# Copyright 1999-2020 Gentoo Authors # Distributed under the terms of the GNU General Public License v2 # @ECLASS: fcaps.eclass # @MAINTAINER: # base-system@gentoo.org # @BLURB: function to set POSIX file-based capabilities # @DESCRIPTION: # This eclass provides a function to set file-based capabilities on binaries. # This is not the same as USE=caps which controls runtime capability changes, # often via packages like libcap. # # Due to probable capability-loss on moving or copying, this happens in # pkg_postinst phase (at least for now). # # @EXAMPLE: # You can manually set the caps on ping and ping6 by doing: # @CODE # pkg_postinst() { # fcaps cap_net_raw bin/ping bin/ping6 # } # @CODE # # Or set it via the global ebuild var FILECAPS: # @CODE # FILECAPS=( # cap_net_raw bin/ping bin/ping6 # ) # @CODE if [[ -z ${_FCAPS_ECLASS} ]]; then _FCAPS_ECLASS=1 IUSE="+filecaps" # Since it is needed in pkg_postinst() it must be in RDEPEND case "${EAPI:-0}" in [0-6]) RDEPEND="filecaps? ( sys-libs/libcap )" ;; *) BDEPEND="filecaps? ( sys-libs/libcap )" RDEPEND="${BDEPEND}" ;; esac # @ECLASS-VARIABLE: FILECAPS # @DEFAULT_UNSET # @DESCRIPTION: # An array of fcap arguments to use to automatically execute fcaps. See that # function for more details. # # All args are consumed until the '--' marker is found. So if you have: # @CODE # FILECAPS=( moo cow -- fat cat -- chubby penguin ) # @CODE # # This will end up executing: # @CODE # fcaps moo cow # fcaps fat cat # fcaps chubby penguin # @CODE # # Note: If you override pkg_postinst, you must call fcaps_pkg_postinst yourself. # @FUNCTION: fcaps # @USAGE: [-o <owner>] [-g <group>] [-m <mode>] [-M <caps mode>] <capabilities> <file[s]> # @DESCRIPTION: # Sets the specified capabilities on the specified files. # # The caps option takes the form as expected by the cap_from_text(3) man page. # If no action is specified, then "=ep" will be used as a default. # # If the file is a relative path (e.g. bin/foo rather than /bin/foo), then the # appropriate path var ($D/$ROOT/etc...) will be prefixed based on the current # ebuild phase. # # The caps mode (default 711) is used to set the permission on the file if # capabilities were properly set on the file. # # If the system is unable to set capabilities, it will use the specified user, # group, and mode (presumably to make the binary set*id). The defaults there # are root:0 and 4711. Otherwise, the ownership and permissions will be # unchanged. fcaps() { debug-print-function ${FUNCNAME} "$@" if [[ ${EUID} != 0 ]] ; then einfo "Insufficient privileges to execute ${FUNCNAME}, skipping." return 0 fi # Process the user options first. local owner='root' local group='0' local mode='4711' local caps_mode='711' while [[ $# -gt 0 ]] ; do case $1 in -o) owner=$2; shift;; -g) group=$2; shift;; -m) mode=$2; shift;; -M) caps_mode=$2; shift;; *) break;; esac shift done [[ $# -lt 2 ]] && die "${FUNCNAME}: wrong arg count" local caps=$1 [[ ${caps} == *[-=+]* ]] || caps+="=ep" shift local root case ${EBUILD_PHASE} in compile|install|preinst) root=${ED:-${D}} ;; postinst) root=${EROOT:-${ROOT}} ;; esac root=${root%/} # Process every file! local file for file ; do [[ ${file} != /* ]] && file="${root}/${file}" if use filecaps ; then # Try to set capabilities. Ignore errors when the # fs doesn't support it, but abort on all others. debug-print "${FUNCNAME}: setting caps '${caps}' on '${file}'" # If everything goes well, we don't want the file to be readable # by people. chmod ${caps_mode} "${file}" || die if ! out=$(LC_ALL=C setcap "${caps}" "${file}" 2>&1) ; then case ${out} in # ENOTSUP and EOPNOTSUPP might be the same value which means # strerror() on them is unstable -- we can get both. #559608 *"Not supported"*|\ *"Operation not supported"*) local fstype=$(stat -f -c %T "${file}") ewarn "Could not set caps on '${file}' due to missing filesystem support:" ewarn "* enable XATTR support for '${fstype}' in your kernel (if configurable)" ewarn "* mount the fs with the user_xattr option (if not the default)" ewarn "* enable the relevant FS_SECURITY option (if configurable)" ;; *) eerror "Setting caps '${caps}' on file '${file}' failed:" eerror "${out}" die "could not set caps" ;; esac else # Sanity check that everything took. setcap -v "${caps}" "${file}" >/dev/null \ || die "Checking caps '${caps}' on '${file}' failed" # Everything worked. Move on to the next file. continue fi fi # If we're still here, setcaps failed. debug-print "${FUNCNAME}: setting owner/mode on '${file}'" chown "${owner}:${group}" "${file}" || die chmod ${mode} "${file}" || die done } # @FUNCTION: fcaps_pkg_postinst # @DESCRIPTION: # Process the FILECAPS array. fcaps_pkg_postinst() { local arg args=() for arg in "${FILECAPS[@]}" "--" ; do if [[ ${arg} == "--" ]] ; then fcaps "${args[@]}" args=() else args+=( "${arg}" ) fi done } EXPORT_FUNCTIONS pkg_postinst fi