[PATCH master] font: fbconsole: fix underflow when printing non-ASCII characters

[PATCH master] font: fbconsole: fix underflow when printing non-ASCII characters

[Ahmad Fatoum]

With signed characters, non-ASCII characters (i.e. valued >= 128)
are negative and remain so when casted to int.

find_font_index will thus multiply the index with a negative number and
look for font data before the actual start of the font.

A cast to unsigned fixes this, because all fonts that trigger this if
clause's branch have 256 characters.

Fixes: 27f79c05ab42 ("video: implement framebuffer console")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 lib/fonts/fonts.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index b3bdaa21a2aa..6047b4cbe223 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -37,7 +37,7 @@ int find_font_index(const struct font_desc *font, int ch)
 	if (font->index == NULL) {
 		index  = DIV_ROUND_UP(font->width, 8);
 		index *= font->height;
-		index *= ch;
+		index *= (unsigned char)ch;
 	} else {
 		/*
 		* FIXME: use binary search instead!
-- 
2.39.5