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authorRoberto Sassu <roberto.sassu@huawei.com>2019-05-29 15:30:33 +0200
committerMimi Zohar <zohar@linux.ibm.com>2019-05-29 23:18:25 -0400
commit221be106d75c1b511973301542f47d6000d0b63e (patch)
tree18f8246e67943de8fc8f5d9ebe2fcb927b8ed391 /security
parentf40019475bbbe9b455e7fd4385fcf13896c492ca (diff)
downloadlinux-221be106d75c1b511973301542f47d6000d0b63e.tar.gz
evm: check hash algorithm passed to init_desc()
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.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/evm/evm_crypto.c3
1 files changed, 3 insertions, 0 deletions
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];
 	}