From 221be106d75c1b511973301542f47d6000d0b63e Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Wed, 29 May 2019 15:30:33 +0200 Subject: [PATCH] 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 Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar --- 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]; }