Check the result of seteuid(), just to be paranoid.

diff --git a/pppd/auth.c b/pppd/auth.c
index 8e1180ddaa49c7894051e95c08a9fe048890cecf..e78773ef90e3c7b8f6706aed07a66cde99bac88a 100644 (file)
--- a/pppd/auth.c
+++ b/pppd/auth.c
@@ -68,7 +68,7 @@
  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#define RCSID  "$Id: auth.c,v 1.109 2006/05/22 00:04:07 paulus Exp $"
+#define RCSID  "$Id: auth.c,v 1.110 2006/06/04 07:04:57 paulus Exp $"
 
 #include <stdio.h>
 #include <stddef.h>
@@ -418,9 +418,13 @@ setupapfile(argv)
     fname = strdup(*argv);
     if (fname == NULL)
        novm("+ua file name");
-    seteuid(getuid());
+    if (seteuid(getuid()) == -1) {
+       option_error("unable to reset uid before opening %s: %m", fname);
+       return ;
+    }
     ufile = fopen(fname, "r");
-    seteuid(0);
+    if (seteuid(0) == -1)
+       fatal("unable to regain privileges: %m");
     if (ufile == NULL) {
        option_error("unable to open user login data file %s", fname);
        return 0;

diff --git a/pppd/options.c b/pppd/options.c
index a270902340af97c0734f41a2411a18e7cea71563..5c9d3a0d9534345460c7dc247521506d59bd630d 100644 (file)
--- a/pppd/options.c
+++ b/pppd/options.c
@@ -40,7 +40,7 @@
  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#define RCSID  "$Id: options.c,v 1.98 2005/07/13 12:31:36 paulus Exp $"
+#define RCSID  "$Id: options.c,v 1.99 2006/06/04 07:04:57 paulus Exp $"
 
 #include <ctype.h>
 #include <stdio.h>
@@ -403,12 +403,14 @@ options_from_file(filename, must_exist, check_prot, priv)
     char args[MAXARGS][MAXWORDLEN];
     char cmd[MAXWORDLEN];
 
-    if (check_prot)
-       seteuid(getuid());
+    if (check_prot && seteuid(getuid()) == -1) {
+       option_error("unable to drop privileges to open %s: %m", filename);
+       return 0;
+    }
     f = fopen(filename, "r");
     err = errno;
-    if (check_prot)
-       seteuid(0);
+    if (check_prot && seteuid(0) == -1)
+       fatal("unable to regain privileges");
     if (f == NULL) {
        errno = err;
        if (!must_exist) {
@@ -1511,14 +1513,16 @@ setlogfile(argv)
 {
     int fd, err;
 
-    if (!privileged_option)
-       seteuid(getuid());
+    if (!privileged_option && seteuid(getuid()) == -1) {
+       option_error("unable to drop permissions to open %s: %m", *argv);
+       return 0;
+    }
     fd = open(*argv, O_WRONLY | O_APPEND | O_CREAT | O_EXCL, 0644);
     if (fd < 0 && errno == EEXIST)
        fd = open(*argv, O_WRONLY | O_APPEND);
     err = errno;
-    if (!privileged_option)
-       seteuid(0);
+    if (!privileged_option && seteuid(0) == -1)
+       fatal("unable to regain privileges: %m");
     if (fd < 0) {
        errno = err;
        option_error("Can't open log file %s: %m", *argv);

diff --git a/pppd/tty.c b/pppd/tty.c
index 1ef8a52eacae3bf8a6560005c2659214e1186622..c356483d1974ee9358010cc585049eddcc1de569 100644 (file)
--- a/pppd/tty.c
+++ b/pppd/tty.c
@@ -68,7 +68,7 @@
  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#define RCSID  "$Id: tty.c,v 1.24 2005/07/12 01:09:05 paulus Exp $"
+#define RCSID  "$Id: tty.c,v 1.25 2006/06/04 07:04:57 paulus Exp $"
 
 #include <stdio.h>
 #include <ctype.h>
@@ -563,12 +563,16 @@ int connect_tty()
                        int err, prio;
 
                        prio = privopen? OPRIO_ROOT: tty_options[0].priority;
-                       if (prio < OPRIO_ROOT)
-                               seteuid(uid);
+                       if (prio < OPRIO_ROOT && seteuid(uid) == -1) {
+                               error("Unable to drop privileges before opening %s: %m\n",
+                                     devnam);
+                               status = EXIT_OPEN_FAILED;
+                               goto errret;
+                       }
                        real_ttyfd = open(devnam, O_NONBLOCK | O_RDWR, 0);
                        err = errno;
-                       if (prio < OPRIO_ROOT)
-                               seteuid(0);
+                       if (prio < OPRIO_ROOT && seteuid(0) == -1)
+                               fatal("Unable to regain privileges");
                        if (real_ttyfd >= 0)
                                break;
                        errno = err;