diff options
Diffstat (limited to 'qemu/roms/ipxe/src/crypto/rsa.c')
| -rw-r--r-- | qemu/roms/ipxe/src/crypto/rsa.c | 705 |
1 files changed, 705 insertions, 0 deletions
diff --git a/qemu/roms/ipxe/src/crypto/rsa.c b/qemu/roms/ipxe/src/crypto/rsa.c new file mode 100644 index 000000000..0ab7b2ad3 --- /dev/null +++ b/qemu/roms/ipxe/src/crypto/rsa.c @@ -0,0 +1,705 @@ +/* + * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include <stdint.h> +#include <stdlib.h> +#include <stdarg.h> +#include <string.h> +#include <errno.h> +#include <ipxe/asn1.h> +#include <ipxe/crypto.h> +#include <ipxe/bigint.h> +#include <ipxe/random_nz.h> +#include <ipxe/md5.h> +#include <ipxe/sha1.h> +#include <ipxe/sha256.h> +#include <ipxe/rsa.h> + +/** @file + * + * RSA public-key cryptography + * + * RSA is documented in RFC 3447. + */ + +/* Disambiguate the various error causes */ +#define EACCES_VERIFY \ + __einfo_error ( EINFO_EACCES_VERIFY ) +#define EINFO_EACCES_VERIFY \ + __einfo_uniqify ( EINFO_EACCES, 0x01, "RSA signature incorrect" ) + +/** "rsaEncryption" object identifier */ +static uint8_t oid_rsa_encryption[] = { ASN1_OID_RSAENCRYPTION }; + +/** "md5WithRSAEncryption" object identifier */ +static uint8_t oid_md5_with_rsa_encryption[] = + { ASN1_OID_MD5WITHRSAENCRYPTION }; + +/** "sha1WithRSAEncryption" object identifier */ +static uint8_t oid_sha1_with_rsa_encryption[] = + { ASN1_OID_SHA1WITHRSAENCRYPTION }; + +/** "sha256WithRSAEncryption" object identifier */ +static uint8_t oid_sha256_with_rsa_encryption[] = + { ASN1_OID_SHA256WITHRSAENCRYPTION }; + +/** "rsaEncryption" OID-identified algorithm */ +struct asn1_algorithm rsa_encryption_algorithm __asn1_algorithm = { + .name = "rsaEncryption", + .pubkey = &rsa_algorithm, + .digest = NULL, + .oid = ASN1_OID_CURSOR ( oid_rsa_encryption ), +}; + +/** "md5WithRSAEncryption" OID-identified algorithm */ +struct asn1_algorithm md5_with_rsa_encryption_algorithm __asn1_algorithm = { + .name = "md5WithRSAEncryption", + .pubkey = &rsa_algorithm, + .digest = &md5_algorithm, + .oid = ASN1_OID_CURSOR ( oid_md5_with_rsa_encryption ), +}; + +/** "sha1WithRSAEncryption" OID-identified algorithm */ +struct asn1_algorithm sha1_with_rsa_encryption_algorithm __asn1_algorithm = { + .name = "sha1WithRSAEncryption", + .pubkey = &rsa_algorithm, + .digest = &sha1_algorithm, + .oid = ASN1_OID_CURSOR ( oid_sha1_with_rsa_encryption ), +}; + +/** "sha256WithRSAEncryption" OID-identified algorithm */ +struct asn1_algorithm sha256_with_rsa_encryption_algorithm __asn1_algorithm = { + .name = "sha256WithRSAEncryption", + .pubkey = &rsa_algorithm, + .digest = &sha256_algorithm, + .oid = ASN1_OID_CURSOR ( oid_sha256_with_rsa_encryption ), +}; + +/** MD5 digestInfo prefix */ +static const uint8_t rsa_md5_prefix_data[] = + { RSA_DIGESTINFO_PREFIX ( MD5_DIGEST_SIZE, ASN1_OID_MD5 ) }; + +/** SHA-1 digestInfo prefix */ +static const uint8_t rsa_sha1_prefix_data[] = + { RSA_DIGESTINFO_PREFIX ( SHA1_DIGEST_SIZE, ASN1_OID_SHA1 ) }; + +/** SHA-256 digestInfo prefix */ +static const uint8_t rsa_sha256_prefix_data[] = + { RSA_DIGESTINFO_PREFIX ( SHA256_DIGEST_SIZE, ASN1_OID_SHA256 ) }; + +/** MD5 digestInfo prefix */ +struct rsa_digestinfo_prefix rsa_md5_prefix __rsa_digestinfo_prefix = { + .digest = &md5_algorithm, + .data = rsa_md5_prefix_data, + .len = sizeof ( rsa_md5_prefix_data ), +}; + +/** SHA-1 digestInfo prefix */ +struct rsa_digestinfo_prefix rsa_sha1_prefix __rsa_digestinfo_prefix = { + .digest = &sha1_algorithm, + .data = rsa_sha1_prefix_data, + .len = sizeof ( rsa_sha1_prefix_data ), +}; + +/** SHA-256 digestInfo prefix */ +struct rsa_digestinfo_prefix rsa_sha256_prefix __rsa_digestinfo_prefix = { + .digest = &sha256_algorithm, + .data = rsa_sha256_prefix_data, + .len = sizeof ( rsa_sha256_prefix_data ), +}; + +/** + * Identify RSA prefix + * + * @v digest Digest algorithm + * @ret prefix RSA prefix, or NULL + */ +static struct rsa_digestinfo_prefix * +rsa_find_prefix ( struct digest_algorithm *digest ) { + struct rsa_digestinfo_prefix *prefix; + + for_each_table_entry ( prefix, RSA_DIGESTINFO_PREFIXES ) { + if ( prefix->digest == digest ) + return prefix; + } + return NULL; +} + +/** + * Free RSA dynamic storage + * + * @v context RSA context + */ +static void rsa_free ( struct rsa_context *context ) { + + free ( context->dynamic ); + context->dynamic = NULL; +} + +/** + * Allocate RSA dynamic storage + * + * @v context RSA context + * @v modulus_len Modulus length + * @v exponent_len Exponent length + * @ret rc Return status code + */ +static int rsa_alloc ( struct rsa_context *context, size_t modulus_len, + size_t exponent_len ) { + unsigned int size = bigint_required_size ( modulus_len ); + unsigned int exponent_size = bigint_required_size ( exponent_len ); + bigint_t ( size ) *modulus; + bigint_t ( exponent_size ) *exponent; + size_t tmp_len = bigint_mod_exp_tmp_len ( modulus, exponent ); + struct { + bigint_t ( size ) modulus; + bigint_t ( exponent_size ) exponent; + bigint_t ( size ) input; + bigint_t ( size ) output; + uint8_t tmp[tmp_len]; + } __attribute__ (( packed )) *dynamic; + + /* Free any existing dynamic storage */ + rsa_free ( context ); + + /* Allocate dynamic storage */ + dynamic = malloc ( sizeof ( *dynamic ) ); + if ( ! dynamic ) + return -ENOMEM; + + /* Assign dynamic storage */ + context->dynamic = dynamic; + context->modulus0 = &dynamic->modulus.element[0]; + context->size = size; + context->max_len = modulus_len; + context->exponent0 = &dynamic->exponent.element[0]; + context->exponent_size = exponent_size; + context->input0 = &dynamic->input.element[0]; + context->output0 = &dynamic->output.element[0]; + context->tmp = &dynamic->tmp; + + return 0; +} + +/** + * Parse RSA integer + * + * @v integer Integer to fill in + * @v raw ASN.1 cursor + * @ret rc Return status code + */ +static int rsa_parse_integer ( struct asn1_cursor *integer, + const struct asn1_cursor *raw ) { + + /* Enter integer */ + memcpy ( integer, raw, sizeof ( *integer ) ); + asn1_enter ( integer, ASN1_INTEGER ); + + /* Skip initial sign byte if applicable */ + if ( ( integer->len > 1 ) && + ( *( ( uint8_t * ) integer->data ) == 0x00 ) ) { + integer->data++; + integer->len--; + } + + /* Fail if cursor or integer are invalid */ + if ( ! integer->len ) + return -EINVAL; + + return 0; +} + +/** + * Parse RSA modulus and exponent + * + * @v modulus Modulus to fill in + * @v exponent Exponent to fill in + * @v