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/* $Id$ */
/***
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 <assert.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#ifdef HAVE_SYS_CAPABILITY_H
#include <sys/capability.h>
#endif
#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#endif
#include <pulsecore/core-error.h>
#include <pulsecore/log.h>
#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 rights.");
#if defined(HAVE_SETRESUID)
setresuid(uid, uid, uid);
#elif defined(HAVE_SETREUID)
setreuid(uid, uid);
#else
setuid(uid);
seteuid(uid);
#endif
}
#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 */
int pa_limit_caps(void) {
int r = -1;
cap_t caps;
cap_value_t nice_cap = CAP_SYS_NICE;
caps = cap_init();
assert(caps);
cap_clear(caps);
cap_set_flag(caps, CAP_PERMITTED, 1, &nice_cap, CAP_SET);
if (cap_set_proc(caps) < 0)
goto fail;
if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) < 0)
goto fail;
pa_log_info("dropped capabilities successfully.");
r = 1;
fail:
cap_free(caps);
return r;
}
/* Drop all capabilities, effectively becoming a normal user */
int pa_drop_caps(void) {
cap_t caps;
int r = -1;
caps = cap_init();
assert(caps);
cap_clear(caps);
prctl(PR_SET_KEEPCAPS, 0, 0, 0, 0);
if (cap_set_proc(caps) < 0) {
pa_log("failed to drop capabilities: %s", pa_cstrerror(errno));
goto fail;
}
r = 0;
fail:
cap_free(caps);
return r;
}
#else
/* NOOPs in case capabilities are not available. */
int pa_limit_caps(void) {
return 0;
}
int pa_drop_caps(void) {
pa_drop_root();
return 0;
}
#endif
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