From 652dee448618589de5528a9e9a36995803f5557a Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Fri, 28 Jan 2022 20:47:49 +0000
Subject: [PATCH] patch 8.2.4245: ":retab 0" may cause illegal memory access

Problem:    ":retab 0" may cause illegal memory access.
Solution:   Limit the value of 'tabstop' to 10000.

---
 src/indent.c                 |  4 ++--
 src/option.c                 | 16 +++++++++-------
 src/testdir/test_options.vim |  2 ++
 src/vim.h                    |  2 ++
 4 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/indent.c b/src/indent.c
index 7d04373..e8e93b9 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -71,7 +71,7 @@ tabstop_set(char_u *var, int **array)
 	int n = atoi((char *)cp);
 
 	// Catch negative values, overflow and ridiculous big values.
-	if (n < 0 || n > 9999)
+	if (n < 0 || n > TABSTOP_MAX)
 	{
 	    semsg(_(e_invarg2), cp);
 	    vim_free(*array);
@@ -1590,7 +1590,7 @@ ex_retab(exarg_T *eap)
 	emsg(_(e_positive));
 	return;
     }
-    if (new_ts < 0 || new_ts > 9999)
+    if (new_ts < 0 || new_ts > TABSTOP_MAX)
     {
 	semsg(_(e_invarg2), eap->arg);
 	return;
diff --git a/src/option.c b/src/option.c
index e9598d6..382b01b 100644
--- a/src/option.c
+++ b/src/option.c
@@ -3557,6 +3557,11 @@ set_num_option(
 	errmsg = e_positive;
 	curbuf->b_p_ts = 8;
     }
+    else if (curbuf->b_p_ts > TABSTOP_MAX)
+    {
+	errmsg = e_invalid_argument;
+	curbuf->b_p_ts = 8;
+    }
     if (p_tm < 0)
     {
 	errmsg = e_positive;
@@ -5758,7 +5763,7 @@ buf_copy_options(buf_T *buf, int flags)
 	    if (p_vsts && p_vsts != empty_option)
 		(void)tabstop_set(p_vsts, &buf->b_p_vsts_array);
 	    else
-		buf->b_p_vsts_array = 0;
+		buf->b_p_vsts_array = NULL;
 	    buf->b_p_vsts_nopaste = p_vsts_nopaste
 				 ? vim_strsave(p_vsts_nopaste) : NULL;
 #endif
@@ -6583,9 +6588,7 @@ paste_option_changed(void)
 	    if (buf->b_p_vsts)
 		free_string_option(buf->b_p_vsts);
 	    buf->b_p_vsts = empty_option;
-	    if (buf->b_p_vsts_array)
-		vim_free(buf->b_p_vsts_array);
-	    buf->b_p_vsts_array = 0;
+	    VIM_CLEAR(buf->b_p_vsts_array);
 #endif
 	}
 
@@ -6631,12 +6634,11 @@ paste_option_changed(void)
 		free_string_option(buf->b_p_vsts);
 	    buf->b_p_vsts = buf->b_p_vsts_nopaste
 			 ? vim_strsave(buf->b_p_vsts_nopaste) : empty_option;
-	    if (buf->b_p_vsts_array)
-		vim_free(buf->b_p_vsts_array);
+	    vim_free(buf->b_p_vsts_array);
 	    if (buf->b_p_vsts && buf->b_p_vsts != empty_option)
 		(void)tabstop_set(buf->b_p_vsts, &buf->b_p_vsts_array);
 	    else
-		buf->b_p_vsts_array = 0;
+		buf->b_p_vsts_array = NULL;
 #endif
 	}
 
diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index 65600ee..d4213c1 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -263,6 +263,8 @@ func Test_set_errors()
   call assert_fails('set shiftwidth=-1', 'E487:')
   call assert_fails('set sidescroll=-1', 'E487:')
   call assert_fails('set tabstop=-1', 'E487:')
+  call assert_fails('set tabstop=10000', 'E474:')
+  call assert_fails('set tabstop=5500000000', 'E474:')
   call assert_fails('set textwidth=-1', 'E487:')
   call assert_fails('set timeoutlen=-1', 'E487:')
   call assert_fails('set updatecount=-1', 'E487:')
diff --git a/src/vim.h b/src/vim.h
index 68e2de1..cd917a3 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2031,6 +2031,8 @@ typedef int sock_T;
 
 #define DICT_MAXNEST 100	// maximum nesting of lists and dicts
 
+#define TABSTOP_MAX 9999
+
 #ifdef FEAT_CLIPBOARD
 
 // VIM_ATOM_NAME is the older Vim-specific selection type for X11.  Still
-- 
2.27.0