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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/security/integrity/ima/ima_appraise.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/security/integrity/ima/ima_appraise.c')
-rw-r--r--kernel/security/integrity/ima/ima_appraise.c400
1 files changed, 400 insertions, 0 deletions
diff --git a/kernel/security/integrity/ima/ima_appraise.c b/kernel/security/integrity/ima/ima_appraise.c
new file mode 100644
index 000000000..4df493e4b
--- /dev/null
+++ b/kernel/security/integrity/ima/ima_appraise.c
@@ -0,0 +1,400 @@
+/*
+ * Copyright (C) 2011 IBM Corporation
+ *
+ * Author:
+ * Mimi Zohar <zohar@us.ibm.com>
+ *
+ * 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, version 2 of the License.
+ */
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/xattr.h>
+#include <linux/magic.h>
+#include <linux/ima.h>
+#include <linux/evm.h>
+#include <crypto/hash_info.h>
+
+#include "ima.h"
+
+static int __init default_appraise_setup(char *str)
+{
+ if (strncmp(str, "off", 3) == 0)
+ ima_appraise = 0;
+ else if (strncmp(str, "log", 3) == 0)
+ ima_appraise = IMA_APPRAISE_LOG;
+ else if (strncmp(str, "fix", 3) == 0)
+ ima_appraise = IMA_APPRAISE_FIX;
+ return 1;
+}
+
+__setup("ima_appraise=", default_appraise_setup);
+
+/*
+ * ima_must_appraise - set appraise flag
+ *
+ * Return 1 to appraise
+ */
+int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
+{
+ if (!ima_appraise)
+ return 0;
+
+ return ima_match_policy(inode, func, mask, IMA_APPRAISE);
+}
+
+static int ima_fix_xattr(struct dentry *dentry,
+ struct integrity_iint_cache *iint)
+{
+ int rc, offset;
+ u8 algo = iint->ima_hash->algo;
+
+ if (algo <= HASH_ALGO_SHA1) {
+ offset = 1;
+ iint->ima_hash->xattr.sha1.type = IMA_XATTR_DIGEST;
+ } else {
+ offset = 0;
+ iint->ima_hash->xattr.ng.type = IMA_XATTR_DIGEST_NG;
+ iint->ima_hash->xattr.ng.algo = algo;
+ }
+ rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
+ &iint->ima_hash->xattr.data[offset],
+ (sizeof(iint->ima_hash->xattr) - offset) +
+ iint->ima_hash->length, 0);
+ return rc;
+}
+
+/* Return specific func appraised cached result */
+enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
+ int func)
+{
+ switch (func) {
+ case MMAP_CHECK:
+ return iint->ima_mmap_status;
+ case BPRM_CHECK:
+ return iint->ima_bprm_status;
+ case MODULE_CHECK:
+ return iint->ima_module_status;
+ case FIRMWARE_CHECK:
+ return iint->ima_firmware_status;
+ case FILE_CHECK:
+ default:
+ return iint->ima_file_status;
+ }
+}
+
+static void ima_set_cache_status(struct integrity_iint_cache *iint,
+ int func, enum integrity_status status)
+{
+ switch (func) {
+ case MMAP_CHECK:
+ iint->ima_mmap_status = status;
+ break;
+ case BPRM_CHECK:
+ iint->ima_bprm_status = status;
+ break;
+ case MODULE_CHECK:
+ iint->ima_module_status = status;
+ break;
+ case FIRMWARE_CHECK:
+ iint->ima_firmware_status = status;
+ break;
+ case FILE_CHECK:
+ default:
+ iint->ima_file_status = status;
+ break;
+ }
+}
+
+static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
+{
+ switch (func) {
+ case MMAP_CHECK:
+ iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED);
+ break;
+ case BPRM_CHECK:
+ iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED);
+ break;
+ case MODULE_CHECK:
+ iint->flags |= (IMA_MODULE_APPRAISED | IMA_APPRAISED);
+ break;
+ case FIRMWARE_CHECK:
+ iint->flags |= (IMA_FIRMWARE_APPRAISED | IMA_APPRAISED);
+ break;
+ case FILE_CHECK:
+ default:
+ iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED);
+ break;
+ }
+}
+
+void ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len,
+ struct ima_digest_data *hash)
+{
+ struct signature_v2_hdr *sig;
+
+ if (!xattr_value || xattr_len < 2)
+ return;
+
+ switch (xattr_value->type) {
+ case EVM_IMA_XATTR_DIGSIG:
+ sig = (typeof(sig))xattr_value;
+ if (sig->version != 2 || xattr_len <= sizeof(*sig))
+ return;
+ hash->algo = sig->hash_algo;
+ break;
+ case IMA_XATTR_DIGEST_NG:
+ hash->algo = xattr_value->digest[0];
+ break;
+ case IMA_XATTR_DIGEST:
+ /* this is for backward compatibility */
+ if (xattr_len == 21) {
+ unsigned int zero = 0;
+ if (!memcmp(&xattr_value->digest[16], &zero, 4))
+ hash->algo = HASH_ALGO_MD5;
+ else
+ hash->algo = HASH_ALGO_SHA1;
+ } else if (xattr_len == 17)
+ hash->algo = HASH_ALGO_MD5;
+ break;
+ }
+}
+
+int ima_read_xattr(struct dentry *dentry,
+ struct evm_ima_xattr_data **xattr_value)
+{
+ struct inode *inode = d_backing_inode(dentry);
+
+ if (!inode->i_op->getxattr)
+ return 0;
+
+ return vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
+ 0, GFP_NOFS);
+}
+
+/*
+ * ima_appraise_measurement - appraise file measurement
+ *
+ * Call evm_verifyxattr() to verify the integrity of 'security.ima'.
+ * Assuming success, compare the xattr hash with the collected measurement.
+ *
+ * Return 0 on success, error code otherwise
+ */
+int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
+ struct file *file, const unsigned char *filename,
+ struct evm_ima_xattr_data *xattr_value,
+ int xattr_len, int opened)
+{
+ static const char op[] = "appraise_data";
+ char *cause = "unknown";
+ struct dentry *dentry = file->f_path.dentry;
+ struct inode *inode = d_backing_inode(dentry);
+ enum integrity_status status = INTEGRITY_UNKNOWN;
+ int rc = xattr_len, hash_start = 0;
+
+ if (!inode->i_op->getxattr)
+ return INTEGRITY_UNKNOWN;
+
+ if (rc <= 0) {
+ if (rc && rc != -ENODATA)
+ goto out;
+
+ cause = "missing-hash";
+ status = INTEGRITY_NOLABEL;
+ if (opened & FILE_CREATED) {
+ iint->flags |= IMA_NEW_FILE;
+ status = INTEGRITY_PASS;
+ }
+ goto out;
+ }
+
+ status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
+ if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
+ if ((status == INTEGRITY_NOLABEL)
+ || (status == INTEGRITY_NOXATTRS))
+ cause = "missing-HMAC";
+ else if (status == INTEGRITY_FAIL)
+ cause = "invalid-HMAC";
+ goto out;
+ }
+ switch (xattr_value->type) {
+ case IMA_XATTR_DIGEST_NG:
+ /* first byte contains algorithm id */
+ hash_start = 1;
+ case IMA_XATTR_DIGEST:
+ if (iint->flags & IMA_DIGSIG_REQUIRED) {
+ cause = "IMA-signature-required";
+ status = INTEGRITY_FAIL;
+ break;
+ }
+ if (xattr_len - sizeof(xattr_value->type) - hash_start >=
+ iint->ima_hash->length)
+ /* xattr length may be longer. md5 hash in previous
+ version occupied 20 bytes in xattr, instead of 16
+ */
+ rc = memcmp(&xattr_value->digest[hash_start],
+ iint->ima_hash->digest,
+ iint->ima_hash->length);
+ else
+ rc = -EINVAL;
+ if (rc) {
+ cause = "invalid-hash";
+ status = INTEGRITY_FAIL;
+ break;
+ }
+ status = INTEGRITY_PASS;
+ break;
+ case EVM_IMA_XATTR_DIGSIG:
+ iint->flags |= IMA_DIGSIG;
+ rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
+ (const char *)xattr_value, rc,
+ iint->ima_hash->digest,
+ iint->ima_hash->length);
+ if (rc == -EOPNOTSUPP) {
+ status = INTEGRITY_UNKNOWN;
+ } else if (rc) {
+ cause = "invalid-signature";
+ status = INTEGRITY_FAIL;
