Merge pull request #22967 from bartonjs/linux_selfsigned_sigcheck

Make OpenSSL verify self-issued signature integrity to match Windows

3 files changed, 54 insertions, 1 deletions

diff --git a/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h b/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
index 9cd689d991..3e405b09da 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
@@ -325,6 +325,7 @@ int EC_POINT_set_affine_coordinates_GF2m(const EC_GROUP *group, EC_POINT *p,
     PER_FUNCTION_BLOCK(X509_STORE_CTX_get_error_depth, true) \
     PER_FUNCTION_BLOCK(X509_STORE_CTX_init, true) \
     PER_FUNCTION_BLOCK(X509_STORE_CTX_new, true) \
+    PER_FUNCTION_BLOCK(X509_STORE_CTX_set_flags, true) \
     PER_FUNCTION_BLOCK(X509_STORE_CTX_set_verify_cb, true) \
     PER_FUNCTION_BLOCK(X509_STORE_free, true) \
     PER_FUNCTION_BLOCK(X509_STORE_new, true) \
@@ -615,6 +616,7 @@ FOR_ALL_OPENSSL_FUNCTIONS
 #define X509_STORE_CTX_get_error_depth X509_STORE_CTX_get_error_depth_ptr
 #define X509_STORE_CTX_init X509_STORE_CTX_init_ptr
 #define X509_STORE_CTX_new X509_STORE_CTX_new_ptr
+#define X509_STORE_CTX_set_flags X509_STORE_CTX_set_flags_ptr
 #define X509_STORE_CTX_set_verify_cb X509_STORE_CTX_set_verify_cb_ptr
 #define X509_STORE_free X509_STORE_free_ptr
 #define X509_STORE_new X509_STORE_new_ptr
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.cpp
index 0a3dfcc2c8..3118c9aa2c 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.cpp
@@ -208,7 +208,14 @@ extern "C" void CryptoNative_X509StoreCtxDestroy(X509_STORE_CTX* v)
 
 extern "C" int32_t CryptoNative_X509StoreCtxInit(X509_STORE_CTX* ctx, X509_STORE* store, X509* x509, X509Stack* extraStore)
 {
-    return X509_STORE_CTX_init(ctx, store, x509, extraStore);
+    int32_t val = X509_STORE_CTX_init(ctx, store, x509, extraStore);
+
+    if (val != 0)
+    {
+        X509_STORE_CTX_set_flags(ctx, X509_V_FLAG_CHECK_SS_SIGNATURE);
+    }
+
+    return val;
 }
 
 extern "C" int32_t CryptoNative_X509VerifyCert(X509_STORE_CTX* ctx)
diff --git a/src/System.Security.Cryptography.X509Certificates/tests/ChainTests.cs b/src/System.Security.Cryptography.X509Certificates/tests/ChainTests.cs
index 3d1d44ec5a..7cf8db6023 100644
--- a/src/System.Security.Cryptography.X509Certificates/tests/ChainTests.cs
+++ b/src/System.Security.Cryptography.X509Certificates/tests/ChainTests.cs
@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
 using Xunit;
@@ -630,5 +631,48 @@ namespace System.Security.Cryptography.X509Certificates.Tests
             using (var chain = X509Chain.Create())
                 Assert.NotNull(chain);
         }
+
+        [Fact]
+        public static void InvalidSelfSignedSignature()
+        {
+            X509ChainStatusFlags expectedFlags;
+
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                expectedFlags = X509ChainStatusFlags.NotSignatureValid;
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                expectedFlags = X509ChainStatusFlags.UntrustedRoot;
+            }
+            else
+            {
+                expectedFlags =
+                    X509ChainStatusFlags.NotSignatureValid |
+                    X509ChainStatusFlags.UntrustedRoot;
+            }
+
+            byte[] certBytes = (byte[])TestData.MicrosoftDotComRootBytes.Clone();
+            // The signature goes up to the very last byte, so flip some bits in it.
+            certBytes[certBytes.Length - 1] ^= 0xFF;
+
+            using (var cert = new X509Certificate2(certBytes))
+            using (ChainHolder holder = new ChainHolder())
+            {
+                X509Chain chain = holder.Chain;
+                X509ChainPolicy policy = chain.ChainPolicy;
+                policy.VerificationTime = cert.NotBefore.AddDays(3);
+                policy.RevocationMode = X509RevocationMode.NoCheck;
+
+                chain.Build(cert);
+
+                X509ChainStatusFlags allFlags =
+                    chain.ChainStatus.Select(cs => cs.Status).Aggregate(
+                        X509ChainStatusFlags.NoError,
+                        (a, b) => a | b);
+
+                Assert.Equal(expectedFlags, allFlags);
+            }
+        }
     }
 }