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Implement Micrososoft.Bcl.Cryptography without System.Security.Cryptography.Algorithms (#85683)
* Implement Micrososoft.Bcl.Cryptography without System.Security.Cryptography.Algorithms * Assert data written * Call Initialize on the right thing
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-15
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3 files changed

+59
-15
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‎src/libraries/Microsoft.Bcl.Cryptography/src/Microsoft.Bcl.Cryptography.csproj‎

Lines changed: 0 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -72,8 +72,4 @@ System.Security.Cryptography.SP800108HmacCounterKdf</PackageDescription>
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<ItemGroup Condition="'$(TargetFrameworkIdentifier)' != '.NETCoreApp'">
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<PackageReference Include="System.Memory" Version="$(SystemMemoryVersion)" />
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</ItemGroup>
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<ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'">
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<PackageReference Include="System.Security.Cryptography.Algorithms" Version="$(SystemSecurityCryptographyAlgorithmsVersion)" />
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</ItemGroup>
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</Project>

‎src/libraries/Microsoft.Bcl.Cryptography/src/System/Security/Cryptography/SP800108HmacCounterKdfImplementationCng.cs‎

Lines changed: 21 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -103,10 +103,28 @@ internal unsafe SP800108HmacCounterKdfImplementationCng(byte[] key, HashAlgorith
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private static byte[] HashOneShot(HashAlgorithmName hashAlgorithm, byte[] data)
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{
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using (IncrementalHash hash = IncrementalHash.CreateHash(hashAlgorithm))
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using (HashAlgorithm hash = CreateHash(hashAlgorithm))
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{
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hash.AppendData(data);
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return hash.GetHashAndReset();
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return hash.ComputeHash(data);
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}
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}
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[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA5350", Justification = "Weak algorithms are used as instructed by the caller")]
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private static HashAlgorithm CreateHash(HashAlgorithmName hashAlgorithm)
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{
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switch (hashAlgorithm.Name)
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{
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case HashAlgorithmNames.SHA1:
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return SHA1.Create();
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case HashAlgorithmNames.SHA256:
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return SHA256.Create();
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case HashAlgorithmNames.SHA384:
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return SHA384.Create();
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case HashAlgorithmNames.SHA512:
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return SHA512.Create();
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default:
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Debug.Fail($"Unexpected hash algorithm '{hashAlgorithm.Name}'.");
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throw new CryptographicException(SR.Format(SR.Cryptography_UnknownHashAlgorithm, hashAlgorithm.Name));
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}
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}
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}

‎src/libraries/Microsoft.Bcl.Cryptography/src/System/Security/Cryptography/SP800108HmacCounterKdfImplementationManaged.cs‎

Lines changed: 38 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -139,7 +139,7 @@ private static void DeriveBytesOneShot(
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// The KDF is defined as K(i) := PRF (KI, [i]2 || Label || 0x00 || Context || [L]2)
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// We know L is already less than 0x1FFFFFFF. h = ceil(L / h) where H is the hash length in bits.
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// So we don't expect i to overflow.
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using (IncrementalHash hash = IncrementalHash.CreateHMAC(hashAlgorithm, key))
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using (HMAC hash = CreateHMAC(hashAlgorithm, key))
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{
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// We use this rented buffer for three things. The first two uints for i and L, and last byte
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// for the zero separator. So this is
@@ -165,19 +165,30 @@ private static void DeriveBytesOneShot(
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for (uint i = 1; !destination.IsEmpty; i++)
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{
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WriteUInt32BigEndian(i, rentedBuffer.AsSpan(IOffset, ILength));
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hash.AppendData(rentedBuffer, IOffset, ILength);
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hash.AppendData(label, 0, labelLength);
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hash.AppendData(rentedBuffer, ZeroOffset, ZeroLength);
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hash.AppendData(context, 0, contextLength);
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hash.AppendData(rentedBuffer, LOffset, LLength);
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byte[] hmac = hash.GetHashAndReset();
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int written;
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written = hash.TransformBlock(rentedBuffer, IOffset, ILength, null, 0);
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Debug.Assert(written == ILength);
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written = hash.TransformBlock(label, 0, labelLength, null, 0);
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Debug.Assert(written == labelLength);
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written = hash.TransformBlock(rentedBuffer, ZeroOffset, ZeroLength, null, 0);
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Debug.Assert(written == ZeroLength);
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written = hash.TransformBlock(context, 0, contextLength, null, 0);
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Debug.Assert(written == contextLength);
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written = hash.TransformBlock(rentedBuffer, LOffset, LLength, null, 0);
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Debug.Assert(written == LLength);
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// Use an empty input for the final transform so that the returned value isn't something
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// we need to clear since the return value is the same as the input.
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hash.TransformFinalBlock(Array.Empty<byte>(), 0, 0);
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byte[] hmac = hash.Hash;
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int needed = Math.Min(destination.Length, hmac.Length);
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hmac.AsSpan(0, needed).CopyTo(destination);
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destination = destination.Slice(needed);
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// Best effort to zero out the key material.
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CryptographicOperations.ZeroMemory(hmac);
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hash.Initialize();
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}
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}
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finally
@@ -199,5 +210,24 @@ private static void WriteUInt32BigEndian(uint value, Span<byte> destination)
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destination[2] = (byte)(value >> 8);
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destination[3] = (byte)(value);
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}
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[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA5350", Justification = "Weak algorithms are used as instructed by the caller")]
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private static HMAC CreateHMAC(HashAlgorithmName hashAlgorithm, byte[] key)
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{
217+
switch (hashAlgorithm.Name)
218+
{
219+
case HashAlgorithmNames.SHA1:
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return new HMACSHA1(key);
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case HashAlgorithmNames.SHA256:
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return new HMACSHA256(key);
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case HashAlgorithmNames.SHA384:
224+
return new HMACSHA384(key);
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case HashAlgorithmNames.SHA512:
226+
return new HMACSHA512(key);
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default:
228+
Debug.Fail($"Unexpected HMAC algorithm '{hashAlgorithm.Name}'.");
229+
throw new CryptographicException(SR.Format(SR.Cryptography_UnknownHashAlgorithm, hashAlgorithm.Name));
230+
}
231+
}
202232
}
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}

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