| /*** |
| This file is part of systemd. |
| |
| Copyright 2010 Lennart Poettering |
| |
| systemd 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. |
| |
| systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <errno.h> |
| #include <malloc.h> |
| #include <stddef.h> |
| #include <string.h> |
| #include <sys/stat.h> |
| #include <sys/time.h> |
| #include <sys/un.h> |
| #include <syslog.h> |
| |
| #ifdef HAVE_SELINUX |
| #include <selinux/context.h> |
| #include <selinux/label.h> |
| #include <selinux/selinux.h> |
| #endif |
| |
| #include "alloc-util.h" |
| #include "log.h" |
| #include "macro.h" |
| #include "path-util.h" |
| #include "selinux-util.h" |
| #include "time-util.h" |
| #include "util.h" |
| |
| #ifdef HAVE_SELINUX |
| DEFINE_TRIVIAL_CLEANUP_FUNC(security_context_t, freecon); |
| DEFINE_TRIVIAL_CLEANUP_FUNC(context_t, context_free); |
| |
| #define _cleanup_security_context_free_ _cleanup_(freeconp) |
| #define _cleanup_context_free_ _cleanup_(context_freep) |
| |
| static int cached_use = -1; |
| static struct selabel_handle *label_hnd = NULL; |
| |
| #define log_enforcing(...) log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG, __VA_ARGS__) |
| #endif |
| |
| bool mac_selinux_have(void) { |
| #ifdef HAVE_SELINUX |
| if (cached_use < 0) |
| cached_use = is_selinux_enabled() > 0; |
| |
| return cached_use; |
| #else |
| return false; |
| #endif |
| } |
| |
| bool mac_selinux_use(void) { |
| if (!mac_selinux_have()) |
| return false; |
| |
| /* Never try to configure SELinux features if we aren't |
| * root */ |
| |
| return getuid() == 0; |
| } |
| |
| void mac_selinux_retest(void) { |
| #ifdef HAVE_SELINUX |
| cached_use = -1; |
| #endif |
| } |
| |
| int mac_selinux_init(void) { |
| int r = 0; |
| |
| #ifdef HAVE_SELINUX |
| usec_t before_timestamp, after_timestamp; |
| struct mallinfo before_mallinfo, after_mallinfo; |
| |
| if (label_hnd) |
| return 0; |
| |
| if (!mac_selinux_use()) |
| return 0; |
| |
| before_mallinfo = mallinfo(); |
| before_timestamp = now(CLOCK_MONOTONIC); |
| |
| label_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0); |
| if (!label_hnd) { |
| log_enforcing("Failed to initialize SELinux context: %m"); |
| r = security_getenforce() == 1 ? -errno : 0; |
| } else { |
| char timespan[FORMAT_TIMESPAN_MAX]; |
| int l; |
| |
| after_timestamp = now(CLOCK_MONOTONIC); |
| after_mallinfo = mallinfo(); |
| |
| l = after_mallinfo.uordblks > before_mallinfo.uordblks ? after_mallinfo.uordblks - before_mallinfo.uordblks : 0; |
| |
| log_debug("Successfully loaded SELinux database in %s, size on heap is %iK.", |
| format_timespan(timespan, sizeof(timespan), after_timestamp - before_timestamp, 0), |
| (l+1023)/1024); |
| } |
| #endif |
| |
| return r; |
| } |
| |
| void mac_selinux_finish(void) { |
| |
| #ifdef HAVE_SELINUX |
| if (!label_hnd) |
| return; |
| |
| selabel_close(label_hnd); |
| label_hnd = NULL; |
| #endif |
| } |
| |
| int mac_selinux_fix(const char *path, bool ignore_enoent, bool ignore_erofs) { |
| |
| #ifdef HAVE_SELINUX |
| struct stat st; |
| int r; |
| |
| assert(path); |
| |
| /* if mac_selinux_init() wasn't called before we are a NOOP */ |
| if (!label_hnd) |
| return 0; |
| |
| r = lstat(path, &st); |
| if (r >= 0) { |
| _cleanup_security_context_free_ security_context_t fcon = NULL; |
| |
| r = selabel_lookup_raw(label_hnd, &fcon, path, st.st_mode); |
| |
| /* If there's no label to set, then exit without warning */ |
| if (r < 0 && errno == ENOENT) |
| return 0; |
| |
| if (r >= 0) { |
| r = lsetfilecon_raw(path, fcon); |
| |
| /* If the FS doesn't support labels, then exit without warning */ |
| if (r < 0 && errno == EOPNOTSUPP) |
