Beyond Linux® From Scratch - Version 7.5

Chapter 4. Security

libcap-2.24

Introduction to libcap

The libcap package implements the user-space interfaces to the POSIX 1003.1e capabilities available in Linux kernels. These capabilities are a partitioning of the all powerful root privilege into a set of distinct privileges.

This package is known to build and work properly using an LFS-7.5 platform.

Package Information

libcap Dependencies

Required

attr-2.4.47

Optional

Linux-PAM-1.1.8

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/libcap

Installation of libcap

Install libcap by running the following commands: 

sed -i 's:LIBDIR:PAM_&:g' pam_cap/Makefile &&
make

This package does not come with a test suite.

If you want to disable installing the static library, use this sed: 

sed -i '/install.*STALIBNAME/ s/^/#/' libcap/Makefile

Now, as the root user: 

make prefix=/usr \
     SBINDIR=/sbin \
     PAM_LIBDIR=/lib \
     RAISE_SETFCAP=no install

Still as the root user, clean up some library locations and permissions: 

chmod -v 755 /usr/lib/libcap.so &&
mv -v /usr/lib/libcap.so.* /lib &&
ln -sfv ../../lib/libcap.so.2 /usr/lib/libcap.so

Command Explanations

sed -i '...', PAM_LIBDIR=/lib: These correct PAM module install location.

RAISE_SETFCAP=no: This parameter skips trying to use setcap on itself. This avoids an installation error if the kernel or file system do not support extended capabilities.

Contents

Installed Programs: capsh, getcap, getpcaps, and setcap
Installed Library: libcap.{so,a}
Installed Directories: None

Short Descriptions

capsh

is a shell wrapper to explore and constrain capability support.

getcap

examines file capabilities.

getpcaps

displays the capabilities on the queried process(es).

setcap

sets file file capabilities.

libcap.{so,a}

contains the libcap API functions.

Last updated on 2014-02-17 15:16:31 -0800