diff options
| author | BALATON Zoltan <balaton@eik.bme.hu> | 2020-04-06 22:34:26 +0200 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2020-04-07 09:25:23 +0200 |
| commit | ac2071c3791b67fc7af78b8ceb320c01ca1b5df7 (patch) | |
| tree | 0e951ae17812aac4ca3ca98d695e6b676480a4e2 /hw/display | |
| parent | 8d1439b692c5dc8edc4d4a1d334afd7070458029 (diff) | |
ati-vga: Fix checks in ati_2d_blt() to avoid crash
In some corner cases (that never happen during normal operation but a
malicious guest could program wrong values) pixman functions were
called with parameters that result in a crash. Fix this and add more
checks to disallow such cases.
Reported-by: Ziming Zhang <ezrakiez@gmail.com>
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Message-id: 20200406204029.19559747D5D@zero.eik.bme.hu
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'hw/display')
| -rw-r--r-- | hw/display/ati_2d.c | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/hw/display/ati_2d.c b/hw/display/ati_2d.c index 42e82311eb..23a8ae0cd8 100644 --- a/hw/display/ati_2d.c +++ b/hw/display/ati_2d.c @@ -53,12 +53,20 @@ void ati_2d_blt(ATIVGAState *s) s->vga.vbe_start_addr, surface_data(ds), surface_stride(ds), surface_bits_per_pixel(ds), (s->regs.dp_mix & GMC_ROP3_MASK) >> 16); - int dst_x = (s->regs.dp_cntl & DST_X_LEFT_TO_RIGHT ? - s->regs.dst_x : s->regs.dst_x + 1 - s->regs.dst_width); - int dst_y = (s->regs.dp_cntl & DST_Y_TOP_TO_BOTTOM ? - s->regs.dst_y : s->regs.dst_y + 1 - s->regs.dst_height); + unsigned dst_x = (s->regs.dp_cntl & DST_X_LEFT_TO_RIGHT ? + s->regs.dst_x : s->regs.dst_x + 1 - s->regs.dst_width); + unsigned dst_y = (s->regs.dp_cntl & DST_Y_TOP_TO_BOTTOM ? + s->regs.dst_y : s->regs.dst_y + 1 - s->regs.dst_height); int bpp = ati_bpp_from_datatype(s); + if (!bpp) { + qemu_log_mask(LOG_GUEST_ERROR, "Invalid bpp\n"); + return; + } int dst_stride = DEFAULT_CNTL ? s->regs.dst_pitch : s->regs.default_pitch; + if (!dst_stride) { + qemu_log_mask(LOG_GUEST_ERROR, "Zero dest pitch\n"); + return; + } uint8_t *dst_bits = s->vga.vram_ptr + (DEFAULT_CNTL ? s->regs.dst_offset : s->regs.default_offset); @@ -82,12 +90,16 @@ void ati_2d_blt(ATIVGAState *s) switch (s->regs.dp_mix & GMC_ROP3_MASK) { case ROP3_SRCCOPY: { - int src_x = (s->regs.dp_cntl & DST_X_LEFT_TO_RIGHT ? - s->regs.src_x : s->regs.src_x + 1 - s->regs.dst_width); - int src_y = (s->regs.dp_cntl & DST_Y_TOP_TO_BOTTOM ? - s->regs.src_y : s->regs.src_y + 1 - s->regs.dst_height); + unsigned src_x = (s->regs.dp_cntl & DST_X_LEFT_TO_RIGHT ? + s->regs.src_x : s->regs.src_x + 1 - s->regs.dst_width); + unsigned src_y = (s->regs.dp_cntl & DST_Y_TOP_TO_BOTTOM ? + s->regs.src_y : s->regs.src_y + 1 - s->regs.dst_height); int src_stride = DEFAULT_CNTL ? s->regs.src_pitch : s->regs.default_pitch; + if (!src_stride) { + qemu_log_mask(LOG_GUEST_ERROR, "Zero source pitch\n"); + return; + } uint8_t *src_bits = s->vga.vram_ptr + (DEFAULT_CNTL ? s->regs.src_offset : s->regs.default_offset); @@ -137,8 +149,10 @@ void ati_2d_blt(ATIVGAState *s) dst_y * surface_stride(ds), s->regs.dst_height * surface_stride(ds)); } - s->regs.dst_x += s->regs.dst_width; - s->regs.dst_y += s->regs.dst_height; + s->regs.dst_x = (s->regs.dp_cntl & DST_X_LEFT_TO_RIGHT ? + dst_x + s->regs.dst_width : dst_x); + s->regs.dst_y = (s->regs.dp_cntl & DST_Y_TOP_TO_BOTTOM ? + dst_y + s->regs.dst_height : dst_y); break; } case ROP3_PATCOPY: @@ -179,7 +193,8 @@ void ati_2d_blt(ATIVGAState *s) dst_y * surface_stride(ds), s->regs.dst_height * surface_stride(ds)); } - s->regs.dst_y += s->regs.dst_height; + s->regs.dst_y = (s->regs.dp_cntl & DST_Y_TOP_TO_BOTTOM ? + dst_y + s->regs.dst_height : dst_y); break; } default: |