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qemu: Security Fix CVE-2016-3712

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affects qemu < 2.6.0

(From OE-Core rev: 6f25d966c41df5315d253859d9ebf231963bf671)

Signed-off-by: Armin Kuster <akuster@mvista.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Armin Kuster 2016-09-19 18:12:42 -07:00 committed by Richard Purdie
parent ffa3a07ac1
commit 98e7d8a9a0
5 changed files with 323 additions and 0 deletions
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73
meta/recipes-devtools/qemu/qemu/CVE-2016-3712_p1.patch Normal file
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@ -0,0 +1,73 @@
From 46aff2c7e91ef9f372ad38ba5e90c42b9b27ac75 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Tue, 26 Apr 2016 14:11:34 +0200
Subject: [PATCH 1/4] vga: add vbe_enabled() helper
Makes code a bit easier to read.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Upstream-Status: Backport
CVE: CVE-2016-3712 patch1
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
hw/display/vga.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/hw/display/vga.c b/hw/display/vga.c
index 442fee9..cc1a682 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -140,6 +140,11 @@ static uint32_t expand4[256];
static uint16_t expand2[256];
static uint8_t expand4to8[16];
+static inline bool vbe_enabled(VGACommonState *s)
+{
+ return s->vbe_regs[VBE_DISPI_INDEX_ENABLE] & VBE_DISPI_ENABLED;
+}
+
static void vga_update_memory_access(VGACommonState *s)
{
hwaddr base, offset, size;
@@ -562,7 +567,7 @@ static void vbe_fixup_regs(VGACommonState *s)
uint16_t *r = s->vbe_regs;
uint32_t bits, linelength, maxy, offset;
- if (!(r[VBE_DISPI_INDEX_ENABLE] & VBE_DISPI_ENABLED)) {
+ if (!vbe_enabled(s)) {
/* vbe is turned off -- nothing to do */
return;
}
@@ -1056,7 +1061,7 @@ static void vga_get_offsets(VGACommonState *s,
{
uint32_t start_addr, line_offset, line_compare;
- if (s->vbe_regs[VBE_DISPI_INDEX_ENABLE] & VBE_DISPI_ENABLED) {
+ if (vbe_enabled(s)) {
line_offset = s->vbe_line_offset;
start_addr = s->vbe_start_addr;
line_compare = 65535;
@@ -1381,7 +1386,7 @@ static int vga_get_bpp(VGACommonState *s)
{
int ret;
- if (s->vbe_regs[VBE_DISPI_INDEX_ENABLE] & VBE_DISPI_ENABLED) {
+ if (vbe_enabled(s)) {
ret = s->vbe_regs[VBE_DISPI_INDEX_BPP];
} else {
ret = 0;
@@ -1393,7 +1398,7 @@ static void vga_get_resolution(VGACommonState *s, int *pwidth, int *pheight)
{
int width, height;
- if (s->vbe_regs[VBE_DISPI_INDEX_ENABLE] & VBE_DISPI_ENABLED) {
+ if (vbe_enabled(s)) {
width = s->vbe_regs[VBE_DISPI_INDEX_XRES];
height = s->vbe_regs[VBE_DISPI_INDEX_YRES];
} else {
--
2.7.4

