From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 3F28B40EB9B; Thu, 30 Jul 2026 15:52:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785426768; cv=none; b=hHJHdb+/nmFZYctJyMnu9GUZ7vlUzJS0mulgB5Mihx1RtV3F5uS3EHxnFlYCiHkpnw05zqLA7IVPXFieX7g445l10ujNAlALYzTeS4RFhzxoTza5b9YhuNV35lEjgS64SatWu8gTD6el45YS7R63Xb+Z8SZgYsQsONx3wzf6bcg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785426768; c=relaxed/simple; bh=Hszp5Ihd0uJ5Ai3i6qglhVHrMe1IjuVkVxQNtWRUzS8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YXKLt2TZV6hK4bplLB+fMaYQMx/ZHB0To4o8jduatOzb5t6aS9+6jIS8JRgdnseFF24hG+pwGsntzUPr7tXGqGkuNY7xrhRPkQ0ZbnDbRO9VI/yk2lswqK+ayJSh16hNHihsxcyscDf4bbu3Z/ZiRV8gqC6k/hR1G07C8gFuGn8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=leicmBOM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="leicmBOM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D29D1F000E9; Thu, 30 Jul 2026 15:52:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785426767; bh=zduzq953dsxf6387/qdF0dG5VXs2ugVcGFyzFh6jfOc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=leicmBOM4EpxSOfnZpyoLAz/si0S07oXuIce15kjdt1MaisuXn/Ert1i0wL7cO7/x MI47a3OEciJN0N3M3VWhNcZSJM1sSKR/CClE1DmHKfFaU+yPDup+Ok+N2o9emEZiLP aLAaUGEoY0uEdXrzG0ojgui4CGac6ATxDXd/Ss/Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuan Tan , Xin Liu , Qianyu Luo , Ren Wei , Eyal Birger , Steffen Klassert , Sasha Levin Subject: [PATCH 6.12 535/602] xfrm: nat_keepalive: avoid double free on send error Date: Thu, 30 Jul 2026 16:15:27 +0200 Message-ID: <20260730141447.261741745@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141435.976815864@linuxfoundation.org> References: <20260730141435.976815864@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qianyu Luo [ Upstream commit 226f4a490d1a938fc838d8f8c46a4eca864c0d78 ] nat_keepalive_send() frees the keepalive skb whenever the IPv4 or IPv6 send helper reports an error. That cleanup is only correct before the skb is handed to the output path. Once ip_build_and_send_pkt() or ip6_xmit() takes ownership, the networking stack may already have consumed the skb before returning an error, so freeing it again is unsafe. Handle the pre-handoff failure cases inside nat_keepalive_send_ipv4() and nat_keepalive_send_ipv6(), where the caller still owns the skb, and keep nat_keepalive_send() responsible only for family dispatch and the unsupported-family cleanup path. Fixes: f531d13bdfe3 ("xfrm: support sending NAT keepalives in ESP in UDP states") Cc: stable@vger.kernel.org Reported-by: Yuan Tan Reported-by: Xin Liu Signed-off-by: Qianyu Luo Signed-off-by: Ren Wei Reviewed-by: Eyal Birger Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/xfrm/xfrm_nat_keepalive.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/net/xfrm/xfrm_nat_keepalive.c +++ b/net/xfrm/xfrm_nat_keepalive.c @@ -55,8 +55,10 @@ static int nat_keepalive_send_ipv4(struc ka->encap_sport, sock_net_uid(net, NULL)); rt = ip_route_output_key(net, &fl4); - if (IS_ERR(rt)) + if (IS_ERR(rt)) { + kfree_skb(skb); return PTR_ERR(rt); + } skb_dst_set(skb, &rt->dst); @@ -101,6 +103,7 @@ static int nat_keepalive_send_ipv6(struc dst = ipv6_stub->ipv6_dst_lookup_flow(net, sk, &fl6, NULL); if (IS_ERR(dst)) { local_unlock_nested_bh(&nat_keepalive_sk_ipv6.bh_lock); + kfree_skb(skb); return PTR_ERR(dst); } @@ -118,7 +121,6 @@ static void nat_keepalive_send(struct na sizeof(struct ipv6hdr)) + sizeof(struct udphdr); const u8 nat_ka_payload = 0xFF; - int err = -EAFNOSUPPORT; struct sk_buff *skb; struct udphdr *uh; @@ -140,16 +142,17 @@ static void nat_keepalive_send(struct na switch (ka->family) { case AF_INET: - err = nat_keepalive_send_ipv4(skb, ka); + nat_keepalive_send_ipv4(skb, ka); break; #if IS_ENABLED(CONFIG_IPV6) case AF_INET6: - err = nat_keepalive_send_ipv6(skb, ka, uh); + nat_keepalive_send_ipv6(skb, ka, uh); break; #endif - } - if (err) + default: kfree_skb(skb); + break; + } } struct nat_keepalive_work_ctx {