_offset; + unsigned sig_len; + const struct section_header *secs; + struct pkcs7_message *pkcs7; + + /* PKCS#7 MS Individual Code Signing content */ + const void *digest; /* Digest */ + unsigned digest_len; /* Digest length */ + enum hash_algo digest_algo; /* Digest algorithm */ +}; + +#define kenter(FMT, ...) \ + pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__) +#define kleave(FMT, ...) \ + pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__) + +/* + * mscode_parser.c + */ +extern int mscode_parse(struct pefile_context *ctx); diff --git a/kernel/crypto/asymmetric_keys/x509.asn1 b/kernel/crypto/asymmetric_keys/x509.asn1 new file mode 100644 index 000000000..aae0cde41 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/x509.asn1 @@ -0,0 +1,60 @@ +Certificate ::= SEQUENCE { + tbsCertificate TBSCertificate ({ x509_note_tbs_certificate }), + signatureAlgorithm AlgorithmIdentifier, + signature BIT STRING ({ x509_note_signature }) + } + +TBSCertificate ::= SEQUENCE { + version [ 0 ] Version DEFAULT, + serialNumber CertificateSerialNumber ({ x509_note_serial }), + signature AlgorithmIdentifier ({ x509_note_pkey_algo }), + issuer Name ({ x509_note_issuer }), + validity Validity, + subject Name ({ x509_note_subject }), + subjectPublicKeyInfo SubjectPublicKeyInfo, + issuerUniqueID [ 1 ] IMPLICIT UniqueIdentifier OPTIONAL, + subjectUniqueID [ 2 ] IMPLICIT UniqueIdentifier OPTIONAL, + extensions [ 3 ] Extensions OPTIONAL + } + +Version ::= INTEGER +CertificateSerialNumber ::= INTEGER + +AlgorithmIdentifier ::= SEQUENCE { + algorithm OBJECT IDENTIFIER ({ x509_note_OID }), + parameters ANY OPTIONAL +} + +Name ::= SEQUENCE OF RelativeDistinguishedName + +RelativeDistinguishedName ::= SET OF AttributeValueAssertion + +AttributeValueAssertion ::= SEQUENCE { + attributeType OBJECT IDENTIFIER ({ x509_note_OID }), + attributeValue ANY ({ x509_extract_name_segment }) + } + +Validity ::= SEQUENCE { + notBefore Time ({ x509_note_not_before }), + notAfter Time ({ x509_note_not_after }) + } + +Time ::= CHOICE { + utcTime UTCTime, + generalTime GeneralizedTime + } + +SubjectPublicKeyInfo ::= SEQUENCE { + algorithm AlgorithmIdentifier, + subjectPublicKey BIT STRING ({ x509_extract_key_data }) + } + +UniqueIdentifier ::= BIT STRING + +Extensions ::= SEQUENCE OF Extension + +Extension ::= SEQUENCE { + extnid OBJECT IDENTIFIER ({ x509_note_OID }), + critical BOOLEAN DEFAULT, + extnValue OCTET STRING ({ x509_process_extension }) + } diff --git a/kernel/crypto/asymmetric_keys/x509_cert_parser.c b/kernel/crypto/asymmetric_keys/x509_cert_parser.c new file mode 100644 index 000000000..a668d9030 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/x509_cert_parser.c @@ -0,0 +1,571 @@ +/* X.509 certificate parser + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "X.509: "fmt +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/oid_registry.h> +#include "public_key.h" +#include "x509_parser.h" +#include "x509-asn1.h" +#include "x509_rsakey-asn1.h" + +struct x509_parse_context { + struct x509_certificate *cert; /* Certificate being constructed */ + unsigned long data; /* Start of data */ + const void *cert_start; /* Start of cert content */ + const void *key; /* Key data */ + size_t key_size; /* Size of key data */ + enum OID last_oid; /* Last OID encountered */ + enum OID algo_oid; /* Algorithm OID */ + unsigned char nr_mpi; /* Number of MPIs stored */ + u8 o_size; /* Size of organizationName (O) */ + u8 cn_size; /* Size of commonName (CN) */ + u8 email_size; /* Size of emailAddress */ + u16 o_offset; /* Offset of organizationName (O) */ + u16 cn_offset; /* Offset of commonName (CN) */ + u16 email_offset; /* Offset of emailAddress */ +}; + +/* + * Free an X.509 certificate + */ +void x509_free_certificate(struct x509_certificate *cert) +{ + if (cert) { + public_key_destroy(cert->pub); + kfree(cert->issuer); + kfree(cert->subject); + kfree(cert->id); + kfree(cert->skid); + kfree(cert->authority); + kfree(cert->sig.digest); + mpi_free(cert->sig.rsa.s); + kfree(cert); + } +} +EXPORT_SYMBOL_GPL(x509_free_certificate); + +/* + * Parse an X.509 certificate + */ +struct x509_certificate *x509_cert_parse(const void *data, size_t datalen) +{ + struct x509_certificate *cert; + struct x509_parse_context *ctx; + struct asymmetric_key_id *kid; + long ret; + + ret = -ENOMEM; + cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL); + if (!cert) + goto error_no_cert; + cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL); + if (!cert->pub) + goto error_no_ctx; + ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL); + if (!ctx) + goto error_no_ctx; + + ctx->cert = cert; + ctx->data = (unsigned long)data; + + /* Attempt to decode the certificate */ + ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen); + if (ret < 0) + goto error_decode; + + /* Decode the public key */ + ret = asn1_ber_decoder(&x509_rsakey_decoder, ctx, + ctx->key, ctx->key_size); + if (ret < 0) + goto error_decode; + + /* Generate cert issuer + serial number key ID */ + kid = asymmetric_key_generate_id(cert->raw_serial, + cert->raw_serial_size, + cert->raw_issuer, + cert->raw_issuer_size); + if (IS_ERR(kid)) { + ret = PTR_ERR(kid); + goto error_decode; + } + cert->id = kid; + + kfree(ctx); + return cert; + +error_decode: + kfree(ctx); +error_no_ctx: + x509_free_certificate(cert); +error_no_cert: + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(x509_cert_parse); + +/* + * Note an OID when we find one for later processing when we know how + * to interpret it. + */ +int x509_note_OID(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + ctx->last_oid = look_up_OID(value, vlen); + if (ctx->last_oid == OID__NR) { + char buffer[50]; + sprint_oid(value, vlen, buffer, sizeof(buffer)); + pr_debug("Unknown OID: [%lu] %s\n", + (unsigned long)value - ctx->data, buffer); + } + return 0; +} + +/* + * Save the position of the TBS data so that we can check the signature over it + * later. + */ +int x509_note_tbs_certificate(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n", + hdrlen, tag, (unsigned long)value - ctx->data, vlen); + + ctx->cert->tbs = value - hdrlen; + ctx->cert->tbs_size = vlen + hdrlen; + return 0; +} + +/* + * Record the public key algorithm + */ +int x509_note_pkey_algo(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + pr_debug("PubKey Algo: %u\n", ctx->last_oid); + + switch (ctx->last_oid) { + case OID_md2WithRSAEncryption: + case OID_md3WithRSAEncryption: + default: + return -ENOPKG; /* Unsupported combination */ + + case OID_md4WithRSAEncryption: + ctx->cert->sig.pkey_hash_algo = HASH_ALGO_MD5; + ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA; + break; + + case OID_sha1WithRSAEncryption: + ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA1; + ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA; + break; + + case OID_sha256WithRSAEncryption: + ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA256; + ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA; + break; + + case OID_sha384WithRSAEncryption: + ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA384; + ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA; + break; + + case OID_sha512WithRSAEncryption: + ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA512; + ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA; + break; + + case OID_sha224WithRSAEncryption: + ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA224; + ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA; + break; + } + + ctx->algo_oid = ctx->last_oid; + return 0; +} + +/* + * Note the whereabouts and type of the signature. + */ +int x509_note_signature(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + pr_debug("Signature type: %u size %zu\n", ctx->last_oid, vlen); + + if (ctx->last_oid != ctx->algo_oid) { + pr_warn("Got