Fix unsafe memory access

[shargon]

Without checking the length, is possible to read arbitrary memory

• Should be merged to master

[erikzhang]

These unsafe methods are designed for performance, so some checks are omitted. They require developers to use them carefully and are not public.

[shargon]

I think that the length should be checked, is easy to forget the previous check, for example in this:

neo/neo/Wallets/SQLite/UserWallet.cs

Lines 34 to 43 in aece82b

	get
	{
	byte[] buffer = LoadStoredData("Version");
	if (buffer == null) return new Version(0, 0);
	int major = buffer.ToInt32(0);
	int minor = buffer.ToInt32(4);
	int build = buffer.ToInt32(8);
	int revision = buffer.ToInt32(12);
	return new Version(major, minor, build, revision);
	}

[erikzhang]

We need these high performance methods in some places.

For example:

neo/neo/Cryptography/Murmur3.cs

Line 35 in b8ad89e

uint k = array.ToUInt32(i);

We can find out where the methods are misused and then use BitConverter.ToXXX() instead.

[shargon]

I will search and fix where the length is not checked, and close this issue

[shargon]

I think that all is fixed now, i close it