[libXt:PATCH] XtAsprintf: Fix memory corruption.

[Cyril Brulebois]

Don't write the null terminator to a random place, this can trigger some
segfault in XtOpenDisplay() and other annoyances.

Debian Bug #617208 <http://bugs.debian.org/617208>

Signed-off-by: Cyril Brulebois <kibi at debian.org>
---
 src/Alloc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)


Alan Coopersmith wrote:
> I can't see why that would make XtAsprintf operate any differently though.

Apparently, having HOME=/ makes the memory corruption hit XtOpenDisplay()'s
%esi register, where app happens to be stored. And right after writing the
null terminator at the wrong place, %esi becomes 0 in XtOpenDisplay()'s
frame. Kaboom.


diff --git a/src/Alloc.c b/src/Alloc.c
index 67413ab..be643a8 100644
--- a/src/Alloc.c
+++ b/src/Alloc.c
@@ -147,7 +147,7 @@ Cardinal XtAsprintf(
     if (len < sizeof(buf))
     {
 	strncpy(*new_string, buf, len);
-	new_string[len] = '\0';
+	(*new_string)[len] = '\0';
     }
     else
     {
-- 
1.7.4.1