From 4cdad8299f605e8b0527391a49311786e0bca35c Mon Sep 17 00:00:00 2001
From: Kamil Dudka <kdudka@redhat.com>
Date: Tue, 20 Mar 2018 16:49:34 +0100
Subject: [PATCH 1/2] input: do not crash if sctofunc() returns NULL

This fixes a regression introduced by commit 54103d8e: a crash that
can be triggered by running 'nano --restrict' and pressing <Insert>.

This addresses https://bugzilla.redhat.com/1558532.

Upstream-commit: b830a7dd384495fb9b882f866b26948025abe136
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
 src/nano.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/nano.c b/src/nano.c
index ad95925..e7b6d62 100644
--- a/src/nano.c
+++ b/src/nano.c
@@ -1712,9 +1712,12 @@ int do_input(bool allow_funcs)
 	if (shortcut == NULL)
 		pletion_line = NULL;
 	else {
-		if (ISSET(VIEW_MODE) && !sctofunc(shortcut)->viewok) {
-			print_view_warning();
-			return ERR;
+		if (ISSET(VIEW_MODE)) {
+			const subnfunc *f = sctofunc(shortcut);
+			if (f && !f->viewok) {
+				print_view_warning();
+				return ERR;
+			}
 		}
 
 		/* If the function associated with this shortcut is
@@ -1787,8 +1790,11 @@ int do_input(bool allow_funcs)
 				wrap_reset();
 #endif
 #ifdef ENABLE_COLOR
-			if (!refresh_needed && !sctofunc(shortcut)->viewok)
-				check_the_multis(openfile->current);
+			if (!refresh_needed) {
+				const subnfunc *f = sctofunc(shortcut);
+				if (f && !f->viewok)
+					check_the_multis(openfile->current);
+			}
 #endif
 			if (!refresh_needed && (shortcut->func == do_delete ||
 									shortcut->func == do_backspace))
-- 
2.14.3


From 25a02d16fc59bbe88cdc51922534436b20187a3d Mon Sep 17 00:00:00 2001
From: Benno Schulenberg <bensberg@telfort.nl>
Date: Tue, 20 Mar 2018 19:56:03 +0100
Subject: [PATCH 2/2] tweaks: factor out the check for 'viewok' into its own
 function

And also prevent a theoretical crash for restricted prompt functions.

Upstream-commit: 8b8c6bb818b21b9c7fcf7481df7154745b4aad41
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
 src/nano.c   | 24 +++++++++++++-----------
 src/prompt.c |  2 +-
 src/proto.h  |  1 +
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/nano.c b/src/nano.c
index e7b6d62..c39622b 100644
--- a/src/nano.c
+++ b/src/nano.c
@@ -1621,6 +1621,14 @@ int do_mouse(void)
 }
 #endif /* ENABLE_MOUSE */
 
+/* Return TRUE when the given shortcut is valid in view mode. */
+bool okay_for_view(const sc *shortcut)
+{
+	const subnfunc *func = sctofunc(shortcut);
+
+	return (func && func->viewok);
+}
+
 /* Read in a keystroke.  Act on the keystroke if it is a shortcut or a toggle;
  * otherwise, insert it into the edit buffer.  If allow_funcs is FALSE, don't
  * do anything with the keystroke -- just return it. */
@@ -1712,12 +1720,9 @@ int do_input(bool allow_funcs)
 	if (shortcut == NULL)
 		pletion_line = NULL;
 	else {
-		if (ISSET(VIEW_MODE)) {
-			const subnfunc *f = sctofunc(shortcut);
-			if (f && !f->viewok) {
-				print_view_warning();
-				return ERR;
-			}
+		if (ISSET(VIEW_MODE) && !okay_for_view(shortcut)) {
+			print_view_warning();
+			return ERR;
 		}
 
 		/* If the function associated with this shortcut is
@@ -1790,11 +1795,8 @@ int do_input(bool allow_funcs)
 				wrap_reset();
 #endif
 #ifdef ENABLE_COLOR
-			if (!refresh_needed) {
-				const subnfunc *f = sctofunc(shortcut);
-				if (f && !f->viewok)
-					check_the_multis(openfile->current);
-			}
+			if (!refresh_needed && !okay_for_view(shortcut))
+				check_the_multis(openfile->current);
 #endif
 			if (!refresh_needed && (shortcut->func == do_delete ||
 									shortcut->func == do_backspace))
diff --git a/src/prompt.c b/src/prompt.c
index e8fbbc0..8ec74fd 100644
--- a/src/prompt.c
+++ b/src/prompt.c
@@ -171,7 +171,7 @@ int do_statusbar_input(bool *finished)
 			/* Handle any other shortcut in the current menu, setting finished
 			 * to TRUE to indicate that we're done after running or trying to
 			 * run its associated function. */
-			if (!ISSET(VIEW_MODE) || sctofunc(shortcut)->viewok)
+			if (!ISSET(VIEW_MODE) || okay_for_view(shortcut))
 				shortcut->func();
 			*finished = TRUE;
 		}
diff --git a/src/proto.h b/src/proto.h
index 86f53d7..5530a90 100644
--- a/src/proto.h
+++ b/src/proto.h
@@ -441,6 +441,7 @@ void disable_flow_control(void);
 void enable_flow_control(void);
 void terminal_init(void);
 void unbound_key(int code);
+bool okay_for_view(const sc *shortcut);
 int do_input(bool allow_funcs);
 void do_output(char *output, size_t output_len, bool allow_cntrls);
 
-- 
2.14.3