Changeset 948 in openpam

Timestamp:

Nov 19, 2020, 5:41:15 AM (7 months ago)

Author:

Dag-Erling Smørgrav

Message:

In openpam_ttyconv(3), wait to print the prompt until after we're ready
to accept input. Otherwise, there is a small but non-zero chance that
input provided after the prompt appears is discarded when we flush the
tty buffer.

Submitted by: Brooks Davis <brooks@…>

Location:

trunk

Files:

• CREDITS (modified) (1 diff)
• HISTORY (modified) (1 diff)
• lib/libpam/openpam_ttyconv.c (modified) (2 diffs)

trunk/CREDITS

@@ -19 +19 @@
         Baptiste Daroussin <bapt@freebsd.org>
         Brian Fundakowski Feldman <green@freebsd.org>
+        Brooks Davis <brooks@freebsd.org>
         Christos Zoulas <christos@netbsd.org>
         Daniel Richard G. <skunk@iskunk.org>

trunk/HISTORY

@@ +1 @@
+OpenPAM ???                                                     2020-07-??
+
+ - BUGFIX: Fix race condition in openpam_ttyconv(3) when used with
+   expect scripts.
+============================================================================
 OpenPAM Tabebuia                                                2019-02-24
 

trunk/lib/libpam/openpam_ttyconv.c

@@ -95 +95 @@
         char ch;
 
-        /* write prompt */
-        if (write(ofd, message, strlen(message)) < 0) {
-                openpam_log(PAM_LOG_ERROR, "write(): %m");
-                return (-1);
-        }
-
         /* turn echo off if requested */
         slflag = 0; /* prevent bogus uninitialized variable warning */
@@ -114 +108 @@
                         return (-1);
                 }
+        }
+
+        /* write prompt */
+        if (write(ofd, message, strlen(message)) < 0) {
+                openpam_log(PAM_LOG_ERROR, "write(): %m");
+                return (-1);
         }