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authorRoberto Sassu2020-04-27 12:28:56 +0200
committerMimi Zohar2020-05-07 21:30:58 -0400
commit53de3b080d5eae31d0de219617155dcc34e7d698 (patch)
treef163f0adbe08a441fa3f511bedf14db99a8da68c /security
parent0014cc04e8ec077dc482f00c87dfd949cfe2b98f (diff)
evm: Check also if *tfm is an error pointer in init_desc()
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: d46eb3699502b ("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>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/evm/evm_crypto.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 35682852ddea..77ad1e5a93e4 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -91,7 +91,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo)
algo = hash_algo_name[hash_algo];
}
- if (*tfm == NULL) {
+ if (IS_ERR_OR_NULL(*tfm)) {
mutex_lock(&mutex);
if (*tfm)
goto out;