Move common credential save and restore code into a separate file.

Improve credential handling in pt_file.c

usr.sbin/mount_portalfs/Makefile

@@ -2,7 +2,7 @@
 # $FreeBSD$
 
 PROG=	mount_portalfs
-SRCS=	mount_portalfs.c activate.c conf.c getmntopts.c pt_conf.c \
+SRCS=	mount_portalfs.c activate.c conf.c cred.c getmntopts.c pt_conf.c \
 	pt_exec.c pt_file.c pt_pipe.c pt_tcp.c pt_tcplisten.c
 MAN=	mount_portalfs.8
 

usr.sbin/mount_portalfs/cred.c

@@ -0,0 +1,75 @@
+/*-
+ * Copyright (C) 2005 Diomidis Spinellis. 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 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 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.
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/syslog.h>
+
+#include "portald.h"
+
+/*
+ * Set the process's credentials to those specified in user,
+ * saveing the existing ones in save.
+ * Return 0 on success, -1 (with errno set) on error.
+ */
+int
+set_user_credentials(struct portal_cred *user, struct portal_cred *save)
+{
+	save->pcr_uid = geteuid();
+	if ((save->pcr_ngroups = getgroups(NGROUPS_MAX, save->pcr_groups)) < 0)
+		return (-1);
+	if (setgroups(user->pcr_ngroups, user->pcr_groups) < 0)
+		return (-1);
+	if (seteuid(user->pcr_uid) < 0)
+		return (-1);
+	return (0);
+}
+
+/*
+ * Restore the process's credentials to the ones specified in save.
+ * Log failures using LOG_ERR.
+ * Return 0 on success, -1 (with errno set) on error.
+ */
+int
+restore_credentials(struct portal_cred *save)
+{
+	if (seteuid(save->pcr_uid) < 0) {
+		syslog(LOG_ERR, "seteuid: %m");
+		return (-1);
+	}
+	if (setgroups(save->pcr_ngroups, save->pcr_groups) < 0) {
+		syslog(LOG_ERR, "setgroups: %m");
+		return (-1);
+	}
+	return (0);
+}

usr.sbin/mount_portalfs/portald.h

@@ -80,3 +80,6 @@ extern int portal_tcplisten(struct portal_cred *,
 extern void activate(qelem *q, int so);
 extern char **conf_match(qelem *q, char *key);
 extern void conf_read(qelem *q, char *conf);
+extern int set_user_credentials(struct portal_cred *user,
+    struct portal_cred *save_area);
+extern int restore_credentials(struct portal_cred *save_area);

usr.sbin/mount_portalfs/pt_file.c

@@ -56,7 +56,7 @@ int *fdp;
 	int fd;
 	char pbuf[MAXPATHLEN];
 	int error;
-	gid_t gidset[NGROUPS];
+	struct portal_cred save_area;
 	int i;
 
 	pbuf[0] = '/';
@@ -67,13 +67,7 @@ int *fdp;
 	printf ("fflag = %x, oflag = %x\n", pcr->pcr_flag, (pcr->pcr_flag)-1);
 #endif
 
-	for (i = 0; i < pcr->pcr_ngroups; i++)
-		gidset[i] = pcr->pcr_groups[i];
-
-	if (setgroups(pcr->pcr_ngroups, gidset) < 0)
-		return (errno);
-
-	if (seteuid(pcr->pcr_uid) < 0)
+	if (set_user_credentials(pcr, &save_area) < 0)
 		return (errno);
 
 	/* dmb convert kernel flags to oflags, see <fcntl.h> */
@@ -83,9 +77,8 @@ int *fdp;
 	else
 		error = 0;
 
-	if (seteuid((uid_t) 0) < 0) {	/* XXX - should reset gidset too */
+	if (restore_credentials(&save_area) < 0) {
 		error = errno;
-		syslog(LOG_ERR, "setcred: %s", strerror(error));
 		if (fd >= 0) {
 			(void) close(fd);
 			fd = -1;

usr.sbin/mount_portalfs/pt_pipe.c

@@ -1,5 +1,5 @@
 /*-
- * Copyright (C) 1005 Diomidis Spinellis. All rights reserved.
+ * Copyright (C) 2005 Diomidis Spinellis. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -64,10 +64,7 @@ int *fdp;
 	int i;
 	char **argv;
 	int argc;
-	/* Variables used to save the the caller's credentials. */
-	uid_t old_uid;
-	int ngroups;
-	gid_t old_groups[NGROUPS_MAX];
+	struct portal_cred save_area;
 
 	/* Validate open mode, and assign roles. */
 	if ((pcr->pcr_flag & FWRITE) && (pcr->pcr_flag & FREAD))
@@ -100,12 +97,7 @@ int *fdp;
 		return (ENOENT);
 
 	/* Swap priviledges. */
-	old_uid = geteuid();
-	if ((ngroups = getgroups(NGROUPS_MAX, old_groups)) < 0)
-		return (errno);
-	if (setgroups(pcr->pcr_ngroups, pcr->pcr_groups) < 0)
-		return (errno);
-	if (seteuid(pcr->pcr_uid) < 0)
+	if (set_user_credentials(pcr, &save_area) < 0)
 		return (errno);
 
 	/* Redirect and spawn the specified process. */
@@ -150,14 +142,8 @@ int *fdp;
 
 done:
 	/* Re-establish our priviledges. */
-	if (seteuid(old_uid) < 0) {
+	if (restore_credentials(&save_area) < 0)
 		error = errno;
-		syslog(LOG_ERR, "seteuid: %m");
-	}
-	if (setgroups(ngroups, old_groups) < 0) {
-		error = errno;
-		syslog(LOG_ERR, "setgroups: %m");
-	}
 
 	/* Set return fd value. */
 	if (error == 0)