| return 0; |
| } |
| } |
| |
| if (r < 0) { |
| /* Ignore ENOENT in some cases */ |
| if (ignore_enoent && errno == ENOENT) |
| return 0; |
| |
| if (ignore_erofs && errno == EROFS) |
| return 0; |
| |
| log_enforcing("Unable to fix SELinux security context of %s: %m", path); |
| if (security_getenforce() == 1) |
| return -errno; |
| } |
| #endif |
| |
| return 0; |
| } |
| |
| int mac_selinux_apply(const char *path, const char *label) { |
| |
| #ifdef HAVE_SELINUX |
| if (!mac_selinux_use()) |
| return 0; |
| |
| assert(path); |
| assert(label); |
| |
| if (setfilecon(path, (security_context_t) label) < 0) { |
| log_enforcing("Failed to set SELinux security context %s on path %s: %m", label, path); |
| if (security_getenforce() > 0) |
| return -errno; |
| } |
| #endif |
| return 0; |
| } |
| |
| int mac_selinux_get_create_label_from_exe(const char *exe, char **label) { |
| int r = -EOPNOTSUPP; |
| |
| #ifdef HAVE_SELINUX |
| _cleanup_security_context_free_ security_context_t mycon = NULL, fcon = NULL; |
| security_class_t sclass; |
| |
| assert(exe); |
| assert(label); |
| |
| if (!mac_selinux_have()) |
| return -EOPNOTSUPP; |
| |
| r = getcon_raw(&mycon); |
| if (r < 0) |
| return -errno; |
| |
| r = getfilecon_raw(exe, &fcon); |
| if (r < 0) |
| return -errno; |
| |
| sclass = string_to_security_class("process"); |
| r = security_compute_create_raw(mycon, fcon, sclass, (security_context_t *) label); |
| if (r < 0) |
| return -errno; |
| #endif |
| |
| return r; |
| } |
| |
| int mac_selinux_get_our_label(char **label) { |
| int r = -EOPNOTSUPP; |
| |
| assert(label); |
| |
| #ifdef HAVE_SELINUX |
| if (!mac_selinux_have()) |
| return -EOPNOTSUPP; |
| |
| r = getcon_raw(label); |
| if (r < 0) |
| return -errno; |
| #endif |
| |
| return r; |
| } |
| |
| int mac_selinux_get_child_mls_label(int socket_fd, const char *exe, const char *exec_label, char **label) { |
| int r = -EOPNOTSUPP; |
| |
| #ifdef HAVE_SELINUX |
| _cleanup_security_context_free_ security_context_t mycon = NULL, peercon = NULL, fcon = NULL; |
| _cleanup_context_free_ context_t pcon = NULL, bcon = NULL; |
| security_class_t sclass; |
| const char *range = NULL; |
| |
| assert(socket_fd >= 0); |
| assert(exe); |
| assert(label); |
| |
| if (!mac_selinux_have()) |
| return -EOPNOTSUPP; |
| |
| r = getcon_raw(&mycon); |
| if (r < 0) |
| return -errno; |
| |
| r = getpeercon_raw(socket_fd, &peercon); |
| if (r < 0) |
| return -errno; |
| |
| if (!exec_label) { |
| /* If there is no context set for next exec let's use context |
| of target executable */ |
| r = getfilecon_raw(exe, &fcon); |
| if (r < 0) |
| return -errno; |
| } |
| |
| bcon = context_new(mycon); |
| if (!bcon) |
| return -ENOMEM; |
| |
| pcon = context_new(peercon); |
| if (!pcon) |
| return -ENOMEM; |
| |
| range = context_range_get(pcon); |
| if (!range) |
| return -errno; |
| |
| r = context_range_set(bcon, range); |
| if (r) |
| return -errno; |
| |
| freecon(mycon); |
| mycon = strdup(context_str(bcon)); |
| if (!mycon) |
| return -ENOMEM; |
| |
| sclass = string_to_security_class("process"); |
| r = security_compute_create_raw(mycon, fcon, sclass, (security_context_t *) label); |
| if (r < 0) |
| return -errno; |
| #endif |
| |
| return r; |
| } |
| |
| char* mac_selinux_free(char *label) { |
| |
| #ifdef HAVE_SELINUX |
| if (!label) |
| return NULL; |
| |
| if (!mac_selinux_have()) |
| return NULL; |
| |
| |
| freecon((security_context_t) label); |
| #endif |
| |
| return NULL; |
| } |
| |
| int mac_selinux_create_file_prepare(const char *path, mode_t mode) { |
| |
| #ifdef HAVE_SELINUX |
| _cleanup_security_context_free_ security_context_t filecon = NULL; |
| int r; |
| |
