util: move all to shared/ and split external dependencies in separate internal libraries

Before:
  $ ldd /lib/systemd/systemd-timestamp
  linux-vdso.so.1 =>  (0x00007fffb05ff000)
  libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f90aac57000)
  libcap.so.2 => /lib64/libcap.so.2 (0x00007f90aaa53000)
  librt.so.1 => /lib64/librt.so.1 (0x00007f90aa84a000)
  libc.so.6 => /lib64/libc.so.6 (0x00007f90aa494000)
  /lib64/ld-linux-x86-64.so.2 (0x00007f90aae90000)
  libdl.so.2 => /lib64/libdl.so.2 (0x00007f90aa290000)
  libattr.so.1 => /lib64/libattr.so.1 (0x00007f90aa08a000)
  libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f90a9e6e000)

After:
  $ ldd systemd-timestamp
  linux-vdso.so.1 =>  (0x00007fff3cbff000)
  libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f5eaa1c3000)
  librt.so.1 => /lib64/librt.so.1 (0x00007f5ea9fbb000)
  libc.so.6 => /lib64/libc.so.6 (0x00007f5ea9c04000)
  /lib64/ld-linux-x86-64.so.2 (0x00007f5eaa3fc000)
  libdl.so.2 => /lib64/libdl.so.2 (0x00007f5ea9a00000)
  libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f5ea97e4000)

1 files changed, 413 insertions, 0 deletions

diff --git a/src/shared/label.c b/src/shared/label.c
new file mode 100644
index 000000000..2c887a0fe
--- /dev/null
+++ b/src/shared/label.c
@@ -0,0 +1,413 @@
+/*-*- 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 General Public License as published by
+  the Free Software Foundation; either version 2 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU 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"
+
+#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(void) {
+        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);
+
+        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_info("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) {
+        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;
+
+                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_fifofile_set(const char *path) {
+        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, S_IFIFO);
+        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_symlinkfile_set(const char *path) {
+        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, S_IFLNK);
+        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_file_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) {
+
+        /* Creates a directory and labels it according to the SELinux policy */
+
+#ifdef HAVE_SELINUX
+        int r;
+        security_context_t fcon = NULL;
+
+        if (!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;
+}