Add name of corrupted certificate to CryptographicException on Mac

* Add name of corrupted certificate to CryptographicException on Mac

When trying to create a CertificateData out of raw X509 byte array it might throw if the data is corrupted. The existing exception message does not provide any information which might help the user identify the corrupted certificate and fix it.

This change, makes a native call to SecCertificateCopySubjectSummary which will provide a human readable summary of the certificate, and will generate an exception message using this string.

Co-authored-by: Jeremy Barton <jbarton@microsoft.com>

src/libraries/Common/src/Interop/OSX/System.Security.Cryptography.Native.Apple/Interop.X509.cs

@@ -20,6 +20,11 @@ internal static partial class AppleCrypto
             out SafeCFDataHandle cfDataOut,
             out int pOSStatus);
 
+        [DllImport(Libraries.AppleCryptoNative)]
+        private static extern int AppleCryptoNative_X509GetSubjectSummary(
+            SafeSecCertificateHandle cert,
+            out SafeCFStringHandle cfSubjectSummaryOut);
+
         [DllImport(Libraries.AppleCryptoNative)]
         private static extern int AppleCryptoNative_X509GetPublicKey(SafeSecCertificateHandle cert, out SafeSecKeyRefHandle publicKey, out int pOSStatus);
 
@@ -72,6 +77,31 @@ internal static byte[] X509GetRawData(SafeSecCertificateHandle cert)
             }
         }
 
+        internal static string? X509GetSubjectSummary(SafeSecCertificateHandle cert)
+        {
+            SafeCFStringHandle subjectSummary;
+
+            int ret = AppleCryptoNative_X509GetSubjectSummary(
+                cert,
+                out subjectSummary);
+
+            using (subjectSummary)
+            {
+                if (ret == 1)
+                {
+                    return CoreFoundation.CFStringToString(subjectSummary);
+                }
+            }
+
+            if (ret == 0)
+            {
+                return null;
+            }
+
+            Debug.Fail($"Unexpected return value {ret}");
+            throw new CryptographicException();
+        }
+
         internal static SafeSecKeyRefHandle X509GetPrivateKeyFromIdentity(SafeSecIdentityHandle identity)
         {
             SafeSecKeyRefHandle key;

src/libraries/Native/Unix/System.Security.Cryptography.Native.Apple/entrypoints.c

@@ -106,6 +106,7 @@ static const Entry s_cryptoAppleNative[] =
     DllImportEntry(AppleCryptoNative_GetOSStatusForChainStatus)
     DllImportEntry(AppleCryptoNative_X509ChainSetTrustAnchorCertificates)
     DllImportEntry(AppleCryptoNative_Pbkdf2)
+    DllImportEntry(AppleCryptoNative_X509GetSubjectSummary)
 };
 
 EXTERN_C const void* CryptoAppleResolveDllImport(const char* name);

src/libraries/Native/Unix/System.Security.Cryptography.Native.Apple/pal_x509.c

@@ -230,3 +230,15 @@ int32_t AppleCryptoNative_X509GetRawData(SecCertificateRef cert, CFDataRef* ppDa
     *pOSStatus = *ppDataOut == NULL ? errSecParam : noErr;
     return (*pOSStatus == noErr);
 }
+
+int32_t AppleCryptoNative_X509GetSubjectSummary(SecCertificateRef cert, CFStringRef* ppSummaryOut)
+{
+    if (ppSummaryOut != NULL)
+        *ppSummaryOut = NULL;
+
+    if (cert == NULL || ppSummaryOut == NULL)
+        return kErrorBadInput;
+
+    *ppSummaryOut = SecCertificateCopySubjectSummary(cert);
+    return (*ppSummaryOut != NULL);
+}

src/libraries/Native/Unix/System.Security.Cryptography.Native.Apple/pal_x509.h

@@ -72,3 +72,13 @@ ppDataOut: Receives a CFDataRef with the exported blob
 pOSStatus: Receives the result of SecItemExport
 */
 PALEXPORT int32_t AppleCryptoNative_X509GetRawData(SecCertificateRef cert, CFDataRef* ppDataOut, int32_t* pOSStatus);
+
+/*
+Extract a string that contains a human-readable summary of the contents of the certificate
+
+Returns 1 on success, 0 on failure, any other value indicates invalid state.
+
+Output:
+ppSummaryOut: Receives a CFDataRef with the exported blob
+*/
+PALEXPORT int32_t AppleCryptoNative_X509GetSubjectSummary(SecCertificateRef cert, CFStringRef* ppSummaryOut);

src/libraries/System.Security.Cryptography.X509Certificates/src/Internal/Cryptography/Pal.OSX/AppleCertificatePal.cs

@@ -399,7 +399,26 @@ private void EnsureCertData()
                 return;
 
             Debug.Assert(!_certHandle.IsInvalid);
-            _certData = new CertificateData(Interop.AppleCrypto.X509GetRawData(_certHandle));
+            string? subjectSummary = Interop.AppleCrypto.X509GetSubjectSummary(_certHandle);
+
+            try
+            {
+                _certData = new CertificateData(Interop.AppleCrypto.X509GetRawData(_certHandle));
+            }
+            catch (CryptographicException e)
+            {
+                if (subjectSummary is null)
+                {
+                    throw;
+                }
+
+                string message = SR.Format(
+                    SR.Cryptography_X509_CertificateCorrupted,
+                    subjectSummary);
+
+                throw new CryptographicException(message, e);
+            }
+
             _readCertData = true;
         }
     }

src/libraries/System.Security.Cryptography.X509Certificates/src/Resources/Strings.resx

@@ -331,6 +331,9 @@
   <data name="Cryptography_X509_NoOrMismatchedPemKey" xml:space="preserve">
     <value>The key contents do not contain a PEM, the content is malformed, or the key does not match the certificate.</value>
   </data>
+  <data name="Cryptography_X509_CertificateCorrupted" xml:space="preserve">
+    <value>Certificate '{0}' is corrupted.</value>
+  </data>
   <data name="InvalidOperation_EnumNotStarted" xml:space="preserve">
     <value>Enumeration has not started. Call MoveNext.</value>
   </data>