[Mesa-dev] [PATCH] mesa: add bounds checking to eliminate buffer overrun

Courtney Goeltzenleuchter courtney at lunarg.com
Fri Feb 14 08:02:11 PST 2014


Forgot to mention. This patch addresses bug
#74988<https://bugs.freedesktop.org/show_bug.cgi?id=74988>
.

No piglit regressions.

Courtney


On Fri, Feb 14, 2014 at 8:52 AM, Courtney Goeltzenleuchter <
courtney at lunarg.com> 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.
>
> Signed-off-by: Courtney Goeltzenleuchter <courtney at LunarG.com>
> ---
>  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 e3862be..f9234b0 100644
> --- a/src/mesa/main/texcompress_etc.c
> +++ b/src/mesa/main/texcompress_etc.c
> @@ -684,9 +684,10 @@ 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;
> @@ -721,9 +722,9 @@ 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 */
> @@ -764,9 +765,9 @@ 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;
>              }
> @@ -801,9 +802,9 @@ 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 */
> @@ -843,9 +844,9 @@ 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;
>              }
> @@ -879,10 +880,10 @@ 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;
>              }
> @@ -890,10 +891,10 @@ 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;
>              }
> @@ -926,10 +927,10 @@ 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;
>              }
> @@ -963,10 +964,10 @@ 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;
>              }
> @@ -974,10 +975,10 @@ 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;
>              }
> @@ -1007,9 +1008,9 @@ 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;
> @@ -1042,9 +1043,9 @@ 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 */
> --
> 1.8.3.2
>
>


-- 
Courtney Goeltzenleuchter
LunarG
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