From 225a09790da0b1605a0b68acbbe1e0f30eee3e6f Mon Sep 17 00:00:00 2001 From: Chad Versace Date: Tue, 18 Nov 2014 21:11:25 -0800 Subject: [PATCH] i965: Use safer pointer arithmetic in intel_texsubimage_tiled_memcpy() This patch reduces the likelihood of pointer arithmetic overflow bugs in intel_texsubimage_tiled_memcpy() , like the one fixed by b69c7c5dac. I haven't yet encountered any overflow bugs in the wild along this patch's codepath. But I recently solved, in commit b69c7c5dac, an overflow bug in a line of code that looks very similar to pointer arithmetic in this function. This patch conceptually applies the same fix as in b69c7c5dac. Instead of retyping the variables, though, this patch adds some casts. (I tried to retype the variables as ptrdiff_t, but it quickly got very messy. The casts are cleaner). Reviewed-by: Kenneth Graunke Signed-off-by: Chad Versace --- src/mesa/drivers/dri/i965/intel_tex_subimage.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/src/mesa/drivers/dri/i965/intel_tex_subimage.c b/src/mesa/drivers/dri/i965/intel_tex_subimage.c index cb5738a..3e4ed1b 100644 --- a/src/mesa/drivers/dri/i965/intel_tex_subimage.c +++ b/src/mesa/drivers/dri/i965/intel_tex_subimage.c @@ -488,8 +488,8 @@ linear_to_tiled(uint32_t xt1, uint32_t xt2, /* Translate by (xt,yt) for single-tile copier. */ tile_copy(x0-xt, x1-xt, x2-xt, x3-xt, y0-yt, y1-yt, - dst + xt * th + yt * dst_pitch, - src + xt + yt * src_pitch, + dst + (ptrdiff_t) xt * th + (ptrdiff_t) yt * dst_pitch, + src + (ptrdiff_t) xt + (ptrdiff_t) yt * src_pitch, src_pitch, swizzle_bit, mem_copy); @@ -654,7 +654,8 @@ intel_texsubimage_tiled_memcpy(struct gl_context * ctx, linear_to_tiled( xoffset * cpp, (xoffset + width) * cpp, yoffset, yoffset + height, - bo->virtual, pixels - yoffset * src_pitch - xoffset * cpp, + bo->virtual, + pixels - (ptrdiff_t) yoffset * src_pitch - (ptrdiff_t) xoffset * cpp, image->mt->pitch, src_pitch, brw->has_swizzling, image->mt->tiling, -- 2.7.4