CVE: CVE-2021-3796
Upstream-Status: Backport
Signed-off-by: Ross Burton <ross.burton@arm.com>

From 1160e5f74b229336502fc376416f21108d36cfc2 Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Sat, 11 Sep 2021 21:14:20 +0200
Subject: [PATCH] patch 8.2.3428: using freed memory when replacing

Problem:    Using freed memory when replacing. (Dhiraj Mishra)
Solution:   Get the line pointer after calling ins_copychar().
---
 src/normal.c              | 10 +++++++---
 src/testdir/test_edit.vim | 14 ++++++++++++++
 src/version.c             |  2 ++
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/normal.c b/src/normal.c
index c4963e621..d6333b948 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -5009,19 +5009,23 @@ nv_replace(cmdarg_T *cap)
 	    {
 		/*
 		 * Get ptr again, because u_save and/or showmatch() will have
-		 * released the line.  At the same time we let know that the
-		 * line will be changed.
+		 * released the line.  This may also happen in ins_copychar().
+		 * At the same time we let know that the line will be changed.
 		 */
-		ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum, TRUE);
 		if (cap->nchar == Ctrl_E || cap->nchar == Ctrl_Y)
 		{
 		  int c = ins_copychar(curwin->w_cursor.lnum
 					   + (cap->nchar == Ctrl_Y ? -1 : 1));
+
+		  ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum, TRUE);
 		  if (c != NUL)
 		    ptr[curwin->w_cursor.col] = c;
 		}
 		else
+		{
+		    ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum, TRUE);
 		    ptr[curwin->w_cursor.col] = cap->nchar;
+		}
 		if (p_sm && msg_silent == 0)
 		    showmatch(cap->nchar);
 		++curwin->w_cursor.col;
diff --git a/src/testdir/test_edit.vim b/src/testdir/test_edit.vim
index 4e29e7fe1..f94e6c181 100644
--- a/src/testdir/test_edit.vim
+++ b/src/testdir/test_edit.vim
@@ -1519,3 +1519,17 @@ func Test_edit_noesckeys()
   bwipe!
   set esckeys
 endfunc
+
+" Test for getting the character of the line below after "p"
+func Test_edit_put_CTRL_E()
+  set encoding=latin1
+  new
+  let @" = ''
+  sil! norm orggRx
+  sil! norm pr
+  call assert_equal(['r', 'r'], getline(1, 2))
+  bwipe!
+  set encoding=utf-8
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index 85bdfc601..1046993d6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3428,
 /**/
     3409,
 /**/