From: Kui-Feng Lee <sinquersw@gmail.com>
To: Martin KaFai Lau <martin.lau@linux.dev>,
Kui-Feng Lee <thinker.li@gmail.com>
Cc: syzbot <syzbot+1336f3d4b10bcda75b89@syzkaller.appspotmail.com>,
andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
daniel@iogearbox.net, haoluo@google.com,
john.fastabend@gmail.com, jolsa@kernel.org, kpsingh@kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
sdf@google.com, song@kernel.org, syzkaller-bugs@googlegroups.com,
yonghong.song@linux.dev
Subject: Re: [syzbot] [bpf?] general protection fault in btf_is_module
Date: Thu, 25 Jan 2024 10:05:52 -0800 [thread overview]
Message-ID: <8a090e68-d0e8-482f-ba87-a0a91ea59d32@gmail.com> (raw)
In-Reply-To: <d6de99ca-64ca-4b21-958d-686efcd3acd8@linux.dev>
On 1/25/24 10:02, Martin KaFai Lau wrote:
> On 1/25/24 1:50 AM, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: d47b9f68d289 libbpf: Correct bpf_core_read.h comment
>> wrt b..
>> git tree: bpf-next
>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=104b1ef7e80000
>> kernel config:
>> https://syzkaller.appspot.com/x/.config?x=719e6acaf392d56b
>> dashboard link:
>> https://syzkaller.appspot.com/bug?extid=1336f3d4b10bcda75b89
>> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils
>> for Debian) 2.40
>> syz repro:
>> https://syzkaller.appspot.com/x/repro.syz?x=10c1a53be80000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1052cec3e80000
>>
>> Downloadable assets:
>> disk image:
>> https://storage.googleapis.com/syzbot-assets/1a9b4a5622fb/disk-d47b9f68.raw.xz
>> vmlinux:
>> https://storage.googleapis.com/syzbot-assets/dd68baeac4fd/vmlinux-d47b9f68.xz
>> kernel image:
>> https://storage.googleapis.com/syzbot-assets/811ba9dc9ddf/bzImage-d47b9f68.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the
>> commit:
>> Reported-by: syzbot+1336f3d4b10bcda75b89@syzkaller.appspotmail.com
>>
>> general protection fault, probably for non-canonical address
>> 0xdffffc000000001b: 0000 [#1] PREEMPT SMP KASAN
>> KASAN: null-ptr-deref in range [0x00000000000000d8-0x00000000000000df]
>> CPU: 0 PID: 5064 Comm: syz-executor334 Not tainted
>> 6.7.0-syzkaller-12348-gd47b9f68d289 #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine,
>> BIOS Google 11/17/2023
>> RIP: 0010:btf_is_module+0x26/0x80 kernel/bpf/btf.c:7441
>> Code: 00 eb f0 90 66 0f 1f 00 55 53 48 89 fb e8 92 24 de ff 48 8d bb
>> d8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6
>> 04 02 84 c0 74 02 7e 48 0f b6 ab d8 00 00 00 31 ff 89 ee e8
>> RSP: 0018:ffffc900039ff828 EFLAGS: 00010206
>> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81a07f47
>> RDX: 000000000000001b RSI: ffffffff81a9fcfe RDI: 00000000000000d8
>> RBP: ffffc900039ffaf0 R08: 0000000000000001 R09: 0000000000000000
>> R10: 0000000000000004 R11: ffffffff8aa0008b R12: ffffc90000ae6038
>> R13: ffffc90000ae6000 R14: 0000000000000000 R15: 0000000000000000
>> FS: 000055555660b380(0000) GS:ffff8880b9800000(0000)
>> knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000001b6b398 CR3: 000000001aaae000 CR4: 00000000003506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> <TASK>
>> check_struct_ops_btf_id kernel/bpf/verifier.c:20302 [inline]
>
> Kui-Feng, it should be due to the commit e3f87fdfed7b ("bpf: hold module
> refcnt in bpf_struct_ops map creation and prog verification."). I think
> it needs a NULL check on the return value from bpf_get_btf_vmlinux().
>
> Please take a look. Thanks.
Sure!