cert with pkey (%u) and sig (%u) algorithm OIDs\n", + ctx->algo_oid, ctx->last_oid); + return -EINVAL; + } + + ctx->cert->raw_sig = value; + ctx->cert->raw_sig_size = vlen; + return 0; +} + +/* + * Note the certificate serial number + */ +int x509_note_serial(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + ctx->cert->raw_serial = value; + ctx->cert->raw_serial_size = vlen; + return 0; +} + +/* + * Note some of the name segments from which we'll fabricate a name. + */ +int x509_extract_name_segment(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + switch (ctx->last_oid) { + case OID_commonName: + ctx->cn_size = vlen; + ctx->cn_offset = (unsigned long)value - ctx->data; + break; + case OID_organizationName: + ctx->o_size = vlen; + ctx->o_offset = (unsigned long)value - ctx->data; + break; + case OID_email_address: + ctx->email_size = vlen; + ctx->email_offset = (unsigned long)value - ctx->data; + break; + default: + break; + } + + return 0; +} + +/* + * Fabricate and save the issuer and subject names + */ +static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen, + unsigned char tag, + char **_name, size_t vlen) +{ + const void *name, *data = (const void *)ctx->data; + size_t namesize; + char *buffer; + + if (*_name) + return -EINVAL; + + /* Empty name string if no material */ + if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) { + buffer = kmalloc(1, GFP_KERNEL); + if (!buffer) + return -ENOMEM; + buffer[0] = 0; + goto done; + } + + if (ctx->cn_size && ctx->o_size) { + /* Consider combining O and CN, but use only the CN if it is + * prefixed by the O, or a significant portion thereof. + */ + namesize = ctx->cn_size; + name = data + ctx->cn_offset; + if (ctx->cn_size >= ctx->o_size && + memcmp(data + ctx->cn_offset, data + ctx->o_offset, + ctx->o_size) == 0) + goto single_component; + if (ctx->cn_size >= 7 && + ctx->o_size >= 7 && + memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0) + goto single_component; + + buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1, + GFP_KERNEL); + if (!buffer) + return -ENOMEM; + + memcpy(buffer, + data + ctx->o_offset, ctx->o_size); + buffer[ctx->o_size + 0] = ':'; + buffer[ctx->o_size + 1] = ' '; + memcpy(buffer + ctx->o_size + 2, + data + ctx->cn_offset, ctx->cn_size); + buffer[ctx->o_size + 2 + ctx->cn_size] = 0; + goto done; + + } else if (ctx->cn_size) { + namesize = ctx->cn_size; + name = data + ctx->cn_offset; + } else if (ctx->o_size) { + namesize = ctx->o_size; + name = data + ctx->o_offset; + } else { + namesize = ctx->email_size; + name = data + ctx->email_offset; + } + +single_component: + buffer = kmalloc(namesize + 1, GFP_KERNEL); + if (!buffer) + return -ENOMEM; + memcpy(buffer, name, namesize); + buffer[namesize] = 0; + +done: + *_name = buffer; + ctx->cn_size = 0; + ctx->o_size = 0; + ctx->email_size = 0; + return 0; +} + +int x509_note_issuer(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + ctx->cert->raw_issuer = value; + ctx->cert->raw_issuer_size = vlen; + return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen); +} + +int x509_note_subject(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + ctx->cert->raw_subject = value; + ctx->cert->raw_subject_size = vlen; + return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen); +} + +/* + * Extract the data for the public key algorithm + */ +int x509_extract_key_data(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + if (ctx->last_oid != OID_rsaEncryption) + return -ENOPKG; + + ctx->cert->pub->pkey_algo = PKEY_ALGO_RSA; + + /* Discard the BIT STRING metadata */ + ctx->key = value + 1; + ctx->key_size = vlen - 1; + return 0; +} + +/* + * Extract a RSA public key value + */ +int rsa_extract_mpi(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + MPI mpi; + + if (ctx->nr_mpi >= ARRAY_SIZE(ctx->cert->pub->mpi)) { + pr_err("Too many public key MPIs in certificate\n"); + return -EBADMSG; + } + + mpi = mpi_read_raw_data(value, vlen); + if (!mpi) + return -ENOMEM; + + ctx->cert->pub->mpi[ctx->nr_mpi++] = mpi; + return 0; +} + +/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */ +#define SEQ_TAG_KEYID (ASN1_CONT << 6) + +/* + * Process certificate extensions that are used to qualify the certificate. + */ +int x509_process_extension(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + struct asymmetric_key_id *kid; + const unsigned char *v = value; + int i; + + pr_debug("Extension: %u\n", ctx->last_oid); + + if (ctx->last_oid == OID_subjectKeyIdentifier) { + /* Get hold of the key fingerprint */ + if (ctx->cert->skid || vlen < 3) + return -EBADMSG; + if (v[0] != ASN1_OTS || v[1] != vlen - 2) + return -EBADMSG; + v += 2; + vlen -= 2; + + ctx->cert->raw_skid_size = vlen; + ctx->cert->raw_skid = v; + kid = asymmetric_key_generate_id(ctx->cert->raw_subject, + ctx->cert->raw_subject_size, + v, vlen); + if (IS_ERR(kid)) + return PTR_ERR(kid); + ctx->cert->skid = kid; + pr_debug("subjkeyid %*phN\n", kid->len, kid->data); + return 0; + } + + if (ctx->last_oid == OID_authorityKeyIdentifier) { + /* Get hold of the CA key fingerprint */ + if (ctx->cert->authority || vlen < 5) + return -EBADMSG; + + /* Authority Key Identifier must be a Constructed SEQUENCE */ + if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5))) + return -EBADMSG; + + /* Authority Key Identifier is not indefinite length */ + if (unlikely(vlen == ASN1_INDEFINITE_LENGTH)) + return -EBADMSG; + + if (vlen < ASN1_INDEFINITE_LENGTH) { + /* Short Form length */ + if (v[1] != vlen - 2 || + v[2] != SEQ_TAG_KEYID || + v[3] > vlen - 4) + return -EBADMSG; + + vlen = v[3]; + v += 4; + } else { + /* Long Form length */ + size_t seq_len = 0; + size_t sub = v[1] - ASN1_INDEFINITE_LENGTH; + + if (sub > 2) + return -EBADMSG; + + /* calculate the length from subsequent octets */ + v += 2; + for (i = 0; i < sub; i++) { + seq_len <<= 8; + seq_len |= v[i]; + } + + if (seq_len != vlen - 2 - sub || + v[sub] != SEQ_TAG_KEYID || + v[sub + 1] > vlen - 4 - sub) + return -EBADMSG; + + vlen = v[sub + 1]; + v += (sub + 2); + } + + kid = asymmetric_key_generate_id(ctx->cert->raw_issuer, + ctx->cert->raw_issuer_size, + v, vlen); + if (IS_ERR(kid)) + return PTR_ERR(kid); + pr_debug("authkeyid %*phN\n", kid->len, kid->data); + ctx->cert->authority = kid; + return 0; + } + + return 0; +} + +/* + * Record a certificate time. + */ +static int x509_note_time(struct tm *tm, size_t hdrlen, + unsigned char tag, + const unsigned char *value, size_t vlen) +{ + const unsigned char *p = value; + +#define dec2bin(X) ((X) - '0') +#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; }) + + if (tag == ASN1_UNITIM) { + /* UTCTime: YYMMDDHHMMSSZ */ + if (vlen != 13) + goto unsupported_time; + tm->tm_year = DD2bin(p); + if (tm->tm_year >= 50) + tm->tm_year += 1900; + else + tm->tm_year += 2000; + } else if (tag == ASN1_GENTIM) { + /* GenTime: YYYYMMDDHHMMSSZ */ + if (vlen != 15) + goto unsupported_time; + tm->tm_year = DD2bin(p) * 100 + DD2bin(p); + } else { + goto unsupported_time; + } + + tm->tm_year -= 1900; + tm->tm_mon = DD2bin(p) - 1; + tm->tm_mday = DD2bin(p); + tm->tm_hour = DD2bin(p); + tm->tm_min = DD2bin(p); + tm->tm_sec = DD2bin(p); + + if (*p != 'Z') + goto unsupported_time; + + return 0; + +unsupported_time: + pr_debug("Got unsupported time [tag %02x]: '%*.