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Subject: Re: [syzbot] KASAN: vmalloc-out-of-bounds Read in bpf_jit_free
To:     syzbot <syzbot+2f649ec6d2eea1495a8f@syzkaller.appspotmail.com>,
        andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
        davem@davemloft.net, dvyukov@google.com, hawk@kernel.org,
        john.fastabend@gmail.com, kafai@fb.com, kernel-team@fb.com,
        kpsingh@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, nogikh@google.com,
        patchwork-bot@kernel.org, song@kernel.org, songliubraving@fb.com,
        syzkaller-bugs@googlegroups.com, yhs@fb.com
References: <0000000000002cb7d405e2e1f886@google.com>
From:   Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <7a5eea26-e379-dfa3-b606-c6a841a2c5fb@iogearbox.net>
Date:   Mon, 4 Jul 2022 11:04:19 +0200
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On 7/3/22 9:57 AM, syzbot wrote:
> syzbot has found a reproducer for the following issue on:

Song, ptal, thanks.

> HEAD commit:    b0d93b44641a selftests/bpf: Skip lsm_cgroup when we don't ..
> git tree:       bpf-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=10c495e0080000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=70e1a4d352a3c6ae
> dashboard link: https://syzkaller.appspot.com/bug?extid=2f649ec6d2eea1495a8f
> 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=11a10a58080000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16ab8cb8080000

Looks like this time syzbot found a repro at least, so this should help making progress.

