Patch "kconfig/nconf: Fix hang when editing symbol with a long prompt" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

kconfig/nconf: Fix hang when editing symbol with a long prompt

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kconfig-nconf-fix-hang-when-editing-symbol-with-a-long-prompt.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ben Hutchings <[email protected]>
Date: Thu, 24 Nov 2016 22:10:23 +0000
Subject: kconfig/nconf: Fix hang when editing symbol with a long prompt

From: Ben Hutchings <[email protected]>

commit 79e51b5c2deea542b3bb8c66e0d502230b017dde upstream.

Currently it is impossible to edit the value of a config symbol with a prompt longer than (terminal width - 2) characters. dialog_inputbox() calculates a negative x-offset for the input window and newwin() fails as this is invalid. It also doesn't check for this failure, so it busy-loops calling wgetch(NULL) which immediately returns -1.

The additions in the offset calculations also don't match the intended size of the window.

Limit the window size and calculate the offset similarly to show_scroll_win().

---
 scripts/kconfig/nconf.gui.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

@@ -364,12 +364,14 @@ int dialog_inputbox(WINDOW *main_window,
 	WINDOW *prompt_win;
 	WINDOW *form_win;
 	PANEL *panel;
-	int i, x, y;
+	int i, x, y, lines, columns, win_lines, win_cols;
 	int res = -1;
 	int cursor_position = strlen(init);
 	int cursor_form_win;
 	char *result = *resultp;
 
+	getmaxyx(stdscr, lines, columns);
+
 	if (strlen(init)+1 > *result_len) {
 		*result_len = strlen(init)+1;
 		*resultp = result = realloc(result, *result_len);

@@ -386,14 +388,19 @@ int dialog_inputbox(WINDOW *main_window,
 	if (title)
 		prompt_width = max(prompt_width, strlen(title));
 
+	win_lines = min(prompt_lines+6, lines-2);
+	win_cols = min(prompt_width+7, columns-2);
+	prompt_lines = max(win_lines-6, 0);
+	prompt_width = max(win_cols-7, 0);
+
 	/* place dialog in middle of screen */
-	y = (getmaxy(stdscr)-(prompt_lines+4))/2;
-	x = (getmaxx(stdscr)-(prompt_width+4))/2;
+	y = (lines-win_lines)/2;
+	x = (columns-win_cols)/2;
 
 	strncpy(result, init, *result_len);
 
 	/* create the windows */
-	win = newwin(prompt_lines+6, prompt_width+7, y, x);
+	win = newwin(win_lines, win_cols, y, x);
 	prompt_win = derwin(win, prompt_lines+1, prompt_width, 2, 2);
 	form_win = derwin(win, 1, prompt_width, prompt_lines+3, 2);
 	keypad(form_win, TRUE);

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/kconfig-nconf-fix-hang-when-editing-symbol-with-a-long-prompt.patch