*s'\n", + tag, (int)vlen, (int)vlen, value); + return -EBADMSG; +} + +int x509_note_not_before(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + return x509_note_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen); +} + +int x509_note_not_after(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + return x509_note_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen); +} diff --git a/kernel/crypto/asymmetric_keys/x509_parser.h b/kernel/crypto/asymmetric_keys/x509_parser.h new file mode 100644 index 000000000..3dfe6b5d6 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/x509_parser.h @@ -0,0 +1,57 @@ +/* X.509 certificate parser internal definitions + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include <linux/time.h> +#include <crypto/public_key.h> + +struct x509_certificate { + struct x509_certificate *next; + struct x509_certificate *signer; /* Certificate that signed this one */ + struct public_key *pub; /* Public key details */ + struct public_key_signature sig; /* Signature parameters */ + char *issuer; /* Name of certificate issuer */ + char *subject; /* Name of certificate subject */ + struct asymmetric_key_id *id; /* Serial number + issuer */ + struct asymmetric_key_id *skid; /* Subject + subjectKeyId (optional) */ + struct asymmetric_key_id *authority; /* Authority key identifier (optional) */ + struct tm valid_from; + struct tm valid_to; + const void *tbs; /* Signed data */ + unsigned tbs_size; /* Size of signed data */ + unsigned raw_sig_size; /* Size of sigature */ + const void *raw_sig; /* Signature data */ + const void *raw_serial; /* Raw serial number in ASN.1 */ + unsigned raw_serial_size; + unsigned raw_issuer_size; + const void *raw_issuer; /* Raw issuer name in ASN.1 */ + const void *raw_subject; /* Raw subject name in ASN.1 */ + unsigned raw_subject_size; + unsigned raw_skid_size; + const void *raw_skid; /* Raw subjectKeyId in ASN.1 */ + unsigned index; + bool seen; /* Infinite recursion prevention */ + bool verified; + bool trusted; + bool unsupported_crypto; /* T if can't be verified due to missing crypto */ +}; + +/* + * x509_cert_parser.c + */ +extern void x509_free_certificate(struct x509_certificate *cert); +extern struct x509_certificate *x509_cert_parse(const void *data, size_t datalen); + +/* + * x509_public_key.c + */ +extern int x509_get_sig_params(struct x509_certificate *cert); +extern int x509_check_signature(const struct public_key *pub, + struct x509_certificate *cert); diff --git a/kernel/crypto/asymmetric_keys/x509_public_key.c b/kernel/crypto/asymmetric_keys/x509_public_key.c new file mode 100644 index 000000000..a6c420316 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/x509_public_key.c @@ -0,0 +1,364 @@ +/* Instantiate a public key crypto key from an X.509 Certificate + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "X.509: "fmt +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/mpi.h> +#include <linux/asn1_decoder.h> +#include <keys/asymmetric-subtype.h> +#include <keys/asymmetric-parser.h> +#include <keys/system_keyring.h> +#include <crypto/hash.h> +#include "asymmetric_keys.h" +#include "public_key.h" +#include "x509_parser.h" + +static bool use_builtin_keys; +static struct asymmetric_key_id *ca_keyid; + +#ifndef MODULE +static int __init ca_keys_setup(char *str) +{ + if (!str) /* default system keyring */ + return 1; + + if (strncmp(str, "id:", 3) == 0) { + struct asymmetric_key_id *p; + p = asymmetric_key_hex_to_key_id(str + 3); + if (p == ERR_PTR(-EINVAL)) + pr_err("Unparsable hex string in ca_keys\n"); + else if (!IS_ERR(p)) + ca_keyid = p; /* owner key 'id:xxxxxx' */ + } else if (strcmp(str, "builtin") == 0) { + use_builtin_keys = true; + } + + return 1; +} +__setup("ca_keys=", ca_keys_setup); +#endif + +/** + * x509_request_asymmetric_key - Request a key by X.509 certificate params. + * @keyring: The keys to search. + * @kid: The key ID. + * @partial: Use partial match if true, exact if false. + * + * Find a key in the given keyring by subject name and key ID. These might, + * for instance, be the issuer name and the authority key ID of an X.509 + * certificate that needs to be verified. + */ +struct key *x509_request_asymmetric_key(struct key *keyring, + const struct asymmetric_key_id *kid, + bool partial) +{ + key_ref_t key; + char *id, *p; + + /* Construct an identifier "id:<keyid>". */ + p = id = kmalloc(2 + 1 + kid->len * 2 + 1, GFP_KERNEL); + if (!id) + return