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cirrus: fix blit region check 

Issues:
 * Doesn't check pitches correctly in case it is negative.
 * Doesn't check width at all.

Turn macro into functions while being at it, also factor out the check
for one region which we then can simply call twice for src + dst.

This is CVE-2014-8106.

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
master
Gerd Hoffmann 2014-11-19 11:37:42 +01:00
parent db12451dec
commit d3532a0db0
1 changed files with 44 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

61
hw/display/cirrus_vga.c
View File

@ -173,20 +173,6 @@
#define CIRRUS_PNPMMIO_SIZE 0x1000
#define BLTUNSAFE(s) \
( \
( /* check dst is within bounds */ \
(s)->cirrus_blt_height * ABS((s)->cirrus_blt_dstpitch) \
+ ((s)->cirrus_blt_dstaddr & (s)->cirrus_addr_mask) > \
(s)->vga.vram_size \
) || \
( /* check src is within bounds */ \
(s)->cirrus_blt_height * ABS((s)->cirrus_blt_srcpitch) \
+ ((s)->cirrus_blt_srcaddr & (s)->cirrus_addr_mask) > \
(s)->vga.vram_size \
) \
)
struct CirrusVGAState;
typedef void (*cirrus_bitblt_rop_t) (struct CirrusVGAState *s,
uint8_t * dst, const uint8_t * src,
@ -279,6 +265,46 @@ static void cirrus_update_memory_access(CirrusVGAState *s);
*
***************************************/
static bool blit_region_is_unsafe(struct CirrusVGAState *s,
int32_t pitch, int32_t addr)
{
if (pitch < 0) {
int64_t min = addr
+ ((int64_t)s->cirrus_blt_height-1) * pitch;
int32_t max = addr
+ s->cirrus_blt_width;
if (min < 0 || max >= s->vga.vram_size) {
return true;
}
} else {
int64_t max = addr
+ ((int64_t)s->cirrus_blt_height-1) * pitch
+ s->cirrus_blt_width;
if (max >= s->vga.vram_size) {
return true;
}
}
return false;
}
static bool blit_is_unsafe(struct CirrusVGAState *s)
{
/* should be the case, see cirrus_bitblt_start */
assert(s->cirrus_blt_width > 0);
assert(s->cirrus_blt_height > 0);
if (blit_region_is_unsafe(s, s->cirrus_blt_dstpitch,
s->cirrus_blt_dstaddr & s->cirrus_addr_mask)) {
return true;
}
if (blit_region_is_unsafe(s, s->cirrus_blt_srcpitch,
s->cirrus_blt_srcaddr & s->cirrus_addr_mask)) {
return true;
}
return false;
}
static void cirrus_bitblt_rop_nop(CirrusVGAState *s,
uint8_t *dst,const uint8_t *src,
int dstpitch,int srcpitch,
@ -636,7 +662,7 @@ static int cirrus_bitblt_common_patterncopy(CirrusVGAState * s,
dst = s->vga.vram_ptr + (s->cirrus_blt_dstaddr & s->cirrus_addr_mask);
if (BLTUNSAFE(s))
if (blit_is_unsafe(s))
return 0;
(*s->cirrus_rop) (s, dst, src,
@ -654,8 +680,9 @@ static int cirrus_bitblt_solidfill(CirrusVGAState *s, int blt_rop)
{
cirrus_fill_t rop_func;
if (BLTUNSAFE(s))
if (blit_is_unsafe(s)) {
return 0;
}
rop_func = cirrus_fill[rop_to_index[blt_rop]][s->cirrus_blt_pixelwidth - 1];
rop_func(s, s->vga.vram_ptr + (s->cirrus_blt_dstaddr & s->cirrus_addr_mask),
s->cirrus_blt_dstpitch,
@ -752,7 +779,7 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int src, int w, int h)
static int cirrus_bitblt_videotovideo_copy(CirrusVGAState * s)
{
if (BLTUNSAFE(s))
if (blit_is_unsafe(s))
return 0;
cirrus_do_copy(s, s->cirrus_blt_dstaddr - s->vga.start_addr,