Subject: Prevent invalid form_update_line() call in formUpdateBuffer()
From: Tatsuya Kinoshita <tats@debian.org>
Bug-Debian: https://github.com/tats/w3m/issues/82
Origin: https://anonscm.debian.org/cgit/collab-maint/w3m.git/commit/?id=dc32152dc051923e322fc251aaa2dbd5e54c0fbf

---
 form.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/form.c b/form.c
index 1aaaf19..162439a 100644
--- a/form.c
+++ b/form.c
@@ -490,7 +490,8 @@ formUpdateBuffer(Anchor *a, Buffer *buf, FormItemList *form)
 		spos = a->start.pos;
 		epos = a->end.pos;
 	    }
-	    if (a->start.line != a->end.line || spos > epos || epos >= l->len || spos < 0 || epos < 0)
+	    if (a->start.line != a->end.line || spos > epos || epos >= l->len ||
+		spos < 0 || epos < 0 || COLPOS(l, epos) < col)
 		break;
 	    pos = form_update_line(l, &p, spos, epos, COLPOS(l, epos) - col,
 				   rows > 1,
-- 
2.10.2