diff --git a/src/video/SDL_surface.c b/src/video/SDL_surface.c index ec981a29c..cc2085689 100644 --- a/src/video/SDL_surface.c +++ b/src/video/SDL_surface.c @@ -33,22 +33,37 @@ SDL_COMPILE_TIME_ASSERT(surface_size_assumptions, sizeof(int) == sizeof(Sint32) && sizeof(size_t) >= sizeof(Sint32)); +SDL_COMPILE_TIME_ASSERT(can_indicate_overflow, SDL_SIZE_MAX > SDL_MAX_SINT32); + /* Public routines */ /* - * Calculate the pad-aligned scanline width of a surface + * Calculate the pad-aligned scanline width of a surface. + * Return SDL_SIZE_MAX on overflow. */ -static Sint64 -SDL_CalculatePitch(Uint32 format, int width) +static size_t +SDL_CalculatePitch(Uint32 format, size_t width) { - Sint64 pitch; + size_t pitch; if (SDL_ISPIXELFORMAT_FOURCC(format) || SDL_BITSPERPIXEL(format) >= 8) { - pitch = ((Sint64)width * SDL_BYTESPERPIXEL(format)); + if (SDL_size_mul_overflow(width, SDL_BYTESPERPIXEL(format), &pitch)) { + return SDL_SIZE_MAX; + } } else { - pitch = (((Sint64)width * SDL_BITSPERPIXEL(format)) + 7) / 8; + if (SDL_size_mul_overflow(width, SDL_BITSPERPIXEL(format), &pitch)) { + return SDL_SIZE_MAX; + } + if (SDL_size_add_overflow(pitch, 7, &pitch)) { + return SDL_SIZE_MAX; + } + pitch /= 8; } - pitch = (pitch + 3) & ~3; /* 4-byte aligning for speed */ + /* 4-byte aligning for speed */ + if (SDL_size_add_overflow(pitch, 3, &pitch)) { + return SDL_SIZE_MAX; + } + pitch &= ~3; return pitch; } @@ -60,14 +75,14 @@ SDL_Surface * SDL_CreateRGBSurfaceWithFormat(Uint32 flags, int width, int height, int depth, Uint32 format) { - Sint64 pitch; + size_t pitch; SDL_Surface *surface; /* The flags are no longer used, make the compiler happy */ (void)flags; pitch = SDL_CalculatePitch(format, width); - if (pitch < 0 || pitch > SDL_MAX_SINT32) { + if (pitch > SDL_MAX_SINT32) { /* Overflow... */ SDL_OutOfMemory(); return NULL; @@ -113,15 +128,15 @@ SDL_CreateRGBSurfaceWithFormat(Uint32 flags, int width, int height, int depth, /* Get the pixels */ if (surface->w && surface->h) { /* Assumptions checked in surface_size_assumptions assert above */ - Sint64 size = ((Sint64)surface->h * surface->pitch); - if (size < 0 || size > SDL_MAX_SINT32) { + size_t size; + if (SDL_size_mul_overflow(surface->h, surface->pitch, &size)) { /* Overflow... */ SDL_FreeSurface(surface); SDL_OutOfMemory(); return NULL; } - surface->pixels = SDL_SIMDAlloc((size_t)size); + surface->pixels = SDL_SIMDAlloc(size); if (!surface->pixels) { SDL_FreeSurface(surface); SDL_OutOfMemory(); @@ -129,7 +144,7 @@ SDL_CreateRGBSurfaceWithFormat(Uint32 flags, int width, int height, int depth, } surface->flags |= SDL_SIMD_ALIGNED; /* This is important for bitmaps */ - SDL_memset(surface->pixels, 0, surface->h * surface->pitch); + SDL_memset(surface->pixels, 0, size); } /* Allocate an empty mapping */