https://lore.kernel.org/bpf/0000000000002cb7d405e2e1f886@google.com/T/#t

> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+2f649ec6d2eea1495a8f@syzkaller.appspotmail.com
> 
> ==================================================================
> BUG: KASAN: vmalloc-out-of-bounds in bpf_jit_binary_free kernel/bpf/core.c:1081 [inline]
> BUG: KASAN: vmalloc-out-of-bounds in bpf_jit_free+0x26c/0x2b0 kernel/bpf/core.c:1206
> Read of size 4 at addr ffffffffa0000000 by task syz-executor334/3608
> 
> CPU: 0 PID: 3608 Comm: syz-executor334 Not tainted 5.19.0-rc2-syzkaller-00498-gb0d93b44641a #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
> Call Trace:
>   <TASK>
>   __dump_stack lib/dump_stack.c:88 [inline]
>   dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
>   print_address_description.constprop.0.cold+0xf/0x495 mm/kasan/report.c:313
>   print_report mm/kasan/report.c:429 [inline]
>   kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
>   bpf_jit_binary_free kernel/bpf/core.c:1081 [inline]
>   bpf_jit_free+0x26c/0x2b0 kernel/bpf/core.c:1206
>   jit_subprogs kernel/bpf/verifier.c:13767 [inline]
>   fixup_call_args kernel/bpf/verifier.c:13796 [inline]
>   bpf_check+0x7035/0xb040 kernel/bpf/verifier.c:15287
>   bpf_prog_load+0xfb2/0x2250 kernel/bpf/syscall.c:2575
>   __sys_bpf+0x11a1/0x5790 kernel/bpf/syscall.c:4934
>   __do_sys_bpf kernel/bpf/syscall.c:5038 [inline]
>   __se_sys_bpf kernel/bpf/syscall.c:5036 [inline]
>   __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5036
>   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+0x46/0xb0
> RIP: 0033:0x7fe5b823e209
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffc68d718c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fe5b823e209
> RDX: 0000000000000070 RSI: 0000000020000440 RDI: 0000000000000005
> RBP: 00007ffc68d718e0 R08: 0000000000000002 R09: 0000000000000001
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
> R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
>   </TASK>
> 
> Memory state around the buggy address:
> BUG: unable to handle page fault for address: fffffbfff3ffffe0
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> PGD 23ffe4067 P4D 23ffe4067 PUD 23ffe3067 PMD 0
> Oops: 0000 [#1] PREEMPT SMP KASAN
> CPU: 0 PID: 3608 Comm: syz-executor334 Not tainted 5.19.0-rc2-syzkaller-00498-gb0d93b44641a #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
> RIP: 0010:memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:55
> Code: cc cc cc cc eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 <f3> a4 c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe
> RSP: 0018:ffffc9000215f7b8 EFLAGS: 00010082
> RAX: ffffc9000215f7c4 RBX: ffffffff9fffff00 RCX: 0000000000000010
> RDX: 0000000000000010 RSI: fffffbfff3ffffe0 RDI: ffffc9000215f7c4
> RBP: ffffffffa0000000 R08: 0000000000000007 R09: 0000000000000000
> R10: 0000000000000014 R11: 0000000000000001 R12: 00000000fffffffe
> R13: ffffffff9fffff80 R14: ffff888025745880 R15: 0000000000000282
> FS:  0000555555ac7300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffffbfff3ffffe0 CR3: 000000007dc79000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>   <TASK>
>   print_memory_metadata+0x5a/0xdf mm/kasan/report.c:404
>   print_report mm/kasan/report.c:430 [inline]
>   kasan_report.cold+0xfe/0x1c6 mm/kasan/report.c:491
>   bpf_jit_binary_free kernel/bpf/core.c:1081 [inline]
>   bpf_jit_free+0x26c/0x2b0 kernel/bpf/core.c:1206
>   jit_subprogs kernel/bpf/verifier.c:13767 [inline]
>   fixup_call_args kernel/bpf/verifier.c:13796 [inline]
>   bpf_check+0x7035/0xb040 kernel/bpf/verifier.c:15287
>   bpf_prog_load+0xfb2/0x2250 kernel/bpf/syscall.c:2575
>   __sys_bpf+0x11a1/0x5790 kernel/bpf/syscall.c:4934
>   __do_sys_bpf kernel/bpf/syscall.c:5038 [inline]
>   __se_sys_bpf kernel/bpf/syscall.c:5036 [inline]
>   __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5036
>   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+0x46/0xb0
> RIP: 0033:0x7fe5b823e209
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 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 c0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffc68d718c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fe5b823e209
> RDX: 0000000000000070 RSI: 0000000020000440 RDI: 0000000000000005
> RBP: 00007ffc68d718e0 R08: 0000000000000002 R09: 0000000000000001
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
> R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
>   </TASK>
> Modules linked in:
> CR2: fffffbfff3ffffe0
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:memcpy_erms+0x6/0x10 arch/x86/lib/memcpy_64.S:55
> Code: cc cc cc cc eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 <f3> a4 c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe
> RSP: 0018:ffffc9000215f7b8 EFLAGS: 00010082
> RAX: ffffc9000215f7c4 RBX: ffffffff9fffff00 RCX: 0000000000000010
> RDX: 0000000000000010 RSI: fffffbfff3ffffe0 RDI: ffffc9000215f7c4
> RBP: ffffffffa0000000 R08: 0000000000000007 R09: 0000000000000000
> R10: 0000000000000014 R11: 0000000000000001 R12: 00000000fffffffe
> R13: ffffffff9fffff80 R14: ffff888025745880 R15: 0000000000000282
> FS:  0000555555ac7300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffffbfff3ffffe0 CR3: 000000007dc79000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess):
>     0:	cc                   	int3
>     1:	cc                   	int3
>     2:	cc                   	int3
>     3:	cc                   	int3
>     4:	eb 1e                	jmp    0x24
>     6:	0f 1f 00             	nopl   (%rax)
>     9:	48 89 f8             	mov    %rdi,%rax
>     c:	48 89 d1             	mov    %rdx,%rcx
>     f:	48 c1 e9 03          	shr    $0x3,%rcx
>    13:	83 e2 07             	and    $0x7,%edx
>    16:	f3 48 a5             	rep movsq %ds:(%rsi),%es:(%rdi)
>    19:	89 d1                	mov    %edx,%ecx
>    1b:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi)
>    1d:	c3                   	retq
>    1e:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
>    24:	48 89 f8             	mov    %rdi,%rax
>    27:	48 89 d1             	mov    %rdx,%rcx
> * 2a:	f3 a4                	rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
>    2c:	c3                   	retq
>    2d:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
>    34:	48 89 f8             	mov    %rdi,%rax
>    37:	48 83 fa 20          	cmp    $0x20,%rdx
>    3b:	72 7e                	jb     0xbb
>    3d:	40 38 fe             	cmp    %dil,%sil
>