Обсуждение: [PATCH] Windows port add support to BCryptGenRandom

Hi,
According to microsoft documentation at:
https://docs.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-cryptgenrandom
The function CryptGenRandom is deprecated, and may can be removed in future release.
This patch add support to use BCryptGenRandom.

BCryptGenRandom apparently works without having to set up an environment before calling.
The drawback, its change causes need to link to bcrypt.lib.

regards,
Ranier Vilela

Forget Mkvcbuild_v1.patch

regards,
Ranier Vilela

On Mon, Dec 16, 2019 at 09:18:10PM +0000, Ranier Vilela wrote:
> According to microsoft documentation at:
> https://docs.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-cryptgenrandom
> The function CryptGenRandom is deprecated, and may can be removed in future release.
> This patch add support to use BCryptGenRandom.

+#if defined(_MSC_VER) && _MSC_VER >= 1900 \
+     && defined(MIN_WINNT) && MIN_WINNT >= 0x0600
+#define USE_WIN32_BCRYPTGENRANDOM
[...]
+       $postgres->AddLibrary('bcrypt.lib') if ($vsVersion > '12.00');

And looking at this page, it is said that the minimum version
supported by this function is Windows 2008:
https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom

Now, your changes in MkvcBuild.pm and the backend code assume that
we need to include bcrypt.lib since MSVC 2015 (at least version
14.00 or _MSC_VER >= 1900.  Do you have a reference about when this
has been introduced in VS?  The MS docs don't seem to hold a hint
about that..
--
Michael

On Tue, Dec 17, 2019 at 03:57:56AM +0000, Ranier Vilela wrote:
> Windows Vista I believe.
> https://github.com/openssl/openssl/blob/master/crypto/rand/rand_win.c
> is the primary font and have more information.

So, this basically matches with what the MS documents tell us, and my
impression: this API is available down to at least MSVC 2008, which is
much more than what we support on HEAD where one can use MSVC 2013 and
newer versions.  Note that for the minimal platforms supported our
documentation cite Windows Server 2008 R2 SP1 and Windows 7, implying
_WIN32_WINNT >= 0x0600.

In short, this means two things:
- Your patch, as presented, is wrong.
- There is no need to make conditional the use of BCryptGenRandom.
--
Michael

On Tue, Dec 17, 2019 at 02:20:20PM +0000, Ranier Vilela wrote:
> As concern [1], at src/include/port/win32.h, the comments still
> references Windows XP and claims about possible MingW break.

This looks like a leftover of d9dd406, which has made the code to
require C99.  As we don't support compilation with Windows XP and
require Windows 7, we should be able to remove all the dance around
MIN_WINNT in win32.h, don't you think?
--
Michael

On Wed, Dec 18, 2019 at 09:52:07AM +0100, Juan José Santamaría Flecha wrote:
> +1, there is a reference in [1] about that is possible to build PostgreSQL
> using the GNU compiler tools for older versions of Windows, that should be
> also updated.

There is actually a little bit more which could be cleaned up.  I am
going to begin a new thread on that after finishing looking.

> [1] https://www.postgresql.org/docs/current/install-windows.html

Are you referring to the part about cygwin?  We could remove all the
paragraph..
--
Michael