• Akira Fujita's avatar
    ext4: Fix insufficient checks in EXT4_IOC_MOVE_EXT · 4a58579b
    Akira Fujita authored
    This patch fixes three problems in the handling of the
    EXT4_IOC_MOVE_EXT ioctl:
    
    1. In current EXT4_IOC_MOVE_EXT, there are read access mode checks for
    original and donor files, but they allow the illegal write access to
    donor file, since donor file is overwritten by original file data.  To
    fix this problem, change access mode checks of original (r->r/w) and
    donor (r->w) files.
    
    2.  Disallow the use of donor files that have a setuid or setgid bits.
    
    3.  Call mnt_want_write() and mnt_drop_write() before and after
    ext4_move_extents() calling to get write access to a mount.
    Signed-off-by: default avatarAkira Fujita <a-fujita@rs.jp.nec.com>
    Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
    4a58579b
ioctl.c 8.54 KB