From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 21 Mar 2015 08:48:34 +0000 (+0200)
Subject: Fix undefined behavior in TUI's TAB expansion
X-Git-Tag: gdb-7.9.1-release~58
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4fa4c2f7bed85f7cb116466d3cf194cdb6271c60;p=thirdparty%2Fbinutils-gdb.git

Fix undefined behavior in TUI's TAB expansion

gdb/ChangeLog:

	* tui/tui-io.c (tui_expand_tabs): Reinitialize the column counter
	before the second loop, to avoid undefined behavior.  Reported by
	Anton Blanchard <anton@samba.org>.

(cherry picked from commit b1a0f704950296b2363192ba91999eef3635700f)
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 37a69e89db2..8f95a2add9e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2015-03-21  Eli Zaretskii  <eliz@gnu.org>
+
+	* tui/tui-io.c (tui_expand_tabs): Reinitialize the column counter
+	before the second loop, to avoid undefined behavior.  Reported by
+	Anton Blanchard <anton@samba.org>.
+
 2015-02-26  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	PR build/18033
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index 13cc5fac4e9..61a8dafe6b3 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -758,20 +758,20 @@ tui_getc (FILE *fp)
 char *
 tui_expand_tabs (const char *string, int col)
 {
-  int n_adjust;
+  int n_adjust, ncol;
   const char *s;
   char *ret, *q;
 
   /* 1. How many additional characters do we need?  */
-  for (n_adjust = 0, s = string; s; )
+  for (ncol = col, n_adjust = 0, s = string; s; )
     {
       s = strpbrk (s, "\t");
       if (s)
 	{
-	  col += (s - string) + n_adjust;
+	  ncol += (s - string) + n_adjust;
 	  /* Adjustment for the next tab stop, minus one for the TAB
 	     we replace with spaces.  */
-	  n_adjust += 8 - (col % 8) - 1;
+	  n_adjust += 8 - (ncol % 8) - 1;
 	  s++;
 	}
     }
@@ -780,7 +780,7 @@ tui_expand_tabs (const char *string, int col)
   ret = q = xmalloc (strlen (string) + n_adjust + 1);
 
   /* 2. Copy the original string while replacing TABs with spaces.  */
-  for (s = string; s; )
+  for (ncol = col, s = string; s; )
     {
       char *s1 = strpbrk (s, "\t");
       if (s1)
@@ -789,12 +789,12 @@ tui_expand_tabs (const char *string, int col)
 	    {
 	      strncpy (q, s, s1 - s);
 	      q += s1 - s;
-	      col += s1 - s;
+	      ncol += s1 - s;
 	    }
 	  do {
 	    *q++ = ' ';
-	    col++;
-	  } while ((col % 8) != 0);
+	    ncol++;
+	  } while ((ncol % 8) != 0);
 	  s1++;
 	}
       else