aboutsummaryrefslogtreecommitdiff
path: root/security
diff options
context:
space:
mode:
authorRyan Ware <ware@linux.intel.com>2016-02-11 15:58:44 -0800
committerJames Morris <james.l.morris@oracle.com>2016-02-12 18:36:47 +1100
commit613317bd212c585c20796c10afe5daaa95d4b0a1 (patch)
tree6bee35907a40edcb437683c4b33f2ee655091a66 /security
parentc05235d50f681bf685e7290cae05ab3b4fa493f3 (diff)
downloadleg-kernel-613317bd212c585c20796c10afe5daaa95d4b0a1.tar.gz
EVM: Use crypto_memneq() for digest comparisons
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>
Diffstat (limited to 'security')
-rw-r--r--security/integrity/evm/evm_main.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index f7160253f17f..e6ea9d4b1de9 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -23,6 +23,7 @@
#include <linux/integrity.h>
#include <linux/evm.h>
#include <crypto/hash.h>
+#include <crypto/algapi.h>
#include "evm.h"
int evm_initialized;
@@ -148,7 +149,7 @@ 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;