From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:35453) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RMGEJ-0000Ba-RT for qemu-devel@nongnu.org; Fri, 04 Nov 2011 05:38:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RMGEI-0005yo-Us for qemu-devel@nongnu.org; Fri, 04 Nov 2011 05:38:31 -0400 Received: from oxygen.pond.sub.org ([78.46.104.156]:50580) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RMGEI-0005yh-Q4 for qemu-devel@nongnu.org; Fri, 04 Nov 2011 05:38:30 -0400 From: Markus Armbruster Date: Fri, 4 Nov 2011 10:38:29 +0100 Message-Id: <1320399509-28669-1-git-send-email-armbru@redhat.com> Subject: [Qemu-devel] [PATCH] console: Fix rendering of VGA underline List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aliguori@us.ibm.com vga_putcharxy()'s underline code sets font_data to 0xffff instead of 0xff. vga_putcharxy() then reads dmask16[0xffff >> 4] and dmask4[0xffff >> 6]. In practice, these out-of-bounds subscripts "only" put a few crap bits into the display surface. For 32 bit pixels, there's no array access. font_data's extra bits go straight into the display surface. Broken when commit 6d6f7c28 implemented underline. Spotted by Coverity. Signed-off-by: Markus Armbruster --- console.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/console.c b/console.c index e43de92..f6fe441 100644 --- a/console.c +++ b/console.c @@ -467,7 +467,7 @@ static void vga_putcharxy(DisplayState *ds, int x, int y, int ch, font_data = *font_ptr++; if (t_attrib->uline && ((i == FONT_HEIGHT - 2) || (i == FONT_HEIGHT - 3))) { - font_data = 0xFFFF; + font_data = 0xFF; } ((uint32_t *)d)[0] = (dmask16[(font_data >> 4)] & xorcol) ^ bgcol; ((uint32_t *)d)[1] = (dmask16[(font_data >> 0) & 0xf] & xorcol) ^ bgcol; @@ -480,7 +480,7 @@ static void vga_putcharxy(DisplayState *ds, int x, int y, int ch, font_data = *font_ptr++; if (t_attrib->uline && ((i == FONT_HEIGHT - 2) || (i == FONT_HEIGHT - 3))) { - font_data = 0xFFFF; + font_data = 0xFF; } ((uint32_t *)d)[0] = (dmask4[(font_data >> 6)] & xorcol) ^ bgcol; ((uint32_t *)d)[1] = (dmask4[(font_data >> 4) & 3] & xorcol) ^ bgcol; @@ -493,7 +493,7 @@ static void vga_putcharxy(DisplayState *ds, int x, int y, int ch, for(i = 0; i < FONT_HEIGHT; i++) { font_data = *font_ptr++; if (t_attrib->uline && ((i == FONT_HEIGHT - 2) || (i == FONT_HEIGHT - 3))) { - font_data = 0xFFFF; + font_data = 0xFF; } ((uint32_t *)d)[0] = (-((font_data >> 7)) & xorcol) ^ bgcol; ((uint32_t *)d)[1] = (-((font_data >> 6) & 1) & xorcol) ^ bgcol; -- 1.7.6.4