ERR_PTR(-ENOMEM); + + if (partial) { + *p++ = 'i'; + *p++ = 'd'; + } else { + *p++ = 'e'; + *p++ = 'x'; + } + *p++ = ':'; + p = bin2hex(p, kid->data, kid->len); + *p = 0; + + pr_debug("Look up: \"%s\"\n", id); + + key = keyring_search(make_key_ref(keyring, 1), + &key_type_asymmetric, id); + if (IS_ERR(key)) + pr_debug("Request for key '%s' err %ld\n", id, PTR_ERR(key)); + kfree(id); + + if (IS_ERR(key)) { + switch (PTR_ERR(key)) { + /* Hide some search errors */ + case -EACCES: + case -ENOTDIR: + case -EAGAIN: + return ERR_PTR(-ENOKEY); + default: + return ERR_CAST(key); + } + } + + pr_devel("<==%s() = 0 [%x]\n", __func__, + key_serial(key_ref_to_ptr(key))); + return key_ref_to_ptr(key); +} +EXPORT_SYMBOL_GPL(x509_request_asymmetric_key); + +/* + * Set up the signature parameters in an X.509 certificate. This involves + * digesting the signed data and extracting the signature. + */ +int x509_get_sig_params(struct x509_certificate *cert) +{ + struct crypto_shash *tfm; + struct shash_desc *desc; + size_t digest_size, desc_size; + void *digest; + int ret; + + pr_devel("==>%s()\n", __func__); + + if (cert->unsupported_crypto) + return -ENOPKG; + if (cert->sig.rsa.s) + return 0; + + cert->sig.rsa.s = mpi_read_raw_data(cert->raw_sig, cert->raw_sig_size); + if (!cert->sig.rsa.s) + return -ENOMEM; + cert->sig.nr_mpi = 1; + + /* Allocate the hashing algorithm we're going to need and find out how + * big the hash operational data will be. + */ + tfm = crypto_alloc_shash(hash_algo_name[cert->sig.pkey_hash_algo], 0, 0); + if (IS_ERR(tfm)) { + if (PTR_ERR(tfm) == -ENOENT) { + cert->unsupported_crypto = true; + return -ENOPKG; + } + return PTR_ERR(tfm); + } + + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); + digest_size = crypto_shash_digestsize(tfm); + + /* We allocate the hash operational data storage on the end of the + * digest storage space. + */ + ret = -ENOMEM; + digest = kzalloc(digest_size + desc_size, GFP_KERNEL); + if (!digest) + goto error; + + cert->sig.digest = digest; + cert->sig.digest_size = digest_size; + + desc = digest + digest_size; + desc->tfm = tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + might_sleep(); + ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, digest); +error: + crypto_free_shash(tfm); + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} +EXPORT_SYMBOL_GPL(x509_get_sig_params); + +/* + * Check the signature on a certificate using the provided public key + */ +int x509_check_signature(const struct public_key *pub, + struct x509_certificate *cert) +{ + int ret; + + pr_devel("==>%s()\n", __func__); + + ret = x509_get_sig_params(cert); + if (ret < 0) + return ret; + + ret = public_key_verify_signature(pub, &cert->sig); + if (ret == -ENOPKG) + cert->unsupported_crypto = true; + pr_debug("Cert Verification: %d\n", ret); + return ret; +} +EXPORT_SYMBOL_GPL(x509_check_signature); + +/* + * Check the new certificate against the ones in the trust keyring. If one of + * those is the signing key and validates the new certificate, then mark the + * new certificate as being trusted. + * + * Return 0 if the new certificate was successfully validated, 1 if we couldn't + * find a matching parent certificate in the trusted list and an error if there + * is a matching certificate but the signature check fails. + */ +static int x509_validate_trust(struct x509_certificate *cert, + struct key *trust_keyring) +{ + struct key *key; + int ret = 1; + + if (!trust_keyring) + return -EOPNOTSUPP; + + if (ca_keyid && !asymmetric_key_id_partial(cert->authority, ca_keyid)) + return -EPERM; + + key = x509_request_asymmetric_key(trust_keyring, cert->authority, + false); + if (!IS_ERR(key)) { + if (!use_builtin_keys + || test_bit(KEY_FLAG_BUILTIN, &key->flags)) + ret = x509_check_signature(key->payload.data, cert); + key_put(key); + } + return ret; +} + +/* + * Attempt to parse a data blob for a key as an X509 