From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3C599242D7F; Wed, 28 Jan 2026 15:53:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769615631; cv=none; b=RlHZkMt+tkPMlTcgTFuk1BFrwZ7/aQ0+8iM7+SqkqlKBT8Igo76nS+aE9wXklEuxBTuGPCp5m/TldsPRNgPM79eRtVZh3vHa5nFkg1CwEoi+KCzZouENdmBrpUTSPKnKDNJOFrWDBPAYszmAfHVAa8WA2QsHg9rqnHgS8FuKJkk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769615631; c=relaxed/simple; bh=fzS1vHdpRSqQ2Z3wpUxA/J/eBxabEmFmZDRgS8uZ5A4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CCa26SzqosyZZ+5B4026K/m4gcyiZ2fzNlN3rXUbOWABJ6S4UtTdBpFKzTGFSS2ZH7vxa1ru8itWprUTbpoE+eegv0hibsERSbvtsQLimvx7E2Yl0RWM08ujEDxhpoQutkQdkV7ODS04U1meBq9bqSrftOVa6oYb9Hi+6hwbifc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=t9PYn43K; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="t9PYn43K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3306C4CEF1; Wed, 28 Jan 2026 15:53:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1769615631; bh=fzS1vHdpRSqQ2Z3wpUxA/J/eBxabEmFmZDRgS8uZ5A4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t9PYn43KhhkGGyS0WkVgdbuDnG+WfqDN1ybR+wJDrywkAm6OHEi0T9hpr+gBJ/AnM 83RKMFwDT6C5M7eN352Rz9gcSzMfcvDGmaCE1VP/yYIxqP02bmHLoW4tOvQytXDi22 QljNOjCWt8fs8FxW3UCf5fQMMGnzjGhuv/WxZKTE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhen Chen , Xin Long , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 034/227] sctp: move SCTP_CMD_ASSOC_SHKEY right after SCTP_CMD_PEER_INIT Date: Wed, 28 Jan 2026 16:21:19 +0100 Message-ID: <20260128145345.571651087@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260128145344.331957407@linuxfoundation.org> References: <20260128145344.331957407@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long [ Upstream commit a80c9d945aef55b23b54838334345f20251dad83 ] A null-ptr-deref was reported in the SCTP transmit path when SCTP-AUTH key initialization fails: ================================================================== KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] CPU: 0 PID: 16 Comm: ksoftirqd/0 Tainted: G W 6.6.0 #2 RIP: 0010:sctp_packet_bundle_auth net/sctp/output.c:264 [inline] RIP: 0010:sctp_packet_append_chunk+0xb36/0x1260 net/sctp/output.c:401 Call Trace: sctp_packet_transmit_chunk+0x31/0x250 net/sctp/output.c:189 sctp_outq_flush_data+0xa29/0x26d0 net/sctp/outqueue.c:1111 sctp_outq_flush+0xc80/0x1240 net/sctp/outqueue.c:1217 sctp_cmd_interpreter.isra.0+0x19a5/0x62c0 net/sctp/sm_sideeffect.c:1787 sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline] sctp_do_sm+0x1a3/0x670 net/sctp/sm_sideeffect.c:1169 sctp_assoc_bh_rcv+0x33e/0x640 net/sctp/associola.c:1052 sctp_inq_push+0x1dd/0x280 net/sctp/inqueue.c:88 sctp_rcv+0x11ae/0x3100 net/sctp/input.c:243 sctp6_rcv+0x3d/0x60 net/sctp/ipv6.c:1127 The issue is triggered when sctp_auth_asoc_init_active_key() fails in sctp_sf_do_5_1C_ack() while processing an INIT_ACK. In this case, the command sequence is currently: - SCTP_CMD_PEER_INIT - SCTP_CMD_TIMER_STOP (T1_INIT) - SCTP_CMD_TIMER_START (T1_COOKIE) - SCTP_CMD_NEW_STATE (COOKIE_ECHOED) - SCTP_CMD_ASSOC_SHKEY - SCTP_CMD_GEN_COOKIE_ECHO If SCTP_CMD_ASSOC_SHKEY fails, asoc->shkey remains NULL, while asoc->peer.auth_capable and asoc->peer.peer_chunks have already been set by SCTP_CMD_PEER_INIT. This allows a DATA chunk with auth = 1 and shkey = NULL to be queued by sctp_datamsg_from_user(). Since command interpretation stops on failure, no COOKIE_ECHO should been sent via SCTP_CMD_GEN_COOKIE_ECHO. However, the T1_COOKIE timer has already been started, and it may enqueue a COOKIE_ECHO into the outqueue later. As a result, the DATA chunk can be transmitted together with the COOKIE_ECHO in sctp_outq_flush_data(), leading to the observed issue. Similar to the other places where it calls sctp_auth_asoc_init_active_key() right after sctp_process_init(), this patch moves the SCTP_CMD_ASSOC_SHKEY immediately after SCTP_CMD_PEER_INIT, before stopping T1_INIT and starting T1_COOKIE. This ensures that if shared key generation fails, authenticated DATA cannot be sent. It also allows the T1_INIT timer to retransmit INIT, giving the client another chance to process INIT_ACK and retry key setup. Fixes: 730fc3d05cd4 ("[SCTP]: Implete SCTP-AUTH parameter processing") Reported-by: Zhen Chen Tested-by: Zhen Chen Signed-off-by: Xin Long Link: https://patch.msgid.link/44881224b375aa8853f5e19b4055a1a56d895813.1768324226.git.lucien.xin@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sctp/sm_statefuns.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 3755ba079d077..7b823d7591419 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -603,6 +603,11 @@ enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, SCTP_PEER_INIT(initchunk)); + /* SCTP-AUTH: generate the association shared keys so that + * we can potentially sign the COOKIE-ECHO. + */ + sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); + /* Reset init error count upon receipt of INIT-ACK. */ sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); @@ -617,11 +622,6 @@ enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); - /* SCTP-AUTH: generate the association shared keys so that - * we can potentially sign the COOKIE-ECHO. - */ - sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); - /* 5.1 C) "A" shall then send the State Cookie received in the * INIT ACK chunk in a COOKIE ECHO chunk, ... */ -- 2.51.0