diff options
| author | Roberto Sassu <roberto.sassu@huawei.com> | 2020-04-27 13:28:56 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-27 18:37:28 +0300 |
| commit | 4c7a2e76ae93577628a022d2d2adf5e0d8a89147 (patch) | |
| tree | f1473662334d3f7ac7e49c49afd299bceec892eb | |
| parent | 904de138bae903a6e377322e64312e22a84f2140 (diff) | |
| download | linux-4c7a2e76ae93577628a022d2d2adf5e0d8a89147.tar.xz | |
evm: Check also if *tfm is an error pointer in init_desc()
[ Upstream commit 53de3b080d5eae31d0de219617155dcc34e7d698 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | security/integrity/evm/evm_crypto.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index 6a314fb0d480..f0878d81dcef 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -96,7 +96,7 @@ 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; |