Add support for OCSP on Linux, overhaul Linux X509Chain processing

This change moves a lot of the chain building work from managed code into the native shim, largely to cut down on the number of P/Invokes required to set up the chain builder.

Once a chain has been built to a point where only one issuer will be considered, if revocation was requested and a CRL is not available, attempt an OCSP request if the certificate indicates the CA has an OCSP endpoint.

Based on CA/Browser Forum's requirements this expects CRL for all intermediates and only attempts OCSP for the end-entity certificate.

"Conforming" OCSP requests are opportunistically cached on the basis that local filesystem re-reads are more reliable (and faster) than doing a live request to the CA.

src/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.ASN1.Nid.cs

@@ -2,15 +2,42 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Collections.Concurrent;
+using System.Diagnostics;
 using System.Runtime.InteropServices;
+using System.Security.Cryptography;
 
 internal static partial class Interop
 {
     internal static partial class Crypto
     {
+        private static readonly ConcurrentDictionary<string, int> s_nidLookup =
+            new ConcurrentDictionary<string, int>();
+
         internal const int NID_undef = 0;
 
         [DllImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_ObjSn2Nid", CharSet = CharSet.Ansi)]
         internal static extern int ObjSn2Nid(string sn);
+
+        [DllImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_ObjTxt2Nid", CharSet = CharSet.Ansi)]
+        private static extern int ObjTxt2Nid(string oid);
+
+        internal static int ResolveRequiredNid(string oid)
+        {
+            return s_nidLookup.GetOrAdd(oid, s => LookupNid(s));
+        }
+
+        private static int LookupNid(string oid)
+        {
+            int nid = ObjTxt2Nid(oid);
+
+            if (nid == NID_undef)
+            {
+                Debug.Fail($"NID Lookup for {oid} failed, only well-known types should be queried.");
+                throw new CryptographicException();
+            }
+
+            return nid;
+        }
     }
 }

src/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.Crypto.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Buffers;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Security.Cryptography;
@@ -108,6 +109,17 @@ private static extern int SetX509ChainVerifyTime(
             int second,
             [MarshalAs(UnmanagedType.Bool)] bool isDst);
 
+        [DllImport(Libraries.CryptoNative)]
+        private static extern int CryptoNative_X509StoreSetVerifyTime(
+            SafeX509StoreHandle ctx,
+            int year,
+            int month,
+            int day,
+            int hour,
+            int minute,
+            int second,
+            [MarshalAs(UnmanagedType.Bool)] bool isDst);
+
         [DllImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_CheckX509IpAddress")]
         internal static extern int CheckX509IpAddress(SafeX509Handle x509, [In]byte[] addressBytes, int addressLen, string hostname, int cchHostname);
 
@@ -119,6 +131,11 @@ internal static byte[] GetAsn1StringBytes(IntPtr asn1)
             return GetDynamicBuffer((ptr, buf, i) => GetAsn1StringBytes(ptr, buf, i), asn1);
         }
 
+        internal static ArraySegment<byte> RentAsn1StringBytes(IntPtr asn1)
+        {
+            return RentDynamicBuffer((ptr, buf, i) => GetAsn1StringBytes(ptr, buf, i), asn1);
+        }
+
         internal static byte[] GetX509Thumbprint(SafeX509Handle x509)
         {
             return GetDynamicBuffer((handle, buf, i) => GetX509Thumbprint(handle, buf, i), x509);
@@ -159,6 +176,28 @@ internal static void SetX509ChainVerifyTime(SafeX509StoreCtxHandle ctx, DateTime
             }
         }
 
