From nobody Wed Sep 30 16:20:07 2026 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0997644C64B; Fri, 7 Aug 2026 06:43:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786085038; cv=none; b=HUWkkxsD1xirwFGnJCbX8kWHiFUeT8xUyTh3ennjyYHr9pKB+ST5tXfqvcrv8NQKRfSrHv0r7TNEtGbRibfevJNmpmRxgACJbmWXAoWottjkwwl57p1MtXloP+rb97j+21NOxsGynb2fgywQ5cmk5Z7+s3peYzMLpptqB0iWyVM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786085038; c=relaxed/simple; bh=ownM38qo6qKUu/ffImXqntcXmjD0N74UnEarE0QoUQQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=SwcCylLW/s3smvHNRjiubvXcwDw33ZRkeB7GQsC1SnX9Sq5xX7Ms5OI5A1tP7hhM21YD/5B/w+NJifQAql2jLSfKDMlNvf6ekT/GfgdmyBjH2a1jgdRkZcbNvKLu3GICRXwTWyUaBin5lLcgDS3aDjoQhSXmWdHr4AF7QM6cJBk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=ik/JaOFV; arc=none smtp.client-ip=117.135.210.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="ik/JaOFV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version: Content-Type; bh=XiEF1RhqiQjGuKkXjKUAZy724ihfORrXJyDL4vNVdqw=; b=ik/JaOFVklvsZsGmbhpbbwCw7E3rY0u5I0VJDDRxZpF6oxN13o2cO1B7idjihD ws9T+FYrmHaPsoek/IzZ3N7aGP3n5d9K2RHhh4laFWYIJoINfvKlPbiPUnuLQAWx ZwJDlytxgL78E6AoVy1iaD6AUo+E7m7xdFTTBOPHe19PY= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g0-4 (Coremail) with SMTP id _____wBXY8eDfnVqS8ZGOQ--.43665S2; Fri, 07 Aug 2026 14:43:17 +0800 (CST) From: luoqing To: l1138897701@163.com, lucien.xin@gmail.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: horms@kernel.org, linux-sctp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v4] sctp: auth: propagate HMAC calculation errors to callers Date: Fri, 7 Aug 2026 14:43:14 +0800 Message-Id: <20260807064314.500742-1-l1138897701@163.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260730064202.792809-1-l1138897701@163.com> References: <20260730064202.792809-1-l1138897701@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wBXY8eDfnVqS8ZGOQ--.43665S2 X-Coremail-Antispam: 1Uf129KBjvJXoW3Ar4xuFyrZw17tF1DZryfXrb_yoWxJFWfp3 Z8CrZYkw1xJr4aqFs3CF48G3WY9ws5C3y3JayYqwsay3Z8Xryrtryjka18KryUCFWkJa42 yw4jgF15Gr1qyFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0piJ5rxUUUUU= X-CM-SenderInfo: jorrjmiyzxliqr6rljoofrz/xtbC3gW4-Gp1foW5zgAA3M From: Qing Luo sctp_auth_calculate_hmac() can fail when building the association secret under memory pressure, but its void return silently leaves the HMAC digest zeroed. On the receive path, sctp_sf_authenticate() compares this zeroed digest against the peer-supplied one using crypto_memneq(), potentially accepting an all-zero HMAC from the peer if the allocation failed. On the send path, sctp_packet_pack() transmits a packet with a zeroed HMAC that the peer would reject. Improve error handling by making sctp_auth_calculate_hmac() return int: - sctp_sf_authenticate() returns SCTP_IERROR_NOMEM instead of accepting a zero HMAC. - sctp_packet_pack() drops the packet on failure instead of transmitting a zeroed HMAC. Update the declaration in auth.h accordingly. Assisted-by: LLM Signed-off-by: Qing Luo Acked-by: Xin Long --- v4: Remove the entry "sctp_auth_chunk_verify()" that has been removed from = the commit message. =20 v3: Add missing SCTP maintainers and sctp mailing list, no code changes --- include/net/sctp/auth.h | 6 +++--- net/sctp/auth.c | 10 ++++++---- net/sctp/output.c | 12 +++++++++--- net/sctp/sm_statefuns.c | 9 ++++++--- 4 files changed, 24 insertions(+), 13 deletions(-) diff --git a/include/net/sctp/auth.h b/include/net/sctp/auth.h index 6f2cd562b1de..eeb3297fe97d 100644 --- a/include/net/sctp/auth.h +++ b/include/net/sctp/auth.h @@ -83,9 +83,9 @@ int sctp_auth_send_cid(enum sctp_cid chunk, const struct sctp_association *asoc); int sctp_auth_recv_cid(enum sctp_cid chunk, const struct sctp_association *asoc); -void sctp_auth_calculate_hmac(const struct sctp_association *asoc, - struct sk_buff *skb, struct sctp_auth_chunk *auth, - struct sctp_shared_key *ep_key, gfp_t gfp); +int sctp_auth_calculate_hmac(const struct sctp_association *asoc, + struct sk_buff *skb, struct sctp_auth_chunk *auth, + struct sctp_shared_key *ep_key, gfp_t gfp); void sctp_auth_shkey_release(struct sctp_shared_key *sh_key); void sctp_auth_shkey_hold(struct sctp_shared_key *sh_key); =20 diff --git a/net/sctp/auth.c b/net/sctp/auth.c index c901d373af80..6de66f56c41c 100644 --- a/net/sctp/auth.c +++ b/net/sctp/auth.c @@ -613,9 +613,9 @@ int sctp_auth_recv_cid(enum sctp_cid chunk, const struc= t sctp_association *asoc) * zero (as shown in Figure 6) followed by all chunks that are placed * after the AUTH chunk in the SCTP packet. */ -void sctp_auth_calculate_hmac(const struct sctp_association *asoc, - struct sk_buff *skb, struct sctp_auth_chunk *auth, - struct sctp_shared_key *ep_key, gfp_t gfp) +int sctp_auth_calculate_hmac(const struct sctp_association *asoc, + struct sk_buff *skb, struct sctp_auth_chunk *auth, + struct sctp_shared_key *ep_key, gfp_t gfp) { struct sctp_auth_bytes *asoc_key; __u16 key_id, hmac_id; @@ -636,7 +636,7 @@ void sctp_auth_calculate_hmac(const struct sctp_associa= tion *asoc, /* ep_key can't be NULL here */ asoc_key =3D sctp_auth_asoc_create_secret(asoc, ep_key, gfp); if (!asoc_key) - return; + return -ENOMEM; =20 free_key =3D 1; } @@ -654,6 +654,8 @@ void sctp_auth_calculate_hmac(const struct sctp_associa= tion *asoc, =20 if (free_key) sctp_auth_key_put(asoc_key); + + return 0; } =20 /* API Helpers */ diff --git a/net/sctp/output.c b/net/sctp/output.c index 23e96305cad7..3d7ead9d40e1 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -517,8 +517,14 @@ static int sctp_packet_pack(struct sctp_packet *packet, } =20 if (auth) { - sctp_auth_calculate_hmac(tp->asoc, nskb, auth, - packet->auth->shkey, gfp); + if (sctp_auth_calculate_hmac(tp->asoc, nskb, auth, + packet->auth->shkey, gfp)) { + sctp_chunk_free(packet->auth); + packet->auth =3D NULL; + if (gso) + kfree_skb(nskb); + return -ENOMEM; + } /* free auth if no more chunks, or add it back */ if (list_empty(&packet->chunk_list)) sctp_chunk_free(packet->auth); @@ -619,7 +625,7 @@ int sctp_packet_transmit(struct sctp_packet *packet, gf= p_t gfp) =20 /* pack up chunks */ pkt_count =3D sctp_packet_pack(packet, head, gso, gfp); - if (!pkt_count) { + if (pkt_count <=3D 0) { kfree_skb(head); goto out; } diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 708fa07d5fff..bb89c9b52e0b 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -4455,9 +4455,12 @@ static enum sctp_ierror sctp_sf_authenticate( =20 memset(digest, 0, sig_len); =20 - sctp_auth_calculate_hmac(asoc, chunk->skb, - (struct sctp_auth_chunk *)chunk->chunk_hdr, - sh_key, GFP_ATOMIC); + if (sctp_auth_calculate_hmac(asoc, chunk->skb, + (struct sctp_auth_chunk *)chunk->chunk_hdr, + sh_key, GFP_ATOMIC)) { + kfree(save_digest); + return SCTP_IERROR_NOMEM; + } =20 /* Discard the packet if the digests do not match */ if (crypto_memneq(save_digest, digest, sig_len)) { --=20 2.25.1 > Returning 0 here is fine, as its only caller, sctp_packet_transmit(), > currently always returns 0. sctp_packet_pack(), on the other hand, returns > the number of packets it builds. > > If you'd like to improve the return value for sctp_packet_transmit(), > that can be done in a separate patch targeting net-next. Hi Longxin Thank you very much for your patient guidance on community patch submission= conventions and your valuable review. I fully take your comment. As you mentioned, returning 0 is acceptable for the moment, given `sctp_pac= ket_transmit()` always returns zero today, while `sctp_packet_pack()` retur= ns the count of generated packets. Although there is no functional bug in the current code, unifying the retur= n=E2=80=91value semantics makes the interface more consistent, which can pr= event latent risks when this code path is extended in the future. I will implement this optimization as a standalone patch for net=E2=80=91ne= xt as you suggested. Please help to evaluate whether this improvement is necessary for mainline.= If maintainers think it brings limited practical benefit, I am okay to dro= p this patch entirely. Thanks, luoqing