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-rw-r--r--gfx/skia/skia/include/core/SkTypes.h6
-rw-r--r--gfx/skia/skia/include/private/SkTDArray.h8
-rw-r--r--gfx/skia/skia/src/core/SkMallocPixelRef.cpp13
-rw-r--r--gfx/skia/skia/src/core/SkMath.cpp15
-rw-r--r--gfx/skia/skia/src/core/SkSafeMath.h106
5 files changed, 145 insertions, 3 deletions
diff --git a/gfx/skia/skia/include/core/SkTypes.h b/gfx/skia/skia/include/core/SkTypes.h
index 0cef8a125..f45c3c2b7 100644
--- a/gfx/skia/skia/include/core/SkTypes.h
+++ b/gfx/skia/skia/include/core/SkTypes.h
@@ -109,6 +109,11 @@ SK_API extern void* sk_calloc(size_t size);
*/
SK_API extern void* sk_calloc_throw(size_t size);
+// Performs a safe multiply count * elemSize, checking for overflow
+SK_API extern void* sk_calloc_throw(size_t count, size_t elemSize);
+SK_API extern void* sk_malloc_throw(size_t count, size_t elemSize);
+SK_API extern void* sk_realloc_throw(void* buffer, size_t count, size_t elemSize);
+
// bzero is safer than memset, but we can't rely on it, so... sk_bzero()
static inline void sk_bzero(void* buffer, size_t size) {
// Please c.f. sk_careful_memcpy. It's undefined behavior to call memset(null, 0, 0).
@@ -295,6 +300,7 @@ template <typename D, typename S> D SkTo(S s) {
#define SK_MaxU32 0xFFFFFFFF
#define SK_MinU32 0
#define SK_NaN32 ((int) (1U << 31))
+#define SK_MaxSizeT SIZE_MAX
/** Returns true if the value can be represented with signed 16bits
*/
diff --git a/gfx/skia/skia/include/private/SkTDArray.h b/gfx/skia/skia/include/private/SkTDArray.h
index f71d35700..a46a05e9d 100644
--- a/gfx/skia/skia/include/private/SkTDArray.h
+++ b/gfx/skia/skia/include/private/SkTDArray.h
@@ -21,7 +21,7 @@ public:
fReserve = fCount = 0;
fArray = NULL;
if (count) {
- fArray = (T*)sk_malloc_throw(count * sizeof(T));
+ fArray = (T*)sk_malloc_throw(count, sizeof(T));
memcpy(fArray, src, sizeof(T) * count);
fReserve = fCount = count;
}
@@ -346,7 +346,7 @@ public:
void shrinkToFit() {
fReserve = fCount;
- fArray = (T*)sk_realloc_throw(fArray, fReserve * sizeof(T));
+ fArray = (T*)sk_realloc_throw(fArray, fReserve, sizeof(T));
}
private:
@@ -359,6 +359,7 @@ private:
* This is the same as calling setCount(count() + delta).
*/
void adjustCount(int delta) {
+ SkASSERT_RELEASE(fCount <= std::numeric_limits<int>::max() - delta);
this->setCount(fCount + delta);
}
@@ -372,9 +373,10 @@ private:
*/
void resizeStorageToAtLeast(int count) {
SkASSERT(count > fReserve);
+ SkASSERT_RELEASE(count <= std::numeric_limits<int>::max() - std::numeric_limits<int>::max() / 5 - 4);
fReserve = count + 4;
fReserve += fReserve / 4;
- fArray = (T*)sk_realloc_throw(fArray, fReserve * sizeof(T));
+ fArray = (T*)sk_realloc_throw(fArray, fReserve, sizeof(T));
}
};
diff --git a/gfx/skia/skia/src/core/SkMallocPixelRef.cpp b/gfx/skia/skia/src/core/SkMallocPixelRef.cpp
index fffc04484..8db704fa4 100644
--- a/gfx/skia/skia/src/core/SkMallocPixelRef.cpp
+++ b/gfx/skia/skia/src/core/SkMallocPixelRef.cpp
@@ -8,8 +8,21 @@
#include "SkMallocPixelRef.h"
#include "SkBitmap.h"
#include "SkReadBuffer.h"
+#include "SkSafeMath.h"
#include "SkWriteBuffer.h"
+void* sk_calloc_throw(size_t count, size_t elemSize) {
+ return sk_calloc_throw(SkSafeMath::Mul(count, elemSize));
+}
+
+void* sk_malloc_throw(size_t count, size_t elemSize) {
+ return sk_malloc_throw(SkSafeMath::Mul(count, elemSize));
+}
+
+void* sk_realloc_throw(void* buffer, size_t count, size_t elemSize) {
+ return sk_realloc_throw(buffer, SkSafeMath::Mul(count, elemSize));
+}
+
// assumes ptr was allocated via sk_malloc
