Hello,
syzbot found the following issue on:
HEAD commit: 7e18e42e4b28 Linux 6.0-rc4
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1551da55080000
kernel config: https://syzkaller.appspot.com/x/.config?x=f4d613baa509128c
dashboard link: https://syzkaller.appspot.com/bug?extid=8b2a08dfbd25fd933d75
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1798cab7080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ccbdc5080000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/da260c675b46/disk-7e18e42e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/58f7bbbaa6ff/vmlinux-7e18e42e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
------------[ cut here ]------------
verifier log line truncated - local buffer too short
WARNING: CPU: 1 PID: 3604 at kernel/bpf/verifier.c:300 bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
Modules linked in:
CPU: 1 PID: 3604 Comm: syz-executor146 Not tainted 6.0.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
RIP: 0010:bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
Code: f5 95 3d 0c 31 ff 89 ee e8 06 07 f0 ff 40 84 ed 75 1a e8 7c 0a f0 ff 48 c7 c7 c0 e7 f3 89 c6 05 d4 95 3d 0c 01 e8 fb 4c ae 07 <0f> 0b e8 62 0a f0 ff 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1
RSP: 0018:ffffc900039bf8a0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff888017a19210 RCX: 0000000000000000
RDX: ffff888021fb1d80 RSI: ffffffff8161f408 RDI: fffff52000737f06
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffffffff89f5aba0
R13: 00000000000003ff R14: ffff888017a19214 R15: ffff888012705800
FS: 0000555555cba300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020100000 CR3: 000000001bf9e000 CR4: 0000000000350ee0
Call Trace:
<TASK>
__btf_verifier_log+0xbb/0xf0 kernel/bpf/btf.c:1375
__btf_verifier_log_type+0x451/0x8f0 kernel/bpf/btf.c:1413
btf_func_proto_check_meta+0x117/0x160 kernel/bpf/btf.c:3905
btf_check_meta kernel/bpf/btf.c:4588 [inline]
btf_check_all_metas+0x3c1/0xa70 kernel/bpf/btf.c:4612
btf_parse_type_sec kernel/bpf/btf.c:4748 [inline]
btf_parse kernel/bpf/btf.c:5031 [inline]
btf_new_fd+0x939/0x1e70 kernel/bpf/btf.c:6710
bpf_btf_load kernel/bpf/syscall.c:4314 [inline]
__sys_bpf+0x13bd/0x6130 kernel/bpf/syscall.c:4998
__do_sys_bpf kernel/bpf/syscall.c:5057 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5055 [inline]
__x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5055
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb092221c29
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff5b0a6878 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb092221c29
RDX: 0000000000000020 RSI: 0000000020000240 RDI: 0000000000000012
RBP: 00007fb0921e5dd0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb0921e5e60
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
---
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 [email protected].
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
On 09/08, syzbot wrote:
> Hello,
> syzbot found the following issue on:
> HEAD commit: 7e18e42e4b28 Linux 6.0-rc4
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1551da55080000
> kernel config: https://syzkaller.appspot.com/x/.config?x=f4d613baa509128c
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=8b2a08dfbd25fd933d75
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU
> Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1798cab7080000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ccbdc5080000
> Downloadable assets:
> disk image:
> https://storage.googleapis.com/syzbot-assets/da260c675b46/disk-7e18e42e.raw.xz
> vmlinux:
> https://storage.googleapis.com/syzbot-assets/58f7bbbaa6ff/vmlinux-7e18e42e.xz
> IMPORTANT: if you fix the issue, please add the following tag to the
> commit:
> Reported-by: [email protected]
> ------------[ cut here ]------------
> verifier log line truncated - local buffer too short
> WARNING: CPU: 1 PID: 3604 at kernel/bpf/verifier.c:300
> bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
