46 lines
1.7 KiB
Diff
46 lines
1.7 KiB
Diff
From: Li Qiang <liqiang6-s@360.cn>
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Date: Wed, 1 Feb 2017 09:35:01 +0100
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Subject: [PATCH] cirrus: fix oob access issue (CVE-2017-2615)
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When doing bitblt copy in backward mode, we should minus the
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blt width first just like the adding in the forward mode. This
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can avoid the oob access of the front of vga's vram.
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Signed-off-by: Li Qiang <liqiang6-s@360.cn>
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{ kraxel: with backward blits (negative pitch) addr is the topmost
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address, so check it as-is against vram size ]
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Cc: qemu-stable@nongnu.org
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Cc: P J P <ppandit@redhat.com>
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Cc: Laszlo Ersek <lersek@redhat.com>
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Cc: Paolo Bonzini <pbonzini@redhat.com>
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Cc: Wolfgang Bumiller <w.bumiller@proxmox.com>
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Fixes: d3532a0db02296e687711b8cdc7791924efccea0 (CVE-2014-8106)
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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Message-id: 1485938101-26602-1-git-send-email-kraxel@redhat.com
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Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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(cherry picked from commit 62d4c6bd5263bb8413a06c80144fc678df6dfb64)
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---
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hw/display/cirrus_vga.c | 7 +++----
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1 file changed, 3 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 7db6409..16f27e8 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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@@ -274,10 +274,9 @@ static bool blit_region_is_unsafe(struct CirrusVGAState *s,
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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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- int32_t max = addr
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- + s->cirrus_blt_width;
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- if (min < 0 || max > s->vga.vram_size) {
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+ + ((int64_t)s->cirrus_blt_height - 1) * pitch
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+ - s->cirrus_blt_width;
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+ if (min < -1 || addr >= s->vga.vram_size) {
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return true;
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}
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} else {
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