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| Code Block | ||
|---|---|---|
| ||
char *charloop_ptr = "example"; int * int_ptr; int *voidPtr2intPtrmkVoidPtr(void *v_pointer){ return v_pointer; } int_ptr = voidPtr2intPtrmkVoidPtr(charloop_ptr); |
In this example the v_pointer might be aligned on a 1 byte boundary. Once it is cast to an int some architectures will require it to be on 4 byte boundaries. Pointers are often cast because a void* cannot be dereferenced. Careless coding can result in an arbitrary pointer type being used irregardless of its alignment.
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Type | Alignment |
|---|---|
| 1 byte aligned |
| 2 byte aligned |
| 4 byte aligned |
| 4 byte aligned |
| 8 byte on Windows, 4 byte on Linux |
Compliant Solution
...
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-Make
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specific
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functions
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(avoid
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use
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of
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void*)
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-Always
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use
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strictest
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alignment
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type
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for
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arbitrary pointers.
| Code Block |
|---|
int *loop_ptr;
int * int_ptr;
int *loopFunction(int *v_pointer){
return v_pointer;
}
int_ptr = loopFunction(loop_ptr);
| Code Block | ||||
|---|---|---|---|---|
| pointers.
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Risk Assessment
Accessing a pointer that is no longer on the correct access boundary can cause a program to crash, give wrong information or have slow pointer accesses (if the architecture does not care about alignment).
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