Re: [syzbot] [xfs?] KASAN: slab-out-of-bounds Read in xfs_getbmap

Darrick J. Wong
2023-05-02T21:24:44Z

On Mon, May 01, 2023 at 11:53:47AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 58390c8ce1bd Merge tag 'iommu-updates-v6.4' of git://git.k..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=11e6af2c280000
> kernel config: https://syzkaller.appspot.com/x/.config?x=5eadbf0d3c2ece89
> dashboard link: https://syzkaller.appspot.com/bug?extid=c103d3808a0de5faaf80
> compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12e25f2c280000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14945d10280000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/60130779f509/disk-58390c8c.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/d7f0cdd29b71/vmlinux-58390c8c.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/de415ad52ae4/bzImage-58390c8c.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/c94bae2c94e1/mount_0.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+c103d3808a0de5faaf80@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in xfs_getbmap+0x1c06/0x1c90 fs/xfs/xfs_bmap_util.c:561
> Read of size 4 at addr ffff88801872aa78 by task syz-executor294/5000
>
> CPU: 1 PID: 5000 Comm: syz-executor294 Not tainted 6.3.0-syzkaller-12049-g58390c8ce1bd #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
> print_address_description mm/kasan/report.c:351 [inline]
> print_report+0x163/0x540 mm/kasan/report.c:462
> kasan_report+0x176/0x1b0 mm/kasan/report.c:572
> xfs_getbmap+0x1c06/0x1c90 fs/xfs/xfs_bmap_util.c:561
> xfs_ioc_getbmap+0x243/0x7a0 fs/xfs/xfs_ioctl.c:1481
> xfs_file_ioctl+0xbf5/0x16a0 fs/xfs/xfs_ioctl.c:1949
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:870 [inline]
> __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7fc886bade49
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 15 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 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fc87f738208 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fc886c3c7b8 RCX: 00007fc886bade49
> RDX: 0000000020000140 RSI: 00000000c0205826 RDI: 0000000000000005
> RBP: 00007fc886c3c7b0 R08: 00007fc87f738700 R09: 0000000000000000
> R10: 00007fc87f738700 R11: 0000000000000246 R12: 00007fc886c3c7bc
> R13: 00007ffdc483022f R14: 00007fc87f738300 R15: 0000000000022000
> </TASK>
>
> Allocated by task 4450:
> kasan_save_stack mm/kasan/common.c:45 [inline]
> kasan_set_track+0x4f/0x70 mm/kasan/common.c:52
> ____kasan_kmalloc mm/kasan/common.c:374 [inline]
> __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:383
> kasan_kmalloc include/linux/kasan.h:196 [inline]
> __do_kmalloc_node mm/slab_common.c:966 [inline]
> __kmalloc_node+0xb8/0x230 mm/slab_common.c:973
> kmalloc_node include/linux/slab.h:579 [inline]
> kvmalloc_node+0x72/0x180 mm/util.c:604
> kvmalloc include/linux/slab.h:697 [inline]
> simple_xattr_alloc+0x43/0xa0 fs/xattr.c:1073
> shmem_initxattrs+0x8e/0x1e0 mm/shmem.c:3290
> security_inode_init_security+0x2df/0x3f0 security/security.c:1630
> shmem_mknod+0xba/0x1c0 mm/shmem.c:2947
> lookup_open fs/namei.c:3492 [inline]
> open_last_lookups fs/namei.c:3560 [inline]
> path_openat+0x13df/0x3170 fs/namei.c:3788
> do_filp_open+0x234/0x490 fs/namei.c:3818
> do_sys_openat2+0x13f/0x500 fs/open.c:1356
> do_sys_open fs/open.c:1372 [inline]
> __do_sys_openat fs/open.c:1388 [inline]
> __se_sys_openat fs/open.c:1383 [inline]
> __x64_sys_openat+0x247/0x290 fs/open.c:1383
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> The buggy address belongs to the object at ffff88801872aa00
> which belongs to the cache kmalloc-64 of size 64