raw ASN.1 cursor + * @ret rc Return status code + */ +static int rsa_parse_mod_exp ( struct asn1_cursor *modulus, + struct asn1_cursor *exponent, + const struct asn1_cursor *raw ) { + struct asn1_bit_string bits; + struct asn1_cursor cursor; + int is_private; + int rc; + + /* Enter subjectPublicKeyInfo/RSAPrivateKey */ + memcpy ( &cursor, raw, sizeof ( cursor ) ); + asn1_enter ( &cursor, ASN1_SEQUENCE ); + + /* Determine key format */ + if ( asn1_type ( &cursor ) == ASN1_INTEGER ) { + + /* Private key */ + is_private = 1; + + /* Skip version */ + asn1_skip_any ( &cursor ); + + } else { + + /* Public key */ + is_private = 0; + + /* Skip algorithm */ + asn1_skip ( &cursor, ASN1_SEQUENCE ); + + /* Enter subjectPublicKey */ + if ( ( rc = asn1_integral_bit_string ( &cursor, &bits ) ) != 0 ) + return rc; + cursor.data = bits.data; + cursor.len = bits.len; + + /* Enter RSAPublicKey */ + asn1_enter ( &cursor, ASN1_SEQUENCE ); + } + + /* Extract modulus */ + if ( ( rc = rsa_parse_integer ( modulus, &cursor ) ) != 0 ) + return rc; + asn1_skip_any ( &cursor ); + + /* Skip public exponent, if applicable */ + if ( is_private ) + asn1_skip ( &cursor, ASN1_INTEGER ); + + /* Extract publicExponent/privateExponent */ + if ( ( rc = rsa_parse_integer ( exponent, &cursor ) ) != 0 ) + return rc; + + return 0; +} + +/** + * Initialise RSA cipher + * + * @v ctx RSA context + * @v key Key + * @v key_len Length of key + * @ret rc Return status code + */ +static int rsa_init ( void *ctx, const void *key, size_t key_len ) { + struct rsa_context *context = ctx; + struct asn1_cursor modulus; + struct asn1_cursor exponent; + struct asn1_cursor cursor; + int rc; + + /* Initialise context */ + memset ( context, 0, sizeof ( *context ) ); + + /* Initialise cursor */ + cursor.data = key; + cursor.len = key_len; + + /* Parse modulus and exponent */ + if ( ( rc = rsa_parse_mod_exp ( &modulus, &exponent, &cursor ) ) != 0 ){ + DBGC ( context, "RSA %p invalid modulus/exponent:\n", context ); + DBGC_HDA ( context, 0, cursor.data, cursor.len ); + goto err_parse; + } + + DBGC ( context, "RSA %p modulus:\n", context ); + DBGC_HDA ( context, 0, modulus.data, modulus.len ); + DBGC ( context, "RSA %p exponent:\n", context ); + DBGC_HDA ( context, 0, exponent.data, exponent.len ); + + /* Allocate dynamic storage */ + if ( ( rc = rsa_alloc ( context, modulus.len, exponent.len ) ) != 0 ) + goto err_alloc; + + /* Construct big integers */ + bigint_init ( ( ( bigint_t ( context->size ) * ) context->modulus0 ), + modulus.data, modulus.len ); + bigint_init ( ( ( bigint_t ( context->exponent_size ) * ) + context->exponent0 ), exponent.data, exponent.len ); + + return 0; + + rsa_free ( context ); + err_alloc: + err_parse: + return rc; +} + +/** + * Calculate RSA maximum output length + * + * @v ctx RSA context + * @ret max_len Maximum output length + */ +static size_t rsa_max_len ( void *ctx ) { + struct rsa_context *context = ctx; + + return context->max_len; +} + +/** + * Perform RSA cipher operation + * + * @v context RSA context + * @v in Input buffer + * @v out Output buffer + */ +static void rsa_cipher ( struct rsa_context *context, + const void *in, void *out ) { + bigint_t ( context->size ) *input = ( ( void * ) context->input0 ); + bigint_t ( context->size ) *output = ( ( void * ) context->output0 ); + bigint_t ( context->size ) *modulus = ( ( void * ) context->modulus0 ); + bigint_t ( context->exponent_size ) *exponent = + ( ( void * ) context->exponent0 ); + + /* Initialise big integer */ + bigint_init ( input, in, context->max_len ); + + /* Perform modular exponentiation */ + bigint_mod_exp ( input, modulus, exponent, output, context->tmp ); + + /* Copy out result */ + bigint_done ( output, out, context->max_len ); +} + +/** + * Encrypt using RSA + * + * @v ctx RSA context + * @v plaintext Plaintext + * @v plaintext_len Length of plaintext + * @v ciphertext Ciphertext + * @ret ciphertext_len Length of ciphertext, or negative error + */ +static int rsa_encrypt ( void *ctx, const void *plaintext, + size_t plaintext_len, void *ciphertext ) { + struct rsa_context *context = ctx; + void *temp; + uint8_t *encoded; + size_t max_len = ( context->max_len - 11 ); + size_t random_nz_len = ( max_len - plaintext_len + 8 ); + int rc; + + /* Sanity check */ + if ( plaintext_len > max_len ) { + DBGC ( context, "RSA %p plaintext too long (%zd bytes, max " + "%zd)\n", context, plaintext_len, max_len ); + return -ERANGE; + } + DBGC ( context, "RSA %p encrypting:\n", context ); + DBGC_HDA ( context, 0, plaintext, plaintext_len ); + + /* Construct encoded message (using the big integer output + * buffer as temporary storage) + */ + temp = context->output0; + encoded = temp; + encoded[0] = 0x00; + encoded[1] = 0x02; + if ( ( rc = get_random_nz ( &encoded[2], random_nz_len ) ) != 0 ) { + DBGC ( context, "RSA %p could not generate random data: %s\n", + context, strerror ( rc ) ); + return rc; + } + encoded[ 2 + random_nz_len ] = 0x00; + memcpy ( &encoded[ context->max_len - plaintext_len ], + plaintext, plaintext_len ); + + /* Encipher the encoded message */ + rsa_cipher ( context, encoded, ciphertext ); + DBGC ( context, "RSA %p encrypted:\n", context ); + DBGC_HDA ( context, 0, ciphertext, context->max_len ); + + return context->max_len; +} + +/** + * Decrypt using RSA + * + * @v ctx RSA context + * @v ciphertext Ciphertext + * @v ciphertext_len Ciphertext length + * @v plaintext Plaintext + * @ret plaintext_len Plaintext length, or negative error + */ +static int rsa_decrypt ( void *ctx, const void *ciphertext, + size_t ciphertext_len, void *plaintext ) { + struct rsa_context *context = ctx; + void *temp; + uint8_t *encoded; + uint8_t *end; + uint8_t *zero; + uint8_t *start; + size_t plaintext_len; + + /* Sanity check */ + if ( ciphertext_len != context->max_len ) { + DBGC ( context, "RSA %p ciphertext incorrect length (%zd " + "bytes, should be %zd)\n", + context, ciphertext_len, context->max_len ); + return -ERANGE; + } + DBGC ( context, "RSA %p decrypting:\n", context ); + DBGC_HDA ( context, 0, ciphertext, ciphertext_len ); + + /* Decipher the message (using the big integer input buffer as + * temporary storage) + */ + temp = context->input0; + encoded = temp; + rsa_cipher ( context, ciphertext, encoded ); + + /* Parse the message */ + end = ( encoded + context->max_len ); + if ( ( encoded[0] != 0x00 ) || ( encoded[1] != 0x02 ) ) + goto invalid; + zero = memchr ( &encoded[2], 0, ( end - &encoded[2] ) ); + if ( ! zero ) + goto invalid; + start = ( zero + 1 ); + plaintext_len = ( end - start ); + + /* Copy out message */ + memcpy ( plaintext, start, plaintext_len ); + DBGC ( context, "RSA %p decrypted:\n", context ); + DBGC_HDA ( context, 0, plaintext, plaintext_len ); + + return plaintext_len; + + invalid: + DBGC ( context, "RSA %p invalid decrypted message:\n", context ); + DBGC_HDA ( context, 0, encoded, context->max_len ); + return -EINVAL; +} + +/** + * Encode RSA digest + * + * @v context RSA context + * @v digest Digest algorithm + * @v value Digest value + * @v encoded Encoded digest + * @ret rc Return status code + */ +static int rsa_encode_digest ( struct rsa_context *context, + struct digest_algorithm *digest, + const void *value, void *encoded ) { + struct rsa_digestinfo_prefix *prefix; + size_t digest_len = digest->digestsize; + uint8_t *temp = encoded; + size_t digestinfo_len; + size_t max_len; + size_t pad_len; + + /* Identify prefix */ + prefix = rsa_find_prefix ( digest ); + if ( ! prefix ) { + DBGC ( context, "RSA %p has no prefix for %s\n", + context, digest->name ); + return -ENOTSUP; + } + digestinfo_len = ( prefix->len + digest_len ); + + /* Sanity check */ + max_len = ( context->max_len - 11 ); + if ( digestinfo_len > max_len ) { + DBGC ( context, "RSA %p %s digestInfo too long (%zd bytes, max" + "%zd)\n", + context, digest->name, digestinfo_len, max_len ); + return -ERANGE; + } + DBGC ( context, "RSA %p encoding %s digest:\n", + context, digest->name ); + DBGC_HDA ( context, 0, value, digest_len ); + + /* Construct encoded message */ + *(temp++) = 0x00; + *(temp++) = 0x01; + pad_len = ( max_len - digestinfo_len + 8 ); + memset ( temp, 0xff, pad_len ); + temp += pad_len; + *(temp++) = 0x00; + memcpy ( temp, prefix->data, prefix->len ); + temp += prefix->len; + memcpy ( temp, value, digest_len ); + temp += digest_len; + assert ( temp == ( encoded + context->max_len ) ); + DBGC ( context, "RSA %p encoded %s digest:\n", context, digest->name ); + DBGC_HDA ( context, 0, encoded, context->max_len ); + + return 0; +} + +/** + * Sign digest value using RSA + * + * @v ctx RSA context + * @v digest Digest algorithm + * @v value Digest value + * @v signature Signature + * @ret signature_len Signature length, or negative error + */ +static int rsa_sign ( void *ctx, struct digest_algorithm *digest, + const void *value, void *signature ) { + struct rsa_context *context = ctx; + void *temp; + int rc; + + DBGC ( context, "RSA %p signing %s digest:\n", context, digest->name ); + DBGC_HDA ( context, 0, value, digest->digestsize ); + + /* Encode digest (using the big integer output buffer as + * temporary storage) + */ + temp = context->output0; + if ( ( rc = rsa_encode_digest ( context, digest, value, temp ) ) != 0 ) + return rc; + + /* Encipher the encoded digest */ + rsa_cipher ( context, temp, signature ); + DBGC ( context, "RSA %p signed %s digest:\n", context, digest->name ); + DBGC_HDA ( context, 0, signature, context->max_len ); + + return context->max_len; +} + +/** + * Verify signed digest value using RSA + * + * @v ctx RSA context + * @v digest Digest algorithm + * @v value Digest value + * @v