> Modules linked in:
> CPU: 1 PID: 3604 Comm: syz-executor146 Not tainted 6.0.0-rc4-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 08/26/2022
> RIP: 0010:bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
> Code: f5 95 3d 0c 31 ff 89 ee e8 06 07 f0 ff 40 84 ed 75 1a e8 7c 0a f0
> ff 48 c7 c7 c0 e7 f3 89 c6 05 d4 95 3d 0c 01 e8 fb 4c ae 07 <0f> 0b e8 62
> 0a f0 ff 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1
> RSP: 0018:ffffc900039bf8a0 EFLAGS: 00010282
> RAX: 0000000000000000 RBX: ffff888017a19210 RCX: 0000000000000000
> RDX: ffff888021fb1d80 RSI: ffffffff8161f408 RDI: fffff52000737f06
> RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
> R10: 0000000080000000 R11: 0000000000000000 R12: ffffffff89f5aba0
> R13: 00000000000003ff R14: ffff888017a19214 R15: ffff888012705800
> FS: 0000555555cba300(0000) GS:ffff8880b9b00000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020100000 CR3: 000000001bf9e000 CR4: 0000000000350ee0
> Call Trace:
> <TASK>
> __btf_verifier_log+0xbb/0xf0 kernel/bpf/btf.c:1375
> __btf_verifier_log_type+0x451/0x8f0 kernel/bpf/btf.c:1413
> btf_func_proto_check_meta+0x117/0x160 kernel/bpf/btf.c:3905
> btf_check_meta kernel/bpf/btf.c:4588 [inline]
> btf_check_all_metas+0x3c1/0xa70 kernel/bpf/btf.c:4612
> btf_parse_type_sec kernel/bpf/btf.c:4748 [inline]
Benjamin, this seems to be coming from BTF loading. Could this be caused
by some of your recent activity with things like:
commit f9b348185f4d684cc19e6bd9b87904823d5aa5ed
Author: Benjamin Tissoires <[email protected]>
Date: Tue Sep 6 17:13:01 2022 +0200
bpf/btf: bump BTF_KFUNC_SET_MAX_CNT
?
I haven't looked too deep, maybe you can give it a shot? There is
reproducer; should be relatively easy to verify. Thx.
> btf_parse kernel/bpf/btf.c:5031 [inline]
> btf_new_fd+0x939/0x1e70 kernel/bpf/btf.c:6710
> bpf_btf_load kernel/bpf/syscall.c:4314 [inline]
> __sys_bpf+0x13bd/0x6130 kernel/bpf/syscall.c:4998
> __do_sys_bpf kernel/bpf/syscall.c:5057 [inline]
> __se_sys_bpf kernel/bpf/syscall.c:5055 [inline]
> __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5055
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7fb092221c29
> Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fff5b0a6878 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb092221c29
> RDX: 0000000000000020 RSI: 0000000020000240 RDI: 0000000000000012
> RBP: 00007fb0921e5dd0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb0921e5e60
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> </TASK>
> ---
> 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 [email protected].
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
On Fri, Sep 9, 2022 at 6:37 PM <[email protected]> wrote:
>
> On 09/08, syzbot wrote:
> > Hello,
>
> > syzbot found the following issue on:
>
> > HEAD commit: 7e18e42e4b28 Linux 6.0-rc4
> > git tree: upstream
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1551da55080000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=f4d613baa509128c
> > dashboard link:
> > https://syzkaller.appspot.com/bug?extid=8b2a08dfbd25fd933d75
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU
> > Binutils for Debian) 2.35.2
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1798cab7080000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ccbdc5080000
>
> > Downloadable assets:
> > disk image:
> > https://storage.googleapis.com/syzbot-assets/da260c675b46/disk-7e18e42e.raw.xz
> > vmlinux:
> > https://storage.googleapis.com/syzbot-assets/58f7bbbaa6ff/vmlinux-7e18e42e.xz
>
> > IMPORTANT: if you fix the issue, please add the following tag to the
> > commit:
> > Reported-by: [email protected]
>
> > ------------[ cut here ]------------
> > verifier log line truncated - local buffer too short
> > WARNING: CPU: 1 PID: 3604 at kernel/bpf/verifier.c:300
> > bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
> > Modules linked in:
> > CPU: 1 PID: 3604 Comm: syz-executor146 Not tainted 6.0.0-rc4-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > Google 08/26/2022
