sfeed_curses

commit a76dc7f57fb6ccd2baf834172f8f66065340c6c3
parent 88398ed1fd8f071a8d31bd64d2e93159f53b559c
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date:   Sat,  8 Aug 2020 19:43:09 +0200

Fix a crash with small window width and garbage data if utf8pad fails

utf8pad: check the return value, do not print if it returns an error (-1).

updategeom(): clamp width and height to sane values.
The height should be >= 1 (to prevent divide-by-zero).
The width can be set to >= 0.

Remove the check in draw() which prevents drawing. If the window is too small
it will now write the data anyway, although the output will not be nicely
formatted.

To reproduce the crash: make the window width exactly the size of the feed pane
width.  Select the items pane (right-arrow) and scroll down.  The logic of
partial row drawing (which is not in draw()) would be executed anyway and use a
negative value for the pane width.

Diffstat:
M
sfeed_curses.c
 | 
21
++++++++++-----------

1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/sfeed_curses.c b/sfeed_curses.c
@@ -365,8 +365,8 @@ void
 printpad(const char *s, int width)
 {
 	char buf[1024];
-	utf8pad(buf, sizeof(buf), s, width, ' ');
-	ttywrite(buf);
+	if (utf8pad(buf, sizeof(buf), s, width, ' ') != -1)
+		ttywrite(buf);
 }
 
 void
@@ -782,7 +782,8 @@ updategeom(void)
 
 	panes[PaneFeeds].x = 0;
 	panes[PaneFeeds].y = 0;
-	panes[PaneFeeds].height = win.height - 1; /* space for statusbar */
+	/* reserve space for statusbar */
+	panes[PaneFeeds].height = win.height > 1 ? win.height - 1 : 1;
 
 	/* NOTE: updatesidebar() must happen before this function for the
 	   remaining width */
@@ -798,7 +799,7 @@ updategeom(void)
 	}
 
 	panes[PaneItems].x = x;
-	panes[PaneItems].width = w - 1; /* rest and space for scrollbar */
+	panes[PaneItems].width = w > 0 ? w - 1 : 0; /* rest and space for scrollbar */
 	panes[PaneItems].height = panes[PaneFeeds].height;
 	panes[PaneItems].y = panes[PaneFeeds].y;
 
@@ -814,7 +815,7 @@ updategeom(void)
 	/* statusbar below */
 	statusbar.width = win.width;
 	statusbar.x = 0;
-	statusbar.y = win.height - 1;
+	statusbar.y = panes[PaneFeeds].height;
 
 	alldirty();
 }
@@ -1364,10 +1365,6 @@ draw(void)
 	struct item *item;
 	size_t i;
 
-	if (win.width <= 1 || win.height <= 3 ||
-	    (!panes[PaneFeeds].hidden && win.width <= panes[PaneFeeds].width + 2))
-		return;
-
 	if (win.dirty) {
 		clearscreen();
 		win.dirty = 0;
@@ -1479,8 +1476,10 @@ feed_row_format(struct pane *p, struct row *row)
 
 	len = snprintf(counts, sizeof(counts), "(%lu/%lu)",
 	               feed->totalnew, feed->total);
-	utf8pad(bufw, sizeof(bufw), feed->name, p->width - len, ' ');
-	snprintf(text, sizeof(text), "%s%s", bufw, counts);
+	if (utf8pad(bufw, sizeof(bufw), feed->name, p->width - len, ' ') != -1)
+		snprintf(text, sizeof(text), "%s%s", bufw, counts);
+	else
+		text[0] = '\0';
 
 	return text;
 }