• Ye Bin's avatar
    ext4: fix WARNING in ext4_update_inline_data · 2b96b4a5
    Ye Bin authored
    Syzbot found the following issue:
    EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none.
    fscrypt: AES-256-CTS-CBC using implementation "cts-cbc-aes-aesni"
    fscrypt: AES-256-XTS using implementation "xts-aes-aesni"
    ------------[ cut here ]------------
    WARNING: CPU: 0 PID: 5071 at mm/page_alloc.c:5525 __alloc_pages+0x30a/0x560 mm/page_alloc.c:5525
    Modules linked in:
    CPU: 1 PID: 5071 Comm: syz-executor263 Not tainted 6.2.0-rc1-syzkaller #0
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
    RIP: 0010:__alloc_pages+0x30a/0x560 mm/page_alloc.c:5525
    RSP: 0018:ffffc90003c2f1c0 EFLAGS: 00010246
    RAX: ffffc90003c2f220 RBX: 0000000000000014 RCX: 0000000000000000
    RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90003c2f248
    RBP: ffffc90003c2f2d8 R08: dffffc0000000000 R09: ffffc90003c2f220
    R10: fffff52000785e49 R11: 1ffff92000785e44 R12: 0000000000040d40
    R13: 1ffff92000785e40 R14: dffffc0000000000 R15: 1ffff92000785e3c
    FS:  0000555556c0d300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007f95d5e04138 CR3: 00000000793aa000 CR4: 00000000003506f0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
     <TASK>
     __alloc_pages_node include/linux/gfp.h:237 [inline]
     alloc_pages_node include/linux/gfp.h:260 [inline]
     __kmalloc_large_node+0x95/0x1e0 mm/slab_common.c:1113
     __do_kmalloc_node mm/slab_common.c:956 [inline]
     __kmalloc+0xfe/0x190 mm/slab_common.c:981
     kmalloc include/linux/slab.h:584 [inline]
     kzalloc include/linux/slab.h:720 [inline]
     ext4_update_inline_data+0x236/0x6b0 fs/ext4/inline.c:346
     ext4_update_inline_dir fs/ext4/inline.c:1115 [inline]
     ext4_try_add_inline_entry+0x328/0x990 fs/ext4/inline.c:1307
     ext4_add_entry+0x5a4/0xeb0 fs/ext4/namei.c:2385
     ext4_add_nondir+0x96/0x260 fs/ext4/namei.c:2772
     ext4_create+0x36c/0x560 fs/ext4/namei.c:2817
     lookup_open fs/namei.c:3413 [inline]
     open_last_lookups fs/namei.c:3481 [inline]
     path_openat+0x12ac/0x2dd0 fs/namei.c:3711
     do_filp_open+0x264/0x4f0 fs/namei.c:3741
     do_sys_openat2+0x124/0x4e0 fs/open.c:1310
     do_sys_open fs/open.c:1326 [inline]
     __do_sys_openat fs/open.c:1342 [inline]
     __se_sys_openat fs/open.c:1337 [inline]
     __x64_sys_openat+0x243/0x290 fs/open.c:1337
     do_syscall_x64 arch/x86/entry/common.c:50 [inline]
     do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
     entry_SYSCALL_64_after_hwframe+0x63/0xcd
    
    Above issue happens as follows:
    ext4_iget
       ext4_find_inline_data_nolock ->i_inline_off=164 i_inline_size=60
    ext4_try_add_inline_entry
       __ext4_mark_inode_dirty
          ext4_expand_extra_isize_ea ->i_extra_isize=32 s_want_extra_isize=44
             ext4_xattr_shift_entries
    	 ->after shift i_inline_off is incorrect, actually is change to 176
    ext4_try_add_inline_entry
      ext4_update_inline_dir
        get_max_inline_xattr_value_size
          if (EXT4_I(inode)->i_inline_off)
    	entry = (struct ext4_xattr_entry *)((void *)raw_inode +
    			EXT4_I(inode)->i_inline_off);
            free += EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
    	->As entry is incorrect, then 'free' may be negative
       ext4_update_inline_data
          value = kzalloc(len, GFP_NOFS);
          -> len is unsigned int, maybe very large, then trigger warning when
             'kzalloc()'
    
    To resolve the above issue we need to update 'i_inline_off' after
    'ext4_xattr_shift_entries()'.  We do not need to set
    EXT4_STATE_MAY_INLINE_DATA flag here, since ext4_mark_inode_dirty()
    already sets this flag if needed.  Setting EXT4_STATE_MAY_INLINE_DATA
    when it is needed may trigger a BUG_ON in ext4_writepages().
    
    Reported-by: syzbot+d30838395804afc2fa6f@syzkaller.appspotmail.com
    Cc: stable@kernel.org
    Signed-off-by: default avatarYe Bin <yebin10@huawei.com>
    Reviewed-by: default avatarJan Kara <jack@suse.cz>
    Link: https://lore.kernel.org/r/20230307015253.2232062-3-yebin@huaweicloud.comSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    2b96b4a5
xattr.c 84.2 KB