diff options
| author | Ryan Ware | 2016-02-11 15:58:44 -0800 |
|---|---|---|
| committer | James Morris | 2016-02-12 18:36:47 +1100 |
| commit | 613317bd212c585c20796c10afe5daaa95d4b0a1 (patch) | |
| tree | 6bee35907a40edcb437683c4b33f2ee655091a66 | |
| parent | c05235d50f681bf685e7290cae05ab3b4fa493f3 (diff) | |
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>
| -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 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; |