patch 9.1.0697: [security]: heap-buffer-overflow in ins_typebuf
Problem: heap-buffer-overflow in ins_typebuf
(SuyueGuo)
Solution: When flushing the typeahead buffer, validate that there
is enough space left
Github Advisory:
https://github.com/vim/vim/security/advisories/GHSA-4ghr-c62x-cqfh
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/getchar.c b/src/getchar.c
index 29323fa..96e180f 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -446,9 +446,18 @@
if (flush_typeahead == FLUSH_MINIMAL)
{
- // remove mapped characters at the start only
- typebuf.tb_off += typebuf.tb_maplen;
- typebuf.tb_len -= typebuf.tb_maplen;
+ // remove mapped characters at the start only,
+ // but only when enough space left in typebuf
+ if (typebuf.tb_off + typebuf.tb_maplen >= typebuf.tb_buflen)
+ {
+ typebuf.tb_off = MAXMAPLEN;
+ typebuf.tb_len = 0;
+ }
+ else
+ {
+ typebuf.tb_off += typebuf.tb_maplen;
+ typebuf.tb_len -= typebuf.tb_maplen;
+ }
#if defined(FEAT_CLIENTSERVER) || defined(FEAT_EVAL)
if (typebuf.tb_len == 0)
typebuf_was_filled = FALSE;