* libmisc/utmp.c: Do not trust the current utmp entry's ut_line.

	Always set ut_line based on ttyname(0).

diff --git a/ChangeLog b/ChangeLog
index 9bd3f942220baa9bd85d1a5056c8c24f13490b82..0d5e41415465c0d73acc95805e70312d37de1180 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,8 @@
 
        * NEWS, src/login.c: Do not trust the current utmp entry's ut_line
        to set PAM_TTY.
+       * libmisc/utmp.c: Do not trust the current utmp entry's ut_line.
+       Always set ut_line based on ttyname(0).
 
 2009-04-15  Nicolas François  <nicolas.francois@centraliens.net>
 

diff --git a/libmisc/utmp.c b/libmisc/utmp.c
index 5218a1e36476e5c5ec4c7795916796c008ca47fc..409a16d60b6401bb47d96d2649147508bac187bf 100644 (file)
--- a/libmisc/utmp.c
+++ b/libmisc/utmp.c
@@ -113,12 +113,22 @@ void checkutmp (bool picky)
                    && (   (LOGIN_PROCESS == ut->ut_type)
                        || (USER_PROCESS  == ut->ut_type))
                    /* A process may have failed to close an entry
-                    * Check if this entry refers to this tty */
+                    * Check if this entry refers to the current tty */
                    && is_my_tty (ut->ut_line)) {
                        break;
                }
        }
 
+       /* We cannot trust the ut_line field. Prepare the new value. */
+       line = ttyname (0);
+       if (NULL == line) {
+               (void) puts (NO_TTY);
+               exit (EXIT_FAILURE);
+       }
+       if (strncmp (line, "/dev/", 5) == 0) {
+               line += 5;
+       }
+
        /* If there is one, just use it, otherwise create a new one. */
        if (NULL != ut) {
                utent = *ut;
@@ -127,23 +137,17 @@ void checkutmp (bool picky)
                        (void) puts (NO_UTENT);
                        exit (EXIT_FAILURE);
                }
-               line = ttyname (0);
-               if (NULL == line) {
-                       (void) puts (NO_TTY);
-                       exit (EXIT_FAILURE);
-               }
-               if (strncmp (line, "/dev/", 5) == 0) {
-                       line += 5;
-               }
                memset ((void *) &utent, 0, sizeof utent);
                utent.ut_type = LOGIN_PROCESS;
                utent.ut_pid = pid;
-               strncpy (utent.ut_line, line, sizeof utent.ut_line);
                /* XXX - assumes /dev/tty?? or /dev/pts/?? */
-               strncpy (utent.ut_id, utent.ut_line + 3, sizeof utent.ut_id);
+               strncpy (utent.ut_id, line + 3, sizeof utent.ut_id);
                strcpy (utent.ut_user, "LOGIN");
                utent.ut_time = time (NULL);
        }
+
+       /* Sanitize / set the ut_line field */
+       strncpy (utent.ut_line, line, sizeof utent.ut_line);
 }
 
 #elif defined(LOGIN_PROCESS)