+ } else {
+ status = INTEGRITY_PASS;
+ }
+ break;
+ default:
+ status = INTEGRITY_UNKNOWN;
+ cause = "unknown-ima-data";
+ break;
+ }
+
+out:
+ if (status != INTEGRITY_PASS) {
+ if ((ima_appraise & IMA_APPRAISE_FIX) &&
+ (!xattr_value ||
+ xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
+ if (!ima_fix_xattr(dentry, iint))
+ status = INTEGRITY_PASS;
+ }
+ integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
+ op, cause, rc, 0);
+ } else {
+ ima_cache_flags(iint, func);
+ }
+ ima_set_cache_status(iint, func, status);
+ return status;
+}
+
+/*
+ * ima_update_xattr - update 'security.ima' hash value
+ */
+void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
+{
+ struct dentry *dentry = file->f_path.dentry;
+ int rc = 0;
+
+ /* do not collect and update hash for digital signatures */
+ if (iint->flags & IMA_DIGSIG)
+ return;
+
+ rc = ima_collect_measurement(iint, file, NULL, NULL);
+ if (rc < 0)
+ return;
+
+ ima_fix_xattr(dentry, iint);
+}
+
+/**
+ * ima_inode_post_setattr - reflect file metadata changes
+ * @dentry: pointer to the affected dentry
+ *
+ * Changes to a dentry's metadata might result in needing to appraise.
+ *
+ * This function is called from notify_change(), which expects the caller
+ * to lock the inode's i_mutex.
+ */
+void ima_inode_post_setattr(struct dentry *dentry)
+{
+ struct inode *inode = d_backing_inode(dentry);
+ struct integrity_iint_cache *iint;
+ int must_appraise, rc;
+
+ if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode)
+ || !inode->i_op->removexattr)
+ return;
+
+ must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
+ iint = integrity_iint_find(inode);
+ if (iint) {
+ iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
+ IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
+ IMA_ACTION_FLAGS);
+ if (must_appraise)
+ iint->flags |= IMA_APPRAISE;
+ }
+ if (!must_appraise)
+ rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
+ return;
+}
+
+/*
+ * ima_protect_xattr - protect 'security.ima'
+ *
+ * Ensure that not just anyone can modify or remove 'security.ima'.
+ */
+static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name,
+ const void *xattr_value, size_t xattr_value_len)
+{
+ if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) {
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ return 1;
+ }
+ return 0;
+}
+
+static void ima_reset_appraise_flags(struct inode *inode, int digsig)
+{
+ struct integrity_iint_cache *iint;
+
+ if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode))
+ return;
+
+ iint = integrity_iint_find(inode);
+ if (!iint)
+ return;
+
+ iint->flags &= ~IMA_DONE_MASK;
+ if (digsig)
+ iint->flags |= IMA_DIGSIG;
+ return;
+}
+
+int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
+ const void *xattr_value, size_t xattr_value_len)
+{
+ const struct evm_ima_xattr_data *xvalue = xattr_value;
+ int result;
+
+ result = ima_protect_xattr(dentry, xattr_name, xattr_value,
+ xattr_value_len);
+ if (result == 1) {
+ if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST))
+ return -EINVAL;
+ ima_reset_appraise_flags(d_backing_inode(dentry),
+ (xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0);
+ result = 0;
+ }
+ return result;
+}
+
+int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
+{
+ int result;
+
+ result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
+ if (result == 1) {
+ ima_reset_appraise_flags(d_backing_inode(dentry), 0);
+ result = 0;
+ }
+ return result;
+}