certificate. + */ +static int x509_key_preparse(struct key_preparsed_payload *prep) +{ + struct asymmetric_key_ids *kids; + struct x509_certificate *cert; + const char *q; + size_t srlen, sulen; + char *desc = NULL, *p; + int ret; + + cert = x509_cert_parse(prep->data, prep->datalen); + if (IS_ERR(cert)) + return PTR_ERR(cert); + + pr_devel("Cert Issuer: %s\n", cert->issuer); + pr_devel("Cert Subject: %s\n", cert->subject); + + if (cert->pub->pkey_algo >= PKEY_ALGO__LAST || + cert->sig.pkey_algo >= PKEY_ALGO__LAST || + cert->sig.pkey_hash_algo >= PKEY_HASH__LAST || + !pkey_algo[cert->pub->pkey_algo] || + !pkey_algo[cert->sig.pkey_algo] || + !hash_algo_name[cert->sig.pkey_hash_algo]) { + ret = -ENOPKG; + goto error_free_cert; + } + + pr_devel("Cert Key Algo: %s\n", pkey_algo_name[cert->pub->pkey_algo]); + pr_devel("Cert Valid From: %04ld-%02d-%02d %02d:%02d:%02d\n", + cert->valid_from.tm_year + 1900, cert->valid_from.tm_mon + 1, + cert->valid_from.tm_mday, cert->valid_from.tm_hour, + cert->valid_from.tm_min, cert->valid_from.tm_sec); + pr_devel("Cert Valid To: %04ld-%02d-%02d %02d:%02d:%02d\n", + cert->valid_to.tm_year + 1900, cert->valid_to.tm_mon + 1, + cert->valid_to.tm_mday, cert->valid_to.tm_hour, + cert->valid_to.tm_min, cert->valid_to.tm_sec); + pr_devel("Cert Signature: %s + %s\n", + pkey_algo_name[cert->sig.pkey_algo], + hash_algo_name[cert->sig.pkey_hash_algo]); + + cert->pub->algo = pkey_algo[cert->pub->pkey_algo]; + cert->pub->id_type = PKEY_ID_X509; + + /* Check the signature on the key if it appears to be self-signed */ + if (!cert->authority || + asymmetric_key_id_same(cert->skid, cert->authority)) { + ret = x509_check_signature(cert->pub, cert); /* self-signed */ + if (ret < 0) + goto error_free_cert; + } else if (!prep->trusted) { + ret = x509_validate_trust(cert, get_system_trusted_keyring()); + if (!ret) + prep->trusted = 1; + } + + /* Propose a description */ + sulen = strlen(cert->subject); + if (cert->raw_skid) { + srlen = cert->raw_skid_size; + q = cert->raw_skid; + } else { + srlen = cert->raw_serial_size; + q = cert->raw_serial; + } + if (srlen > 1 && *q == 0) { + srlen--; + q++; + } + + ret = -ENOMEM; + desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL); + if (!desc) + goto error_free_cert; + p = memcpy(desc, cert->subject, sulen); + p += sulen; + *p++ = ':'; + *p++ = ' '; + p = bin2hex(p, q, srlen); + *p = 0; + + kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL); + if (!kids) + goto error_free_desc; + kids->id[0] = cert->id; + kids->id[1] = cert->skid; + + /* We're pinning the module by being linked against it */ + __module_get(public_key_subtype.owner); + prep->type_data[0] = &public_key_subtype; + prep->type_data[1] = kids; + prep->payload[0] = cert->pub; + prep->description = desc; + prep->quotalen = 100; + + /* We've finished with the certificate */ + cert->pub = NULL; + cert->id = NULL; + cert->skid = NULL; + desc = NULL; + ret = 0; + +error_free_desc: + kfree(desc); +error_free_cert: + x509_free_certificate(cert); + return ret; +} + +static struct asymmetric_key_parser x509_key_parser = { + .owner = THIS_MODULE, + .name = "x509", + .parse = x509_key_preparse, +}; + +/* + * Module stuff + */ +static int __init x509_key_init(void) +{ + return register_asymmetric_key_parser(&x509_key_parser); +} + +static void __exit x509_key_exit(void) +{ + unregister_asymmetric_key_parser(&x509_key_parser); +} + +module_init(x509_key_init); +module_exit(x509_key_exit); + +MODULE_DESCRIPTION("X.509 certificate parser"); +MODULE_LICENSE("GPL"); diff --git a/kernel/crypto/asymmetric_keys/x509_rsakey.asn1 b/kernel/crypto/asymmetric_keys/x509_rsakey.asn1 new file mode 100644 index 000000000..4ec7cc653 --- /dev/null +++ b/kernel/crypto/asymmetric_keys/x509_rsakey.asn1 @@ -0,0 +1,4 @@ +RSAPublicKey ::= SEQUENCE { + modulus INTEGER ({ rsa_extract_mpi }), -- n + publicExponent INTEGER ({ rsa_extract_mpi }) -- e + } |