From e5e959835b195c023d1f685ef4dbbcfc3b5120b2 Mon Sep 17 00:00:00 2001
From: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Tue, 25 Oct 2022 17:11:11 +0200
Subject: [PATCH] fix buffer overflow when handling long composed input
To reproduce the issue:
"
If you already have the multi-key enabled on your system, then add this line
to your ~/.XCompose file:
[...]
<question> <T> <E> <S> <T> <question> :
"1234567890123456789012345678901234567890123456789012345678901234567890"
"
Reported by and an initial patch by Andy Gozas <andy@gozas.me>, thanks!
Adapted the patch, for now st (like dmenu) handles a fixed amount of composed
characters, or otherwise ignores it. This is done for simplicity sake.
---
x.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/x.c b/x.c
index 2a3bd38..aa09997 100644
--- a/x.c
+++ b/x.c
@@ -1833,7 +1833,7 @@ void
kpress(XEvent *ev)
{
XKeyEvent *e = &ev->xkey;
- KeySym ksym;
+ KeySym ksym = NoSymbol;
char buf[64], *customkey;
int len;
Rune c;
@@ -1843,10 +1843,13 @@ kpress(XEvent *ev)
if (IS_SET(MODE_KBDLOCK))
return;
- if (xw.ime.xic)
+ if (xw.ime.xic) {
len = XmbLookupString(xw.ime.xic, e, buf, sizeof buf, &ksym, &status);
- else
+ if (status == XBufferOverflow)
+ return;
+ } else {
len = XLookupString(e, buf, sizeof buf, &ksym, NULL);
+ }
/* 1. shortcuts */
for (bp = shortcuts; bp < shortcuts + LEN(shortcuts); bp++) {
if (ksym == bp->keysym && match(bp->mod, e->state)) {