From 1c3dd8ddcba63c1af5112e567215b3cec2de11d0 Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Sat, 17 Sep 2022 19:43:23 +0100
Subject: [PATCH] patch 9.0.0490: using freed memory with cmdwin and BufEnter
 autocmd

Problem:    Using freed memory with cmdwin and BufEnter autocmd.
Solution:   Make sure pointer to b_p_iminsert is still valid.
---
 src/ex_getln.c               |  8 ++++++--
 src/testdir/test_cmdline.vim | 10 ++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/ex_getln.c b/src/ex_getln.c
index 8dc03dc..535bfb5 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -1607,6 +1607,7 @@ getcmdline_int(
 #endif
     expand_T	xpc;
     long	*b_im_ptr = NULL;
+    buf_T	*b_im_ptr_buf = NULL;	// buffer where b_im_ptr is valid
     cmdline_info_T save_ccline;
     int		did_save_ccline = FALSE;
     int		cmdline_type;
@@ -1703,6 +1704,7 @@ getcmdline_int(
 	    b_im_ptr = &curbuf->b_p_iminsert;
 	else
 	    b_im_ptr = &curbuf->b_p_imsearch;
+	b_im_ptr_buf = curbuf;
 	if (*b_im_ptr == B_IMODE_LMAP)
 	    State |= MODE_LANGMAP;
 #ifdef HAVE_INPUT_METHOD
@@ -2060,7 +2062,8 @@ getcmdline_int(
 		goto cmdline_not_changed;
 
 	case Ctrl_HAT:
-		cmdline_toggle_langmap(b_im_ptr);
+		cmdline_toggle_langmap(
+				    buf_valid(b_im_ptr_buf) ? b_im_ptr : NULL);
 		goto cmdline_not_changed;
 
 //	case '@':   only in very old vi
@@ -2573,7 +2576,8 @@ returncmd:
 #endif
 
 #ifdef HAVE_INPUT_METHOD
-    if (b_im_ptr != NULL && *b_im_ptr != B_IMODE_LMAP)
+    if (b_im_ptr != NULL && buf_valid(b_im_ptr_buf)
+						  && *b_im_ptr != B_IMODE_LMAP)
 	im_save_status(b_im_ptr);
     im_set_active(FALSE);
 #endif
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 08e2de7..440df96 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -3447,4 +3447,14 @@ func Test_cmdwin_virtual_edit()
   set ve= cpo-=$
 endfunc
 
+" This was using a pointer to a freed buffer
+func Test_cmdwin_freed_buffer_ptr()
+  au BufEnter * next 0| file 
+  edit 0
+  silent! norm q/
+
+  au! BufEnter
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
-- 
2.27.0