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@xxxxxxxxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
v2: sent as standalone patch targeting net instead of net-next.
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);
base-commit: 715c7a36d59f54162a26fac1d1ed8dc087a24cf1
--
2.50.1
