Re: [PATCH 1/4] evm: check hash algorithm passed to init_desc()
From: Mimi Zohar <zohar@linux.ibm.com>
Date: 2019-05-20 21:19:25
Also in:
linux-doc, linux-integrity, lkml, stable
On Thu, 2019-05-16 at 18:12 +0200, Roberto Sassu wrote:
This patch prevents memory access beyond the evm_tfm array by checking the
validity of the index (hash algorithm) passed to init_desc(). The hash
algorithm can be arbitrarily set if the security.ima xattr type is not
EVM_XATTR_HMAC.
Fixes: 5feeb61183dde ("evm: Allow non-SHA1 digital signatures")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Cc: stable@vger.kernel.orgThanks!
quoted hunk ↗ jump to hunk
--- security/integrity/evm/evm_crypto.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index e11564eb645b..82a38e801ee4 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c@@ -89,6 +89,9 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) tfm = &hmac_tfm; algo = evm_hmac; } else { + if (hash_algo >= HASH_ALGO__LAST) + return ERR_PTR(-EINVAL); + tfm = &evm_tfm[hash_algo]; algo = hash_algo_name[hash_algo]; }