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cirrus: fix oob access in mode4and5 write functions

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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
This commit is contained in:
Gerd Hoffmann 2017-10-11 10:43:14 +02:00
parent b0898b42ef
commit eb38e1bc37
1 changed files with 2 additions and 4 deletions
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6
hw/display/cirrus_vga.c
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@ -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);
}