[PATCH 6.18 137/227] bonding: provide a net pointer to __skb_flow_dissect()

Greg Kroah-Hartman
2026-01-28T15:59:33Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 5f9b329096596b7e53e07d041d7fca4cbe1be752 ]

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>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20260120161744.1893263-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/bonding/bond_main.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index c66cb2d43dcf1..595fda2444b1f 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4187,8 +4187,9 @@ static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb, const v
case BOND_XMIT_POLICY_ENCAP23:
case BOND_XMIT_POLICY_ENCAP34:
memset(fk, 0, sizeof(*fk));
- return __skb_flow_dissect(NULL, skb, &flow_keys_bonding,
- fk, data, l2_proto, nhoff, hlen, 0);
+ return __skb_flow_dissect(dev_net(bond->dev), skb,
+ &flow_keys_bonding, fk, data,
+ l2_proto, nhoff, hlen, 0);
default:
break;
}
--
2.51.0