keyboard: Fix insert_text() string utility
strncat() into a newly allocated buffer isn't well-defined. I don't know
how this didn't crash all the time, getting blocks from malloc() with
a NUL in the first byte must be fairly common.
Closes: https://bugs.freedesktop.org/show_bug.cgi?id=71750
diff --git a/clients/keyboard.c b/clients/keyboard.c
index e08a5fa..963382c 100644
--- a/clients/keyboard.c
+++ b/clients/keyboard.c
@@ -384,12 +384,13 @@
static char *
insert_text(const char *text, uint32_t offset, const char *insert)
{
- char *new_text = xmalloc(strlen(text) + strlen(insert) + 1);
+ int tlen = strlen(text), ilen = strlen(insert);
+ char *new_text = xmalloc(tlen + ilen + 1);
- strncat(new_text, text, offset);
- new_text[offset] = '\0';
- strcat(new_text, insert);
- strcat(new_text, text + offset);
+ memcpy(new_text, text, offset);
+ memcpy(new_text + offset, insert, ilen);
+ memcpy(new_text + offset + ilen, text + offset, tlen - offset);
+ new_text[tlen + ilen] = '\0';
return new_text;
}