From: Stanislav Fomichev <stfomichev@gmail.com>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
syzbot+c46409299c70a221415e@syzkaller.appspotmail.com,
Matteo Croce <mcroce@redhat.com>,
Stanislav Fomichev <sdf@fomichev.me>
Subject: Re: [PATCH net] bonding: provide a net pointer to __skb_flow_dissect()
Date: Tue, 20 Jan 2026 12:01:20 -0800 [thread overview]
Message-ID: <aW_fEILfgvum4B1c@mini-arch> (raw)
In-Reply-To: <20260120161744.1893263-1-edumazet@google.com>
On 01/20, Eric Dumazet wrote:
> After 3cbf4ffba5ee ("net: plumb network namespace into __skb_flow_dissect")
> we have to provide a net pointer to __skb_flow_dissect(),
> either via skb->dev, skb->sk, or a user provided pointer.
>
> In the following case, syzbot was able to cook a bare skb.
>
> WARNING: net/core/flow_dissector.c:1131 at __skb_flow_dissect+0xb57/0x68b0 net/core/flow_dissector.c:1131, CPU#1: syz.2.1418/11053
> Call Trace:
> <TASK>
> bond_flow_dissect drivers/net/bonding/bond_main.c:4093 [inline]
> __bond_xmit_hash+0x2d7/0xba0 drivers/net/bonding/bond_main.c:4157
> bond_xmit_hash_xdp drivers/net/bonding/bond_main.c:4208 [inline]
> bond_xdp_xmit_3ad_xor_slave_get drivers/net/bonding/bond_main.c:5139 [inline]
> bond_xdp_get_xmit_slave+0x1fd/0x710 drivers/net/bonding/bond_main.c:5515
> xdp_master_redirect+0x13f/0x2c0 net/core/filter.c:4388
> bpf_prog_run_xdp include/net/xdp.h:700 [inline]
> bpf_test_run+0x6b2/0x7d0 net/bpf/test_run.c:421
> bpf_prog_test_run_xdp+0x795/0x10e0 net/bpf/test_run.c:1390
> bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4703
> __sys_bpf+0x562/0x860 kernel/bpf/syscall.c:6182
> __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
> __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
> __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6272
> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
>
> Fixes: 58deb77cc52d ("bonding: balance ICMP echoes in layer3+4 mode")
> Reported-by: syzbot+c46409299c70a221415e@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/netdev/696faa23.050a0220.4cb9c.001f.GAE@google.com/T/#u
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Matteo Croce <mcroce@redhat.com>
> Cc: Stanislav Fomichev <sdf@fomichev.me>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
next prev parent reply other threads:[~2026-01-20 20:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 16:17 [PATCH net] bonding: provide a net pointer to __skb_flow_dissect() Eric Dumazet
2026-01-20 20:01 ` Stanislav Fomichev [this message]
2026-01-22 3:30 ` patchwork-bot+netdevbpf
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