• Satyam Sharma's avatar
    Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check · 3bd858ab
    Satyam Sharma authored
    Introduce is_owner_or_cap() macro in fs.h, and convert over relevant
    users to it. This is done because we want to avoid bugs in the future
    where we check for only effective fsuid of the current task against a
    file's owning uid, without simultaneously checking for CAP_FOWNER as
    well, thus violating its semantics.
    [ XFS uses special macros and structures, and in general looked ...
    untouchable, so we leave it alone -- but it has been looked over. ]
    The (current->fsuid != inode->i_uid) check in generic_permission() and
    exec_permission_lite() is left alone, because those operations are
    covered by CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH. Similarly operations
    falling under the purview of CAP_CHOWN and CAP_LEASE are also left alone.
    Signed-off-by: default avatarSatyam Sharma <ssatyam@cse.iitk.ac.in>
    Cc: Al Viro <viro@ftp.linux.org.uk>
    Acked-by: default avatarSerge E. Hallyn <serge@hallyn.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
acl.c 6.05 KB