From nobody Fri Oct 2 01:15:10 2026 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [40.65.178.148]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 617AB36C597; Thu, 6 Aug 2026 17:16:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=40.65.178.148 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786036600; cv=none; b=Lz0EPRSsRztBfdkZvwo0QQlHy0er8MTfkjZfPkyraKzTeml+vKU55CZy1eiY/bu6CTb1uecnF1EWaC0v43DyBOjmMf5xCN5JPpu1FfU50kGGLzUs1n8uc8cymIEOu2QIKhF2UtQxu/hARqt1sqdPLyy/6hFbKcRTmlNknLPtT5g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786036600; c=relaxed/simple; bh=CwuWe3oIk4AzuGunWz+SP2Hs726ScsZkq/Uf4Lf1ouI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=iDt2/57NGEeMkW4+uMPPlHpotiK1F7SLt7/CfEov1NXgu3QktCIoDSjkwU15DBjuhNUR++dKppdgXidRUQMWeBG7/oBisFDx24ncnMbYL+ykuTH74z+bQBWh99bd2QwtC9VNJ/ounp6dXcvQ9qwQpgf/JDc9QHTsAuD66DAt5/0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b=OwszU2L3; arc=none smtp.client-ip=40.65.178.148 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mails.tsinghua.edu.cn Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mails.tsinghua.edu.cn header.i=@mails.tsinghua.edu.cn header.b="OwszU2L3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mails.tsinghua.edu.cn; s=dkim; h=Received:From:To:Cc:Subject: Date:Message-Id:MIME-Version:Content-Transfer-Encoding; bh=8Ptg1 mK2PwCN7Sdld8TRmpv3xMzurCdFmlSv2qo+IKs=; b=OwszU2L3q7fYOa6pQObbA XHZp1hbKXDlAclWDXfLXFrzNpttuUurzVObzcfdQWCdb0qILDPdhA4prUFDWbSDD n4KG8snUhlM1kj5BQxIvRTtY3tA3dSW6r+l2XAuWV8raQnp8Wl7NXB8w/8uTcH86 OOwqTI8WqSepdkrygyVb7c= Received: from gpu-server-2.tailcd67b0.ts.net (unknown [101.52.241.91]) by web1 (Coremail) with SMTP id yAQGZQCXO8tfwXRqRwFEAQ--.57940S2; Fri, 07 Aug 2026 01:16:16 +0800 (CST) From: Yuxiang Yang To: linux-sctp@vger.kernel.org, netdev@vger.kernel.org Cc: marcelo.leitner@gmail.com, lucien.xin@gmail.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, linux-kernel@vger.kernel.org, Yuxiang Yang , stable@vger.kernel.org, Yizhou Zhao , Ao Wang , Xuewei Feng , Qi Li , Ke Xu , yyxroy22@gmail.com Subject: [PATCH net] sctp: fix use-after-free of cached ASCONF chunk Date: Fri, 7 Aug 2026 01:16:14 +0800 Message-Id: <20260806171614.945331-1-yangyx22@mails.tsinghua.edu.cn> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: yAQGZQCXO8tfwXRqRwFEAQ--.57940S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Cr15JFyUGF4UZFy7AF1DJrb_yoW8WFy8p3 98Zr4rtryUGr18ArZ3JFn0ga1Ikws3J39xKryqyw4fZFs8Xr1Yk347K3WUtr40kF4kAayS grW3tF4UXF1qyFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9C1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l8cAvFVAK 0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4 x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4U JwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJwAac4AC62xK8xCEY4vEwIxC4wAS0I 0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VCjz48v1sIE Y20_GrWkJr1UJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjI I2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS14v26r4a6rW5 MxkIecxEwVAFwVW8MxAIw28IcxkI7VAKI48JMxAIw28IcVCjz48v1sIEY20_GrWkJr1UJw CFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE 14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2 IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxK x2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI 0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUyE__UUUUU= X-CM-SenderInfo: 51dqw5r0ssqzpdlo2hxwvl0wxkxdhvlgxou0/ Content-Type: text/plain; charset="utf-8" addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal ASCONF-ACK completion path releases the chunk and clears the pointer. However, sctp_asconf_queue_teardown() releases the cached chunk without clearing addip_last_asconf. During peer restart handling, sctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes sctp_asconf_queue_teardown() while the association remains alive and leaves the pointer dangling. A delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(), which accesses the stale chunk and passes it to sctp_process_asconf_ack(), causing a use-after-free and a second release. Clear addip_last_asconf after releasing the cached chunk. This restores the invariant that a non-NULL pointer always references a live chunk. Fixes: a000c01e60e4 ("sctp: stop pending timers and purge queues when peer = restart asoc") Cc: stable@vger.kernel.org Assisted-by: Claude-Code:GLM-5.2 Signed-off-by: Yuxiang Yang --- net/sctp/associola.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/sctp/associola.c b/net/sctp/associola.c index b6ac096..cf3e807 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -1709,6 +1709,8 @@ void sctp_asconf_queue_teardown(struct sctp_associati= on *asoc) sctp_assoc_free_asconf_queue(asoc); =20 /* Free any cached ASCONF chunk. */ - if (asoc->addip_last_asconf) + if (asoc->addip_last_asconf) { sctp_chunk_free(asoc->addip_last_asconf); + asoc->addip_last_asconf =3D NULL; + } } --=20 2.25.1