static void sk_free_releaseproc(void* ptr, void*) {
sk_free(ptr);
diff --git a/gfx/skia/skia/src/core/SkMath.cpp b/gfx/skia/skia/src/core/SkMath.cpp
index 6eff790c8..84796c522 100644
--- a/gfx/skia/skia/src/core/SkMath.cpp
+++ b/gfx/skia/skia/src/core/SkMath.cpp
@@ -84,3 +84,18 @@ float SkScalarSinCos(float radians, float* cosValue) {
}
return sinValue;
}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+size_t SkSafeMath::Add(size_t x, size_t y) {
+ SkSafeMath tmp;
+ size_t sum = tmp.add(x, y);
+ return tmp.ok() ? sum : SK_MaxSizeT;
+}
+
+size_t SkSafeMath::Mul(size_t x, size_t y) {
+ SkSafeMath tmp;
+ size_t prod = tmp.mul(x, y);
+ return tmp.ok() ? prod : SK_MaxSizeT;
+}
+
diff --git a/gfx/skia/skia/src/core/SkSafeMath.h b/gfx/skia/skia/src/core/SkSafeMath.h
new file mode 100644
index 000000000..0bc0fbfac
--- /dev/null
+++ b/gfx/skia/skia/src/core/SkSafeMath.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSafeMath_DEFINED
+#define SkSafeMath_DEFINED
+
+#include "SkTypes.h"
+
+// SkSafeMath always check that a series of operations do not overflow.
+// This must be correct for all platforms, because this is a check for safety at runtime.
+
+class SkSafeMath {
+public:
+ SkSafeMath() = default;
+
+ bool ok() const { return fOK; }
+ explicit operator bool() const { return fOK; }
+
+ size_t mul(size_t x, size_t y) {
+ return sizeof(size_t) == sizeof(uint64_t) ? mul64(x, y) : mul32(x, y);
+ }
+
+ size_t add(size_t x, size_t y) {
+ size_t result = x + y;
+ fOK &= result >= x;
+ return result;
+ }
+
+ /**
+ * Return a + b, unless this result is an overflow/underflow. In those cases, fOK will
+ * be set to false, and it is undefined what this returns.
+ */
+ int addInt(int a, int b) {
+ if (b < 0 && a < std::numeric_limits<int>::min() - b) {
+ fOK = false;
+ return a;
+ } else if (b > 0 && a > std::numeric_limits<int>::max() - b) {
+ fOK = false;
+ return a;
+ }
+ return a + b;
+ }
+
+ size_t alignUp(size_t x, size_t alignment) {
+ SkASSERT(alignment && !(alignment & (alignment - 1)));
+ return add(x, alignment - 1) & ~(alignment - 1);
+ }
+
+ template <typename T> T castTo(size_t value) {
+ if (!SkTFitsIn<T>(value)) {
+ fOK = false;
+ }
+ return static_cast<T>(value);
+ }
+
+ // These saturate to their results
+ static size_t Add(size_t x, size_t y);
+ static size_t Mul(size_t x, size_t y);
+ static size_t Align4(size_t x) {
+ SkSafeMath safe;
+ return safe.alignUp(x, 4);
+ }
+
+private:
+ uint32_t mul32(uint32_t x, uint32_t y) {
+ uint64_t bx = x;
+ uint64_t by = y;
+ uint64_t result = bx * by;
+ fOK &= result >> 32 == 0;
+ return result;
+ }
+
+ uint64_t mul64(uint64_t x, uint64_t y) {
+ if (x <= std::numeric_limits<uint64_t>::max() >> 32
+ && y <= std::numeric_limits<uint64_t>::max() >> 32) {
+ return x * y;
+ } else {
+ auto hi = [](uint64_t x) { return x >> 32; };
+ auto lo = [](uint64_t x) { return x & 0xFFFFFFFF; };
+
+ uint64_t lx_ly = lo(x) * lo(y);
+ uint64_t hx_ly = hi(x) * lo(y);
+ uint64_t lx_hy = lo(x) * hi(y);
+ uint64_t hx_hy = hi(x) * hi(y);
+ uint64_t result = 0;
+ result = this->add(lx_ly, (hx_ly << 32));
+ result = this->add(result, (lx_hy << 32));
+ fOK &= (hx_hy + (hx_ly >> 32) + (lx_hy >> 32)) == 0;
+
+ #if defined(SK_DEBUG) && defined(__clang__) && defined(__x86_64__)
+ auto double_check = (unsigned __int128)x * y;
+ SkASSERT(result == (double_check & 0xFFFFFFFFFFFFFFFF));
+ SkASSERT(!fOK || (double_check >> 64 == 0));
+ #endif
+
+ return result;
+ }
+ }
+ bool fOK = true;
+};
+
+#endif//SkSafeMath_DEFINED
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 04:26:38 +0000