linux-kernel - Re: Bug: use-after-free in __bitmap

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Message-Id: <BD5F6754-166A-40CB-A97B-B722039B845A@m.fudan.edu.cn>
Date: Sat, 28 Dec 2024 16:13:27 +0800
From: Kun Hu <huk23@...udan.edu.cn>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: yury.norov@...il.com,
 linux@...musvillemoes.dk,
 pabeni@...hat.com,
 jacob.e.keller@...el.com,
 linux-kernel@...r.kernel.org,
 "jjtan24@...udan.edu.cn" <jjtan24@...udan.edu.cn>,
 ocfs2-devel@...ts.linux.dev
Subject: Re: Bug: use-after-free in __bitmap_weight



> 2024年12月27日 06:19，Andrew Morton <akpm@...ux-foundation.org> 写道：
> 
> On Tue, 24 Dec 2024 19:37:29 +0800 Kun Hu <huk23@...udan.edu.cn> wrote:
> 
>> Hello,
>> 
>> When using fuzzer tool to fuzz the latest Linux kernel, the following crash
>> was triggered.
> 
> Thanks.  Let's cc the ocfs2 list.
> 
>> HEAD commit: 78d4f34e2115b517bcbfe7ec0d018bbbb6f9b0b8
>> git tree: upstream
>> Console output: https://drive.google.com/file/d/1CJ3VaQxlqkGdcEitM_aoSuzeCpfUWrAi/view?usp=sharing
>> Kernel config: https://drive.google.com/file/d/1RhT5dFTs6Vx1U71PbpenN7TPtnPoa3NI/view?usp=sharing
>> C reproducer: /
>> Syzlang reproducer: /
>> 
>> 
>> Unfortunately, we're getting a stable reproduction of the program. If you fix this issue, please add the following tag to the commit:
>> Reported-by: Kun Hu <huk23@...udan.edu.cn>
>> 
>> (syz.0.394,3922,2):ocfs2_mknod:298 ERROR: status = -2
>> (syz.0.394,3922,2):ocfs2_mknod:502 ERROR: status = -2
>> (syz.0.394,3922,2):ocfs2_create:676 ERROR: status = -2
>> ==================================================================
>> BUG: KASAN: use-after-free in __bitmap_weight+0xf9/0x110 lib/bitmap.c:340
>> Read of size 8 at addr ff11000056367000 by task syz.0.394/3922
>> 
>> CPU: 2 UID: 0 PID: 3922 Comm: syz.0.394 Not tainted 6.13.0-rc3 #5
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
>> Call Trace:
>> <TASK>
>> __dump_stack lib/dump_stack.c:94 [inline]
>> dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120
>> print_address_description mm/kasan/report.c:378 [inline]
>> print_report+0xcf/0x5f0 mm/kasan/report.c:489
>> kasan_report+0x93/0xc0 mm/kasan/report.c:602
>> __bitmap_weight+0xf9/0x110 lib/bitmap.c:340
>> bitmap_weight include/linux/bitmap.h:446 [inline]
>> memweight+0x120/0x1c0 lib/memweight.c:24
>> ocfs2_local_alloc_count_bits fs/ocfs2/localalloc.c:817 [inline]
>> ocfs2_reserve_local_alloc_bits+0x3e1/0x10a0 fs/ocfs2/localalloc.c:655
>> ocfs2_reserve_clusters_with_limit+0x7eb/0xcd0 fs/ocfs2/suballoc.c:1166
>> ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1227 [inline]
>> ocfs2_lock_allocators+0x351/0x610 fs/ocfs2/suballoc.c:2746
>> ocfs2_extend_allocation+0x274/0x17d0 fs/ocfs2/file.c:589
>> ocfs2_allocate_unwritten_extents+0x22c/0x740 fs/ocfs2/file.c:1496
>> __ocfs2_change_file_space+0xba0/0x1090 fs/ocfs2/file.c:2023
>> ocfs2_fallocate+0x271/0x300 fs/ocfs2/file.c:2138
>> vfs_fallocate+0x49d/0xeb0 fs/open.c:327
>> ksys_fallocate+0x55/0xa0 fs/open.c:351
>> __do_sys_fallocate fs/open.c:356 [inline]
>> __se_sys_fallocate fs/open.c:354 [inline]
>> __x64_sys_fallocate+0x97/0x100 fs/open.c:354
>> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>> do_syscall_64+0xc3/0x1d0 arch/x86/entry/common.c:83
>> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> RIP: 0033:0x7f9d68c8d71d
>> Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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:00007f9d678bfba8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
>> RAX: ffffffffffffffda RBX: 00007f9d68e50058 RCX: 00007f9d68c8d71d
>> RDX: 00000000000000fa RSI: 0000000000000000 RDI: 0000000000000004
>> RBP: 00007f9d68d02425 R08: 0000000000000000 R09: 0000000000000000
>> R10: 000000000000ffff R11: 0000000000000246 R12: 0000000000000000
>> R13: 00007f9d68e50064 R14: 00007f9d68e500f0 R15: 00007f9d678bfd40
>> </TASK>
>> 
>> The buggy address belongs to the physical page:
>> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7f pfn:0x56367
>> flags: 0x100000000000000(node=0|zone=1)
>> raw: 0100000000000000 ffd4000001221708 ffd40000012ea688 0000000000000000
>> raw: 000000000000007f 0000000000000000 00000000ffffffff 0000000000000000
>> page dumped because: kasan: bad access detected
>> 
>> Memory state around the buggy address:
>> ff11000056366f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> ff11000056366f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>>> ff11000056367000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>> ^
>> ff11000056367080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>> ff11000056367100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>> ==================================================================
>> OCFS2: ERROR (device loop0): ocfs2_reserve_local_alloc_bits: local alloc inode 10712166395476743305 says it has 2419393108 used bits, but a count shows 145657
>> On-disk corruption discovered. Please run fsck.ocfs2 once the filesystem is unmounted.
>> OCFS2: Returning error to the calling process.
>> (syz.0.394,3922,2):ocfs2_reserve_local_alloc_bits:710 ERROR: status = -5
>> (syz.0.394,3922,2):ocfs2_reserve_clusters_with_limit:1170 ERROR: status = -5
>> (syz.0.394,3922,2):ocfs2_reserve_clusters_with_limit:1219 ERROR: status = -5
>> (syz.0.394,3922,2):ocfs2_lock_allocators:2749 ERROR: status = -5
>> (syz.0.394,3922,2):ocfs2_extend_allocation:592 ERROR: status = -5
>> (syz.0.394,3922,2):ocfs2_allocate_unwritten_extents:1499 ERROR: status = -5
>> (syz.0.394,3922,2):__ocfs2_change_file_space:2045 ERROR: status = -5
>> 
>> 
>> ---------------
>> thanks,
>> Kun Hu


If you need any more information, please don't hesitate to let me know.

—————
Best regards,
Kun Hu