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/***
This file is part of PulseAudio.
Copyright 2004-2006 Lennart Poettering
Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <pulse/i18n.h>
#include <pulsecore/macro.h>
#include <pulsecore/core-error.h>
#include <pulsecore/log.h>
#include <pulsecore/core-util.h>
#ifdef HAVE_SYS_CAPABILITY_H
#include <sys/capability.h>
#endif
#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#endif
#include "caps.h"
/* Glibc <= 2.2 has broken unistd.h */
#if defined(linux) && (__GLIBC__ <= 2 && __GLIBC_MINOR__ <= 2)
int setresgid(gid_t r, gid_t e, gid_t s);
int setresuid(uid_t r, uid_t e, uid_t s);
#endif
#ifdef HAVE_GETUID
/* Drop root rights when called SUID root */
void pa_drop_root(void) {
uid_t uid = getuid();
if (uid == 0 || geteuid() != 0)
return;
pa_log_info(_("Dropping root priviliges."));
#if defined(HAVE_SETRESUID)
pa_assert_se(setresuid(uid, uid, uid) >= 0);
#elif defined(HAVE_SETREUID)
pa_assert_se(setreuid(uid, uid) >= 0);
#else
pa_assert_se(setuid(uid) >= 0);
pa_assert_se(seteuid(uid) >= 0);
#endif
pa_assert_se(getuid() == uid);
pa_assert_se(geteuid() == uid);
}
#else
void pa_drop_root(void) {
}
#endif
#if defined(HAVE_SYS_CAPABILITY_H) && defined(HAVE_SYS_PRCTL_H)
/* Limit permitted capabilities set to CAPSYS_NICE */
void pa_limit_caps(void) {
cap_t caps;
cap_value_t nice_cap = CAP_SYS_NICE;
pa_assert_se(caps = cap_init());
pa_assert_se(cap_clear(caps) == 0);
pa_assert_se(cap_set_flag(caps, CAP_EFFECTIVE, 1, &nice_cap, CAP_SET) == 0);
pa_assert_se(cap_set_flag(caps, CAP_PERMITTED, 1, &nice_cap, CAP_SET) == 0);
if (cap_set_proc(caps) < 0)
/* Hmm, so we couldn't limit our caps, which probably means we
* hadn't any in the first place, so let's just make sure of
* that */
pa_drop_caps();
else
pa_log_info(_("Limited capabilities successfully to CAP_SYS_NICE."));
pa_assert_se(cap_free(caps) == 0);
pa_assert_se(prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == 0);
}
/* Drop all capabilities, effectively becoming a normal user */
void pa_drop_caps(void) {
cap_t caps;
#ifndef __OPTIMIZE__
/* Valgrind doesn't not know set_caps, so we bypass it here -- but
* only in development builds.*/
if (pa_in_valgrind() && !pa_have_caps())
return;
#endif
pa_assert_se(prctl(PR_SET_KEEPCAPS, 0, 0, 0, 0) == 0);
pa_assert_se(caps = cap_init());
pa_assert_se(cap_clear(caps) == 0);
pa_assert_se(cap_set_proc(caps) == 0);
pa_assert_se(cap_free(caps) == 0);
pa_assert_se(!pa_have_caps());
}
pa_bool_t pa_have_caps(void) {
cap_t caps;
cap_flag_value_t flag = CAP_CLEAR;
#ifdef __OPTIMIZE__
pa_assert_se(caps = cap_get_proc());
#else
if (!(caps = cap_get_proc()))
return FALSE;
#endif
pa_assert_se(cap_get_flag(caps, CAP_SYS_NICE, CAP_EFFECTIVE, &flag) >= 0);
pa_assert_se(cap_free(caps) == 0);
return flag == CAP_SET;
}
#else
/* NOOPs in case capabilities are not available. */
void pa_limit_caps(void) {
}
void pa_drop_caps(void) {
pa_drop_root();
}
pa_bool_t pa_have_caps(void) {
return FALSE;
}
#endif
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