我有一个模板函数,它具有执行归零的特化:
template <class T>
void SecureWipeBuffer(T *buf, size_t n)
{
volatile T *p = buf+n;
while (n--)
*((volatile T*)(--p)) = 0;
}
...
template <>
void SecureWipeBuffer(word64* p, size_t n)
{
asm volatile("rep stosq" : "+c"(n), "+D"(p) : "a"(0) : "memory");
}
Coverity 在 SecureWipeBuffer
上产生了一个发现:
word64 val;
...
SecureWipeBuffer(&val, 1);
结果是:
>>> CID 164713: Incorrect expression (SIZEOF_MISMATCH)
>>> Passing argument "&val" of type "word64 *" and argument "1UL" to function "SecureWipeBuffer" is suspicious because "sizeof (word64)" /*8*/ is expected.
275 SecureWipeBuffer(&val, 1);
如何训练 Coverity SecureWipeBuffer
计算元素数,而不是字节数?
编辑:我们在 Windows 代码中发现了两个相似的发现。此外,Coverity 正在生成关于标准库函数的调查结果。它好像没有意识到 C++ 处理的是元素计数,而不是字节计数。
以下是来自 <xmemory>
中的 Microsoft 标准库代码
25 if (_Count == 0)
26 ;
27 else if (((size_t)(-1) / sizeof (_Ty) < _Count)
CID 12348 (#1 of 1): Wrong sizeof argument (SIZEOF_MISMATCH)
suspicious_sizeof: Passing argument _Count * 4U /* sizeof (std::allocator<void *>::value_type) */
to function operator new which returns a value of type std::allocator<void *>::value_type is suspicious.
28 || (_Ptr = ::operator new(_Count * sizeof (_Ty))) == 0)
29 _Xbad_alloc(); // report no memory
最佳答案
我找到了这个 Github ,它试图通过这样做来抑制*:
std::fill_n(out, spec_.width_ - 1, fill);
out += spec_.width_ - 1;
} else if (spec_.align_ == ALIGN_CENTER) {
// coverity[suspicious_sizeof]
out = writer_.fill_padding(out, spec_.width_, 1, fill);
} else {
std::fill_n(out + 1, spec_.width_ - 1, fill);
Silencing false positives in Coverity Prevent 中也有建议,这里介绍了另一种方法:Coverity SA - excluding boost, stlport errors .
*我不确定这是否是您想要的,但我只有这些!
关于c++ - 如何针对 "suspicious sizeof"或 SIZEOF_MISMATCH 结果训练 Coverity?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38386419/