capability.conf(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COLOPHON

CAPABILITY.CONF(5)         File Formats Manual        CAPABILITY.CONF(5)

NAME         top

       capability.conf - pam_cap module configuration file

SYNOPSIS         top

       /etc/security/capability.conf

DESCRIPTION         top

       The syntax for lines in this configuration file is:

       # <-- ´#´ precedes a comment

       <IAB><SPACE><WHO>

       Where <IAB> refers to the text format for an inheritable IAB
       capability tuple, cap_iab(3) , or the words all or none.

       The reserved word all does not grant all the inheritable
       capabilities, but acts as a simple pass-through for any
       prevailing IAB tuple capabilities. The reserved word none refers
       to an empty Inheritable capability set (and by extension an empty
       Ambient vector).

       Here <WHO> refers to the space separated PAM username values that
       will be granted the specified IAB tuple. A name prefixed with the
       character @ refers to the locally defined /etc/group etc users
       listed under that group name. An asterisk "*" can be used to
       denote all users.

       The parsing of the file chooses the first line that applies to
       the authenticating user, and attempts to apply that and only
       that.

       Examples of valid syntax are:

           # only root gets to keep what it had
           all                                root

           # this should fire for user beta only, who will have
           # cap_chown dropped from their bounding set.
           !cap_chown                         beta

           # the next one should snag the members of the ´three´ group
           # granting them cap_setuid and cap_chown
           cap_setuid,cap_chown               @three

           # this would apply to beta and gamma, but beta is already
           # granted a lack of cap_chown above. Further, if gamma is
           # in the ´three´ group, it would not reach this line.
           cap_chown                          beta gamma

           # members of the ´one´ group are granted the cap_setuid Inheritable
           # capability, but cap_chown is dropped from their bounding set.
           !cap_chown,cap_setuid              @one

           # user alpha gets an ambient capability (unless it is also
           # a member of the groups ´one´ or ´three´).
           ^cap_setuid                        alpha

           # user delta (if not a member of groups ´one´ and ´three´) will get
           # cap_chown and cap_setgid Ambient capabilities, but have cap_setuid
           # dropped from its bounding set.
           ^cap_chown,^cap_setgid,!cap_setuid delta

           # any remaining members of group ´four´ will get the cap_setuid
           # Inheritable capability.
           cap_setuid                         @four

SEE ALSO         top

       pam_cap(8), cap_iab(3).

COLOPHON         top

       This page is part of the libcap (capabilities commands and
       library) project.  Information about the project can be found at
       ⟨https://git.kernel.org/pub/scm/libs/libcap/libcap.git/⟩.  If you
       have a bug report for this manual page, send it to
       morgan@kernel.org (please put "libcap" in the Subject line).
       This page was obtained from the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/libs/libcap/libcap.git/⟩ on
       2024-06-14.  (At that time, the date of the most recent commit
       that was found in the repository was 2024-05-18.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

                               April 2024             CAPABILITY.CONF(5)

Pages that refer to this page: pam_cap(8)