From nobody Wed Jun 17 04:17:32 2026 Received: from zg8tmtyylji0my4xnjqumte4.icoremail.net (zg8tmtyylji0my4xnjqumte4.icoremail.net [162.243.164.118]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9017A1E5724; Wed, 22 Apr 2026 10:58:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.243.164.118 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776855521; cv=none; b=GeVBsXolvHPUtDh2nYhsW53kQMNSOCP3LMjCyEYF6pb4MK4F+rjJBMcPhsNZXz7evcAXgXPkOTELzVN6SRWvnJvDGM3DzK12kPuxaIriHXaF+EaQ/rQqAY6UxkTdCB/AA+0qOQNRUhvsyOEnTMefzZ9SbjbZVlYSBI/SzYBOtVE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776855521; c=relaxed/simple; bh=TTcsVqyO+cRvqywCmON3S9sMBf2mjoLY9CJLaCXlzM0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=E0br4zTHTBt4ID2BB5ppPHioo+moVFXZaOJ6T6FYUhtQ98Y2fegjEuY0FuUIVhkVeBI0RbFYb2hC3h+osoDETokPTn7fFTdrP9m1Hqlrba/r6StpySawrMYj02JGrS+78/q224KEHGeSZ6J70lnBy6GI49BnuBPIFcAoTKeMlOA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=stu.xidian.edu.cn; spf=pass smtp.mailfrom=stu.xidian.edu.cn; dkim=fail (0-bit key) header.d=stu.xidian.edu.cn header.i=@stu.xidian.edu.cn header.b=3LEM8CEX reason="key not found in DNS"; arc=none smtp.client-ip=162.243.164.118 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=stu.xidian.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=stu.xidian.edu.cn Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=stu.xidian.edu.cn header.i=@stu.xidian.edu.cn header.b="3LEM8CEX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stu.xidian.edu.cn; s=dkim; h=Received:From:To:Cc:Subject:Date: Message-Id:MIME-Version:Content-Transfer-Encoding; bh=AAAU2GMGPr G1zZgq/1GH5AH+uMaADrCdJyeoKBuVvpc=; b=3LEM8CEX7eLAr6z97RMBLHwYm0 ib+ZC7IDSXJKR60LlXKVusSu1YQWlkafM75br5ylG7sUVguXsQiD2fthunltI2K5 JIVsN07kao1siFB8G06UWNQBbLRZfOQpAIbGIZtpTHifv/SxM4Y90czCNqwK8r9J aDUxnfooA6pj5+0F4= Received: from wmy.localdomain (unknown [113.200.174.100]) by hzbj-edu-front-3.icoremail.net (Coremail) with SMTP id BbQMCkCmxjC8qehpyyKzAQ--.8112S2; Wed, 22 Apr 2026 18:58:16 +0800 (CST) From: Mingyu Wang <25181214217@stu.xidian.edu.cn> To: willemdebruijn.kernel@gmail.com, davem@davemloft.net, dsahern@kernel.org, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Mingyu Wang <25181214217@stu.xidian.edu.cn> Subject: [PATCH] ipv6: udp: fix memory leak in udpv6_sendmsg error path Date: Wed, 22 Apr 2026 18:58:02 +0800 Message-Id: <20260422105802.486216-1-25181214217@stu.xidian.edu.cn> X-Mailer: git-send-email 2.34.1 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: BbQMCkCmxjC8qehpyyKzAQ--.8112S2 X-Coremail-Antispam: 1UD129KBjvJXoW7CrWUKFW7Jr15Jw18CFykXwb_yoW8Gr1kpw 4xKw4Yyr4DJrnxKFyxJ3WxZr15uayFqFyY9F13uas2krnxGF1xJr40vF4jqa1rAFs5uw45 ZayvqFW5uFyDCw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBa14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1j6r1xM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gr 1j6F4UJwAac4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40E FcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr 0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8v x2IErcIFxwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCF04k20x vY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I 3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIx AIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIxAI cVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2js IEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUQvtAUUUUU= X-CM-SenderInfo: qsvrmiqsrujiux6v33wo0lvxldqovvfxof0/1tbiAgULEWnnlGSYMwAAsI Content-Type: text/plain; charset="utf-8" During fuzzing with failslab enabled, a memory leak was observed in the IPv6 UDP send path. When sending via the lockless fast path (!corkreq), udpv6_sendmsg() calls ip6_make_skb() and assumes that the routing entry (dst_entry) reference has been stolen by the callee. However, if ip6_make_skb() fails early (e.g., due to an ENOMEM from memory allocation failure), it returns an error pointer without consuming the dst reference. Since udpv6_sendmsg() unconditionally jumps to the 'out_no_dst' label, the unconsumed dst_entry is never released, resulting in a memory leak. Fix this by explicitly calling dst_release(dst) when ip6_make_skb() returns an error. Signed-off-by: Mingyu Wang <25181214217@stu.xidian.edu.cn> --- net/ipv6/udp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 15e032194ecc..b83ecfd729af 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1706,8 +1706,11 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *ms= g, size_t len) dst_rt6_info(dst), msg->msg_flags, &cork); err =3D PTR_ERR(skb); - if (!IS_ERR_OR_NULL(skb)) + if (!IS_ERR_OR_NULL(skb)) { err =3D udp_v6_send_skb(skb, fl6, &cork.base); + } else { + dst_release(dst); + } /* ip6_make_skb steals dst reference */ goto out_no_dst; } --=20 2.34.1