summaryrefslogtreecommitdiffstats
path: root/lib/selinux.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/selinux.c')
-rw-r--r--lib/selinux.c203
1 files changed, 203 insertions, 0 deletions
diff --git a/lib/selinux.c b/lib/selinux.c
new file mode 100644
index 0000000..8cc444f
--- /dev/null
+++ b/lib/selinux.c
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2011 , Peter Vrabec <pvrabec@redhat.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the copyright holders or contributors may not be used to
+ * endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#ifdef WITH_SELINUX
+
+#include <stdio.h>
+#include "defines.h"
+
+#include <selinux/selinux.h>
+#include <selinux/context.h>
+#include "prototypes.h"
+
+static bool selinux_checked = false;
+static bool selinux_enabled;
+
+/*
+ * set_selinux_file_context - Set the security context before any file or
+ * directory creation.
+ *
+ * set_selinux_file_context () should be called before any creation
+ * of file, symlink, directory, ...
+ *
+ * Callers may have to Reset SELinux to create files with default
+ * contexts with reset_selinux_file_context
+ */
+int set_selinux_file_context (const char *dst_name)
+{
+ /*@null@*/security_context_t scontext = NULL;
+
+ if (!selinux_checked) {
+ selinux_enabled = is_selinux_enabled () > 0;
+ selinux_checked = true;
+ }
+
+ if (selinux_enabled) {
+ /* Get the default security context for this file */
+ if (matchpathcon (dst_name, 0, &scontext) < 0) {
+ if (security_getenforce () != 0) {
+ return 1;
+ }
+ }
+ /* Set the security context for the next created file */
+ if (setfscreatecon (scontext) < 0) {
+ if (security_getenforce () != 0) {
+ return 1;
+ }
+ }
+ freecon (scontext);
+ }
+ return 0;
+}
+
+/*
+ * reset_selinux_file_context - Reset the security context to the default
+ * policy behavior
+ *
+ * reset_selinux_file_context () should be called after the context
+ * was changed with set_selinux_file_context ()
+ */
+int reset_selinux_file_context (void)
+{
+ if (!selinux_checked) {
+ selinux_enabled = is_selinux_enabled () > 0;
+ selinux_checked = true;
+ }
+ if (selinux_enabled) {
+ if (setfscreatecon (NULL) != 0) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/*
+ * Log callback for libselinux internal error reporting.
+ */
+__attribute__((__format__ (printf, 2, 3)))
+static int selinux_log_cb (int type, const char *fmt, ...) {
+ va_list ap;
+ char *buf;
+ int r;
+#ifdef WITH_AUDIT
+ static int selinux_audit_fd = -2;
+#endif
+
+ va_start (ap, fmt);
+ r = vasprintf (&buf, fmt, ap);
+ va_end (ap);
+
+ if (r < 0) {
+ return 0;
+ }
+
+#ifdef WITH_AUDIT
+ if (-2 == selinux_audit_fd) {
+ selinux_audit_fd = audit_open ();
+
+ if (-1 == selinux_audit_fd) {
+ /* You get these only when the kernel doesn't have
+ * audit compiled in. */
+ if ( (errno != EINVAL)
+ && (errno != EPROTONOSUPPORT)
+ && (errno != EAFNOSUPPORT)) {
+
+ (void) fputs (_("Cannot open audit interface.\n"),
+ stderr);
+ SYSLOG ((LOG_WARN, "Cannot open audit interface."));
+ }
+ }
+ }
+
+ if (-1 != selinux_audit_fd) {
+ if (SELINUX_AVC == type) {
+ if (audit_log_user_avc_message (selinux_audit_fd,
+ AUDIT_USER_AVC, buf, NULL, NULL,
+ NULL, 0) > 0) {
+ goto skip_syslog;
+ }
+ } else if (SELINUX_ERROR == type) {
+ if (audit_log_user_avc_message (selinux_audit_fd,
+ AUDIT_USER_SELINUX_ERR, buf, NULL, NULL,
+ NULL, 0) > 0) {
+ goto skip_syslog;
+ }
+ }
+ }
+#endif
+
+ SYSLOG ((LOG_WARN, "libselinux: %s", buf));
+
+skip_syslog:
+ free (buf);
+
+ return 0;
+}
+
+/*
+ * check_selinux_permit - Check whether SELinux grants the given
+ * operation
+ *
+ * Parameter is the SELinux permission name, e.g. rootok
+ *
+ * Returns 0 when permission is granted
+ * or something failed but running in
+ * permissive mode
+ */
+int check_selinux_permit (const char *perm_name)
+{
+ char *user_context_str;
+ int r;
+
+ if (0 == is_selinux_enabled ()) {
+ return 0;
+ }
+
+ selinux_set_callback (SELINUX_CB_LOG, (union selinux_callback) selinux_log_cb);
+
+ if (getprevcon (&user_context_str) != 0) {
+ fprintf (stderr,
+ _("%s: can not get previous SELinux process context: %s\n"),
+ Prog, strerror (errno));
+ SYSLOG ((LOG_WARN,
+ "can not get previous SELinux process context: %s",
+ strerror (errno)));
+ return (security_getenforce () != 0);
+ }
+
+ r = selinux_check_access (user_context_str, user_context_str, "passwd", perm_name, NULL);
+ freecon (user_context_str);
+ return r;
+}
+
+#else /* !WITH_SELINUX */
+extern int errno; /* warning: ANSI C forbids an empty source file */
+#endif /* !WITH_SELINUX */