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 7A15E35C6A8; Fri, 9 Oct 2026 14:24:17 +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=1791555858; cv=none; b=cOF5A5g+Lt59QkJThNeeRRWLIZqsRzJPcrWBJLo0OcqV2qaq9Vc5J/PSwxOXYXMZq9QyrrmCWzQ7obGWOMsB0D+ZvSkMnJfqslugnGvwfitGZrLev/bkqYvbOD78vctuQ9ktV+SX13Hl1frGJ2EOXKWQolB+q7M7SpVrhNbzXvA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791555858; c=relaxed/simple; bh=kAXfjEPBGgwa4eGuMmzzCIiUNeG5rJ/KK03Gqsq1ADw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cLGSbyVTOjxF6NPlnzbN+b6PPVvI0gCVJxKioaJMH3iNgJflyxA0jd7P2wbc0+sC3V2te38O0nsQKRw9cY8cO63hC/rJ8YpWLejPloBCtdlG/3jHf8RIEFwG8SvSY/31xwDWmP0+qfkwj9tudOwrGtxvraO6XqxV56Uv6mMWODc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sdIUZyZG; 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="sdIUZyZG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE97E1F000FF; Fri, 9 Oct 2026 14:24:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791555857; bh=UjTTaeZYgIpK88OpnYyECFGMcHUe6GkVWr12GMb+ZRQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sdIUZyZGfWC+wIptxw+JtNo0JilfgdoG2DQUx0oApuhCFzmOWJ794T3n3Mn60qb0g HNLLJdmm8MMwMU9QmHLJJVG511AWx6934Lt3Q4p+xgRBibeSu3V3uA226z+Z7HytEg EDbKMkYQoy8X+e/aPnJx1s0dGJzUUFy8DugCYuck= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+9408fbe0e6452a12e9ab@syzkaller.appspotmail.com, Eric Dumazet , Xuanqiang Luo , Ido Schimmel , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 129/403] ipv6: sr: use skb_get_hash_net() in seg6_make_flowlabel() Date: Fri, 9 Oct 2026 16:08:10 +0200 Message-ID: <20261009140955.094774195@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261009140952.119038291@linuxfoundation.org> References: <20261009140952.119038291@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 8ec454dcd00ce3375119111c6394964455b36d0d ] Since commit d58e468b1112 ("flow_dissector: implements flow dissector BPF hook") __skb_flow_dissect() needs a net pointer, either from skb->dev, skb->sk, or since commit 3cbf4ffba5ee ("net: plumb network namespace into __skb_flow_dissect") a caller provided pointer. syzbot was able to reach seg6_make_flowlabel() with an skb having neither skb->dev nor skb->sk set: a TIPC UDP bearer sends a discovery message through an IPv4 route using seg6 encap, while net.ipv6.seg6_flowlabel is set to 1. seg6_make_flowlabel() already has a net pointer, use skb_get_hash_net(). WARNING: net/core/flow_dissector.c:1131 at __skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126, CPU#0: syz.0.17/4930 Call trace: __skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126 (P) __skb_get_hash_net+0xe0/0x29c net/core/flow_dissector.c:1903 skb_get_hash include/linux/skbuff.h:1663 [inline] seg6_make_flowlabel+0xcc/0x1ec net/ipv6/seg6_iptunnel.c:132 __seg6_do_srh_encap+0x320/0xbf4 net/ipv6/seg6_iptunnel.c:161 seg6_do_srh+0x4b4/0xa44 net/ipv6/seg6_iptunnel.c:431 seg6_output_core+0x164/0x688 net/ipv6/seg6_iptunnel.c:681 seg6_output+0x44/0x1ac net/ipv6/seg6_iptunnel.c:744 lwtunnel_output+0x3d0/0x664 net/core/lwtunnel.c:356 dst_output include/net/dst.h:470 [inline] ip_local_out+0x110/0x148 net/ipv4/ip_output.c:131 iptunnel_xmit+0x50c/0xd38 net/ipv4/ip_tunnel_core.c:97 udp_tunnel_xmit_skb+0x220/0x348 net/ipv4/udp_tunnel_core.c:187 tipc_udp_xmit+0x75c/0x9c0 net/tipc/udp_media.c:202 tipc_udp_send_msg+0x214/0x374 net/tipc/udp_media.c:274 tipc_bearer_xmit_skb+0x260/0x3b0 net/tipc/bearer.c:576 tipc_enable_bearer net/tipc/bearer.c:366 [inline] __tipc_nl_bearer_enable+0xc90/0xfb0 net/tipc/bearer.c:1048 tipc_nl_bearer_enable+0x2c/0x48 net/tipc/bearer.c:1057 genl_family_rcv_msg_doit+0x1e4/0x2d4 net/netlink/genetlink.c:1114 Fixes: d58e468b1112 ("flow_dissector: implements flow dissector BPF hook") Reported-by: syzbot+9408fbe0e6452a12e9ab@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6abac2eb.3654fce1.1bec97.0000.GAE@google.com/ Signed-off-by: Eric Dumazet Reviewed-by: Xuanqiang Luo Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260928194524.3617299-1-edumazet@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/seg6_iptunnel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index ead677bca4901..d18f73ccf3d4a 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -116,7 +116,7 @@ static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb, u32 hash; if (do_flowlabel > 0) { - hash = skb_get_hash(skb); + hash = skb_get_hash_net(net, skb); hash = rol32(hash, 16); flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK; } else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) { -- 2.53.0