Blame SOURCES/kvm-display-cirrus-check-vga-bits-per-pixel-bpp-value.patch

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From e0ec8bdaf64a147c83334ae6f59e279c4560d01b Mon Sep 17 00:00:00 2001
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From: Gerd Hoffmann <kraxel@redhat.com>
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Date: Tue, 7 Feb 2017 10:07:47 +0100
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Subject: [PATCH 3/8] display: cirrus: check vga bits per pixel(bpp) value
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RH-Author: Gerd Hoffmann <kraxel@redhat.com>
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Message-id: <1486462072-32174-3-git-send-email-kraxel@redhat.com>
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Patchwork-id: 73568
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O-Subject: [RHEL-7.4 qemu-kvm PATCH 2/7] display: cirrus: check vga bits per pixel(bpp) value
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Bugzilla: 1418232
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RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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From: Prasad J Pandit <pjp@fedoraproject.org>
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In Cirrus CLGD 54xx VGA Emulator, if cirrus graphics mode is VGA,
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'cirrus_get_bpp' returns zero(0), which could lead to a divide
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by zero error in while copying pixel data. The same could occur
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via blit pitch values. Add check to avoid it.
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Reported-by: Huawei PSIRT <psirt@huawei.com>
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Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
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Message-id: 1476776717-24807-1-git-send-email-ppandit@redhat.com
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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(cherry picked from commit 4299b90e9ba9ce5ca9024572804ba751aa1a7e70)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/display/cirrus_vga.c | 14 ++++++++++----
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 1 file changed, 10 insertions(+), 4 deletions(-)
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diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
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index c42dfcf..dacfac6 100644
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--- a/hw/display/cirrus_vga.c
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+++ b/hw/display/cirrus_vga.c
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@@ -267,6 +267,9 @@ static void cirrus_update_memory_access(CirrusVGAState *s);
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 static bool blit_region_is_unsafe(struct CirrusVGAState *s,
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                                   int32_t pitch, int32_t addr)
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 {
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+    if (!pitch) {
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+        return true;
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+    }
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     if (pitch < 0) {
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         int64_t min = addr
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             + ((int64_t)s->cirrus_blt_height-1) * pitch;
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@@ -710,7 +713,7 @@ static int cirrus_bitblt_videotovideo_patterncopy(CirrusVGAState * s)
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                                             s->cirrus_addr_mask));
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 }
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-static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
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+static int cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
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 {
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     int sx = 0, sy = 0;
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     int dx = 0, dy = 0;
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@@ -724,6 +727,9 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
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         int width, height;
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         depth = s->vga.get_bpp(&s->vga) / 8;
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+        if (!depth) {
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+            return 0;
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+        }
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         s->vga.get_resolution(&s->vga, &width, &height);
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         /* extra x, y */
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@@ -778,6 +784,8 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
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     cirrus_invalidate_region(s, s->cirrus_blt_dstaddr,
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 				s->cirrus_blt_dstpitch, s->cirrus_blt_width,
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 				s->cirrus_blt_height);
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+
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+    return 1;
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 }
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 static int cirrus_bitblt_videotovideo_copy(CirrusVGAState * s)
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@@ -785,11 +793,9 @@ static int cirrus_bitblt_videotovideo_copy(CirrusVGAState * s)
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     if (blit_is_unsafe(s))
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         return 0;
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-    cirrus_do_copy(s, s->cirrus_blt_dstaddr - s->vga.start_addr,
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+    return cirrus_do_copy(s, s->cirrus_blt_dstaddr - s->vga.start_addr,
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             s->cirrus_blt_srcaddr - s->vga.start_addr,
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             s->cirrus_blt_width, s->cirrus_blt_height);
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-
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-    return 1;
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 }
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 /***************************************
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-- 
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1.8.3.1
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