> > RIP: 0010:bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
> > Code: f5 95 3d 0c 31 ff 89 ee e8 06 07 f0 ff 40 84 ed 75 1a e8 7c 0a f0
> > ff 48 c7 c7 c0 e7 f3 89 c6 05 d4 95 3d 0c 01 e8 fb 4c ae 07 <0f> 0b e8 62
> > 0a f0 ff 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1
> > RSP: 0018:ffffc900039bf8a0 EFLAGS: 00010282
> > RAX: 0000000000000000 RBX: ffff888017a19210 RCX: 0000000000000000
> > RDX: ffff888021fb1d80 RSI: ffffffff8161f408 RDI: fffff52000737f06
> > RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
> > R10: 0000000080000000 R11: 0000000000000000 R12: ffffffff89f5aba0
> > R13: 00000000000003ff R14: ffff888017a19214 R15: ffff888012705800
> > FS: 0000555555cba300(0000) GS:ffff8880b9b00000(0000)
> > knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 0000000020100000 CR3: 000000001bf9e000 CR4: 0000000000350ee0
> > Call Trace:
> > <TASK>
> > __btf_verifier_log+0xbb/0xf0 kernel/bpf/btf.c:1375
> > __btf_verifier_log_type+0x451/0x8f0 kernel/bpf/btf.c:1413
> > btf_func_proto_check_meta+0x117/0x160 kernel/bpf/btf.c:3905
> > btf_check_meta kernel/bpf/btf.c:4588 [inline]
> > btf_check_all_metas+0x3c1/0xa70 kernel/bpf/btf.c:4612
> > btf_parse_type_sec kernel/bpf/btf.c:4748 [inline]
>
> Benjamin, this seems to be coming from BTF loading. Could this be caused
> by some of your recent activity with things like:
>
> commit f9b348185f4d684cc19e6bd9b87904823d5aa5ed
> Author: Benjamin Tissoires <[email protected]>
> Date: Tue Sep 6 17:13:01 2022 +0200
>
> bpf/btf: bump BTF_KFUNC_SET_MAX_CNT
>
> ?
I doubt this commit is the culprit for 2 reasons:
- BTF_KFUNC_SET_MAX_CNT just sets the size of an internal memory chunk
where we store kfunc definitions. I don't really see how this could be
linked to a verifier log being full
- this commit has been applied on Sep 7, and the first crash in the
dashboard was from Sep 5. So unless the dates are wrong, I don't think
this commit creates the crash.
Unfortunately, I am really new into the bpf/btf world, and I have no
ideas on what could be the cause of that crash. We probably need a
bisect, but I'll be out next week at plumbers, so can't really work on
that now.
Cheers,
Benjamin
>
> I haven't looked too deep, maybe you can give it a shot? There is
> reproducer; should be relatively easy to verify. Thx.
>
>
> > btf_parse kernel/bpf/btf.c:5031 [inline]
> > btf_new_fd+0x939/0x1e70 kernel/bpf/btf.c:6710
> > bpf_btf_load kernel/bpf/syscall.c:4314 [inline]
> > __sys_bpf+0x13bd/0x6130 kernel/bpf/syscall.c:4998
> > __do_sys_bpf kernel/bpf/syscall.c:5057 [inline]
> > __se_sys_bpf kernel/bpf/syscall.c:5055 [inline]
> > __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5055
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > RIP: 0033:0x7fb092221c29
> > Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007fff5b0a6878 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb092221c29
> > RDX: 0000000000000020 RSI: 0000000020000240 RDI: 0000000000000012
> > RBP: 00007fb0921e5dd0 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb0921e5e60
> > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> > </TASK>
>
>
> > ---
> > 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 [email protected].
>
> > syzbot will keep track of this issue. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > syzbot can test patches for this issue, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
>
On 09/09, Benjamin Tissoires wrote:
> On Fri, Sep 9, 2022 at 6:37 PM <[email protected]> wrote:
> >
> > On 09/08, syzbot wrote:
> > > Hello,
> >
> > > syzbot found the following issue on:
> >
> > > HEAD commit: 7e18e42e4b28 Linux 6.0-rc4
> > > git tree: upstream
> > > console+strace:
> https://syzkaller.appspot.com/x/log.txt?x=1551da55080000
> > > kernel config:
> https://syzkaller.appspot.com/x/.config?x=f4d613baa509128c
> > > dashboard link:
> > > https://syzkaller.appspot.com/bug?extid=8b2a08dfbd25fd933d75
> > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU
> > > Binutils for Debian) 2.35.2
> > > syz repro:
> https://syzkaller.appspot.com/x/repro.syz?x=1798cab7080000
> > > C reproducer:
> https://syzkaller.appspot.com/x/repro.c?x=16ccbdc5080000
> >
> > > Downloadable assets:
> > > disk image:
> > >
> https://storage.googleapis.com/syzbot-assets/da260c675b46/disk-7e18e42e.raw.xz
> > > vmlinux:
> > >
> https://storage.googleapis.com/syzbot-assets/58f7bbbaa6ff/vmlinux-7e18e42e.xz
> >
> > > IMPORTANT: if you fix the issue, please add the following tag to the
> > > commit:
> > > Reported-by: [email protected]
> >
> > > ------------[ cut here ]------------
> > > verifier log line truncated - local buffer too short
> > > WARNING: CPU: 1 PID: 3604 at kernel/bpf/verifier.c:300
> > > bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
> > > Modules linked in:
> > > CPU: 1 PID: 3604 Comm: syz-executor146 Not tainted
> 6.0.0-rc4-syzkaller #0
> > > Hardware name: Google Google Compute Engine/Google Compute Engine,
> BIOS
> > > Google 08/26/2022
> > > RIP: 0010:bpf_verifier_vlog+0x267/0x3c0 kernel/bpf/verifier.c:300
> > > Code: f5 95 3d 0c 31 ff 89 ee e8 06 07 f0 ff 40 84 ed 75 1a e8 7c 0a
> f0
> > > ff 48 c7 c7 c0 e7 f3 89 c6 05 d4 95 3d 0c 01 e8 fb 4c ae 07 <0f> 0b
> e8 62
> > > 0a f0 ff 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1
> > > RSP: 0018:ffffc900039bf8a0 EFLAGS: 00010282
> > > RAX: 0000000000000000 RBX: ffff888017a19210 RCX: 0000000000000000
> > > RDX: ffff888021fb1d80 RSI: ffffffff8161f408 RDI: fffff52000737f06
> > > RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
> > > R10: 0000000080000000 R11: 0000000000000000 R12: ffffffff89f5aba0
> > > R13: 00000000000003ff R14: ffff888017a19214 R15: ffff888012705800
> > > FS: 0000555555cba300(0000) GS:ffff8880b9b00000(0000)
> > > knlGS:0000000000000000
> > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 0000000020100000 CR3: 000000001bf9e000 CR4: 0000000000350ee0
> > > Call Trace:
> > > <TASK>
> > > __btf_verifier_log+0xbb/0xf0 kernel/bpf/btf.c:1375
> > > __btf_verifier_log_type+0x451/0x8f0 kernel/bpf/btf.c:1413
> > > btf_func_proto_check_meta+0x117/0x160 kernel/bpf/btf.c:3905
> > > btf_check_meta kernel/bpf/btf.c:4588 [inline]
> > > btf_check_all_metas+0x3c1/0xa70 kernel/bpf/btf.c:4612
> > > btf_parse_type_sec kernel/bpf/btf.c:4748 [inline]
> >
> > Benjamin, this seems to be coming from BTF loading. Could this be caused
> > by some of your recent activity with things like:
> >
> > commit f9b348185f4d684cc19e6bd9b87904823d5aa5ed
> > Author: Benjamin Tissoires <[email protected]>
> > Date: Tue Sep 6 17:13:01 2022 +0200
> >
> > bpf/btf: bump BTF_KFUNC_SET_MAX_CNT
> >
> > ?
> I doubt this commit is the culprit for 2 reasons:
> - BTF_KFUNC_SET_MAX_CNT just sets the size of an internal memory chunk
> where we store kfunc definitions. I don't really see how this could be
> linked to a verifier log being full
> - this commit has been applied on Sep 7, and the first crash in the
> dashboard was from Sep 5. So unless the dates are wrong, I don't think
> this commit creates the crash.
> Unfortunately, I am really new into the bpf/btf world, and I have no
> ideas on what could be the cause of that crash. We probably need a
> bisect, but I'll be out next week at plumbers, so can't really work on
> that now.
Yeah, good point. I've run the repro. I think the issue is that
syzkaller is able to pass btf with a super long random name which
then hits BPF_VERIFIER_TMP_LOG_SIZE while printing the verifier
log line. Seems like a non-issue to me, but maybe we need to
add some extra validation..
Sorry for tagging you here, you were that last to touch that
kernel/bpf/btf.c so were an obvious target :-) But it seems like
it's just a coincidence, the issue still happens on 5.19.
> Cheers,
> Benjamin
> >
> > I haven't looked too deep, maybe you can give it a shot? There is
> > reproducer; should be relatively easy to verify. Thx.
