diff options
author | Lennart Poettering <lennart@poettering.net> | 2005-10-30 18:21:57 +0000 |
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committer | Lennart Poettering <lennart@poettering.net> | 2005-10-30 18:21:57 +0000 |
commit | aedd4e87362371d83dd64d0bfb03ea3e5526607f (patch) | |
tree | cbe35acdb665b1ffeb0fa81220cb0d44549dfc4c /avahi-daemon/caps.c | |
parent | d8260fdf4310e135f301d0b8296aeffa02f5f494 (diff) |
* add chroot() support on Linux
git-svn-id: file:///home/lennart/svn/public/avahi/trunk@907 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe
Diffstat (limited to 'avahi-daemon/caps.c')
-rw-r--r-- | avahi-daemon/caps.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/avahi-daemon/caps.c b/avahi-daemon/caps.c new file mode 100644 index 0000000..2d0f39a --- /dev/null +++ b/avahi-daemon/caps.c @@ -0,0 +1,116 @@ +/* $Id$ */ + +/*** + This file is part of avahi. + + avahi 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 2.1 of the + License, or (at your option) any later version. + + avahi 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 Lesser General + Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with avahi; 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 <errno.h> +#include <string.h> +#include <sys/capability.h> +#include <sys/prctl.h> + +#include <avahi-core/log.h> + +#include "caps.h" + +int avahi_caps_reduce(void) { + int ret = 0; + cap_t caps; + static cap_value_t cap_values[] = { CAP_SYS_CHROOT, CAP_SETUID, CAP_SETGID }; + + /* Let's reduce our caps to the minimum set and tell Linux to keep + * them accross setuid(). This is called before we droppped + * priviliges. */ + + caps = cap_init(); + assert(caps); + cap_clear(caps); + + cap_set_flag(caps, CAP_EFFECTIVE, 3, cap_values, CAP_SET); + cap_set_flag(caps, CAP_PERMITTED, 3, cap_values, CAP_SET); + + if (cap_set_proc(caps) < 0) { + avahi_log_error("cap_set_proc() failed: %s", strerror(errno)); + ret = -1; + } + cap_free(caps); + + /* Retain capabilities accros setuid() */ + if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) < 0) { + avahi_log_error("prctl(PR_SET_KEEPCAPS) failed: %s", strerror(errno)); + ret = -1; + } + + return ret; +} + +int avahi_caps_reduce2(void) { + int ret = 0; + cap_t caps; + static cap_value_t cap_values[] = { CAP_SYS_CHROOT }; + + /* Reduce our caps to the bare minimum and tell Linux not to keep + * them across setuid(). This is called after we dropped + * privilige. */ + + /* No longer retain caps across setuid() */ + if (prctl(PR_SET_KEEPCAPS, 0, 0, 0, 0) < 0) { + avahi_log_error("prctl(PR_SET_KEEPCAPS) failed: %s", strerror(errno)); + ret = -1; + } + + caps = cap_init(); + assert(caps); + cap_clear(caps); + + /* setuid() zeroed our effective caps, let's get them back */ + cap_set_flag(caps, CAP_EFFECTIVE, 1, cap_values, CAP_SET); + cap_set_flag(caps, CAP_PERMITTED, 1, cap_values, CAP_SET); + + if (cap_set_proc(caps) < 0) { + avahi_log_error("cap_set_proc() failed: %s", strerror(errno)); + ret = -1; + } + cap_free(caps); + + return ret; +} + +int avahi_caps_drop_all(void) { + cap_t caps; + int ret = 0; + + /* Drop all capabilities and turn ourselves into a normal user process */ + + caps = cap_init(); + assert(caps); + cap_clear(caps); + + if (cap_set_proc(caps) < 0) { + avahi_log_error("cap_set_proc() failed: %s", strerror(errno)); + ret = -1; + } + cap_free(caps); + + return ret; +} |