[Mesa-stable] [Mesa-dev] [PATCH] mesa: add bounds checking to eliminate buffer overrun
Courtney Goeltzenleuchter
courtney at lunarg.com
Tue Apr 8 08:08:57 PDT 2014
Apologies folks, I had made those changes and somehow grabbed the wrong
patch when I went to add the bug reference. Ugh.
This time for sure! I'll follow this with the -- real -- patch.
Courtney
On Tue, Apr 8, 2014 at 1:28 AM, Kenneth Graunke <kenneth at whitecape.org>wrote:
> On 04/07/2014 09:20 PM, Courtney Goeltzenleuchter wrote:
> > Decompressing ETC2 textures was causing intermitent segfault
> > by copying resulting 4x4 texel block to the destination texture
> > regardless of the size of the destination texture. Issue found
> > via application crash in GLBenchmark 3.0's Manhattan test.
> >
> > v2: add more explanatory comments
> > v3: add bugzilla reference
> > v4: Correct cc syntax in commit log
> >
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74988
> > Cc: "9.2 10.0 10.1" <mesa-stable at lists.freedesktop.org>
> > ---
> > src/mesa/main/texcompress_etc.c | 49
> +++++++++++++++++++++--------------------
> > 1 file changed, 25 insertions(+), 24 deletions(-)
> >
> > diff --git a/src/mesa/main/texcompress_etc.c
> b/src/mesa/main/texcompress_etc.c
> > index cbda689..39775e2 100644
> > --- a/src/mesa/main/texcompress_etc.c
> > +++ b/src/mesa/main/texcompress_etc.c
> > @@ -683,9 +683,10 @@ etc2_unpack_rgb8(uint8_t *dst_row,
> > etc2_rgb8_parse_block(&block, src,
> > false /* punchthrough_alpha */);
> >
> > - for (j = 0; j < bh; j++) {
> > + /* be sure to stay within the bounds of the texture */
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_rgb8_fetch_texel(&block, i, j, dst,
> > false /* punchthrough_alpha */);
> > dst[3] = 255;
> > @@ -720,9 +721,9 @@ etc2_unpack_srgb8(uint8_t *dst_row,
> > etc2_rgb8_parse_block(&block, src,
> > false /* punchthrough_alpha */);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_rgb8_fetch_texel(&block, i, j, dst,
> > false /* punchthrough_alpha */);
> > /* Convert to MESA_FORMAT_B8G8R8A8_SRGB */
> > @@ -763,9 +764,9 @@ etc2_unpack_rgba8(uint8_t *dst_row,
> > for (x = 0; x < width; x+= bw) {
> > etc2_rgba8_parse_block(&block, src);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_rgba8_fetch_texel(&block, i, j, dst);
> > dst += comps;
> > }
> > @@ -800,9 +801,9 @@ etc2_unpack_srgb8_alpha8(uint8_t *dst_row,
> > for (x = 0; x < width; x+= bw) {
> > etc2_rgba8_parse_block(&block, src);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_rgba8_fetch_texel(&block, i, j, dst);
> >
> > /* Convert to MESA_FORMAT_B8G8R8A8_SRGB */
> > @@ -842,9 +843,9 @@ etc2_unpack_r11(uint8_t *dst_row,
> > for (x = 0; x < width; x+= bw) {
> > etc2_r11_parse_block(&block, src);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps *
> comp_size;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_r11_fetch_texel(&block, i, j, dst);
> > dst += comps * comp_size;
> > }
> > @@ -878,10 +879,10 @@ etc2_unpack_rg11(uint8_t *dst_row,
> > /* red component */
> > etc2_r11_parse_block(&block, src);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride +
> > x * comps * comp_size;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_r11_fetch_texel(&block, i, j, dst);
> > dst += comps * comp_size;
> > }
> > @@ -889,10 +890,10 @@ etc2_unpack_rg11(uint8_t *dst_row,
> > /* green component */
> > etc2_r11_parse_block(&block, src + 8);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride +
> > x * comps * comp_size;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_r11_fetch_texel(&block, i, j, dst + comp_size);
> > dst += comps * comp_size;
> > }
> > @@ -925,10 +926,10 @@ etc2_unpack_signed_r11(uint8_t *dst_row,
> > for (x = 0; x < width; x+= bw) {
> > etc2_r11_parse_block(&block, src);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride +
> > x * comps * comp_size;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_signed_r11_fetch_texel(&block, i, j, dst);
> > dst += comps * comp_size;
> > }
> > @@ -962,10 +963,10 @@ etc2_unpack_signed_rg11(uint8_t *dst_row,
> > /* red component */
> > etc2_r11_parse_block(&block, src);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride +
> > x * comps * comp_size;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_signed_r11_fetch_texel(&block, i, j, dst);
> > dst += comps * comp_size;
> > }
> > @@ -973,10 +974,10 @@ etc2_unpack_signed_rg11(uint8_t *dst_row,
> > /* green component */
> > etc2_r11_parse_block(&block, src + 8);
> >
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride +
> > x * comps * comp_size;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_signed_r11_fetch_texel(&block, i, j, dst +
> comp_size);
> > dst += comps * comp_size;
> > }
> > @@ -1006,9 +1007,9 @@ etc2_unpack_rgb8_punchthrough_alpha1(uint8_t
> *dst_row,
> > for (x = 0; x < width; x+= bw) {
> > etc2_rgb8_parse_block(&block, src,
> > true /* punchthrough_alpha */);
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_rgb8_fetch_texel(&block, i, j, dst,
> > true /* punchthrough_alpha */);
> > dst += comps;
> > @@ -1041,9 +1042,9 @@ etc2_unpack_srgb8_punchthrough_alpha1(uint8_t
> *dst_row,
> > for (x = 0; x < width; x+= bw) {
> > etc2_rgb8_parse_block(&block, src,
> > true /* punchthrough_alpha */);
> > - for (j = 0; j < bh; j++) {
> > + for (j = 0; j < bh && (j+y) < height; j++) {
> > uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
> > - for (i = 0; i < bw; i++) {
> > + for (i = 0; i < bw && (i+x) < width; i++) {
> > etc2_rgb8_fetch_texel(&block, i, j, dst,
> > true /* punchthrough_alpha */);
> > /* Convert to MESA_FORMAT_B8G8R8A8_SRGB */
> >
>
> As is,
> Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
>
> I do like Ian's suggestion (from 2014-02-14), where he suggested doing:
>
> const unsigned h = MIN2(bh, height - y);
> const unsigned w = MIN2(bw, width - x);
>
> ...
>
> for (j = 0; j < h; j++) {
>
> ...
>
> for (i = 0; i < w; i++) {
>
> That keeps the loop termination conditions as a simple comparison,
> rather than two comparisons, an add, and a logical-and.
>
> --Ken
>
>
--
Courtney Goeltzenleuchter
LunarG
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