Commit 6e322a9e authored May 29, 2019 by Roberto Sassu Committed by Greg Kroah-Hartman Jun 09, 2019

evm: check hash algorithm passed to init_desc()



commit 221be106d75c1b511973301542f47d6000d0b63e upstream.

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: 5feeb611 ("evm: Allow non-SHA1 digital signatures")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent f85b87a9

security/integrity/evm/evm_crypto.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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];
		}