AuroraMiddleware/skia2
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Disable the CFI sanitizer only when casting pointers.

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The cast of newly-allocated memory to T* is the only thing that triggers
a CFI error; we can let CFI instrument the rest of the code normally.

Change-Id: I0e6ab76dbddf031967bee34f5a05986ff58e6714
Bug: skia:13339
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/545676
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
This commit is contained in:
John Stiles 2022-06-01 14:32:43 +00:00 committed by SkCQ
parent bebf8e34c3
commit 5723585ba3
1 changed files with 9 additions and 7 deletions
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16
include/private/SkTArray.h
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@ -461,7 +461,7 @@ protected:
}
private:
// We disable Control-Flow Integrity sanitization (go/cfi) when updating the item-array buffer.
// We disable Control-Flow Integrity sanitization (go/cfi) when casting item-array buffers.
// CFI flags this code as dangerous because we are casting `buffer` to a T* while the buffer's
// contents might still be uninitialized memory. When T has a vtable, this is especially risky
// because we could hypothetically access a virtual method on fItemArray and jump to an
@ -469,6 +469,10 @@ private:
// way, and we don't want to construct a T before the user requests one. There's no real risk
// here, so disable CFI when doing these casts.
SK_ATTRIBUTE(no_sanitize("cfi"))
static T* TCast(void* buffer) {
return (T*)buffer;
}
void init(int count) {
fCount = SkToU32(count);
if (!count) {
@ -476,13 +480,12 @@ private:
fItemArray = nullptr;
} else {
fAllocCount = SkToU32(std::max(count, kMinHeapAllocCount));
fItemArray = (T*)sk_malloc_throw((size_t)fAllocCount, sizeof(T));
fItemArray = TCast(sk_malloc_throw((size_t)fAllocCount, sizeof(T)));
}
fOwnMemory = true;
fReserved = false;
}
SK_ATTRIBUTE(no_sanitize("cfi"))
void initWithPreallocatedStorage(int count, void* preallocStorage, int preallocCount) {
SkASSERT(count >= 0);
SkASSERT(preallocCount > 0);
@ -492,11 +495,11 @@ private:
fReserved = false;
if (count > preallocCount) {
fAllocCount = SkToU32(std::max(count, kMinHeapAllocCount));
fItemArray = (T*)sk_malloc_throw(fAllocCount, sizeof(T));
fItemArray = TCast(sk_malloc_throw(fAllocCount, sizeof(T)));
fOwnMemory = true;
} else {
fAllocCount = SkToU32(preallocCount);
fItemArray = (T*)preallocStorage;
fItemArray = TCast(preallocStorage);
fOwnMemory = false;
}
}
@ -543,7 +546,6 @@ private:
return ptr;
}
SK_ATTRIBUTE(no_sanitize("cfi"))
void checkRealloc(int delta, ReallocType reallocType) {
SkASSERT(fCount >= 0);
SkASSERT(fAllocCount >= 0);
@ -577,7 +579,7 @@ private:
fAllocCount = SkToU32(Sk64_pin_to_s32(newAllocCount));
SkASSERT(fAllocCount >= newCount);
T* newItemArray = (T*)sk_malloc_throw((size_t)fAllocCount, sizeof(T));
T* newItemArray = TCast(sk_malloc_throw((size_t)fAllocCount, sizeof(T)));
this->move(newItemArray);
if (fOwnMemory) {
sk_free(fItemArray);