From 8fefee2d41b4cce49a791895327aaa8cea7c2c5d Mon Sep 17 00:00:00 2001
From: Benno Schulenberg <bensberg@telfort.nl>
Date: Sat, 10 Feb 2024 11:56:23 +0100
Subject: [PATCH] undo: prevent a use-after-free, reported by `correctmost`

When the cursor is on the last line, and an undo removes this line,
do not let 'openfile->current' become invalid.

This fixes https://savannah.gnu.org/bugs/?65279.

Bug existed since version 6.3, commit eea3e1f0.

(It should have been fixed in commit 9410a556, more than a year ago.)
---
 src/utils.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/utils.c b/src/utils.c
index d39e6098..071846c2 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -436,6 +436,8 @@ void remove_magicline(void)
 {
 	if (openfile->filebot->data[0] == '\0' &&
 				openfile->filebot != openfile->filetop) {
+		if (openfile->current == openfile->filebot)
+			openfile->current = openfile->current->prev;
 		openfile->filebot = openfile->filebot->prev;
 		delete_node(openfile->filebot->next);
 		openfile->filebot->next = NULL;