• Wang Shilong's avatar
    ext4: fix setattr project check in fssetxattr ioctl · dc7ac6c4
    Wang Shilong authored
    Currently, project quota could be changed by fssetxattr
    ioctl, and existed permission check inode_owner_or_capable()
    is obviously not enough, just think that common users could
    change project id of file, that could make users to
    break project quota easily.
    
    This patch try to follow same regular of xfs project
    quota:
    
    "Project Quota ID state is only allowed to change from
    within the init namespace. Enforce that restriction only
    if we are trying to change the quota ID state.
    Everything else is allowed in user namespaces."
    
    Besides that, check and set project id'state should
    be an atomic operation, protect whole operation with
    inode lock, ext4_ioctl_setproject() is only used for
    ioctl EXT4_IOC_FSSETXATTR, we have held mnt_want_write_file()
    before ext4_ioctl_setflags(), and ext4_ioctl_setproject()
    is called after ext4_ioctl_setflags(), we could share
    codes, so remove it inside ext4_ioctl_setproject().
    Signed-off-by: default avatarWang Shilong <wshilong@ddn.com>
    Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    Reviewed-by: default avatarAndreas Dilger <adilger@dilger.ca>
    Cc: stable@kernel.org
    dc7ac6c4
ioctl.c 27.9 KB