From 23c19e2ca736722a9523b64b07cda7efab7b6c57 Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Fri, 15 Aug 2014 13:28:52 +0300 Subject: 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 Signed-off-by: Mimi Zohar --- security/integrity/ima/ima_crypto.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index 2d103dc13d90..1178b307d562 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -116,7 +116,10 @@ static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo) 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); -- cgit v1.2.3