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vga: stop passing pointers to vga_draw_line* functions

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Instead pass around the address (aka offset into vga memory).
Add vga_read_* helper functions which apply vbe_size_mask to
the address, to make sure the address stays within the valid
range, similar to the cirrus blitter fixes (commits ffaf857778
and 026aeffcb4).

Impact:  DoS for privileged guest users.  qemu crashes with
a segfault, when hitting the guard page after vga memory
allocation, while reading vga memory for display updates.

Fixes: CVE-2017-13672
Cc: P J P <ppandit@redhat.com>
Reported-by: David Buchanan <d@vidbuchanan.co.uk>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20170828122906.18993-1-kraxel@redhat.com
This commit is contained in:
Gerd Hoffmann 2017-08-28 14:29:06 +02:00
parent e65294157d
commit 3d90c62548
3 changed files with 114 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

202
hw/display/vga-helpers.h
View File

@ -95,20 +95,46 @@ static void vga_draw_glyph9(uint8_t *d, int linesize,
} while (--h);
}
static inline uint8_t vga_read_byte(VGACommonState *vga, uint32_t addr)
{
return vga->vram_ptr[addr & vga->vbe_size_mask];
}
static inline uint16_t vga_read_word_le(VGACommonState *vga, uint32_t addr)
{
uint32_t offset = addr & vga->vbe_size_mask & ~1;
uint16_t *ptr = (uint16_t *)(vga->vram_ptr + offset);
return lduw_le_p(ptr);
}
static inline uint16_t vga_read_word_be(VGACommonState *vga, uint32_t addr)
{
uint32_t offset = addr & vga->vbe_size_mask & ~1;
uint16_t *ptr = (uint16_t *)(vga->vram_ptr + offset);
return lduw_be_p(ptr);
}
static inline uint32_t vga_read_dword_le(VGACommonState *vga, uint32_t addr)
{
uint32_t offset = addr & vga->vbe_size_mask & ~3;
uint32_t *ptr = (uint32_t *)(vga->vram_ptr + offset);
return ldl_le_p(ptr);
}
/*
* 4 color mode
*/
static void vga_draw_line2(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line2(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
uint32_t plane_mask, *palette, data, v;
int x;
palette = s1->last_palette;
plane_mask = mask16[s1->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
palette = vga->last_palette;
plane_mask = mask16[vga->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
width >>= 3;
for(x = 0; x < width; x++) {
data = ((uint32_t *)s)[0];
data = vga_read_dword_le(vga, addr);
data &= plane_mask;
v = expand2[GET_PLANE(data, 0)];
v |= expand2[GET_PLANE(data, 2)] << 2;
@ -124,7 +150,7 @@ static void vga_draw_line2(VGACommonState *s1, uint8_t *d,
((uint32_t *)d)[6] = palette[(v >> 4) & 0xf];
((uint32_t *)d)[7] = palette[(v >> 0) & 0xf];
d += 32;
s += 4;
addr += 4;
}
}
@ -134,17 +160,17 @@ static void vga_draw_line2(VGACommonState *s1, uint8_t *d,
/*
* 4 color mode, dup2 horizontal
*/
static void vga_draw_line2d2(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line2d2(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
uint32_t plane_mask, *palette, data, v;
int x;
palette = s1->last_palette;
plane_mask = mask16[s1->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
palette = vga->last_palette;
plane_mask = mask16[vga->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
width >>= 3;
for(x = 0; x < width; x++) {
data = ((uint32_t *)s)[0];
data = vga_read_dword_le(vga, addr);
data &= plane_mask;
v = expand2[GET_PLANE(data, 0)];
v |= expand2[GET_PLANE(data, 2)] << 2;
@ -160,24 +186,24 @@ static void vga_draw_line2d2(VGACommonState *s1, uint8_t *d,
PUT_PIXEL2(d, 6, palette[(v >> 4) & 0xf]);
PUT_PIXEL2(d, 7, palette[(v >> 0) & 0xf]);
d += 64;
s += 4;
addr += 4;
}
}
/*
* 16 color mode
*/
static void vga_draw_line4(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line4(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
uint32_t plane_mask, data, v, *palette;
int x;
palette = s1->last_palette;
plane_mask = mask16[s1->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
palette = vga->last_palette;
plane_mask = mask16[vga->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
width >>= 3;
for(x = 0; x < width; x++) {
data = ((uint32_t *)s)[0];
data = vga_read_dword_le(vga, addr);
data &= plane_mask;
v = expand4[GET_PLANE(data, 0)];
v |= expand4[GET_PLANE(data, 1)] << 1;
@ -192,24 +218,24 @@ static void vga_draw_line4(VGACommonState *s1, uint8_t *d,
((uint32_t *)d)[6] = palette[(v >> 4) & 0xf];
((uint32_t *)d)[7] = palette[(v >> 0) & 0xf];
d += 32;
s += 4;
addr += 4;
}
}
/*
* 16 color mode, dup2 horizontal
*/
static void vga_draw_line4d2(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line4d2(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
uint32_t plane_mask, data, v, *palette;
int x;
palette = s1->last_palette;
plane_mask = mask16[s1->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
palette = vga->last_palette;
plane_mask = mask16[vga->ar[VGA_ATC_PLANE_ENABLE] & 0xf];
width >>= 3;
for(x = 0; x < width; x++) {
data = ((uint32_t *)s)[0];
data = vga_read_dword_le(vga, addr);
data &= plane_mask;
v = expand4[GET_PLANE(data, 0)];
v |= expand4[GET_PLANE(data, 1)] << 1;
@ -224,7 +250,7 @@ static void vga_draw_line4d2(VGACommonState *s1, uint8_t *d,
PUT_PIXEL2(d, 6, palette[(v >> 4) & 0xf]);
PUT_PIXEL2(d, 7, palette[(v >> 0) & 0xf]);
d += 64;
s += 4;
addr += 4;
}
}
@ -233,21 +259,21 @@ static void vga_draw_line4d2(VGACommonState *s1, uint8_t *d,
*
* XXX: add plane_mask support (never used in standard VGA modes)
*/
static void vga_draw_line8d2(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line8d2(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
