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    SubjectAre path-based LSM hooks called from the wrong places?

    Hi Kentaro,

    I've just been looking at some of the VFS syscall routines, such as
    notify_change(), with an eye to calling it from FS-Cache to grow a file. I
    see that whilst notify_change() calls the inode-based LSM hooks (as drive
    SELinux), it doesn't call the path-based LSM hooks (as drive other security
    modules). It leaves that to the callers, such as do_sys_ftruncate().

    I see that vfs_mkdir(), for example, is similar, in that vfs_mkdir() - which
    I'm calling from FS-Cache - invokes the inode-based LSM hooks, but it bypasses
    the path-based LSM hooks as those are called from sys_mkdir().

    It would appear that path-based LSM hooks may well be being called from the
    wrong places. They were added in:

    commit be6d3e56a6b9b3a4ee44a0685e39e595073c6f0d
    Author: Kentaro Takeda <>
    Date: Wed Dec 17 13:24:15 2008 +0900

    introduce new LSM hooks where vfsmount is available.

    Add new LSM hooks for path-based checks. Call them on directory-modifying
    operations at the points where we still know the vfsmount involved.

    Signed-off-by: Kentaro Takeda <>
    Signed-off-by: Tetsuo Handa <>
    Signed-off-by: Toshiharu Harada <>
    Signed-off-by: Al Viro <>

    Using sys_mkdir() and suchlike directly from within the kernel would add a lot
    of overhead as I'd have to generate a full pathname for each call, whereas
    vfs_mkdir() or notify_change() allows me to start from an inode I already


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