/*-*- 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 <sys/stat.h> #include <unistd.h> #include <malloc.h> #include <sys/socket.h> #include <sys/un.h> #include "label.h" #include "util.h" #include "path-util.h" #ifdef HAVE_SELINUX #include <selinux/selinux.h> #include <selinux/label.h> static struct selabel_handle *label_hnd = NULL; static int use_selinux_cached = -1; static inline bool use_selinux(void) { if (use_selinux_cached < 0) use_selinux_cached = is_selinux_enabled() > 0; return use_selinux_cached; } void label_retest_selinux(void) { use_selinux_cached = -1; } #endif int label_init(const char *prefix) { int r = 0; #ifdef HAVE_SELINUX usec_t before_timestamp, after_timestamp; struct mallinfo before_mallinfo, after_mallinfo; if (!use_selinux()) 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_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG, "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), (l+1023)/1024); } #endif return r; } int label_fix(const char *path, bool ignore_enoent, bool ignore_erofs) { int r = 0; #ifdef HAVE_SELINUX struct stat st; security_context_t fcon; if (!use_selinux() || !label_hnd) return 0; r = lstat(path, &st); if (r == 0) { 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); freecon(fcon); /* If the FS doesn't support labels, then exit without warning */ if (r < 0 && errno == ENOTSUP) 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_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG, "Unable to fix label of %s: %m", path); r = security_getenforce() == 1 ? -errno : 0; } #endif return r; } void label_finish(void) { #ifdef HAVE_SELINUX if (use_selinux() && label_hnd) selabel_close(label_hnd); #endif } int label_get_create_label_from_exe(const char *exe, char **label) { int r = 0; #ifdef HAVE_SELINUX security_context_t mycon = NULL, fcon = NULL; security_class_t sclass; if (!use_selinux()) { *label = NULL; return 0; } r = getcon(&mycon); if (r < 0) goto fail; r = getfilecon(exe, &fcon); if (r < 0) goto fail; sclass = string_to_security_class("process"); r = security_compute_create(mycon, fcon, sclass, (security_context_t *) label); if (r == 0) log_debug("SELinux Socket context for %s will be set to %s", exe, *label); fail: if (r < 0 && security_getenforce() == 1) r = -errno; freecon(mycon); freecon(fcon); #endif return r; } int label_context_set(const char *path, mode_t mode) { int r = 0; #ifdef HAVE_SELINUX security_context_t filecon = NULL; if (!use_selinux() || !label_hnd) return 0; r = selabel_lookup_raw(label_hnd, &filecon, path, mode); if (r < 0) r = -errno; else if (r == 0) { r = setfscreatecon(filecon); if (r < 0) { log_error("Failed to set SELinux file context on %s: %m", path); r = -errno; } freecon(filecon); } if (r < 0 && security_getenforce() == 0) r = 0; #endif return r; } int label_socket_set(const char *label) { #ifdef HAVE_SELINUX if (!use_selinux()) return 0; if (setsockcreatecon((security_context_t) label) < 0) { log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG, "Failed to set SELinux context (%s) on socket: %m", label); if (security_getenforce() == 1) return -errno; } #endif return 0; } void label_context_clear(void) { #ifdef HAVE_SELINUX if (!use_selinux()) return; setfscreatecon(NULL); #endif } void label_socket_clear(void) { #ifdef HAVE_SELINUX if (!use_selinux()) return; setsockcreatecon(NULL); #endif } void label_free(const char *label) { #ifdef HAVE_SELINUX if (!use_selinux()) return; freecon((security_context_t) label); #endif } int label_mkdir(const char *path, mode_t mode, bool apply) { /* Creates a directory and labels it according to the SELinux policy */ #ifdef HAVE_SELINUX int r; security_context_t fcon = NULL; if (!apply || !use_selinux() || !label_hnd) goto skipped; if (path_is_absolute(path)) r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFDIR); else { char *newpath; newpath = path_make_absolute_cwd(path); if (!newpath) return -ENOMEM; r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFDIR); free(newpath); } if (r == 0) r = setfscreatecon(fcon); if (r < 0 && errno != ENOENT) { log_error("Failed to set security context %s for %s: %m", fcon, path); if (security_getenforce() == 1) { r = -errno; goto finish; } } r = mkdir(path, mode); if (r < 0) r = -errno; finish: setfscreatecon(NULL); freecon(fcon); return r; skipped: #endif return mkdir(path, mode) < 0 ? -errno : 0; } int label_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 int r; security_context_t fcon = NULL; const struct sockaddr_un *un; char *path = NULL; assert(fd >= 0); assert(addr); assert(addrlen >= sizeof(sa_family_t)); if (!use_selinux() || !label_hnd) goto skipped; /* Filter out non-local sockets */ if (addr->sa_family != AF_UNIX) goto skipped; /* Filter out anonymous sockets */ if (addrlen < sizeof(sa_family_t) + 1) goto skipped; /* Filter out abstract namespace sockets */ un = (const struct sockaddr_un*) addr; if (un->sun_path[0] == 0) goto skipped; path = strndup(un->sun_path, addrlen - offsetof(struct sockaddr_un, sun_path)); if (!path) return -ENOMEM; if (path_is_absolute(path)) r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFSOCK); else { char *newpath; newpath = path_make_absolute_cwd(path); if (!newpath) { free(path); return -ENOMEM; } r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFSOCK); free(newpath); } if (r == 0) r = setfscreatecon(fcon); if (r < 0 && errno != ENOENT) { log_error("Failed to set security context %s for %s: %m", fcon, path); if (security_getenforce() == 1) { r = -errno; goto finish; } } r = bind(fd, addr, addrlen); if (r < 0) r = -errno; finish: setfscreatecon(NULL); freecon(fcon); free(path); return r; skipped: #endif return bind(fd, addr, addrlen) < 0 ? -errno : 0; }