+        internal static void X509StoreSetVerifyTime(SafeX509StoreHandle ctx, DateTime verifyTime)
+        {
+            // OpenSSL is going to convert our input time to universal, so we should be in Local or
+            // Unspecified (local-assumed).
+            Debug.Assert(verifyTime.Kind != DateTimeKind.Utc, "UTC verifyTime should have been normalized to Local");
+
+            int succeeded = CryptoNative_X509StoreSetVerifyTime(
+                ctx,
+                verifyTime.Year,
+                verifyTime.Month,
+                verifyTime.Day,
+                verifyTime.Hour,
+                verifyTime.Minute,
+                verifyTime.Second,
+                verifyTime.IsDaylightSavingTime());
+
+            if (succeeded != 1)
+            {
+                throw Interop.Crypto.CreateOpenSslCryptographicException();
+            }
+        }
+
         private static byte[] GetDynamicBuffer<THandle>(NegativeSizeReadMethod<THandle> method, THandle handle)
         {
             int negativeSize = method(handle, null, 0);
@@ -179,5 +218,28 @@ private static byte[] GetDynamicBuffer<THandle>(NegativeSizeReadMethod<THandle>
 
             return bytes;
         }
+
+        private static ArraySegment<byte> RentDynamicBuffer<THandle>(NegativeSizeReadMethod<THandle> method, THandle handle)
+        {
+            int negativeSize = method(handle, null, 0);
+
+            if (negativeSize > 0)
+            {
+                throw Interop.Crypto.CreateOpenSslCryptographicException();
+            }
+
+            int targetSize = -negativeSize;
+            byte[] bytes = ArrayPool<byte>.Shared.Rent(targetSize);
+
+            int ret = method(handle, bytes, targetSize);
+
+            if (ret != 1)
+            {
+                ArrayPool<byte>.Shared.Return(bytes);
+                throw Interop.Crypto.CreateOpenSslCryptographicException();
+            }
+
+            return new ArraySegment<byte>(bytes, 0, targetSize);
+        }
     }
 }

src/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.Encode.cs

@@ -3,9 +3,9 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Buffers;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
-using System.Security.Cryptography;
 
 internal static partial class Interop
 {
@@ -15,14 +15,17 @@ internal static partial class Crypto
 
         internal delegate int EncodeFunc<in THandle>(THandle handle, byte[] buf);
 
-        internal static byte[] OpenSslEncode<THandle>(GetEncodedSizeFunc<THandle> getSize, EncodeFunc<THandle> encode, THandle handle)
+        internal static byte[] OpenSslEncode<THandle>(
+            GetEncodedSizeFunc<THandle> getSize,
+            EncodeFunc<THandle> encode,
+            THandle handle)
             where THandle : SafeHandle
         {
             int size = getSize(handle);
 
             if (size < 1)
             {
-                throw Crypto.CreateOpenSslCryptographicException();
+                throw CreateOpenSslCryptographicException();
             }
 
             byte[] data = new byte[size];
@@ -42,5 +45,40 @@ internal static byte[] OpenSslEncode<THandle>(GetEncodedSizeFunc<THandle> getSiz
 
             return data;
         }
+
+        internal static ArraySegment<byte> OpenSslRentEncode<THandle>(
+            GetEncodedSizeFunc<THandle> getSize,
+            EncodeFunc<THandle> encode,
+            THandle handle)
+            where THandle : SafeHandle
+        {
+            int size = getSize(handle);
+
+            if (size < 1)
+            {
+                throw CreateOpenSslCryptographicException();
+            }
+
+            byte[] data = ArrayPool<byte>.Shared.Rent(size);
+
+            int size2 = encode(handle, data);
+            if (size2 < 1)
+            {
+                Debug.Fail(
+                    $"{nameof(OpenSslEncode)}: {nameof(getSize)} succeeded ({size}) and {nameof(encode)} failed ({size2})");
+
+                // Since we don't know what was written, assume it was secret and clear the value.
+                // (It doesn't matter much, since we're behind Debug.Fail)
+                ArrayPool<byte>.Shared.Return(data, clearArray: true);
+
+                // If it ever happens, ensure the error queue gets cleared.
+                // And since it didn't write the data, reporting an exception is good too.
+                throw CreateOpenSslCryptographicException();
+            }
+
+            Debug.Assert(size == size2);
+
+            return new ArraySegment<byte>(data, 0, size2);
+        }
     }
 }

