diff options
| author | Roberto Sassu <roberto.sassu@huawei.com> | 2020-04-27 12:28:56 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-27 16:40:23 +0200 |
| commit | b30282c3bcc7542fe3faf9f5e1a0980c3c28a507 (patch) | |
| tree | 3cccc6fcca634a58e62e3aa0b7161ef12c2d3059 /security | |
| parent | 3c74e59f30ccfb4937a9814631cc828f64427de3 (diff) | |
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>
Diffstat (limited to 'security')
| -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 461f8d891579..44352b0b7510 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -47,7 +47,7 @@ static struct shash_desc *init_desc(char type) algo = evm_hash; } - if (*tfm == NULL) { + if (IS_ERR_OR_NULL(*tfm)) { mutex_lock(&mutex); if (*tfm) goto out; |