ima: prevent buffer overflow in ima_alloc_tfm()
This patch fixes the case where the file's signature/hash xattr contains
an invalid hash algorithm. Although we can not verify the xattr, we still
need to measure the file. Use the default IMA hash algorithm.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 2d103dc..1178b30 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -116,7 +116,10 @@
struct crypto_shash *tfm = ima_shash_tfm;
int rc;
- if (algo != ima_hash_algo && algo < HASH_ALGO__LAST) {
+ if (algo < 0 || algo >= HASH_ALGO__LAST)
+ algo = ima_hash_algo;
+
+ if (algo != ima_hash_algo) {
tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
if (IS_ERR(tfm)) {
rc = PTR_ERR(tfm);