From ed3044b9c810c5c24eb2830053fbfe5fd134c5d4 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 18 Aug 2025 13:54:23 -0700 Subject: sctp: Fix MAC comparison to be constant-time commit dd91c79e4f58fbe2898dac84858033700e0e99fb upstream. To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Link: https://patch.msgid.link/20250818205426.30222-3-ebiggers@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/sctp/sm_make_chunk.c | 3 ++- net/sctp/sm_statefuns.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c index 08527d882e56..eb2ed7db3fe1 100644 --- a/net/sctp/sm_make_chunk.c +++ b/net/sctp/sm_make_chunk.c @@ -31,6 +31,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include +#include #include #include #include @@ -1796,7 +1797,7 @@ struct sctp_association *sctp_unpack_cookie( } } - if (memcmp(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) { + if (crypto_memneq(digest, cookie->signature, SCTP_SIGNATURE_SIZE)) { *error = -SCTP_IERROR_BAD_SIG; goto fail; } diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 2d88654e8d8e..cd18b22b2bba 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -30,6 +30,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include #include #include @@ -4416,7 +4417,7 @@ static enum sctp_ierror sctp_sf_authenticate( sh_key, GFP_ATOMIC); /* Discard the packet if the digests do not match */ - if (memcmp(save_digest, digest, sig_len)) { + if (crypto_memneq(save_digest, digest, sig_len)) { kfree(save_digest); return SCTP_IERROR_BAD_SIG; } -- cgit v1.2.3