Adding upstream version 1:4.13+dfsg1.upstream/1%4.13+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 210 insertions, 0 deletions

diff --git a/lib/selinux.c b/lib/selinux.c
new file mode 100644
index 0000000..ad639bd
--- /dev/null
+++ b/lib/selinux.c
@@ -0,0 +1,210 @@
+/*
+ * SPDX-FileCopyrightText: 2011       , Peter Vrabec <pvrabec@redhat.com>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ifdef WITH_SELINUX
+
+#include <stdio.h>
+#include "defines.h"
+
+#include <selinux/selinux.h>
+#include <selinux/label.h>
+#include "prototypes.h"
+
+#include "shadowlog_internal.h"
+
+static bool selinux_checked = false;
+static bool selinux_enabled;
+static /*@null@*/struct selabel_handle *selabel_hnd = NULL;
+
+static void cleanup(void)
+{
+	if (selabel_hnd) {
+		selabel_close(selabel_hnd);
+		selabel_hnd = NULL;
+	}
+}
+
+void reset_selinux_handle (void)
+{
+    cleanup();
+}
+
+/*
+ * 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, mode_t mode)
+{
+	if (!selinux_checked) {
+		selinux_enabled = is_selinux_enabled () > 0;
+		selinux_checked = true;
+	}
+
+	if (selinux_enabled) {
+		/* Get the default security context for this file */
+
+		/*@null@*/char *fcontext_raw = NULL;
+		int r;
+
+		if (selabel_hnd == NULL) {
+			selabel_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0);
+			if (selabel_hnd == NULL) {
+				return security_getenforce () != 0;
+			}
+			(void) atexit(cleanup);
+		}
+
+		r = selabel_lookup_raw(selabel_hnd, &fcontext_raw, dst_name, mode);
+		if (r < 0) {
+			/* No context specified for the searched path */
+			if (errno == ENOENT) {
+				return 0;
+			}
+
+			return security_getenforce () != 0;
+		}
+
+		/* Set the security context for the next created file */
+		r = setfscreatecon_raw (fcontext_raw);
+		freecon (fcontext_raw);
+		if (r < 0) {
+			return security_getenforce () != 0;
+		}
+	}
+	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_raw (NULL) != 0) {
+			return security_getenforce () != 0;
+		}
+	}
+	return 0;
+}
+
+/*
+ *  Log callback for libselinux internal error reporting.
+ */
+format_attr(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"),
+			              shadow_logfd);
+			    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_raw;
+	int r;
+
+	if (0 == is_selinux_enabled ()) {
+		return 0;
+	}
+
+	selinux_set_callback (SELINUX_CB_LOG, (union selinux_callback) selinux_log_cb);
+
+	if (getprevcon_raw (&user_context_raw) != 0) {
+		fprintf (shadow_logfd,
+		    _("%s: can not get previous SELinux process context: %s\n"),
+		    shadow_progname, 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_raw, user_context_raw, "passwd", perm_name, NULL);
+	freecon (user_context_raw);
+	return r;
+}
+
+#else				/* !WITH_SELINUX */
+extern int errno;		/* warning: ANSI C forbids an empty source file */
+#endif				/* !WITH_SELINUX */