uint32_t *palette;
int x;
palette = s1->last_palette;
palette = vga->last_palette;
width >>= 3;
for(x = 0; x < width; x++) {
PUT_PIXEL2(d, 0, palette[s[0]]);
PUT_PIXEL2(d, 1, palette[s[1]]);
PUT_PIXEL2(d, 2, palette[s[2]]);
PUT_PIXEL2(d, 3, palette[s[3]]);
PUT_PIXEL2(d, 0, palette[vga_read_byte(vga, addr + 0)]);
PUT_PIXEL2(d, 1, palette[vga_read_byte(vga, addr + 1)]);
PUT_PIXEL2(d, 2, palette[vga_read_byte(vga, addr + 2)]);
PUT_PIXEL2(d, 3, palette[vga_read_byte(vga, addr + 3)]);
d += 32;
s += 4;
addr += 4;
}
}
@ -256,63 +282,63 @@ static void vga_draw_line8d2(VGACommonState *s1, uint8_t *d,
*
* XXX: add plane_mask support (never used in standard VGA modes)
*/
static void vga_draw_line8(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line8(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
uint32_t *palette;
int x;
palette = s1->last_palette;
palette = vga->last_palette;
width >>= 3;
for(x = 0; x < width; x++) {
((uint32_t *)d)[0] = palette[s[0]];
((uint32_t *)d)[1] = palette[s[1]];
((uint32_t *)d)[2] = palette[s[2]];
((uint32_t *)d)[3] = palette[s[3]];
((uint32_t *)d)[4] = palette[s[4]];
((uint32_t *)d)[5] = palette[s[5]];
((uint32_t *)d)[6] = palette[s[6]];
((uint32_t *)d)[7] = palette[s[7]];
((uint32_t *)d)[0] = palette[vga_read_byte(vga, addr + 0)];
((uint32_t *)d)[1] = palette[vga_read_byte(vga, addr + 1)];
((uint32_t *)d)[2] = palette[vga_read_byte(vga, addr + 2)];
((uint32_t *)d)[3] = palette[vga_read_byte(vga, addr + 3)];
((uint32_t *)d)[4] = palette[vga_read_byte(vga, addr + 4)];
((uint32_t *)d)[5] = palette[vga_read_byte(vga, addr + 5)];
((uint32_t *)d)[6] = palette[vga_read_byte(vga, addr + 6)];
((uint32_t *)d)[7] = palette[vga_read_byte(vga, addr + 7)];
d += 32;
s += 8;
addr += 8;
}
}
/*
* 15 bit color
*/
static void vga_draw_line15_le(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line15_le(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
int w;
uint32_t v, r, g, b;
w = width;
do {
v = lduw_le_p((void *)s);
v = vga_read_word_le(vga, addr);
r = (v >> 7) & 0xf8;
g = (v >> 2) & 0xf8;
b = (v << 3) & 0xf8;
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 2;
addr += 2;
d += 4;
} while (--w != 0);
}
static void vga_draw_line15_be(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line15_be(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
int w;
uint32_t v, r, g, b;
w = width;
do {
v = lduw_be_p((void *)s);
v = vga_read_word_be(vga, addr);
r = (v >> 7) & 0xf8;
g = (v >> 2) & 0xf8;
b = (v << 3) & 0xf8;
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 2;
addr += 2;
d += 4;
} while (--w != 0);
}
@ -320,38 +346,38 @@ static void vga_draw_line15_be(VGACommonState *s1, uint8_t *d,
/*
* 16 bit color
*/
static void vga_draw_line16_le(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line16_le(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
int w;
uint32_t v, r, g, b;
w = width;
do {
v = lduw_le_p((void *)s);
v = vga_read_word_le(vga, addr);
r = (v >> 8) & 0xf8;
g = (v >> 3) & 0xfc;
b = (v << 3) & 0xf8;
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 2;
addr += 2;
d += 4;
} while (--w != 0);
}
static void vga_draw_line16_be(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line16_be(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
int w;
uint32_t v, r, g, b;
w = width;
do {
v = lduw_be_p((void *)s);
v = vga_read_word_be(vga, addr);
r = (v >> 8) & 0xf8;
g = (v >> 3) & 0xfc;
b = (v << 3) & 0xf8;
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 2;
addr += 2;
d += 4;
} while (--w != 0);
}
@ -359,36 +385,36 @@ static void vga_draw_line16_be(VGACommonState *s1, uint8_t *d,
/*
* 24 bit color
*/
static void vga_draw_line24_le(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line24_le(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
int w;
uint32_t r, g, b;
w = width;
do {
b = s[0];
g = s[1];
r = s[2];
b = vga_read_byte(vga, addr + 0);
g = vga_read_byte(vga, addr + 1);
r = vga_read_byte(vga, addr + 2);
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 3;
addr += 3;
d += 4;
} while (--w != 0);
}
static void vga_draw_line24_be(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line24_be(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
int w;
uint32_t r, g, b;
w = width;
do {
r = s[0];
g = s[1];
b = s[2];
r = vga_read_byte(vga, addr + 0);
g = vga_read_byte(vga, addr + 1);
b = vga_read_byte(vga, addr + 2);
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 3;
addr += 3;
d += 4;
} while (--w != 0);
}
@ -396,44 +422,36 @@ static void vga_draw_line24_be(VGACommonState *s1, uint8_t *d,
/*
* 32 bit color
*/
static void vga_draw_line32_le(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line32_le(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
#ifndef HOST_WORDS_BIGENDIAN
memcpy(d, s, width * 4);
#else
int w;
uint32_t r, g, b;
w = width;
do {
b = s[0];
g = s[1];
r = s[2];
b = vga_read_byte(vga, addr + 0);
g = vga_read_byte(vga, addr + 1);
r = vga_read_byte(vga, addr + 2);
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 4;
addr += 4;
d += 4;
} while (--w != 0);
#endif
}
static void vga_draw_line32_be(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width)
static void vga_draw_line32_be(VGACommonState *vga, uint8_t *d,
uint32_t addr, int width)
{
#ifdef HOST_WORDS_BIGENDIAN
memcpy(d, s, width * 4);
#else
int w;
uint32_t r, g, b;
w = width;
do {
r = s[1];
g = s[2];
b = s[3];
r = vga_read_byte(vga, addr + 1);
g = vga_read_byte(vga, addr + 2);
b = vga_read_byte(vga, addr + 3);
((uint32_t *)d)[0] = rgb_to_pixel32(r, g, b);
s += 4;
addr += 4;
d += 4;
} while (--w != 0);
#endif
}

