mptcp: clear use_ack and use_map when dropping other suboptions

This patch cleared use_ack and use_map when dropping other suboptions to
fix the following syzkaller BUG:

[   15.223006] BUG: unable to handle page fault for address: 0000000000223b10
[   15.223700] #PF: supervisor read access in kernel mode
[   15.224209] #PF: error_code(0x0000) - not-present page
[   15.224724] PGD b8d5067 P4D b8d5067 PUD c0a5067 PMD 0
[   15.225237] Oops: 0000 [#1] SMP
[   15.225556] CPU: 0 PID: 7747 Comm: syz-executor Not tainted 5.10.0-rc6+ #24
[   15.226281] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[   15.227292] RIP: 0010:skb_release_data+0x89/0x1e0
[   15.227816] Code: 5b 5d 41 5c 41 5d 41 5e 41 5f e9 02 06 8a ff e8 fd 05 8a ff 45 31 ed 80 7d 02 00 4c 8d 65 30 74 55 e8 eb 05 8a ff 49 8b 1c 24 <4c> 8b 7b 08 41 f6 c7 01 0f 85 18 01 00 00 e8 d4 05 8a ff 8b 43 34
[   15.229669] RSP: 0018:ffffc900019c7c08 EFLAGS: 00010293
[   15.230188] RAX: ffff88800daad900 RBX: 0000000000223b08 RCX: 0000000000000006
[   15.230895] RDX: 0000000000000000 RSI: ffffffff818e06c5 RDI: ffff88807f6dc700
[   15.231593] RBP: ffff88807f71a4c0 R08: 0000000000000001 R09: 0000000000000001
[   15.232299] R10: ffffc900019c7c18 R11: 0000000000000000 R12: ffff88807f71a4f0
[   15.233007] R13: 0000000000000000 R14: ffff88807f6dc700 R15: 0000000000000002
[   15.233714] FS:  00007f65d9b5f700(0000) GS:ffff88807c400000(0000) knlGS:0000000000000000
[   15.234509] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.235081] CR2: 0000000000223b10 CR3: 000000000b883000 CR4: 00000000000006f0
[   15.235788] Call Trace:
[   15.236042]  skb_release_all+0x28/0x30
[   15.236419]  __kfree_skb+0x11/0x20
[   15.236768]  tcp_data_queue+0x270/0x1240
[   15.237161]  ? tcp_urg+0x50/0x2a0
[   15.237496]  tcp_rcv_established+0x39a/0x890
[   15.237997]  ? mark_held_locks+0x49/0x70
[   15.238467]  tcp_v4_do_rcv+0xb9/0x270
[   15.238915]  __release_sock+0x8a/0x160
[   15.239365]  release_sock+0x32/0xd0
[   15.239793]  __inet_stream_connect+0x1d2/0x400
[   15.240313]  ? do_wait_intr_irq+0x80/0x80
[   15.240791]  inet_stream_connect+0x36/0x50
[   15.241275]  mptcp_stream_connect+0x69/0x1b0
[   15.241787]  __sys_connect+0x122/0x140
[   15.242236]  ? syscall_enter_from_user_mode+0x17/0x50
[   15.242836]  ? lockdep_hardirqs_on_prepare+0xd4/0x170
[   15.243436]  __x64_sys_connect+0x1a/0x20
[   15.243924]  do_syscall_64+0x33/0x40
[   15.244313]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   15.244821] RIP: 0033:0x7f65d946e469
[   15.245183] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
[   15.247019] RSP: 002b:00007f65d9b5eda8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
[   15.247770] RAX: ffffffffffffffda RBX: 000000000049bf00 RCX: 00007f65d946e469
[   15.248471] RDX: 0000000000000010 RSI: 00000000200000c0 RDI: 0000000000000005
[   15.249205] RBP: 000000000049bf00 R08: 0000000000000000 R09: 0000000000000000
[   15.249908] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049bf0c
[   15.250603] R13: 00007fffe8a25cef R14: 00007f65d9b3f000 R15: 0000000000000003
[   15.251312] Modules linked in:
[   15.251626] CR2: 0000000000223b10
[   15.251965] BUG: kernel NULL pointer dereference, address: 0000000000000048
[   15.252005] ---[ end trace f5c51fe19123c773 ]---
[   15.252822] #PF: supervisor read access in kernel mode
[   15.252823] #PF: error_code(0x0000) - not-present page
[   15.252825] PGD c6c6067 P4D c6c6067 PUD c0d8067
[   15.253294] RIP: 0010:skb_release_data+0x89/0x1e0
[   15.253910] PMD 0
[   15.253914] Oops: 0000 [#2] SMP
[   15.253917] CPU: 1 PID: 7746 Comm: syz-executor Tainted: G      D           5.10.0-rc6+ #24
[   15.253920] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[   15.254435] Code: 5b 5d 41 5c 41 5d 41 5e 41 5f e9 02 06 8a ff e8 fd 05 8a ff 45 31 ed 80 7d 02 00 4c 8d 65 30 74 55 e8 eb 05 8a ff 49 8b 1c 24 <4c> 8b 7b 08 41 f6 c7 01 0f 85 18 01 00 00 e8 d4 05 8a ff 8b 43 34
[   15.254899] RIP: 0010:skb_release_data+0x89/0x1e0
