qemu/0041-cirrus-fix-oob-access-in-mode4and5-.patch
2017-10-26 14:38:26 +00:00

58 lines
1.9 KiB
Diff

From f3c7b39cec549039b89fa1c6b2ab238b4bac1a97 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 18 Oct 2017 14:54:15 -0600
Subject: [PATCH] cirrus: fix oob access in mode4and5 write functions
Move dst calculation into the loop, so we apply the mask on each
interation and will not overflow vga memory.
Cc: Prasad J Pandit <pjp@fedoraproject.org>
Reported-by: Niu Guoxiang <niuguoxiang@huawei.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20171011084314.21752-1-kraxel@redhat.com
[BR: BSC#1063122 CVE-2017-15289]
Signed-off-by: Bruce Rogers <brogers@suse.com
---
hw/display/cirrus_vga.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index afc290ab91..077a8cb74f 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -2038,15 +2038,14 @@ static void cirrus_mem_writeb_mode4and5_8bpp(CirrusVGAState * s,
unsigned val = mem_value;
uint8_t *dst;
- dst = s->vga.vram_ptr + (offset &= s->cirrus_addr_mask);
for (x = 0; x < 8; x++) {
+ dst = s->vga.vram_ptr + ((offset + x) & s->cirrus_addr_mask);
if (val & 0x80) {
*dst = s->cirrus_shadow_gr1;
} else if (mode == 5) {
*dst = s->cirrus_shadow_gr0;
}
val <<= 1;
- dst++;
}
memory_region_set_dirty(&s->vga.vram, offset, 8);
}
@@ -2060,8 +2059,8 @@ static void cirrus_mem_writeb_mode4and5_16bpp(CirrusVGAState * s,
unsigned val = mem_value;
uint8_t *dst;
- dst = s->vga.vram_ptr + (offset &= s->cirrus_addr_mask);
for (x = 0; x < 8; x++) {
+ dst = s->vga.vram_ptr + ((offset + 2 * x) & s->cirrus_addr_mask & ~1);
if (val & 0x80) {
*dst = s->cirrus_shadow_gr1;
*(dst + 1) = s->vga.gr[0x11];
@@ -2070,7 +2069,6 @@ static void cirrus_mem_writeb_mode4and5_16bpp(CirrusVGAState * s,
*(dst + 1) = s->vga.gr[0x10];
}
val <<= 1;
- dst += 2;
}
memory_region_set_dirty(&s->vga.vram, offset, 16);
}