>
>
>> check_attach_btf_id kernel/bpf/verifier.c:20730 [inline]
>> bpf_check+0x6cfe/0x9df0 kernel/bpf/verifier.c:20898
>> bpf_prog_load+0x14dc/0x2310 kernel/bpf/syscall.c:2769
>> __sys_bpf+0xbf7/0x4a00 kernel/bpf/syscall.c:5463
>> __do_sys_bpf kernel/bpf/syscall.c:5567 [inline]
>> __se_sys_bpf kernel/bpf/syscall.c:5565 [inline]
>> __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5565
>> 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: 0033:0x7f4dbbe514a9
>> 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:00007ffe76acbe18 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
>> RAX: ffffffffffffffda RBX: 00007ffe76acbff8 RCX: 00007f4dbbe514a9
>> RDX: 00000000000000a0 RSI: 00000000200009c0 RDI: 0000000000000005
>> RBP: 00007f4dbbec4610 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
>> R13: 00007ffe76acbfe8 R14: 0000000000000001 R15: 0000000000000001
>> </TASK>
>> Modules linked in:
>> ---[ end trace 0000000000000000 ]---
>> RIP: 0010:btf_is_module+0x26/0x80 kernel/bpf/btf.c:7441
>> Code: 00 eb f0 90 66 0f 1f 00 55 53 48 89 fb e8 92 24 de ff 48 8d bb
>> d8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6
>> 04 02 84 c0 74 02 7e 48 0f b6 ab d8 00 00 00 31 ff 89 ee e8
>> RSP: 0018:ffffc900039ff828 EFLAGS: 00010206
>> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81a07f47
>> RDX: 000000000000001b RSI: ffffffff81a9fcfe RDI: 00000000000000d8
>> RBP: ffffc900039ffaf0 R08: 0000000000000001 R09: 0000000000000000
>> R10: 0000000000000004 R11: ffffffff8aa0008b R12: ffffc90000ae6038
>> R13: ffffc90000ae6000 R14: 0000000000000000 R15: 0000000000000000
>> FS: 000055555660b380(0000) GS:ffff8880b9800000(0000)
>> knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000001b6b398 CR3: 000000001aaae000 CR4: 00000000003506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> ----------------
>> Code disassembly (best guess):
>> 0: 00 eb add %ch,%bl
>> 2: f0 90 lock nop
>> 4: 66 0f 1f 00 nopw (%rax)
>> 8: 55 push %rbp
>> 9: 53 push %rbx
>> a: 48 89 fb mov %rdi,%rbx
>> d: e8 92 24 de ff call 0xffde24a4
>> 12: 48 8d bb d8 00 00 00 lea 0xd8(%rbx),%rdi
>> 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
>> 20: fc ff df
>> 23: 48 89 fa mov %rdi,%rdx
>> 26: 48 c1 ea 03 shr $0x3,%rdx
>> * 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <--
>> trapping instruction
>> 2e: 84 c0 test %al,%al
>> 30: 74 02 je 0x34
>> 32: 7e 48 jle 0x7c
>> 34: 0f b6 ab d8 00 00 00 movzbl 0xd8(%rbx),%ebp
>> 3b: 31 ff xor %edi,%edi
>> 3d: 89 ee mov %ebp,%esi
>> 3f: e8 .byte 0xe8
>>
>>
>> ---
>> This report is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at syzkaller@googlegroups.com.
>>
>> syzbot will keep track of this issue. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>>
>> If the report is already addressed, let syzbot know by replying with:
>> #syz fix: exact-commit-title
>>
>> If you want syzbot to run the reproducer, reply with:
>> #syz test: git://repo/address.git branch-or-commit-hash
>> If you attach or paste a git patch, syzbot will apply it before testing.
>>
>> If you want to overwrite report's subsystems, reply with:
>> #syz set subsystems: new-subsystem
>> (See the list of subsystem names on the web dashboard)
>>
>> If the report is a duplicate of another one, reply with:
>> #syz dup: exact-subject-of-another-report
>>
>> If you want to undo deduplication, reply with:
>> #syz undup
>
>
prev parent reply other threads:[~2024-01-25 18:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-25 9:50 [syzbot] [bpf?] general protection fault in btf_is_module syzbot
2024-01-25 18:02 ` Martin KaFai Lau
2024-01-25 18:05 ` Kui-Feng Lee [this message]
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