Hello
Crypto++ 5.6.0 triggers this valgrind error:
Source and destination overlap in memcpy(0x7feffef40, 0x7feffef40, 56)
at 0x4A0809B: memcpy (mc_replace_strmem.c:482)
by 0x52D115: CryptoPP::IteratedHashBase<unsigned int,
CryptoPP::HashTransformation>::Update(unsigned char const*,
unsigned long) (iterhash.cpp:69)
by 0x4FD045: CryptoPP::HashFilter::Put2(unsigned char const*, unsigned long,
int, bool) (filters.cpp:735)
...
According to the manpage of memcpy (Ubuntu 10.04) this should not be the
case:
"The memcpy() function copies n bytes from memory area src to memory
area dest. The memory areas should not overlap."
Whenever this error occurs, both pointers are the same.
The attached patch simply fixes this situation by adding an if-statement
that suppresses the memcpy call if the pointers are identical.
Regards, Peter.
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diff -Nur 5.6.0/iterhash.cpp 5.6.0-patched/iterhash.cpp
--- 5.6.0/iterhash.cpp 2009-03-15 02:48:02.000000000 +0100
+++ 5.6.0-patched/iterhash.cpp 2010-08-03 21:28:51.000000000 +0200
@@ -66,7 +66,8 @@
} while (len >= blockSize);
}
- memcpy(data, input, len);
+ if (data!=input)
+ memcpy(data, input, len);
}
template <class T, class BASE> byte * IteratedHashBase<T, BASE>::CreateUpdateSpace(size_t &size)
