Subject: [syzbot] [tipc?] general protection fault in tipc_udp_nl_dump_remoteip

From: syzbot <[email-masked]>
Date: Tue, 23 Jan 2024 01:11:21 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    39369c9a6e09 selftests: netdevsim: add a config file
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=1383ebbde80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6d54ca15e81ba55f
dashboard link: https://syzkaller.appspot.com/bug?extid=314c727eef32ba20b65d
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3095adfa6c3d/disk-39369c9a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/105f20ab46b4/vmlinux-39369c9a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2d8afb887806/bzImage-39369c9a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 14603 Comm: syz-executor.3 Not tainted 6.7.0-syzkaller-04690-g39369c9a6e09 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
RIP: 0010:tipc_udp_nl_dump_remoteip+0x3c7/0xa60 net/tipc/udp_media.c:513
Code: 48 c1 ea 03 80 3c 02 00 0f 85 df 05 00 00 48 8b 9b 98 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 7b c8 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 6b 06 00 00 48 8b 03 48 39 d9 4c 8d 70 c8 0f 84
RSP: 0018:ffffc900160171e8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff88804cc52098
RDX: 0000000000000000 RSI: ffffffff8a288b69 RDI: 0000000000000005
RBP: ffff888047885780 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000001000 R12: 0000000000000000
R13: ffffc90016017268 R14: ffff888047885780 R15: ffffffffffffffc8
FS:  00007f35d634c6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1f7a57b038 CR3: 000000002bfe0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 genl_dumpit+0x119/0x220 net/netlink/genetlink.c:1025
 netlink_dump+0x588/0xca0 net/netlink/af_netlink.c:2264
 __netlink_dump_start+0x6d0/0x9c0 net/netlink/af_netlink.c:2370
 genl_family_rcv_msg_dumpit+0x1e1/0x2d0 net/netlink/genetlink.c:1074
 genl_family_rcv_msg net/netlink/genetlink.c:1190 [inline]
 genl_rcv_msg+0x470/0x800 net/netlink/genetlink.c:1208
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2543
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1217
 netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
 netlink_unicast+0x53b/0x810 net/netlink/af_netlink.c:1367
 netlink_sendmsg+0x8b7/0xd70 net/netlink/af_netlink.c:1908
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0xd5/0x180 net/socket.c:745
 ____sys_sendmsg+0x6ac/0x940 net/socket.c:2584
 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2638
 __sys_sendmsg+0x117/0x1e0 net/socket.c:2667
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f35d567cda9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f35d634c0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f35d57abf80 RCX: 00007f35d567cda9
RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
RBP: 00007f35d56c947a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f35d57abf80 R15: 00007ffed090ed98
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:tipc_udp_nl_dump_remoteip+0x3c7/0xa60 net/tipc/udp_media.c:513
Code: 48 c1 ea 03 80 3c 02 00 0f 85 df 05 00 00 48 8b 9b 98 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 7b c8 48 89 da 48 c1 ea 03 <80> 3c 02 00 0f 85 6b 06 00 00 48 8b 03 48 39 d9 4c 8d 70 c8 0f 84
RSP: 0018:ffffc900160171e8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff88804cc52098
RDX: 0000000000000000 RSI: ffffffff8a288b69 RDI: 0000000000000005
RBP: ffff888047885780 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000001000 R12: 0000000000000000
R13: ffffc90016017268 R14: ffff888047885780 R15: ffffffffffffffc8
FS:  00007f35d634c6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc4601dcf78 CR3: 000000002bfe0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 c1 ea 03          	shr    $0x3,%rdx
   4:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   8:	0f 85 df 05 00 00    	jne    0x5ed
   e:	48 8b 9b 98 00 00 00 	mov    0x98(%rbx),%rbx
  15:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1c:	fc ff df
  1f:	4c 8d 7b c8          	lea    -0x38(%rbx),%r15
  23:	48 89 da             	mov    %rbx,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 6b 06 00 00    	jne    0x69f
  34:	48 8b 03             	mov    (%rbx),%rax
  37:	48 39 d9             	cmp    %rbx,%rcx
  3a:	4c 8d 70 c8          	lea    -0x38(%rax),%r14
  3e:	0f                   	.byte 0xf
  3f:	84                   	.byte 0x84

---
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