To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.
Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers ebiggers@kernel.org --- net/ipv6/seg6_hmac.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c index f78ecb6ad8383..5dae892bbc73b 100644 --- a/net/ipv6/seg6_hmac.c +++ b/net/ipv6/seg6_hmac.c @@ -33,10 +33,11 @@ #include <net/ip6_route.h> #include <net/addrconf.h> #include <net/xfrm.h>
#include <crypto/hash.h> +#include <crypto/utils.h> #include <net/seg6.h> #include <net/genetlink.h> #include <net/seg6_hmac.h> #include <linux/random.h>
@@ -278,11 +279,11 @@ bool seg6_hmac_validate_skb(struct sk_buff *skb) return false;
if (seg6_hmac_compute(hinfo, srh, &ipv6_hdr(skb)->saddr, hmac_output)) return false;
- if (memcmp(hmac_output, tlv->hmac, SEG6_HMAC_FIELD_LEN) != 0) + if (crypto_memneq(hmac_output, tlv->hmac, SEG6_HMAC_FIELD_LEN)) return false;
return true; } EXPORT_SYMBOL(seg6_hmac_validate_skb);