From f6d28fe2c95c678cc3202cc5dc825a3fcc709e93 Mon Sep 17 00:00:00 2001
From: Christian Brabandt <cb@256bit.org>
Date: Tue, 5 Sep 2023 20:18:06 +0200
Subject: [PATCH] patch 9.0.1873: [security] heap-buffer-overflow in
 vim_regsub_both

Problem:  heap-buffer-overflow in vim_regsub_both
Solution: Disallow exchanging windows when textlock is active

Signed-off-by: Christian Brabandt <cb@256bit.org>
---
 src/ex_cmds.c                         |   3 +++
 src/testdir/crash/vim_regsub_both_poc | Bin 0 -> 244 bytes
 src/testdir/test_crash.vim            |   9 +++++++++
 src/version.c                         |   2 ++
 src/window.c                          |   5 +++++
 5 files changed, 19 insertions(+)
 create mode 100644 src/testdir/crash/vim_regsub_both_poc

diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 4f1d93244f021..566ed7dad32d0 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -4519,6 +4519,9 @@ ex_substitute(exarg_T *eap)
 		{
 		    nmatch = curbuf->b_ml.ml_line_count - sub_firstlnum + 1;
 		    skip_match = TRUE;
+		    // safety check
+		    if (nmatch < 0)
+			goto skip;
 		}
 
 		// Need room for:
diff --git a/src/testdir/crash/vim_regsub_both_poc b/src/testdir/crash/vim_regsub_both_poc
new file mode 100644
index 0000000000000000000000000000000000000000..19a57114be60c39dfb8b97ab95118caad7105322
GIT binary patch
literal 244
zcmYL@u?oU45QgJ=E>7wo7(ub^V#X>I9DITfBATT%DHd#_Jq=oiK7nuKlexsSir#Yn
zfA{m<B^MexE?{~X<*LZKtPFbnHppBg5J!ja@-H<t70C%{5kLtz<CCd7<AG(oh#jS6
zO@V0{?(hgFNikapux!?xfJQ6-<Lan~ZFR~b#rf8lhvA%bK&ROpJr1ghAXki*!Rk65
v$T~i_-E3>H8rf3+3Z>%?=~|?P^W2;zo`V?09hL8cMqn5hX5S&gzO3L4CoE1h

literal 0
HcmV?d00001

diff --git a/src/testdir/test_crash.vim b/src/testdir/test_crash.vim
index e0884e5a058ee..f7b528c3e98d7 100644
--- a/src/testdir/test_crash.vim
+++ b/src/testdir/test_crash.vim
@@ -46,6 +46,7 @@ func Test_crash1()
 
   let file = 'crash/poc_tagfunc.vim'
   let args = printf(cmn_args, vim, file)
+  " using || because this poc causes vim to exit with exitstatus != 0
   call term_sendkeys(buf, args ..
     \ '  || echo "crash 5: [OK]" >> X_crash1_result.txt' .. "\<cr>")
 
@@ -59,6 +60,13 @@ func Test_crash1()
   call delete('X')
   call TermWait(buf, 3000)
 
+  let file = 'crash/vim_regsub_both_poc'
+  let args = printf(cmn_args, vim, file)
+  " using || because this poc causes vim to exit with exitstatus != 0
+  call term_sendkeys(buf, args ..
+    \ '  && echo "crash 7: [OK]" >> X_crash1_result.txt' .. "\<cr>")
+  call TermWait(buf, 1000)
+
   " clean up
   exe buf .. "bw!"
 
@@ -71,6 +79,7 @@ func Test_crash1()
       \ 'crash 4: [OK]',
       \ 'crash 5: [OK]',
       \ 'crash 6: [OK]',
+      \ 'crash 7: [OK]',
       \ ]
 
   call assert_equal(expected, getline(1, '$'))
diff --git a/src/version.c b/src/version.c
index a5e570e9314fd..2faa9e668ec6f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1873,
 /**/
     1872,
 /**/
diff --git a/src/window.c b/src/window.c
index 1af2395df8b91..f77ede330d304 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1733,6 +1733,11 @@ win_exchange(long Prenum)
 	beep_flush();
 	return;
     }
+    if (text_or_buf_locked())
+    {
+	beep_flush();
+	return;
+    }
 
 #ifdef FEAT_GUI
     need_mouse_correct = TRUE;