From 9eba0da958d33ef3582667e09701865980595361 Mon Sep 17 00:00:00 2001
From: Mark Nudelman <markn@greenwoodsoftware.com>
Date: Sun, 19 Sep 2021 14:25:39 -1000
Subject: [PATCH] Don't read or write history file in secure mode.

---
 NEWS     | 6 ++++++
 cmdbuf.c | 9 ++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/NEWS b/NEWS
index 164fcf86..49152695 100644
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,8 @@
 
 * Allow option name in -- command to end with '=' in addition to '\n'.
 
+* Don't read or write history file in secure mode.
+
 * Fix display of multibyte and double-width chars in prompt.
 
 * Fix ESC-BACKSPACE command when BACKSPACE key does not send 0x08.
@@ -32,6 +34,10 @@
 
 * Fix bug when empty file is modified while viewing it.
 
+* Fix bug when parsing a malformed lesskey file.
+
+* Fix buffer overflow when invoking lessecho with more than 63 -m/-n options.
+
 ======================================================================
 
 	Major changes between "less" versions 581 and 590
diff --git a/cmdbuf.c b/cmdbuf.c
index dd135382..f4f8f3ea 100644
--- a/cmdbuf.c
+++ b/cmdbuf.c
@@ -24,6 +24,7 @@ extern int sc_width;
 extern int utf_mode;
 extern int no_hist_dups;
 extern int marks_modified;
+extern int secure;
 
 static char cmdbuf[CMDBUF_SIZE]; /* Buffer for holding a multi-char command */
 static int cmd_col;              /* Current column of the cursor */
@@ -1524,6 +1525,8 @@ read_cmdhist(action, uparam, skip_search, skip_shell)
 	int skip_search;
 	int skip_shell;
 {
+	if (secure)
+		return;
 	read_cmdhist2(action, uparam, skip_search, skip_shell);
 	(*action)(uparam, NULL, NULL); /* signal end of file */
 }
@@ -1673,6 +1676,7 @@ make_file_private(f)
 /*
  * Does the history file need to be updated?
  */
+#if CMD_HISTORY
 	static int
 histfile_modified(VOID_PARAM)
 {
@@ -1682,12 +1686,11 @@ histfile_modified(VOID_PARAM)
 	if (mlist_shell.modified)
 		return 1;
 #endif
-#if CMD_HISTORY
 	if (marks_modified)
 		return 1;
-#endif
 	return 0;
 }
+#endif
 
 /*
  * Update the .lesshst file.
@@ -1705,7 +1708,7 @@ save_cmdhist(VOID_PARAM)
 	FILE *fout = NULL;
 	int histsize = 0;
 
-	if (!histfile_modified())
+	if (secure || !histfile_modified())
 		return;
 	histname = histfile_name(0);
 	if (histname == NULL)