Subject: [syzbot] [mm?] [hardening?] BUG: bad usercopy in raw_getsockopt

From: syzbot <[email-masked]>
Date: Tue, 20 Feb 2024 07:40:22 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    74293ea1c4db net: sysfs: Do not create sysfs for non BQL d..
git tree:       net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13dcc4b4180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=970c7b6c80a096da
dashboard link: https://syzkaller.appspot.com/bug?extid=0c35af046fa98c893c84
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10f38cf8180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=136d41c2180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9bca2f6e074e/disk-74293ea1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/611a08387d8f/vmlinux-74293ea1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/78c388071345/bzImage-74293ea1.xz

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

usercopy: Kernel memory exposure attempt detected from null address (offset 0, size 4)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:102!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 5070 Comm: syz-executor201 Not tainted 6.8.0-rc4-syzkaller-01053-g74293ea1c4db #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:usercopy_abort+0x84/0x90 mm/usercopy.c:102
Code: 49 89 ce 48 c7 c3 40 db b7 8b 48 0f 44 de 48 c7 c7 e0 d9 b7 8b 4c 89 de 48 89 c1 41 52 41 56 53 e8 01 c5 60 09 48 83 c4 18 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003a3fc50 EFLAGS: 00010296
RAX: 0000000000000057 RBX: ffffffff8bb7db20 RCX: b071ef5fcc834300
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffffffffffffff R08: ffffffff81753e6c R09: 1ffff92000747f28
R10: dffffc0000000000 R11: fffff52000747f29 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555555f8e380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001480 CR3: 000000001f404000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __check_object_size+0x601/0xa00
 check_object_size include/linux/thread_info.h:215 [inline]
 check_copy_size include/linux/thread_info.h:251 [inline]
 copy_to_user include/linux/uaccess.h:190 [inline]
 raw_getsockopt+0x37a/0x490 net/can/raw.c:852
 do_sock_getsockopt+0x373/0x850 net/socket.c:2373
 __sys_getsockopt+0x270/0x330 net/socket.c:2402
 __do_sys_getsockopt net/socket.c:2412 [inline]
 __se_sys_getsockopt net/socket.c:2409 [inline]
 __x64_sys_getsockopt+0xb5/0xd0 net/socket.c:2409
 do_syscall_64+0xf9/0x240
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f21bfe782a9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcdfc8f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007ffcdfc8f208 RCX: 00007f21bfe782a9
RDX: 0000000000000008 RSI: 0000000000000065 RDI: 0000000000000003
RBP: 00007f21bfeeb610 R08: 0000000020001480 R09: 00007ffcdfc8f208
R10: 0000000020001440 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffcdfc8f1f8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:usercopy_abort+0x84/0x90 mm/usercopy.c:102
Code: 49 89 ce 48 c7 c3 40 db b7 8b 48 0f 44 de 48 c7 c7 e0 d9 b7 8b 4c 89 de 48 89 c1 41 52 41 56 53 e8 01 c5 60 09 48 83 c4 18 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003a3fc50 EFLAGS: 00010296
RAX: 0000000000000057 RBX: ffffffff8bb7db20 RCX: b071ef5fcc834300
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffffffffffffff R08: ffffffff81753e6c R09: 1ffff92000747f28
R10: dffffc0000000000 R11: fffff52000747f29 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555555f8e380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001480 CR3: 000000001f404000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

---
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