5
hw/display/vga.c
View File

@ -1005,7 +1005,7 @@ void vga_mem_writeb(VGACommonState *s, hwaddr addr, uint32_t val)
}
typedef void vga_draw_line_func(VGACommonState *s1, uint8_t *d,
const uint8_t *s, int width);
uint32_t srcaddr, int width);
#include "vga-helpers.h"
@ -1666,7 +1666,7 @@ static void vga_draw_graphic(VGACommonState *s, int full_update)
if (y_start < 0)
y_start = y;
if (!(is_buffer_shared(surface))) {
vga_draw_line(s, d, s->vram_ptr + addr, width);
vga_draw_line(s, d, addr, width);
if (s->cursor_draw_line)
s->cursor_draw_line(s, d, y);
}
@ -2170,6 +2170,7 @@ void vga_common_init(VGACommonState *s, Object *obj, bool global_vmstate)
if (!s->vbe_size) {
s->vbe_size = s->vram_size;
}
s->vbe_size_mask = s->vbe_size - 1;
s->is_vbe_vmstate = 1;
memory_region_init_ram_nomigrate(&s->vram, obj, "vga.vram", s->vram_size,

1
hw/display/vga_int.h
View File

@ -94,6 +94,7 @@ typedef struct VGACommonState {
uint32_t vram_size;
uint32_t vram_size_mb; /* property */
uint32_t vbe_size;
uint32_t vbe_size_mask;
uint32_t latch;
bool has_chain4_alias;
MemoryRegion chain4_alias;