From e56700784b7585dddff0713ea52b2b00b8531b7f Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Thu, 5 Oct 2017 14:51:19 +0200 Subject: [PATCH 23/27] vga: stop passing pointers to vga_draw_line* functions RH-Author: Gerd Hoffmann Message-id: <20171005145119.15277-8-kraxel@redhat.com> Patchwork-id: 76828 O-Subject: [RHEL-7.5 qemu-kvm PATCH 7/7] vga: stop passing pointers to vga_draw_line* functions Bugzilla: 1486642 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Thomas Huth RH-Acked-by: Miroslav Rezanina 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 Reported-by: David Buchanan Signed-off-by: Gerd Hoffmann Message-id: 20170828122906.18993-1-kraxel@redhat.com (cherry picked from commit 3d90c6254863693a6b13d918d2b8682e08bbc681) Signed-off-by: Miroslav Rezanina --- hw/display/vga-helpers.h | 202 ++++++++++++++++++++++++++--------------------- hw/display/vga.c | 5 +- hw/display/vga_int.h | 1 + 3 files changed, 114 insertions(+), 94 deletions(-) diff --git a/hw/display/vga-helpers.h b/hw/display/vga-helpers.h index 94f6de2..5a752b3 100644 --- a/hw/display/vga-helpers.h +++ b/hw/display/vga-helpers.h @@ -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 } diff --git a/hw/display/vga.c b/hw/display/vga.c index 4618823..5b0b864 100644 --- a/hw/display/vga.c +++ b/hw/display/vga.c @@ -1045,7 +1045,7 @@ 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" @@ -1682,7 +1682,7 @@ static void vga_draw_graphic(VGACommonState *s, int full_update) if (page1 > page_max) page_max = page1; 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); } @@ -2162,6 +2162,7 @@ void vga_common_init(VGACommonState *s) 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(&s->vram, "vga.vram", s->vram_size); diff --git a/hw/display/vga_int.h b/hw/display/vga_int.h index 7c758ac..94add2f 100644 --- a/hw/display/vga_int.h +++ b/hw/display/vga_int.h @@ -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; MemoryRegion *chain4_alias; uint8_t sr_index; -- 1.8.3.1