diff options
Diffstat (limited to 'src/shared/selinux-util.c')
| -rw-r--r-- | src/shared/selinux-util.c | 481 |
1 files changed, 475 insertions, 6 deletions
diff --git a/src/shared/selinux-util.c b/src/shared/selinux-util.c index 026ae5a9e8..05ed61c6dc 100644 --- a/src/shared/selinux-util.c +++ b/src/shared/selinux-util.c @@ -19,33 +19,502 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ +#include <errno.h> +#include <unistd.h> +#include <malloc.h> +#include <sys/un.h> +#ifdef HAVE_SELINUX +#include <selinux/selinux.h> +#include <selinux/label.h> +#include <selinux/context.h> +#endif + +#include "strv.h" +#include "path-util.h" #include "selinux-util.h" #ifdef HAVE_SELINUX +DEFINE_TRIVIAL_CLEANUP_FUNC(security_context_t, freecon); +DEFINE_TRIVIAL_CLEANUP_FUNC(context_t, context_free); -#include <selinux/selinux.h> +#define _cleanup_security_context_free_ _cleanup_(freeconp) +#define _cleanup_context_free_ _cleanup_(context_freep) static int use_selinux_cached = -1; +static struct selabel_handle *label_hnd = NULL; +#endif bool use_selinux(void) { - +#ifdef HAVE_SELINUX if (use_selinux_cached < 0) use_selinux_cached = is_selinux_enabled() > 0; return use_selinux_cached; +#else + return false; +#endif } void retest_selinux(void) { +#ifdef HAVE_SELINUX use_selinux_cached = -1; +#endif } -#else +int label_init(const char *prefix) { + int r = 0; -bool use_selinux(void) { - return false; +#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, 0), + (l+1023)/1024); + } +#endif + + return r; } -void retest_selinux(void) { +int label_fix_selinux(const char *path, bool ignore_enoent, bool ignore_erofs) { + int r = 0; + +#ifdef HAVE_SELINUX + struct stat st; + security_context_t fcon; + + if (!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()) + return; + + if (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_get_our_label(char **label) { + int r = -EOPNOTSUPP; + +#ifdef HAVE_SELINUX + char *l = NULL; + + r = getcon(&l); + if (r < 0) + return r; + + *label = l; #endif + + return r; +} + +int label_get_child_mls_label(int socket_fd, const char *exe, char **label) { + int r = -EOPNOTSUPP; + +#ifdef HAVE_SELINUX + + _cleanup_security_context_free_ security_context_t mycon = NULL, peercon = NULL, fcon = NULL, ret = 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); + + r = getcon(&mycon); + if (r < 0) { + r = -EINVAL; + goto out; + } + + r = getpeercon(socket_fd, &peercon); + if (r < 0) { + r = -EINVAL; + goto out; + } + + r = getexeccon(&fcon); + if (r < 0) { + r = -EINVAL; + goto out; + } + + if (!fcon) { + /* If there is no context set for next exec let's use context + of target executable */ + r = getfilecon(exe, &fcon); + if (r < 0) { + r = -errno; + goto out; + } + } + + bcon = context_new(mycon); + if (!bcon) { + r = -ENOMEM; + goto out; + } + + pcon = context_new(peercon); + if (!pcon) { + r = -ENOMEM; + goto out; + } + + range = context_range_get(pcon); + if (!range) { + r = -errno; + goto out; + } + + r = context_range_set(bcon, range); + if (r) { + r = -errno; + goto out; + } + + freecon(mycon); + mycon = strdup(context_str(bcon)); + if (!mycon) { + r = -errno; + goto out; + } + + sclass = string_to_security_class("process"); + r = security_compute_create(mycon, fcon, sclass, &ret); + if (r < 0) { + r = -EINVAL; + goto out; + } + + *label = ret; + ret = NULL; + r = 0; + +out: + if (r < 0 && security_getenforce() == 1) + return r; +#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 && errno != ENOENT) + 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 + PROTECT_ERRNO; + + if (!use_selinux()) + return; + + setfscreatecon(NULL); +#endif +} + +void label_socket_clear(void) { + +#ifdef HAVE_SELINUX + PROTECT_ERRNO; + + 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_selinux(const char *path, mode_t mode) { + int r = 0; + +#ifdef HAVE_SELINUX + /* Creates a directory and labels it according to the SELinux policy */ + security_context_t fcon = NULL; + + if (!label_hnd) + return 0; + + if (path_is_absolute(path)) + r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFDIR); + else { + _cleanup_free_ char *newpath; + + newpath = path_make_absolute_cwd(path); + if (!newpath) + return -ENOMEM; + + r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFDIR); + } + + 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); +#endif + + return r; +} + +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 + security_context_t fcon = NULL; + const struct sockaddr_un *un; + char *path; + int r; + + 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 = 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; + + newpath = path_make_absolute_cwd(path); + if (!newpath) + return -ENOMEM; + + r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFSOCK); + } + + 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); + + return r; + +skipped: +#endif + return bind(fd, addr, addrlen) < 0 ? -errno : 0; +} + +int label_apply(const char *path, const char *label) { + int r = 0; + +#ifdef HAVE_SELINUX + if (!use_selinux()) + return 0; + + r = setfilecon(path, (char *)label); +#endif + return r; +} |