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* [Qemu-devel] [PATCH] display: cirrus: check vga bits per pixel(bpp) value
@ 2016-10-18  7:45 P J P
  2016-11-15 16:43 ` P J P
  2016-11-16 14:13 ` Marc-André Lureau
  0 siblings, 2 replies; 9+ messages in thread
From: P J P @ 2016-10-18  7:45 UTC (permalink / raw)
  To: Qemu Developers; +Cc: Peter Maydell, Huawei PSIRT, Prasad J Pandit

From: Prasad J Pandit <pjp@fedoraproject.org>

In Cirrus CLGD 54xx VGA Emulator, if cirrus graphics mode is VGA,
'cirrus_get_bpp' returns zero(0), which could lead to a divide
by zero error in while copying pixel data. The same could occur
via blit pitch values. Add check to avoid it.

Reported-by: Huawei PSIRT <psirt@huawei.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/display/cirrus_vga.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 3d712d5..bdb092e 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -272,6 +272,9 @@ static void cirrus_update_memory_access(CirrusVGAState *s);
 static bool blit_region_is_unsafe(struct CirrusVGAState *s,
                                   int32_t pitch, int32_t addr)
 {
+    if (!pitch) {
+        return true;
+    }
     if (pitch < 0) {
         int64_t min = addr
             + ((int64_t)s->cirrus_blt_height-1) * pitch;
@@ -715,7 +718,7 @@ static int cirrus_bitblt_videotovideo_patterncopy(CirrusVGAState * s)
                                             s->cirrus_addr_mask));
 }
 
-static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
+static int cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
 {
     int sx = 0, sy = 0;
     int dx = 0, dy = 0;
@@ -729,6 +732,9 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
         int width, height;
 
         depth = s->vga.get_bpp(&s->vga) / 8;
+        if (!depth) {
+            return 0;
+        }
         s->vga.get_resolution(&s->vga, &width, &height);
 
         /* extra x, y */
@@ -783,6 +789,8 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
     cirrus_invalidate_region(s, s->cirrus_blt_dstaddr,
 				s->cirrus_blt_dstpitch, s->cirrus_blt_width,
 				s->cirrus_blt_height);
+
+    return 1;
 }
 
 static int cirrus_bitblt_videotovideo_copy(CirrusVGAState * s)
@@ -790,11 +798,9 @@ static int cirrus_bitblt_videotovideo_copy(CirrusVGAState * s)
     if (blit_is_unsafe(s))
         return 0;
 
-    cirrus_do_copy(s, s->cirrus_blt_dstaddr - s->vga.start_addr,
+    return cirrus_do_copy(s, s->cirrus_blt_dstaddr - s->vga.start_addr,
             s->cirrus_blt_srcaddr - s->vga.start_addr,
             s->cirrus_blt_width, s->cirrus_blt_height);
-
-    return 1;
 }
 
 /***************************************
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2017-01-23 11:57 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-10-18  7:45 [Qemu-devel] [PATCH] display: cirrus: check vga bits per pixel(bpp) value P J P
2016-11-15 16:43 ` P J P
2016-11-16 14:13 ` Marc-André Lureau
2016-11-28  6:22   ` P J P
2016-12-05  7:33     ` P J P
2017-01-11 14:59     ` Alberto Garcia
2017-01-11 20:43       ` Gerd Hoffmann
2017-01-20  9:46         ` Wolfgang Bumiller
2017-01-23 11:56           ` Gerd Hoffmann

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