diff options
Diffstat (limited to 'system/xen/patches/xsa179-qemuu-4.6-0001-vga-fix-banked-access-bounds-checking-CVE-2016-3710.patch')
| -rw-r--r-- | system/xen/patches/xsa179-qemuu-4.6-0001-vga-fix-banked-access-bounds-checking-CVE-2016-3710.patch | 108 |
1 files changed, 0 insertions, 108 deletions
diff --git a/system/xen/patches/xsa179-qemuu-4.6-0001-vga-fix-banked-access-bounds-checking-CVE-2016-3710.patch b/system/xen/patches/xsa179-qemuu-4.6-0001-vga-fix-banked-access-bounds-checking-CVE-2016-3710.patch deleted file mode 100644 index 3ad3cf4327..0000000000 --- a/system/xen/patches/xsa179-qemuu-4.6-0001-vga-fix-banked-access-bounds-checking-CVE-2016-3710.patch +++ /dev/null @@ -1,108 +0,0 @@ -From b16db5ab2d0c5ff755e08942f4c8e8f9f8618eae Mon Sep 17 00:00:00 2001 -From: Gerd Hoffmann <kraxel@redhat.com> -Date: Tue, 26 Apr 2016 08:49:10 +0200 -Subject: [PATCH 1/5] vga: fix banked access bounds checking (CVE-2016-3710) - -vga allows banked access to video memory using the window at 0xa00000 -and it supports a different access modes with different address -calculations. - -The VBE bochs extentions support banked access too, using the -VBE_DISPI_INDEX_BANK register. The code tries to take the different -address calculations into account and applies different limits to -VBE_DISPI_INDEX_BANK depending on the current access mode. - -Which is probably effective in stopping misprogramming by accident. -But from a security point of view completely useless as an attacker -can easily change access modes after setting the bank register. - -Drop the bogus check, add range checks to vga_mem_{readb,writeb} -instead. - -Fixes: CVE-2016-3710 -Reported-by: Qinghao Tang <luodalongde@gmail.com> -Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> -Signed-off-by: Stefano Stabellini <sstabellini@kernel.org> ---- - hw/display/vga.c | 24 ++++++++++++++++++------ - 1 file changed, 18 insertions(+), 6 deletions(-) - -diff --git a/hw/display/vga.c b/hw/display/vga.c -index 52eaf05..b577712 100644 ---- a/hw/display/vga.c -+++ b/hw/display/vga.c -@@ -178,6 +178,7 @@ static void vga_update_memory_access(VGACommonState *s) - break; - } - base += isa_mem_base; -+ assert(offset + size <= s->vram_size); - memory_region_init_alias(&s->chain4_alias, memory_region_owner(&s->vram), - "vga.chain4", &s->vram, offset, size); - memory_region_add_subregion_overlap(s->legacy_address_space, base, -@@ -715,11 +716,7 @@ void vbe_ioport_write_data(void *opaque, uint32_t addr, uint32_t val) - vbe_fixup_regs(s); - break; - case VBE_DISPI_INDEX_BANK: -- if (s->vbe_regs[VBE_DISPI_INDEX_BPP] == 4) { -- val &= (s->vbe_bank_mask >> 2); -- } else { -- val &= s->vbe_bank_mask; -- } -+ val &= s->vbe_bank_mask; - s->vbe_regs[s->vbe_index] = val; - s->bank_offset = (val << 16); - vga_update_memory_access(s); -@@ -818,13 +815,21 @@ uint32_t vga_mem_readb(VGACommonState *s, hwaddr addr) - - if (s->sr[VGA_SEQ_MEMORY_MODE] & VGA_SR04_CHN_4M) { - /* chain 4 mode : simplest access */ -+ assert(addr < s->vram_size); - ret = s->vram_ptr[addr]; - } else if (s->gr[VGA_GFX_MODE] & 0x10) { - /* odd/even mode (aka text mode mapping) */ - plane = (s->gr[VGA_GFX_PLANE_READ] & 2) | (addr & 1); -- ret = s->vram_ptr[((addr & ~1) << 1) | plane]; -+ addr = ((addr & ~1) << 1) | plane; -+ if (addr >= s->vram_size) { -+ return 0xff; -+ } -+ ret = s->vram_ptr[addr]; - } else { - /* standard VGA latched access */ -+ if (addr * sizeof(uint32_t) >= s->vram_size) { -+ return 0xff; -+ } - s->latch = ((uint32_t *)s->vram_ptr)[addr]; - - if (!(s->gr[VGA_GFX_MODE] & 0x08)) { -@@ -881,6 +886,7 @@ void vga_mem_writeb(VGACommonState *s, hwaddr addr, uint32_t val) - plane = addr & 3; - mask = (1 << plane); - if (s->sr[VGA_SEQ_PLANE_WRITE] & mask) { -+ assert(addr < s->vram_size); - s->vram_ptr[addr] = val; - #ifdef DEBUG_VGA_MEM - printf("vga: chain4: [0x" TARGET_FMT_plx "]\n", addr); -@@ -894,6 +900,9 @@ void vga_mem_writeb(VGACommonState *s, hwaddr addr, uint32_t val) - mask = (1 << plane); - if (s->sr[VGA_SEQ_PLANE_WRITE] & mask) { - addr = ((addr & ~1) << 1) | plane; -+ if (addr >= s->vram_size) { -+ return; -+ } - s->vram_ptr[addr] = val; - #ifdef DEBUG_VGA_MEM - printf("vga: odd/even: [0x" TARGET_FMT_plx "]\n", addr); -@@ -967,6 +976,9 @@ void vga_mem_writeb(VGACommonState *s, hwaddr addr, uint32_t val) - mask = s->sr[VGA_SEQ_PLANE_WRITE]; - s->plane_updated |= mask; /* only used to detect font change */ - write_mask = mask16[mask]; -+ if (addr * sizeof(uint32_t) >= s->vram_size) { -+ return; -+ } - ((uint32_t *)s->vram_ptr)[addr] = - (((uint32_t *)s->vram_ptr)[addr] & ~write_mask) | - (val & write_mask); --- -1.9.1 - |