From fe33acc7162d7f1cf7bf86f1d7cb31aa22f5d58e Mon Sep 17 00:00:00 2001
From: Bill Kendrick <nbs@sonic.net>
Date: Sat, 3 Jun 2023 14:10:13 -0700
Subject: [PATCH] Don't crash on un-wordexp()'able arguments!

We run shell expansion on configuration arguments,
e.g. `printcommand`, but it would crash if the config
file's input was not quoted, e.g.

  printcommand=pstopdf - - > $HOME/print.pdf

Now echo'ing an error to stderr and moving on.
Be sure to quote, e.g.

  printcommand="pstopdf - - > $HOME/print.pdf"
---
 docs/CHANGES.txt |  6 ++++++
 src/tuxpaint.c   | 17 ++++++++++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/docs/CHANGES.txt b/docs/CHANGES.txt
index 33214aafe..55d4b4d32 100644
--- a/docs/CHANGES.txt
+++ b/docs/CHANGES.txt
@@ -94,6 +94,12 @@ https://tuxpaint.org/
       data beyond the end of the data (copied from the original PNG).
       Bill Kendrick <bill@newbreedsoftware.com>
 
+    * Shell expansion (via wordexp()) of configuration options containing
+      spaces (e.g., `printcommand=ps2pdf - - > $HOME/print.pdf`) would
+      fail & cause a crash.  It now shows an error and recommends adding
+      quotes. (e.g., `printcommand="ps2pdf - - > $HOME/print.pdf"`)
+      Bill Kendrick <bill@newbreedsoftware.com>
+
   * Localization Updates:
     ---------------------
     * Russian translaton
diff --git a/src/tuxpaint.c b/src/tuxpaint.c
index 17fe69738..90106b8f0 100644
--- a/src/tuxpaint.c
+++ b/src/tuxpaint.c
@@ -22,7 +22,7 @@
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   (See COPYING.txt)
 
-  June 14, 2002 - June 1, 2023
+  June 14, 2002 - June 3, 2023
 */
 
 #include "platform.h"
@@ -19648,6 +19648,8 @@ void do_print(void)
   else
     pcmd = printcommand;
 
+  DEBUG_PRINTF("printcmd: %s\n", printcommand);
+
   pi = popen(pcmd, "w");
 
   if (pi == NULL)
@@ -27752,8 +27754,17 @@ static void parse_file_options(struct cfginfo *restrict tmpcfg, const char *file
     wordexp_t result;
 
     wordexp(arg, &result, 0);
-    arg = strdup(result.we_wordv[0]);
-    wordfree(&result);
+    if (result.we_wordv != NULL)
+    {
+      DEBUG_PRINTF("wordexp result.we_wordv of `%s` was `%s`\n", str, result.we_wordv[0]);
+      arg = strdup(result.we_wordv[0]);
+      wordfree(&result);
+    }
+    else
+    {
+      fprintf(stderr, "Shell expansion of `%s` failed! (You probably need to wrap it in quotes (\")!)\n", str);
+      continue;
+    }
 #endif
 #endif