diff options
| author | Ryan Ware <ware@linux.intel.com> | 2016-02-11 15:58:44 -0800 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-03-04 10:18:41 -0500 |
| commit | 6702fc0c98d40442f9e74e10c499d68cd96455df (patch) | |
| tree | eb8694a96d551c669f5c9e057b13f16ee831a4f9 /security | |
| parent | b42e89beb60b3b618b180349a0e3b02ae3d4657e (diff) | |
EVM: Use crypto_memneq() for digest comparisons
[ Upstream commit 613317bd212c585c20796c10afe5daaa95d4b0a1 ]
This patch fixes vulnerability CVE-2016-2085. The problem exists
because the vm_verify_hmac() function includes a use of memcmp().
Unfortunately, this allows timing side channel attacks; specifically
a MAC forgery complexity drop from 2^128 to 2^12. This patch changes
the memcmp() to the cryptographically safe crypto_memneq().
Reported-by: Xiaofei Rex Guo <xiaofei.rex.guo@intel.com>
Signed-off-by: Ryan Ware <ware@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/evm/evm_main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 4ada1a97a60b..e1998df4c160 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -24,6 +24,7 @@ #include <linux/evm.h> #include <linux/magic.h> #include <crypto/hash.h> +#include <crypto/algapi.h> #include "evm.h" int evm_initialized; @@ -149,7 +150,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, xattr_value_len, calc.digest); if (rc) break; - rc = memcmp(xattr_data->digest, calc.digest, + rc = crypto_memneq(xattr_data->digest, calc.digest, sizeof(calc.digest)); if (rc) rc = -EINVAL; |