| assert(path); |
| |
| if (!label_hnd) |
| return 0; |
| |
| if (path_is_absolute(path)) |
| r = selabel_lookup_raw(label_hnd, &filecon, path, mode); |
| else { |
| _cleanup_free_ char *newpath = NULL; |
| |
| r = path_make_absolute_cwd(path, &newpath); |
| if (r < 0) |
| return r; |
| |
| r = selabel_lookup_raw(label_hnd, &filecon, newpath, mode); |
| } |
| |
| if (r < 0) { |
| /* No context specified by the policy? Proceed without setting it. */ |
| if (errno == ENOENT) |
| return 0; |
| |
| log_enforcing("Failed to determine SELinux security context for %s: %m", path); |
| } else { |
| if (setfscreatecon_raw(filecon) >= 0) |
| return 0; /* Success! */ |
| |
| log_enforcing("Failed to set SELinux security context %s for %s: %m", filecon, path); |
| } |
| |
| if (security_getenforce() > 0) |
| return -errno; |
| |
| #endif |
| return 0; |
| } |
| |
| void mac_selinux_create_file_clear(void) { |
| |
| #ifdef HAVE_SELINUX |
| PROTECT_ERRNO; |
| |
| if (!mac_selinux_use()) |
| return; |
| |
| setfscreatecon_raw(NULL); |
| #endif |
| } |
| |
| int mac_selinux_create_socket_prepare(const char *label) { |
| |
| #ifdef HAVE_SELINUX |
| if (!mac_selinux_use()) |
| return 0; |
| |
| assert(label); |
| |
| if (setsockcreatecon((security_context_t) label) < 0) { |
| log_enforcing("Failed to set SELinux security context %s for sockets: %m", label); |
| |
| if (security_getenforce() == 1) |
| return -errno; |
| } |
| #endif |
| |
| return 0; |
| } |
| |
| void mac_selinux_create_socket_clear(void) { |
| |
| #ifdef HAVE_SELINUX |
| PROTECT_ERRNO; |
| |
| if (!mac_selinux_use()) |
| return; |
| |
| setsockcreatecon_raw(NULL); |
| #endif |
| } |
| |
| int mac_selinux_bind(int fd, const struct sockaddr *addr, socklen_t addrlen) { |
| |
| /* Binds a socket and label its file system object according to the SELinux policy */ |
| |
| #ifdef HAVE_SELINUX |
| _cleanup_security_context_free_ security_context_t fcon = NULL; |
| const struct sockaddr_un *un; |
| bool context_changed = false; |
| char *path; |
| int r; |
| |
| assert(fd >= 0); |
| assert(addr); |
| assert(addrlen >= sizeof(sa_family_t)); |
| |
| if (!label_hnd) |
| goto skipped; |
| |
| /* Filter out non-local sockets */ |
| if (addr->sa_family != AF_UNIX) |
| goto skipped; |
| |
| /* Filter out anonymous sockets */ |
| if (addrlen < offsetof(struct sockaddr_un, sun_path) + 1) |
| goto skipped; |
| |
| /* Filter out abstract namespace sockets */ |
| un = (const struct sockaddr_un*) addr; |
| if (un->sun_path[0] == 0) |
| goto skipped; |
| |
| path = strndupa(un->sun_path, addrlen - offsetof(struct sockaddr_un, sun_path)); |
| |
| if (path_is_absolute(path)) |
| r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFSOCK); |
| else { |
| _cleanup_free_ char *newpath = NULL; |
| |
| r = path_make_absolute_cwd(path, &newpath); |
| if (r < 0) |
| return r; |
| |
| r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFSOCK); |
| } |
| |
| if (r < 0) { |
| /* No context specified by the policy? Proceed without setting it */ |
| if (errno == ENOENT) |
| goto skipped; |
| |
| log_enforcing("Failed to determine SELinux security context for %s: %m", path); |
| if (security_getenforce() > 0) |
| return -errno; |
| |
| } else { |
| if (setfscreatecon_raw(fcon) < 0) { |
| log_enforcing("Failed to set SELinux security context %s for %s: %m", fcon, path); |
| if (security_getenforce() > 0) |
| return -errno; |
| } else |
| context_changed = true; |
| } |
| |
| r = bind(fd, addr, addrlen) < 0 ? -errno : 0; |
| |
| if (context_changed) |
| setfscreatecon_raw(NULL); |
| |
| return r; |
| |
| skipped: |
| #endif |
| if (bind(fd, addr, addrlen) < 0) |
| return -errno; |
| |
| return 0; |
| } |