gh-99108: Replace SHA2-224 & 256 with verified code from HACL* (#99109)

replacing hashlib primitives (for the non-OpenSSL case) with verified implementations from HACL*. This is the first PR in the series, and focuses specifically on SHA2-256 and SHA2-224.

This PR imports Hacl_Streaming_SHA2 into the Python tree. This is the HACL* implementation of SHA2, which combines a core implementation of SHA2 along with a layer of buffer management that allows updating the digest with any number of bytes. This supersedes the previous implementation in the tree.

@franziskuskiefer was kind enough to benchmark the changes: in addition to being verified (thus providing significant safety and security improvements), this implementation also provides a sizeable performance boost!

```
---------------------------------------------------------------
Benchmark                     Time             CPU   Iterations
---------------------------------------------------------------
Sha2_256_Streaming            3163 ns      3160 ns       219353     // this PR
LibTomCrypt_Sha2_256          5057 ns      5056 ns       136234     // library used by Python currently
``` 

The changes in this PR are as follows:
- import the subset of HACL* that covers SHA2-256/224 into `Modules/_hacl`
- rewire sha256module.c to use the HACL* implementation

Co-authored-by: Gregory P. Smith [Google LLC] <greg@krypto.org>
Co-authored-by: Erlend E. Aasland <erlend.aasland@protonmail.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/Lib/test/test_hashlib.py b/Lib/test/test_hashlib.py
index 450dc49..9c92b4e 100644
--- a/Lib/test/test_hashlib.py
+++ b/Lib/test/test_hashlib.py
@@ -22,6 +22,7 @@ from test import support
 from test.support import _4G, bigmemtest
 from test.support.import_helper import import_fresh_module
 from test.support import os_helper
+from test.support import requires_resource
 from test.support import threading_helper
 from test.support import warnings_helper
 from http.client import HTTPException
@@ -354,6 +355,15 @@ class HashLibTestCase(unittest.TestCase):
             self.assertEqual(m1.digest(*args), m4_copy.digest(*args))
             self.assertEqual(m4.digest(*args), m4_digest)
 
+    @requires_resource('cpu')
+    def test_sha256_update_over_4gb(self):
+        zero_1mb = b"\0" * 1024 * 1024
+        h = hashlib.sha256()
+        for i in range(0, 4096):
+            h.update(zero_1mb)
+        h.update(b"hello world")
+        self.assertEqual(h.hexdigest(), "a5364f7a52ebe2e25f1838a4ca715a893b6fd7a23f2a0d9e9762120da8b1bf53")
+
     def check(self, name, data, hexdigest, shake=False, **kwargs):
         length = len(hexdigest)//2
         hexdigest = hexdigest.lower()