132
meta/recipes-devtools/qemu/qemu/CVE-2016-3712_p2.patch Normal file
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@ -0,0 +1,132 @@
From 2f2f74e87c15e830f5a4dda7a166effcab5047ec Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Tue, 26 Apr 2016 15:24:18 +0200
Subject: [PATCH 2/4] vga: factor out vga register setup
When enabling vbe mode qemu will setup a bunch of vga registers to make
sure the vga emulation operates in correct mode for a linear
framebuffer. Move that code to a separate function so we can call it
from other places too.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Upstream-Status: Backport
CVE: CVE-2016-3712 patch2
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
hw/display/vga.c | 78 ++++++++++++++++++++++++++++++++------------------------
1 file changed, 44 insertions(+), 34 deletions(-)
diff --git a/hw/display/vga.c b/hw/display/vga.c
index cc1a682..f1987e3 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -642,6 +642,49 @@ static void vbe_fixup_regs(VGACommonState *s)
s->vbe_start_addr = offset / 4;
}
+/* we initialize the VGA graphic mode */
+static void vbe_update_vgaregs(VGACommonState *s)
+{
+ int h, shift_control;
+
+ if (!vbe_enabled(s)) {
+ /* vbe is turned off -- nothing to do */
+ return;
+ }
+
+ /* graphic mode + memory map 1 */
+ s->gr[VGA_GFX_MISC] = (s->gr[VGA_GFX_MISC] & ~0x0c) | 0x04 |
+ VGA_GR06_GRAPHICS_MODE;
+ s->cr[VGA_CRTC_MODE] |= 3; /* no CGA modes */
+ s->cr[VGA_CRTC_OFFSET] = s->vbe_line_offset >> 3;
+ /* width */
+ s->cr[VGA_CRTC_H_DISP] =
+ (s->vbe_regs[VBE_DISPI_INDEX_XRES] >> 3) - 1;
+ /* height (only meaningful if < 1024) */
+ h = s->vbe_regs[VBE_DISPI_INDEX_YRES] - 1;
+ s->cr[VGA_CRTC_V_DISP_END] = h;
+ s->cr[VGA_CRTC_OVERFLOW] = (s->cr[VGA_CRTC_OVERFLOW] & ~0x42) |
+ ((h >> 7) & 0x02) | ((h >> 3) & 0x40);
+ /* line compare to 1023 */
+ s->cr[VGA_CRTC_LINE_COMPARE] = 0xff;
+ s->cr[VGA_CRTC_OVERFLOW] |= 0x10;
+ s->cr[VGA_CRTC_MAX_SCAN] |= 0x40;
+
+ if (s->vbe_regs[VBE_DISPI_INDEX_BPP] == 4) {
+ shift_control = 0;
+ s->sr[VGA_SEQ_CLOCK_MODE] &= ~8; /* no double line */
+ } else {
+ shift_control = 2;
+ /* set chain 4 mode */
+ s->sr[VGA_SEQ_MEMORY_MODE] |= VGA_SR04_CHN_4M;
+ /* activate all planes */
+ s->sr[VGA_SEQ_PLANE_WRITE] |= VGA_SR02_ALL_PLANES;
+ }
+ s->gr[VGA_GFX_MODE] = (s->gr[VGA_GFX_MODE] & ~0x60) |
+ (shift_control << 5);
+ s->cr[VGA_CRTC_MAX_SCAN] &= ~0x9f; /* no double scan */
+}
+
static uint32_t vbe_ioport_read_index(void *opaque, uint32_t addr)
{
VGACommonState *s = opaque;
@@ -728,52 +771,19 @@ void vbe_ioport_write_data(void *opaque, uint32_t addr, uint32_t val)
case VBE_DISPI_INDEX_ENABLE:
if ((val & VBE_DISPI_ENABLED) &&
!(s->vbe_regs[VBE_DISPI_INDEX_ENABLE] & VBE_DISPI_ENABLED)) {
- int h, shift_control;
s->vbe_regs[VBE_DISPI_INDEX_VIRT_WIDTH] = 0;
s->vbe_regs[VBE_DISPI_INDEX_X_OFFSET] = 0;
s->vbe_regs[VBE_DISPI_INDEX_Y_OFFSET] = 0;
s->vbe_regs[VBE_DISPI_INDEX_ENABLE] |= VBE_DISPI_ENABLED;
vbe_fixup_regs(s);
+ vbe_update_vgaregs(s);
/* clear the screen */
if (!(val & VBE_DISPI_NOCLEARMEM)) {
memset(s->vram_ptr, 0,
s->vbe_regs[VBE_DISPI_INDEX_YRES] * s->vbe_line_offset);
}
-
- /* we initialize the VGA graphic mode */
- /* graphic mode + memory map 1 */
- s->gr[VGA_GFX_MISC] = (s->gr[VGA_GFX_MISC] & ~0x0c) | 0x04 |
- VGA_GR06_GRAPHICS_MODE;
- s->cr[VGA_CRTC_MODE] |= 3; /* no CGA modes */
- s->cr[VGA_CRTC_OFFSET] = s->vbe_line_offset >> 3;
- /* width */
- s->cr[VGA_CRTC_H_DISP] =
- (s->vbe_regs[VBE_DISPI_INDEX_XRES] >> 3) - 1;
- /* height (only meaningful if < 1024) */
- h = s->vbe_regs[VBE_DISPI_INDEX_YRES] - 1;
- s->cr[VGA_CRTC_V_DISP_END] = h;
- s->cr[VGA_CRTC_OVERFLOW] = (s->cr[VGA_CRTC_OVERFLOW] & ~0x42) |
- ((h >> 7) & 0x02) | ((h >> 3) & 0x40);
- /* line compare to 1023 */
- s->cr[VGA_CRTC_LINE_COMPARE] = 0xff;
- s->cr[VGA_CRTC_OVERFLOW] |= 0x10;
- s->cr[VGA_CRTC_MAX_SCAN] |= 0x40;
-
- if (s->vbe_regs[VBE_DISPI_INDEX_BPP] == 4) {
- shift_control = 0;
- s->sr[VGA_SEQ_CLOCK_MODE] &= ~8; /* no double line */
- } else {
- shift_control = 2;
- /* set chain 4 mode */
- s->sr[VGA_SEQ_MEMORY_MODE] |= VGA_SR04_CHN_4M;
- /* activate all planes */
- s->sr[VGA_SEQ_PLANE_WRITE] |= VGA_SR02_ALL_PLANES;
- }
- s->gr[VGA_GFX_MODE] = (s->gr[VGA_GFX_MODE] & ~0x60) |
- (shift_control << 5);
- s->cr[VGA_CRTC_MAX_SCAN] &= ~0x9f; /* no double scan */
} else {
s->bank_offset = 0;
}
--
2.7.4