> >
> >
> > > btf_parse kernel/bpf/btf.c:5031 [inline]
> > > btf_new_fd+0x939/0x1e70 kernel/bpf/btf.c:6710
> > > bpf_btf_load kernel/bpf/syscall.c:4314 [inline]
> > > __sys_bpf+0x13bd/0x6130 kernel/bpf/syscall.c:4998
> > > __do_sys_bpf kernel/bpf/syscall.c:5057 [inline]
> > > __se_sys_bpf kernel/bpf/syscall.c:5055 [inline]
> > > __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5055
> > > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> > > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > > RIP: 0033:0x7fb092221c29
> > > Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
> > > RSP: 002b:00007fff5b0a6878 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> > > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb092221c29
> > > RDX: 0000000000000020 RSI: 0000000020000240 RDI: 0000000000000012
> > > RBP: 00007fb0921e5dd0 R08: 0000000000000000 R09: 0000000000000000
> > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb0921e5e60
> > > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> > > </TASK>
> >
> >
> > > ---
> > > 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 [email protected].
> >
> > > syzbot will keep track of this issue. See:
> > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > > syzbot can test patches for this issue, for details see:
> > > https://goo.gl/tpsmEJ#testing-patches
> >
Hi all,
On Fri, Sep 09, 2022 at 12:54:06PM -0700, [email protected] wrote:
> On 09/09, Benjamin Tissoires wrote:
> Yeah, good point. I've run the repro. I think the issue is that
> syzkaller is able to pass btf with a super long random name which
> then hits BPF_VERIFIER_TMP_LOG_SIZE while printing the verifier
> log line. Seems like a non-issue to me, but maybe we need to
> add some extra validation..
In btf_func_proto_check_meta():
if (t->name_off) {
btf_verifier_log_type(env, t, "Invalid name");
return -EINVAL;
}
In the verifier log, maybe we should just say that BTF_KIND_FUNC_PROTO "must
not have a name" [1], instead of printing out the user-provided
(potentially very long) name and say it's "Invalid" ?
Similarly, for name-too-long errors, should we truncate the name to
KSYM_NAME_LEN bytes (see __btf_name_valid()) in the log ?
[1] commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO")
Thanks,
Peilin Ye
On Fri, Sep 09, 2022 at 02:43:18PM -0700, [email protected] wrote:
> On 09/09, Peilin Ye wrote:
> > On Fri, Sep 09, 2022 at 12:54:06PM -0700, [email protected] wrote:
> > > On 09/09, Benjamin Tissoires wrote:
> > > Yeah, good point. I've run the repro. I think the issue is that
> > > syzkaller is able to pass btf with a super long random name which
> > > then hits BPF_VERIFIER_TMP_LOG_SIZE while printing the verifier
> > > log line. Seems like a non-issue to me, but maybe we need to
> > > add some extra validation..
>
> > In btf_func_proto_check_meta():
>
> > if (t->name_off) {
> > btf_verifier_log_type(env, t, "Invalid name");
> > return -EINVAL;
> > }
>
> > In the verifier log, maybe we should just say that BTF_KIND_FUNC_PROTO
> > "must
> > not have a name" [1], instead of printing out the user-provided
> > (potentially very long) name and say it's "Invalid" ?
>
> > Similarly, for name-too-long errors, should we truncate the name to
> > KSYM_NAME_LEN bytes (see __btf_name_valid()) in the log ?
>
> Both suggestions sound good to me. Care to cook and send a patch with a
> fix?
Sure, I will work on it.
Thanks,
Peilin Ye
On 09/09, Peilin Ye wrote:
> Hi all,
> On Fri, Sep 09, 2022 at 12:54:06PM -0700, [email protected] wrote:
> > On 09/09, Benjamin Tissoires wrote:
> > Yeah, good point. I've run the repro. I think the issue is that
> > syzkaller is able to pass btf with a super long random name which
> > then hits BPF_VERIFIER_TMP_LOG_SIZE while printing the verifier
> > log line. Seems like a non-issue to me, but maybe we need to
> > add some extra validation..
> In btf_func_proto_check_meta():
> if (t->name_off) {
> btf_verifier_log_type(env, t, "Invalid name");
> return -EINVAL;
> }
> In the verifier log, maybe we should just say that
> BTF_KIND_FUNC_PROTO "must
> not have a name" [1], instead of printing out the user-provided
> (potentially very long) name and say it's "Invalid" ?
> Similarly, for name-too-long errors, should we truncate the name to
> KSYM_NAME_LEN bytes (see __btf_name_valid()) in the log ?
Both suggestions sound good to me. Care to cook and send a patch with a
fix?
> [1] commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC and
> BTF_KIND_FUNC_PROTO")
> Thanks,
> Peilin Ye