Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-17 17:41:44 +00:00
Code Issues Packages Projects Releases Wiki Activity

evm: Check also if *tfm is an error pointer in init_desc()

Browse Source 
This patch avoids a kernel panic due to accessing an error pointer set by
crypto_alloc_shash(). It occurs especially when there are many files that
require an unsupported algorithm, as it would increase the likelihood of
the following race condition:

Task A: *tfm = crypto_alloc_shash() <= error pointer
Task B: if (*tfm == NULL) <= *tfm is not NULL, use it
Task B: rc = crypto_shash_init(desc) <= panic
Task A: *tfm = NULL

This patch uses the IS_ERR_OR_NULL macro to determine whether or not a new
crypto context must be created.

Cc: stable@vger.kernel.org
Fixes: d46eb36995 ("evm: crypto hash replaced by shash")
Co-developed-by: Krzysztof Struczynski <krzysztof.struczynski@huawei.com>
Signed-off-by: Krzysztof Struczynski <krzysztof.struczynski@huawei.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Roberto Sassu 2020-04-27 12:28:56 +02:00 committed by Mimi Zohar
parent 0014cc04e8
commit 53de3b080d
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
security/integrity/evm/evm_crypto.c
View File

@ -91,7 +91,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo)
algo = hash_algo_name[hash_algo]; algo = hash_algo_name[hash_algo];
} }
if (*tfm == NULL) { if (IS_ERR_OR_NULL(*tfm)) {
mutex_lock(&mutex); mutex_lock(&mutex);
if (*tfm) if (*tfm)
goto out; goto out;