From 9a8d289fbcb7dfd1fc74959e9930b406e76b2002 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Mon, 28 Jul 2014 07:59:49 -0400 Subject: [PATCH] ima: fix ima_alloc_atfm() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The patch 3bcced39ea7d: "ima: use ahash API for file hash calculation" from Feb 26, 2014, leads to the following static checker warning: security/integrity/ima/ima_crypto.c:204 ima_alloc_atfm()          error: buffer overflow 'hash_algo_name' 17 <= 17 Unlike shash tfm memory, which is allocated on initialization, the ahash tfm memory allocation is deferred until needed. This patch fixes the case where ima_ahash_tfm has not yet been allocated and 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. Changelog: - set valid algo before testing tfm - based on Dmitry's comment Reported-by: Dan Carpenter Signed-off-by: Mimi Zohar Signed-off-by: Dmitry Kasatkin --- 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 0bd732843fe7..2d103dc13d90 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -200,7 +200,10 @@ static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo) struct crypto_ahash *tfm = ima_ahash_tfm; int rc; - if ((algo != ima_hash_algo && algo < HASH_ALGO__LAST) || !tfm) { + if (algo < 0 || algo >= HASH_ALGO__LAST) + algo = ima_hash_algo; + + if (algo != ima_hash_algo || !tfm) { tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0); if (!IS_ERR(tfm)) { if (algo == ima_hash_algo) -- 2.20.1