6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yue Haibing yuehaibing@huawei.com
[ Upstream commit 22fc46cea91df3dce140a7dc6847c6fcf0354505 ]
atmarpd_dev_ops does not implement the send method, which may cause crash as bellow.
BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: Oops: 0010 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0018:ffffc9000d3cf778 EFLAGS: 00010246 RAX: 1ffffffff1910dd1 RBX: 00000000000000c0 RCX: dffffc0000000000 RDX: ffffc9000dc82000 RSI: ffff88803e4c4640 RDI: ffff888052cd0000 RBP: ffffc9000d3cf8d0 R08: ffff888052c9143f R09: 1ffff1100a592287 R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff92001a79f00 R13: ffff888052cd0000 R14: ffff88803e4c4640 R15: ffffffff8c886e88 FS: 00007fbc762566c0(0000) GS:ffff88808d6c2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000041f1b000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> vcc_sendmsg+0xa10/0xc50 net/atm/common.c:644 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 ____sys_sendmsg+0x52d/0x830 net/socket.c:2566 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620 __sys_sendmmsg+0x227/0x430 net/socket.c:2709 __do_sys_sendmmsg net/socket.c:2736 [inline] __se_sys_sendmmsg net/socket.c:2733 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2733 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+e34e5e6b5eddb0014def@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/682f82d5.a70a0220.1765ec.0143.GAE@google.com/T Signed-off-by: Yue Haibing yuehaibing@huawei.com Reviewed-by: Kuniyuki Iwashima kuniyu@google.com Link: https://patch.msgid.link/20250705085228.329202-1-yuehaibing@huawei.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/atm/clip.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/net/atm/clip.c b/net/atm/clip.c index 0baade6febed8..ebba0d6ae3248 100644 --- a/net/atm/clip.c +++ b/net/atm/clip.c @@ -632,8 +632,16 @@ static void atmarpd_close(struct atm_vcc *vcc) module_put(THIS_MODULE); }
+static int atmarpd_send(struct atm_vcc *vcc, struct sk_buff *skb) +{ + atm_return_tx(vcc, skb); + dev_kfree_skb_any(skb); + return 0; +} + static const struct atmdev_ops atmarpd_dev_ops = { - .close = atmarpd_close + .close = atmarpd_close, + .send = atmarpd_send };