34
meta/recipes-devtools/qemu/qemu/CVE-2016-3712_p3.patch Normal file
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@ -0,0 +1,34 @@
From a6e5e5dd4bbc022acbd10ebcf415a6a57418d09e Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Tue, 26 Apr 2016 15:39:22 +0200
Subject: [PATCH 3/4] vga: update vga register setup on vbe changes
Call the new vbe_update_vgaregs() function on vbe configuration
changes, to make sure vga registers are up-to-date.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Upstream-Status: Backport
CVE: CVE-2016-3712 patch3
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
hw/display/vga.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/display/vga.c b/hw/display/vga.c
index f1987e3..10ac7df 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -761,6 +761,7 @@ void vbe_ioport_write_data(void *opaque, uint32_t addr, uint32_t val)
case VBE_DISPI_INDEX_Y_OFFSET:
s->vbe_regs[s->vbe_index] = val;
vbe_fixup_regs(s);
+ vbe_update_vgaregs(s);
break;
case VBE_DISPI_INDEX_BANK:
val &= s->vbe_bank_mask;
--
2.7.4

80
meta/recipes-devtools/qemu/qemu/CVE-2016-3712_p4.patch Normal file
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@ -0,0 +1,80 @@
From 44b86aa32e4147c727fadd9a0f0bc503a5dedb72 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Tue, 26 Apr 2016 14:48:06 +0200
Subject: [PATCH 4/4] vga: make sure vga register setup for vbe stays intact
(CVE-2016-3712).
Call vbe_update_vgaregs() when the guest touches GFX, SEQ or CRT
registers, to make sure the vga registers will always have the
values needed by vbe mode. This makes sure the sanity checks
applied by vbe_fixup_regs() are effective.
Without this guests can muck with shift_control, can turn on planar
vga modes or text mode emulation while VBE is active, making qemu
take code paths meant for CGA compatibility, but with the very
large display widths and heigts settable using VBE registers.
Which is good for one or another buffer overflow. Not that
critical as they typically read overflows happening somewhere
in the display code. So guests can DoS by crashing qemu with a
segfault, but it is probably not possible to break out of the VM.
Fixes: CVE-2016-3712
Reported-by: Zuozhi Fzz <zuozhi.fzz@alibaba-inc.com>
Reported-by: P J P <ppandit@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Upstream-Status: Backport
CVE: CVE-2016-3712 patch4 ( the fix)
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
hw/display/vga.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/hw/display/vga.c b/hw/display/vga.c
index 10ac7df..679070e 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -140,6 +140,8 @@ static uint32_t expand4[256];
static uint16_t expand2[256];
static uint8_t expand4to8[16];
+static void vbe_update_vgaregs(VGACommonState *s);
+
static inline bool vbe_enabled(VGACommonState *s)
{
return s->vbe_regs[VBE_DISPI_INDEX_ENABLE] & VBE_DISPI_ENABLED;
@@ -482,6 +484,7 @@ void vga_ioport_write(void *opaque, uint32_t addr, uint32_t val)
printf("vga: write SR%x = 0x%02x\n", s->sr_index, val);
#endif
s->sr[s->sr_index] = val & sr_mask[s->sr_index];
+ vbe_update_vgaregs(s);
if (s->sr_index == VGA_SEQ_CLOCK_MODE) {
s->update_retrace_info(s);
}
@@ -513,6 +516,7 @@ void vga_ioport_write(void *opaque, uint32_t addr, uint32_t val)
printf("vga: write GR%x = 0x%02x\n", s->gr_index, val);
#endif
s->gr[s->gr_index] = val & gr_mask[s->gr_index];
+ vbe_update_vgaregs(s);
vga_update_memory_access(s);
break;
case VGA_CRT_IM:
@@ -531,10 +535,12 @@ void vga_ioport_write(void *opaque, uint32_t addr, uint32_t val)
if (s->cr_index == VGA_CRTC_OVERFLOW) {
s->cr[VGA_CRTC_OVERFLOW] = (s->cr[VGA_CRTC_OVERFLOW] & ~0x10) |
(val & 0x10);
+ vbe_update_vgaregs(s);
}
return;
}
s->cr[s->cr_index] = val;
+ vbe_update_vgaregs(s);
switch(s->cr_index) {
case VGA_CRTC_H_TOTAL:
--
2.7.4

4
meta/recipes-devtools/qemu/qemu_2.4.0.bb
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@ -21,6 +21,10 @@ SRC_URI += "file://configure-fix-Darwin-target-detection.patch \
file://CVE-2016-2197.patch \
file://CVE-2016-2198.patch \
file://CVE-2016-3710.patch \
file://CVE-2016-3712_p1.patch \
file://CVE-2016-3712_p2.patch \
file://CVE-2016-3712_p3.patch \
file://CVE-2016-3712_p4.patch \
"
SRC_URI_prepend = "http://wiki.qemu-project.org/download/${BP}.tar.bz2"
SRC_URI[md5sum] = "186ee8194140a484a455f8e3c74589f4"