signature Signature + * @v signature_len Signature length + * @ret rc Return status code + */ +static int rsa_verify ( void *ctx, struct digest_algorithm *digest, + const void *value, const void *signature, + size_t signature_len ) { + struct rsa_context *context = ctx; + void *temp; + void *expected; + void *actual; + int rc; + + /* Sanity check */ + if ( signature_len != context->max_len ) { + DBGC ( context, "RSA %p signature incorrect length (%zd " + "bytes, should be %zd)\n", + context, signature_len, context->max_len ); + return -ERANGE; + } + DBGC ( context, "RSA %p verifying %s digest:\n", + context, digest->name ); + DBGC_HDA ( context, 0, value, digest->digestsize ); + DBGC_HDA ( context, 0, signature, signature_len ); + + /* Decipher the signature (using the big integer input buffer + * as temporary storage) + */ + temp = context->input0; + expected = temp; + rsa_cipher ( context, signature, expected ); + DBGC ( context, "RSA %p deciphered signature:\n", context ); + DBGC_HDA ( context, 0, expected, context->max_len ); + + /* Encode digest (using the big integer output buffer as + * temporary storage) + */ + temp = context->output0; + actual = temp; + if ( ( rc = rsa_encode_digest ( context, digest, value, actual ) ) !=0 ) + return rc; + + /* Verify the signature */ + if ( memcmp ( actual, expected, context->max_len ) != 0 ) { + DBGC ( context, "RSA %p signature verification failed\n", + context ); + return -EACCES_VERIFY; + } + + DBGC ( context, "RSA %p signature verified successfully\n", context ); + return 0; +} + +/** + * Finalise RSA cipher + * + * @v ctx RSA context + */ +static void rsa_final ( void *ctx ) { + struct rsa_context *context = ctx; + + rsa_free ( context ); +} + +/** + * Check for matching RSA public/private key pair + * + * @v private_key Private key + * @v private_key_len Private key length + * @v public_key Public key + * @v public_key_len Public key length + * @ret rc Return status code + */ +static int rsa_match ( const void *private_key, size_t private_key_len, + const void *public_key, size_t public_key_len ) { + struct asn1_cursor private_modulus; + struct asn1_cursor private_exponent; + struct asn1_cursor private_cursor; + struct asn1_cursor public_modulus; + struct asn1_cursor public_exponent; + struct asn1_cursor public_cursor; + int rc; + + /* Initialise cursors */ + private_cursor.data = private_key; + private_cursor.len = private_key_len; + public_cursor.data = public_key; + public_cursor.len = public_key_len; + + /* Parse moduli and exponents */ + if ( ( rc = rsa_parse_mod_exp ( &private_modulus, &private_exponent, + &private_cursor ) ) != 0 ) + return rc; + if ( ( rc = rsa_parse_mod_exp ( &public_modulus, &public_exponent, + &public_cursor ) ) != 0 ) + return rc; + + /* Compare moduli */ + if ( asn1_compare ( &private_modulus, &public_modulus ) != 0 ) + return -ENOTTY; + + return 0; +} + +/** RSA public-key algorithm */ +struct pubkey_algorithm rsa_algorithm = { + .name = "rsa", + .ctxsize = sizeof ( struct rsa_context ), + .init = rsa_init, + .max_len = rsa_max_len, + .encrypt = rsa_encrypt, + .decrypt = rsa_decrypt, + .sign = rsa_sign, + .verify = rsa_verify, + .final = rsa_final, + .match = rsa_match, +}; |