Fix for new Kerberos4. Make a fist cut at PAM-ising while I'm here.

1 files changed, 142 insertions, 0 deletions

diff --git a/libexec/rlogind/auth_pam.c b/libexec/rlogind/auth_pam.c
new file mode 100644
index 0000000..e452107
--- /dev/null
+++ b/libexec/rlogind/auth_pam.c
@@ -0,0 +1,142 @@
+/*-
+ * Copyright (c) 1999 John Polstra
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ *
+ *	$FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <security/pam_appl.h>
+#include <security/pam_misc.h>
+#include <paths.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+/*
+ * Attempt to authenticate the user using PAM.  Returns 0 if the user is
+ * authenticated, or 1 if not authenticated.  If some sort of PAM system
+ * error occurs (e.g., the "/etc/pam.conf" file is missing) then this
+ * function returns -1.  This can be used as an indication that we should
+ * fall back to a different authentication mechanism.
+ */
+
+int
+auth_pam(char *username)
+{
+	struct passwd *pawd;
+	pam_handle_t *pamh = NULL;
+	const char *tmpl_user;
+	const void *item;
+	int rval;
+	char *tty, *ttyn;
+	char hostname[MAXHOSTNAMELEN];
+	char tname[sizeof(_PATH_TTY) + 10];
+	int e;
+
+	static struct pam_conv conv = { misc_conv, NULL };
+
+	ttyn = ttyname(STDIN_FILENO);
+
+	if (ttyn == NULL || *ttyn == '\0') {
+		(void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
+		ttyn = tname;
+	}
+	if ((tty = strrchr(ttyn, '/')) != NULL)
+		++tty;
+	else
+		tty = ttyn;
+
+	rval = gethostname(hostname, sizeof(hostname));
+
+	if (rval < 0) {
+		syslog(LOG_ERR, "auth_pam: Failed to resolve local hostname");
+		return -1;
+	}
+	if ((e = pam_start("rshd", username, &conv, &pamh)) != PAM_SUCCESS) {
+		syslog(LOG_ERR, "pam_start: %s", pam_strerror(pamh, e));
+		return -1;
+	}
+	if ((e = pam_set_item(pamh, PAM_TTY, tty)) != PAM_SUCCESS) {
+		syslog(LOG_ERR, "pam_set_item(PAM_TTY): %s",
+			pam_strerror(pamh, e));
+		return -1;
+	}
+	if (hostname != NULL &&
+		(e = pam_set_item(pamh,PAM_RHOST, hostname)) != PAM_SUCCESS) {
+		syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s",
+			pam_strerror(pamh, e));
+		return -1;
+	}
+
+	e = pam_authenticate(pamh, 0);
+
+	switch (e) {
+	case PAM_SUCCESS:
+		/*
+		 * With PAM we support the concept of a "template"
+		 * user.  The user enters a login name which is
+		 * authenticated by PAM, usually via a remote service
+		 * such as RADIUS or TACACS+.  If authentication
+		 * succeeds, a different but related "template" name
+		 * is used for setting the credentials, shell, and
+		 * home directory.  The name the user enters need only
+		 * exist on the remote authentication server, but the
+		 * template name must be present in the local password
+		 * database.
+		 *
+		 * This is supported by two various mechanisms in the
+		 * individual modules.  However, from the application's
+		 * point of view, the template user is always passed
+		 * back as a changed value of the PAM_USER item.
+		 */
+		if ((e = pam_get_item(pamh, PAM_USER, &item)) ==
+			PAM_SUCCESS) {
+			    tmpl_user = (const char *) item;
+			    if (strcmp(username, tmpl_user) != 0)
+			            pawd = getpwnam(tmpl_user);
+		} else
+			    syslog(LOG_ERR, "Couldn't get PAM_USER: %s", pam_strerror(pamh, e));
+		rval = 0;
+		break;
+
+	case PAM_AUTH_ERR:
+	case PAM_USER_UNKNOWN:
+	case PAM_MAXTRIES:
+		rval = 1;
+		break;
+
+	default:
+		syslog(LOG_ERR, "auth_pam: %s", pam_strerror(pamh, e));
+		rval = -1;
+		break;
+	}
+	if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
+		syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
+		rval = -1;
+	}
+	return rval;
+}