• Dave Chinner's avatar
    xfs: fix overflow in xfs_attr3_leaf_verify · 837514f7
    Dave Chinner authored
    generic/070 on 64k block size filesystems is failing with a verifier
    corruption on writeback or an attribute leaf block:
    
    [   94.973083] XFS (pmem0): Metadata corruption detected at xfs_attr3_leaf_verify+0x246/0x260, xfs_attr3_leaf block 0x811480
    [   94.975623] XFS (pmem0): Unmount and run xfs_repair
    [   94.976720] XFS (pmem0): First 128 bytes of corrupted metadata buffer:
    [   94.978270] 000000004b2e7b45: 00 00 00 00 00 00 00 00 3b ee 00 00 00 00 00 00  ........;.......
    [   94.980268] 000000006b1db90b: 00 00 00 00 00 81 14 80 00 00 00 00 00 00 00 00  ................
    [   94.982251] 00000000433f2407: 22 7b 5c 82 2d 5c 47 4c bb 31 1c 37 fa a9 ce d6  "{\.-\GL.1.7....
    [   94.984157] 0000000010dc7dfb: 00 00 00 00 00 81 04 8a 00 0a 18 e8 dd 94 01 00  ................
    [   94.986215] 00000000d5a19229: 00 a0 dc f4 fe 98 01 68 f0 d8 07 e0 00 00 00 00  .......h........
    [   94.988171] 00000000521df36c: 0c 2d 32 e2 fe 20 01 00 0c 2d 58 65 fe 0c 01 00  .-2.. ...-Xe....
    [   94.990162] 000000008477ae06: 0c 2d 5b 66 fe 8c 01 00 0c 2d 71 35 fe 7c 01 00  .-[f.....-q5.|..
    [   94.992139] 00000000a4a6bca6: 0c 2d 72 37 fc d4 01 00 0c 2d d8 b8 f0 90 01 00  .-r7.....-......
    [   94.994789] XFS (pmem0): xfs_do_force_shutdown(0x8) called from line 1453 of file fs/xfs/xfs_buf.c. Return address = ffffffff815365f3
    
    This is failing this check:
    
                    end = ichdr.freemap[i].base + ichdr.freemap[i].size;
                    if (end < ichdr.freemap[i].base)
    >>>>>                   return __this_address;
                    if (end > mp->m_attr_geo->blksize)
                            return __this_address;
    
    And from the buffer output above, the freemap array is:
    
    	freemap[0].base = 0x00a0
    	freemap[0].size = 0xdcf4	end = 0xdd94
    	freemap[1].base = 0xfe98
    	freemap[1].size = 0x0168	end = 0x10000
    	freemap[2].base = 0xf0d8
    	freemap[2].size = 0x07e0	end = 0xf8b8
    
    These all look valid - the block size is 0x10000 and so from the
    last check in the above verifier fragment we know that the end
    of freemap[1] is valid. The problem is that end is declared as:
    
    	uint16_t	end;
    
    And (uint16_t)0x10000 = 0. So we have a verifier bug here, not a
    corruption. Fix the verifier to use uint32_t types for the check and
    hence avoid the overflow.
    
    Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=201577Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
    Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    837514f7
xfs_attr_leaf.c 81.9 KB