src/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OCSP.cs

@@ -0,0 +1,128 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Security.Cryptography;
+using System.Security.Cryptography.X509Certificates;
+using Microsoft.Win32.SafeHandles;
+
+internal static partial class Interop
+{
+    internal static partial class Crypto
+    {
+        [DllImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_OcspRequestDestroy")]
+        internal static extern void OcspRequestDestroy(IntPtr ocspReq);
+
+        [DllImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_GetOcspRequestDerSize")]
+        internal static extern int GetOcspRequestDerSize(SafeOcspRequestHandle req);
+
+        [DllImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_EncodeOcspRequest")]
+        internal static extern int EncodeOcspRequest(SafeOcspRequestHandle req, byte[] buf);
+
+        [DllImport(Libraries.CryptoNative)]
+        private static extern SafeOcspResponseHandle CryptoNative_DecodeOcspResponse(ref byte buf, int len);
+
+        internal static SafeOcspResponseHandle DecodeOcspResponse(ReadOnlySpan<byte> buf)
+        {
+            return CryptoNative_DecodeOcspResponse(
+                ref MemoryMarshal.GetReference(buf),
+                buf.Length);
+        }
+
+        [DllImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_OcspResponseDestroy")]
+        internal static extern void OcspResponseDestroy(IntPtr ocspReq);
+
+
+        [DllImport(Libraries.CryptoNative)]
+        private static extern X509VerifyStatusCode CryptoNative_X509ChainGetCachedOcspStatus(SafeX509StoreCtxHandle ctx, string cachePath);
+
+        internal static X509VerifyStatusCode X509ChainGetCachedOcspStatus(SafeX509StoreCtxHandle ctx, string cachePath)
+        {
+            X509VerifyStatusCode response = CryptoNative_X509ChainGetCachedOcspStatus(ctx, cachePath);
+
+            if (response < 0)
+            {
+                Debug.Fail($"Unexpected response from X509ChainGetCachedOcspSuccess: {response}");
+                throw new CryptographicException();
+            }
+
+            return response;
+        }
+
+        [DllImport(Libraries.CryptoNative)]
+        private static extern X509VerifyStatusCode CryptoNative_X509ChainVerifyOcsp(
+            SafeX509StoreCtxHandle ctx,
+            SafeOcspRequestHandle req,
+            SafeOcspResponseHandle resp,
+            string cachePath);
+
+        internal static X509VerifyStatusCode X509ChainVerifyOcsp(
+            SafeX509StoreCtxHandle ctx,
+            SafeOcspRequestHandle req,
+            SafeOcspResponseHandle resp,
+            string cachePath)
+        {
+            X509VerifyStatusCode response = CryptoNative_X509ChainVerifyOcsp(ctx, req, resp, cachePath);
+
+            if (response < 0)
+            {
+                Debug.Fail($"Unexpected response from X509ChainGetCachedOcspSuccess: {response}");
+                throw new CryptographicException();
+            }
+
+            return response;
+        }
+
+        [DllImport(Libraries.CryptoNative)]
+        private static extern SafeOcspRequestHandle CryptoNative_X509ChainBuildOcspRequest(SafeX509StoreCtxHandle storeCtx);
+
+        internal static SafeOcspRequestHandle X509ChainBuildOcspRequest(SafeX509StoreCtxHandle storeCtx)
+        {
+            SafeOcspRequestHandle req = CryptoNative_X509ChainBuildOcspRequest(storeCtx);
+
+            if (req.IsInvalid)
+            {
+                req.Dispose();
+                throw CreateOpenSslCryptographicException();
+            }
+
+            return req;
+        }
+    }
+}
+
+namespace System.Security.Cryptography.X509Certificates
+{
+    internal class SafeOcspRequestHandle : SafeHandleZeroOrMinusOneIsInvalid
+    {
+        public SafeOcspRequestHandle()
+            : base(true)
+        {
+        }
+
+        protected override bool ReleaseHandle()
+        {
+            Interop.Crypto.OcspRequestDestroy(handle);
+            handle = IntPtr.Zero;
+            return true;
+        }
+    }
+
+    internal class SafeOcspResponseHandle : SafeHandleZeroOrMinusOneIsInvalid
+    {
+        public SafeOcspResponseHandle()
+            : base(true)
+        {
+        }
+
+        protected override bool ReleaseHandle()
+        {
+            Interop.Crypto.OcspResponseDestroy(handle);
+            handle = IntPtr.Zero;
+            return true;
+        }
+    }
+}