svn commit: r319453 - head/contrib/telnet/telnetd

[Stephen J. Kiernan]

Author: stevek
Date: Thu Jun  1 19:21:30 2017
New Revision: 319453
URL: https://svnweb.freebsd.org/changeset/base/319453

Log:
  Fix memory leak in edithost
  
  The problem is that when the parameter 'pat' is null, the function locally
  allocates a NULL string but never frees it.
  
  Instead of tracking the local alloc, it is noted that the while(*pat) never
  enters when there is a local alloc.
  So instead of doing the local alloc, check that 'pat' is null before the
  while(*pat) loop.
  
  Found using clang's static analyzer - scan-build
  
  Submitted by:	Thomas Rix <trix at juniper.net>
  Reviewed by:	markm
  Approved by:	sjg (mentor)
  MFC after:	1 week
  Differential Revision:	https://reviews.freebsd.org/D9689

Modified:
  head/contrib/telnet/telnetd/utility.c

Modified: head/contrib/telnet/telnetd/utility.c
==============================================================================
--- head/contrib/telnet/telnetd/utility.c	Thu Jun  1 18:39:54 2017	(r319452)
+++ head/contrib/telnet/telnetd/utility.c	Thu Jun  1 19:21:30 2017	(r319453)
@@ -360,30 +360,30 @@ edithost(char *pat, char *host)
 {
 	char *res = editedhost;
 
-	if (!pat)
-		pat = strdup("");
-	while (*pat) {
-		switch (*pat) {
+	if (pat) {
+		while (*pat) {
+			switch (*pat) {
 
-		case '#':
-			if (*host)
-				host++;
-			break;
+			case '#':
+				if (*host)
+					host++;
+				break;
 
-		case '@':
-			if (*host)
-				*res++ = *host++;
-			break;
+			case '@':
+				if (*host)
+					*res++ = *host++;
+				break;
 
-		default:
-			*res++ = *pat;
-			break;
+			default:
+				*res++ = *pat;
+				break;
+			}
+			if (res == &editedhost[sizeof editedhost - 1]) {
+				*res = '\0';
+				return;
+			}
+			pat++;
 		}
-		if (res == &editedhost[sizeof editedhost - 1]) {
-			*res = '\0';
-			return;
-		}
-		pat++;
 	}
 	if (*host)
 		(void) strncpy(res, host,