> The buggy address is located 79 bytes to the right of
> allocated 41-byte region [ffff88801872aa00, ffff88801872aa29)
>
> The buggy address belongs to the physical page:
> page:ffffea000061ca80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1872a
> flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
> page_type: 0xffffffff()
> raw: 00fff00000000200 ffff888012441640 ffffea0000ad39c0 dead000000000002
> raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 4439, tgid 4439 (S02sysctl), ts 15189537421, free_ts 15177747790
> set_page_owner include/linux/page_owner.h:31 [inline]
> post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1722
> prep_new_page mm/page_alloc.c:1729 [inline]
> get_page_from_freelist+0x321c/0x33a0 mm/page_alloc.c:3493
> __alloc_pages+0x255/0x670 mm/page_alloc.c:4759
> alloc_slab_page+0x6a/0x160 mm/slub.c:1851
> allocate_slab mm/slub.c:1998 [inline]
> new_slab+0x84/0x2f0 mm/slub.c:2051
> ___slab_alloc+0xa85/0x10a0 mm/slub.c:3192
> __slab_alloc mm/slub.c:3291 [inline]
> __slab_alloc_node mm/slub.c:3344 [inline]
> slab_alloc_node mm/slub.c:3441 [inline]
> __kmem_cache_alloc_node+0x1b8/0x290 mm/slub.c:3490
> kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1057
> kmalloc include/linux/slab.h:559 [inline]
> load_elf_binary+0x1cdb/0x2830 fs/binfmt_elf.c:910
> search_binary_handler fs/exec.c:1737 [inline]
> exec_binprm fs/exec.c:1779 [inline]
> bprm_execve+0x90e/0x1740 fs/exec.c:1854
> do_execveat_common+0x580/0x720 fs/exec.c:1962
> do_execve fs/exec.c:2036 [inline]
> __do_sys_execve fs/exec.c:2112 [inline]
> __se_sys_execve fs/exec.c:2107 [inline]
> __x64_sys_execve+0x92/0xa0 fs/exec.c:2107
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> page last free stack trace:
> reset_page_owner include/linux/page_owner.h:24 [inline]
> free_pages_prepare mm/page_alloc.c:1302 [inline]
> free_unref_page_prepare+0x903/0xa30 mm/page_alloc.c:2555
> free_unref_page_list+0x596/0x830 mm/page_alloc.c:2696
> release_pages+0x2193/0x2470 mm/swap.c:1042
> tlb_batch_pages_flush mm/mmu_gather.c:97 [inline]
> tlb_flush_mmu_free mm/mmu_gather.c:292 [inline]
> tlb_flush_mmu+0x100/0x210 mm/mmu_gather.c:299
> tlb_finish_mmu+0xd4/0x1f0 mm/mmu_gather.c:391
> exit_mmap+0x3da/0xaf0 mm/mmap.c:3123
> __mmput+0x115/0x3c0 kernel/fork.c:1351
> exec_mmap+0x672/0x700 fs/exec.c:1035
> begin_new_exec+0x665/0xf10 fs/exec.c:1294
> load_elf_binary+0x95d/0x2830 fs/binfmt_elf.c:1001
> search_binary_handler fs/exec.c:1737 [inline]
> exec_binprm fs/exec.c:1779 [inline]
> bprm_execve+0x90e/0x1740 fs/exec.c:1854
> do_execveat_common+0x580/0x720 fs/exec.c:1962
> do_execve fs/exec.c:2036 [inline]
> __do_sys_execve fs/exec.c:2112 [inline]
> __se_sys_execve fs/exec.c:2107 [inline]
> __x64_sys_execve+0x92/0xa0 fs/exec.c:2107
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Memory state around the buggy address:
> ffff88801872a900: 00 00 00 00 00 01 fc fc fc fc fc fc fc fc fc fc
> ffff88801872a980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> >ffff88801872aa00: 00 00 00 00 00 01 fc fc fc fc fc fc fc fc fc fc
> ^
> ffff88801872aa80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
> ffff88801872ab00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
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>
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>
> If the bug is already fixed, let syzbot know by replying with:
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>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git inodegc-fixes-6.4_2023-05-01

--D

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