From: Pádraig Brady <P@draigBrady.com>
Date: Sun, 19 Mar 2023 22:22:18 +0000 (+0000)
Subject: stty: ensure arbitrary data is not displayed
X-Git-Tag: v9.2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb745e3b95a79bdad98aaa9c4e753145f995c313;p=thirdparty%2Fcoreutils.git

stty: ensure arbitrary data is not displayed

* src/stty.c (main): Use static structures to ensure
they're initialized (to zero), so that random data is
not displayed, or compared resulting in a inaccurate
failure reported to users.  This was seen on musl libc
where some parts of the termios c_cc array were
not initialized by tcgetattr().
Reported by Bruno Haible.
---

diff --git a/src/stty.c b/src/stty.c
index fb7feefaba..607a4e7bb3 100644
--- a/src/stty.c
+++ b/src/stty.c
@@ -1290,7 +1290,9 @@ apply_settings (bool checking, char const *device_name,
 int
 main (int argc, char **argv)
 {
-  struct termios mode;
+  /* Initialize to all zeroes so there is no risk memcmp will report a
+     spurious difference in an uninitialized portion of the structure.  */
+  static struct termios mode;
 
   enum output_type output_type;
   int optc;
@@ -1426,7 +1428,9 @@ main (int argc, char **argv)
 
   if (require_set_attr)
     {
-      struct termios new_mode;
+      /* Initialize to all zeroes so there is no risk memcmp will report a
+         spurious difference in an uninitialized portion of the structure.  */
+      static struct termios new_mode;
 
       if (tcsetattr (STDIN_FILENO, tcsetattr_options, &mode))
         die (EXIT_FAILURE, errno, "%s", quotef (device_name));