src/shared: refactor shared code

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>

1 files changed, 247 insertions, 0 deletions

diff --git a/src/shared/label.c b/src/shared/label.c
new file mode 100644
index 0000000000..dca2a21228
--- /dev/null
+++ b/src/shared/label.c
@@ -0,0 +1,247 @@
+/*-*- 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 <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 <stdbool.h>
+#include <selinux/selinux.h>
+#include <selinux/label.h>
+
+static struct selabel_handle *label_hnd = NULL;
+static int use_selinux_cached = -1;
+
+bool use_selinux(void) {
+        if (use_selinux_cached < 0)
+                use_selinux_cached = is_selinux_enabled() > 0;
+
+        return use_selinux_cached;
+}
+#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, 0),
+                          (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_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;
+}
+
+void label_context_clear(void) {
+
+#ifdef HAVE_SELINUX
+        if (!use_selinux())
+                return;
+
+        setfscreatecon(NULL);
+#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_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;
+}