lkml.org 
[lkml]   [2017]   [Jun]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH 10/23] KEYS: encrypted: use constant-time HMAC comparison
From
Date
From: Eric Biggers <ebiggers@google.com>

MACs should, in general, be compared using crypto_memneq() to prevent
timing attacks.

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---

security/keys/encrypted-keys/encrypted.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c
index 702c80662069..5c98c2fe03f0 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -30,6 +30,7 @@
#include <linux/scatterlist.h>
#include <linux/ctype.h>
#include <crypto/aes.h>
+#include <crypto/algapi.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include <crypto/skcipher.h>
@@ -534,8 +535,8 @@ static int datablob_hmac_verify(struct encrypted_key_payload *epayload,
ret = calc_hmac(digest, derived_key, sizeof derived_key, p, len);
if (ret < 0)
goto out;
- ret = memcmp(digest, epayload->format + epayload->datablob_len,
- sizeof digest);
+ ret = crypto_memneq(digest, epayload->format + epayload->datablob_len,
+ sizeof(digest));
if (ret) {
ret = -EINVAL;
dump_hmac("datablob",
\
 
 \ /
  Last update: 2017-06-12 01:29    [W:0.105 / U:0.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site