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 EC5BA43CE6B; Mon, 17 Aug 2026 14:53:41 +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=1786978424; cv=none; b=Dr0u1ezeCk5ltBiTSmAVpV0ENIzVYuGLndPmT3Q5jernLmhcO3XAc7vx4z2uE5em+cZd5Z5SXrQrNom/c38CF0QBsKSbhD/oaY6Q++OGgpbt3XbvFRbdmBKp7TioIgyJqsA2NElYmEJzsoSoYrxdQyHBuj5nGJ3/XDEx4y1mqyk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786978424; c=relaxed/simple; bh=Ha0U/bGHBWNh8rrl+yY80SGrKn+G6ocf6Ghdq+4F2RU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G/+6Qa53v8Yzr6CMw1tXXjwD84GrTBc1JRzdxcX1/0P4m5ddRfO85rRKu+E/unTNVThd0YgnOXC/pDNrtS9tXBDafr8YrJmy8lgRHwjlsAtseWKQOmlyqtsLQsXUW4u0b6In9Q7++UDfV0TwbTWNjOTPV6YC4Il9FguU4DEHxFw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=a4qDjTKS; 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="a4qDjTKS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A2931F000E9; Mon, 17 Aug 2026 14:53:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786978421; bh=uZO1AE396YXDqtBCdfQrfoHeLxeh0UFOuil/1p5qmNc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=a4qDjTKS0QFWdeDjpMjXdZnFM6xxLMkffBqoe2hDpyhjBPtqzaIea8Dqt3pwscQFZ GnoxBA7MKFZ0koW3YNJwEFm54JeRm3FBb12zd0FuI6BhmZQGP8GvXp2y2qwZVDKnp0 XA8DmJ8V0/WfAMSemJNL3BKXe5rWJGx41N/s/eOQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xuanqiang Luo , Antoine Tenart , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 030/156] udp: fix potential use-after-free in tunnel segmentation Date: Mon, 17 Aug 2026 15:32:44 +0200 Message-ID: <20260817132535.799651807@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132534.666299318@linuxfoundation.org> References: <20260817132534.666299318@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xuanqiang Luo [ Upstream commit d0f86fb36eb260abd10007b62c9dcc1028e03e61 ] __skb_udp_tunnel_segment() gets the UDP header before ensuring the tunnel header is in the skb head. If the pull reallocates skb->head, the saved UDP header pointer is no longer valid. Get the UDP header after the pull to avoid a potential use-after-free. Fixes: dbef491ebe7f ("udp: Use uh->len instead of skb->len to compute checksum in segmentation") Signed-off-by: Xuanqiang Luo Reviewed-by: Antoine Tenart Link: https://patch.msgid.link/20260730093554.68127-1-xuanqiang.luo@linux.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/udp_offload.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 84ae2759ff195..b9b21e5af1a7f 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -22,17 +22,19 @@ static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); bool remcsum, need_csum, offload_csum, gso_partial; struct sk_buff *segs = ERR_PTR(-EINVAL); - struct udphdr *uh = udp_hdr(skb); u16 mac_offset = skb->mac_header; __be16 protocol = skb->protocol; u16 mac_len = skb->mac_len; int udp_offset, outer_hlen; + struct udphdr *uh; __wsum partial; bool need_ipsec; if (unlikely(!pskb_may_pull(skb, tnl_hlen))) goto out; + uh = udp_hdr(skb); + /* Adjust partial header checksum to negate old length. * We cannot rely on the value contained in uh->len as it is * possible that the actual value exceeds the boundaries of the -- 2.53.0