[   15.254902] Code: 5b 5d 41 5c 41 5d 41 5e 41 5f e9 02 06 8a ff e8 fd 05 8a ff 45 31 ed 80 7d 02 00 4c 8d 65 30 74 55 e8 eb 05 8a ff 49 8b 1c 24 <4c> 8b 7b 08 41 f6 c7 01 0f 85 18 01 00 00 e8 d4 05 8a ff 8b 43 34
[   15.254905] RSP: 0018:ffffc900019bfc08 EFLAGS: 00010293
[   15.255376] RSP: 0018:ffffc900019c7c08 EFLAGS: 00010293
[   15.255580]
[   15.255583] RAX: ffff888004a7ac80 RBX: 0000000000000040 RCX: 0000000000000000
[   15.255912]
[   15.256724] RDX: 0000000000000000 RSI: ffffffff818e06c5 RDI: ffff88807f6ddd00
[   15.257620] RAX: ffff88800daad900 RBX: 0000000000223b08 RCX: 0000000000000006
[   15.259817] RBP: ffff88800e9006c0 R08: 0000000000000000 R09: 0000000000000000
[   15.259818] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88800e9006f0
[   15.259820] R13: 0000000000000000 R14: ffff88807f6ddd00 R15: 0000000000000002
[   15.259822] FS:  00007fae4a60a700(0000) GS:ffff88807c500000(0000) knlGS:0000000000000000
[   15.259826] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.260296] RDX: 0000000000000000 RSI: ffffffff818e06c5 RDI: ffff88807f6dc700
[   15.262514] CR2: 0000000000000048 CR3: 000000000b89c000 CR4: 00000000000006e0
[   15.262515] Call Trace:
[   15.262519]  skb_release_all+0x28/0x30
[   15.262523]  __kfree_skb+0x11/0x20
[   15.263054] RBP: ffff88807f71a4c0 R08: 0000000000000001 R09: 0000000000000001
[   15.263680]  tcp_data_queue+0x270/0x1240
[   15.263843] R10: ffffc900019c7c18 R11: 0000000000000000 R12: ffff88807f71a4f0
[   15.264693]  ? tcp_urg+0x50/0x2a0
[   15.264856] R13: 0000000000000000 R14: ffff88807f6dc700 R15: 0000000000000002
[   15.265720]  tcp_rcv_established+0x39a/0x890
[   15.266438] FS:  00007f65d9b5f700(0000) GS:ffff88807c400000(0000) knlGS:0000000000000000
[   15.267283]  ? __schedule+0x3fa/0x880
[   15.267287]  tcp_v4_do_rcv+0xb9/0x270
[   15.267290]  __release_sock+0x8a/0x160
[   15.268049] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.268788]  release_sock+0x32/0xd0
[   15.268791]  __inet_stream_connect+0x1d2/0x400
[   15.268795]  ? do_wait_intr_irq+0x80/0x80
[   15.269593] CR2: 0000000000223b10 CR3: 000000000b883000 CR4: 00000000000006f0
[   15.270246]  inet_stream_connect+0x36/0x50
[   15.270250]  mptcp_stream_connect+0x69/0x1b0
[   15.270253]  __sys_connect+0x122/0x140
[   15.271097] Kernel panic - not syncing: Fatal exception
[   15.271820]  ? syscall_enter_from_user_mode+0x17/0x50
[   15.283542]  ? lockdep_hardirqs_on_prepare+0xd4/0x170
[   15.284275]  __x64_sys_connect+0x1a/0x20
[   15.284853]  do_syscall_64+0x33/0x40
[   15.285369]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   15.286105] RIP: 0033:0x7fae49f19469
[   15.286638] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
[   15.289295] RSP: 002b:00007fae4a609da8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
[   15.290375] RAX: ffffffffffffffda RBX: 000000000049bf00 RCX: 00007fae49f19469
[   15.291403] RDX: 0000000000000010 RSI: 00000000200000c0 RDI: 0000000000000005
[   15.292437] RBP: 000000000049bf00 R08: 0000000000000000 R09: 0000000000000000
[   15.293456] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049bf0c
[   15.294473] R13: 00007fff0004b6bf R14: 00007fae4a5ea000 R15: 0000000000000003
[   15.295492] Modules linked in:
[   15.295944] CR2: 0000000000000048
[   15.296567] Kernel Offset: disabled
[   15.296941] ---[ end Kernel panic - not syncing: Fatal exception ]---
Reported-by: Christoph Paasch <cpaasch@apple.com>
Fixes: 84dfe367 (mptcp: send out dedicated ADD_ADDR packet)
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/ccca4e8f01457a1b495c5d612ed16c5f7a585706.1608010058.git.geliangtang@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/mptcp/options.c

@@ -606,6 +606,8 @@ static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *
 	    skb && skb_is_tcp_pure_ack(skb)) {
 		pr_debug("drop other suboptions");
 		opts->suboptions = 0;
+		opts->ext_copy.use_ack = 0;
+		opts->ext_copy.use_map = 0;
 		remaining += opt_size;
 		drop_other_suboptions = true;
 	}