/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** 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 "path-util.h" #include "selinux-util.h" #include "log.h" #include "macro.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(const char *prefix) { int r = 0; #ifdef HAVE_SELINUX usec_t before_timestamp, after_timestamp; struct mallinfo before_mallinfo, after_mallinfo; if (!mac_selinux_use()) return 0; if (label_hnd) return 0; before_mallinfo = mallinfo(); before_timestamp = now(CLOCK_MONOTONIC); if (prefix) { struct selinux_opt options[] = { { .type = SELABEL_OPT_SUBSET, .value = prefix }, }; label_hnd = selabel_open(SELABEL_CTX_FILE, options, ELEMENTSOF(options)); } else 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(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(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(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(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(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(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(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(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(NULL); return r; skipped: #endif if (bind(fd, addr, addrlen) < 0) return -errno; return 0; }