| From a458b2902115b26a25d67393b12ddd57d1216aaa Mon Sep 17 00:00:00 2001 |
| From: Eric Biggers <ebiggers@kernel.org> |
| Date: Mon, 18 Aug 2025 13:27:24 -0700 |
| Subject: ipv6: sr: Fix MAC comparison to be constant-time |
| |
| From: Eric Biggers <ebiggers@kernel.org> |
| |
| commit a458b2902115b26a25d67393b12ddd57d1216aaa upstream. |
| |
| 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> |
| Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it> |
| Link: https://patch.msgid.link/20250818202724.15713-1-ebiggers@kernel.org |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/ipv6/seg6_hmac.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/net/ipv6/seg6_hmac.c |
| +++ b/net/ipv6/seg6_hmac.c |
| @@ -35,6 +35,7 @@ |
| #include <net/xfrm.h> |
| |
| #include <crypto/hash.h> |
| +#include <crypto/algapi.h> |
| #include <net/seg6.h> |
| #include <net/genetlink.h> |
| #include <net/seg6_hmac.h> |
| @@ -269,7 +270,7 @@ bool seg6_hmac_validate_skb(struct sk_bu |
| 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; |
