1/*** 2 This file is part of PulseAudio. 3 4 Copyright 2004-2006 Lennart Poettering 5 Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB 6 7 PulseAudio is free software; you can redistribute it and/or modify 8 it under the terms of the GNU Lesser General Public License as published 9 by the Free Software Foundation; either version 2.1 of the License, 10 or (at your option) any later version. 11 12 PulseAudio is distributed in the hope that it will be useful, but 13 WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 General Public License for more details. 16 17 You should have received a copy of the GNU Lesser General Public License 18 along with PulseAudio; if not, see <http://www.gnu.org/licenses/>. 19***/ 20 21#ifdef HAVE_CONFIG_H 22#include <config.h> 23#endif 24 25#include <unistd.h> 26#include <errno.h> 27#include <sys/types.h> 28 29#include <pulsecore/i18n.h> 30#include <pulsecore/macro.h> 31#include <pulsecore/log.h> 32 33#ifdef HAVE_SYS_CAPABILITY_H 34#include <sys/capability.h> 35#endif 36 37#include "caps.h" 38 39/* Glibc <= 2.2 has broken unistd.h */ 40#if defined(__linux__) && (__GLIBC__ <= 2 && __GLIBC_MINOR__ <= 2) 41int setresgid(gid_t r, gid_t e, gid_t s); 42int setresuid(uid_t r, uid_t e, uid_t s); 43#endif 44 45/* Drop root rights when called SUID root */ 46void pa_drop_root(void) { 47 48#ifdef HAVE_GETUID 49 uid_t uid; 50 gid_t gid; 51 52 pa_log_debug("Cleaning up privileges."); 53 uid = getuid(); 54 gid = getgid(); 55 56#if defined(HAVE_SETRESUID) 57 pa_assert_se(setresuid(uid, uid, uid) >= 0); 58 pa_assert_se(setresgid(gid, gid, gid) >= 0); 59#elif defined(HAVE_SETREUID) 60 pa_assert_se(setreuid(uid, uid) >= 0); 61 pa_assert_se(setregid(gid, gid) >= 0); 62#else 63 pa_assert_se(setuid(uid) >= 0); 64 pa_assert_se(seteuid(uid) >= 0); 65 pa_assert_se(setgid(gid) >= 0); 66 pa_assert_se(setegid(gid) >= 0); 67#endif 68 69 pa_assert_se(getuid() == uid); 70 pa_assert_se(geteuid() == uid); 71 pa_assert_se(getgid() == gid); 72 pa_assert_se(getegid() == gid); 73 74 if (uid != 0) 75 pa_drop_caps(); 76#endif 77} 78 79void pa_drop_caps(void) { 80#ifdef HAVE_SYS_CAPABILITY_H 81#if defined(__linux__) 82 cap_t caps; 83 pa_assert_se(caps = cap_init()); 84 pa_assert_se(cap_clear(caps) == 0); 85 pa_assert_se(cap_set_proc(caps) == 0); 86 pa_assert_se(cap_free(caps) == 0); 87#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) 88 /* FreeBSD doesn't have this functionality, even though sys/capability.h is 89 * available. See https://bugs.freedesktop.org/show_bug.cgi?id=72580 */ 90 pa_log_warn("FreeBSD cannot drop extra capabilities, implementation needed."); 91#else 92#error "Don't know how to do capabilities on your system. Please send a patch." 93#endif /* __linux__ */ 94#else /* HAVE_SYS_CAPABILITY_H */ 95 pa_log_warn("Normally all extra capabilities would be dropped now, but " 96 "that's impossible because PulseAudio was built without " 97 "capabilities support."); 98#endif 99} 100