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-rw-r--r--security/integrity/ima/ima_appraise.c106
1 files changed, 86 insertions, 20 deletions
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 2d4becab8918..734e9468aca0 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -15,6 +15,7 @@
#include <linux/magic.h>
#include <linux/ima.h>
#include <linux/evm.h>
+#include <crypto/hash_info.h>
#include "ima.h"
@@ -43,19 +44,31 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
}
static int ima_fix_xattr(struct dentry *dentry,
- struct integrity_iint_cache *iint)
+ struct integrity_iint_cache *iint)
{
- iint->ima_xattr.type = IMA_XATTR_DIGEST;
- return __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
- (u8 *)&iint->ima_xattr,
- sizeof(iint->ima_xattr), 0);
+ 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) {
+ switch (func) {
case MMAP_CHECK:
return iint->ima_mmap_status;
case BPRM_CHECK:
@@ -71,7 +84,7 @@ enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
static void ima_set_cache_status(struct integrity_iint_cache *iint,
int func, enum integrity_status status)
{
- switch(func) {
+ switch (func) {
case MMAP_CHECK:
iint->ima_mmap_status = status;
break;
@@ -90,7 +103,7 @@ static void ima_set_cache_status(struct integrity_iint_cache *iint,
static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
{
- switch(func) {
+ switch (func) {
case MMAP_CHECK:
iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED);
break;
@@ -107,6 +120,50 @@ static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
}
}
+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 = dentry->d_inode;
+
+ 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
*
@@ -116,23 +173,22 @@ static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
* 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 file *file, const unsigned char *filename,
+ struct evm_ima_xattr_data *xattr_value,
+ int xattr_len)
{
struct dentry *dentry = file->f_dentry;
struct inode *inode = dentry->d_inode;
- struct evm_ima_xattr_data *xattr_value = NULL;
enum integrity_status status = INTEGRITY_UNKNOWN;
const char *op = "appraise_data";
char *cause = "unknown";
- int rc;
+ int rc = xattr_len, hash_start = 0;
if (!ima_appraise)
return 0;
if (!inode->i_op->getxattr)
return INTEGRITY_UNKNOWN;
- rc = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)&xattr_value,
- 0, GFP_NOFS);
if (rc <= 0) {
if (rc && rc != -ENODATA)
goto out;
@@ -153,14 +209,25 @@ int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
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;
}
- rc = memcmp(xattr_value->digest, iint->ima_xattr.digest,
- IMA_DIGEST_SIZE);
+ 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;
@@ -171,9 +238,9 @@ int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
case EVM_IMA_XATTR_DIGSIG:
iint->flags |= IMA_DIGSIG;
rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
- xattr_value->digest, rc - 1,
- iint->ima_xattr.digest,
- IMA_DIGEST_SIZE);
+ (const char *)xattr_value, rc,
+ iint->ima_hash->digest,
+ iint->ima_hash->length);
if (rc == -EOPNOTSUPP) {
status = INTEGRITY_UNKNOWN;
} else if (rc) {
@@ -203,7 +270,6 @@ out:
ima_cache_flags(iint, func);
}
ima_set_cache_status(iint, func, status);
- kfree(xattr_value);
return status;
}
@@ -219,7 +285,7 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
if (iint->flags & IMA_DIGSIG)
return;
- rc = ima_collect_measurement(iint, file);
+ rc = ima_collect_measurement(iint, file, NULL, NULL);
if (rc < 0)
return;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.