support SslStream SSLKEYLOGFILE in debug builds

src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OpenSsl.cs

@@ -21,6 +21,10 @@ internal static partial class Interop
 {
     internal static partial class OpenSsl
     {
+#if DEBUG
+        private static readonly string? s_keyLogFile = Environment.GetEnvironmentVariable("SSLKEYLOGFILE");
+        private static readonly FileStream? s_fileStream = s_keyLogFile != null ? File.Open(s_keyLogFile, FileMode.Append, FileAccess.Write, FileShare.ReadWrite) : null;
+#endif
         private const string DisableTlsResumeCtxSwitch = "System.Net.Security.DisableTlsResume";
         private const string DisableTlsResumeEnvironmentVariable = "DOTNET_SYSTEM_NET_SECURITY_DISABLETLSRESUME";
         private const string TlsCacheSizeCtxName = "System.Net.Security.TlsCacheSize";
@@ -236,6 +240,12 @@ internal static unsafe SafeSslContextHandle AllocateSslContext(SslAuthentication
                         Ssl.SslCtxSetDefaultOcspCallback(sslCtx);
                     }
                 }
+#if DEBUG
+                if (s_fileStream != null)
+                {
+                    Ssl.SslCtxSetKeylogCallback(sslCtx, &KeyLogCallback);
+                }
+#endif
             }
             catch
             {
@@ -783,6 +793,23 @@ private static unsafe void RemoveSessionCallback(IntPtr ctx, IntPtr session)
             ctxHandle.RemoveSession(name);
         }
 
+#if DEBUG
+        [UnmanagedCallersOnly]
+        private static unsafe void KeyLogCallback(IntPtr ssl, char* line)
+        {
+            Debug.Assert(s_fileStream != null);
+            ReadOnlySpan<byte> data = MemoryMarshal.CreateReadOnlySpanFromNullTerminated((byte*)line);
+            if (data.Length > 0)
+            {
+                lock (s_fileStream)
+                {
+                    s_fileStream.Write(data);
+                    s_fileStream.WriteByte((byte)'\n');
+                }
+            }
+        }
+#endif
+
         private static int BioRead(SafeBioHandle bio, byte[] buffer, int count)
         {
             Debug.Assert(buffer != null);

src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.SslCtx.cs

@@ -33,6 +33,9 @@ internal static partial class Ssl
         [LibraryImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_SslCtxSetAlpnSelectCb")]
         internal static unsafe partial void SslCtxSetAlpnSelectCb(SafeSslContextHandle ctx, delegate* unmanaged<IntPtr, byte**, byte*, byte*, uint, IntPtr, int> callback, IntPtr arg);
 
+        [LibraryImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_SslCtxSetKeylogCallback")]
+        internal static unsafe partial void SslCtxSetKeylogCallback(SafeSslContextHandle ctx, delegate* unmanaged<IntPtr, char*, void> callback);
+
         [LibraryImport(Libraries.CryptoNative, EntryPoint = "CryptoNative_SslCtxSetCaching")]
         internal static unsafe partial int SslCtxSetCaching(SafeSslContextHandle ctx, int mode, int cacheSize, int contextIdLength, Span<byte> contextId, delegate* unmanaged<IntPtr, IntPtr, int> neewSessionCallback, delegate* unmanaged<IntPtr, IntPtr, void> removeSessionCallback);
 

src/libraries/System.Net.Quic/src/System/Net/Quic/Internal/MsQuicTlsSecret.cs

@@ -15,7 +15,7 @@ namespace System.Net.Quic;
 internal sealed class MsQuicTlsSecret : IDisposable
 {
     private static readonly string? s_keyLogFile = Environment.GetEnvironmentVariable("SSLKEYLOGFILE");
-    private static readonly FileStream? s_fileStream = s_keyLogFile != null ? File.Open(s_keyLogFile, FileMode.Append, FileAccess.Write) : null;
+    private static readonly FileStream? s_fileStream = s_keyLogFile != null ? File.Open(s_keyLogFile, FileMode.Append, FileAccess.Write, FileShare.ReadWrite) : null;
 
     private unsafe QUIC_TLS_SECRETS* _tlsSecrets;
 

src/native/libs/System.Security.Cryptography.Native/apibridge.c

@@ -809,6 +809,12 @@ void local_SSL_set_security_level(SSL* ssl, int32_t level)
     (void)level;
 }
 
+void local_SSL_CTX_set_keylog_callback(SSL_CTX *ctx, SSL_CTX_keylog_cb_func cb)
+{
+    (void)ctx;
+    (void)cb;
+}
+
 int local_BIO_up_ref(BIO *bio)
 {
     if (!bio)

src/native/libs/System.Security.Cryptography.Native/apibridge.h

@@ -59,3 +59,5 @@ const X509_ALGOR* local_X509_get0_tbs_sigalg(const X509* x509);
 X509_PUBKEY* local_X509_get_X509_PUBKEY(const X509* x509);
 int32_t local_X509_get_version(const X509* x509);
 int32_t local_X509_up_ref(X509* x509);
+typedef void (*SSL_CTX_keylog_cb_func)(const SSL *ssl, const char *line);
+void local_SSL_CTX_set_keylog_callback(SSL_CTX *ctx, SSL_CTX_keylog_cb_func cb);

src/native/libs/System.Security.Cryptography.Native/entrypoints.c

@@ -302,6 +302,7 @@ static const Entry s_cryptoNative[] =
     DllImportEntry(CryptoNative_SslCtxSetCiphers)
     DllImportEntry(CryptoNative_SslCtxSetDefaultOcspCallback)
     DllImportEntry(CryptoNative_SslCtxSetEncryptionPolicy)
+    DllImportEntry(CryptoNative_SslCtxSetKeylogCallback)
     DllImportEntry(CryptoNative_SetCiphers)
     DllImportEntry(CryptoNative_SslCreate)
     DllImportEntry(CryptoNative_SslCtxCheckPrivateKey)

src/native/libs/System.Security.Cryptography.Native/opensslshim.h

@@ -509,6 +509,7 @@ int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, unsigned char *md, size_t len);
     LIGHTUP_FUNCTION(SSL_CTX_set_ciphersuites) \
     REQUIRED_FUNCTION(SSL_CTX_set_client_cert_cb) \
     REQUIRED_FUNCTION(SSL_CTX_set_ex_data) \
+    FALLBACK_FUNCTION(SSL_CTX_set_keylog_callback) \
     REQUIRED_FUNCTION(SSL_CTX_set_quiet_shutdown) \
     FALLBACK_FUNCTION(SSL_CTX_set_options) \
     FALLBACK_FUNCTION(SSL_CTX_set_security_level) \
@@ -1005,6 +1006,7 @@ FOR_ALL_OPENSSL_FUNCTIONS
 #define SSL_CTX_set_client_cert_cb SSL_CTX_set_client_cert_cb_ptr
 #define SSL_CTX_set_ex_data SSL_CTX_set_ex_data_ptr
 #define SSL_CTX_set_options SSL_CTX_set_options_ptr
+#define SSL_CTX_set_keylog_callback SSL_CTX_set_keylog_callback_ptr
 #define SSL_CTX_set_quiet_shutdown SSL_CTX_set_quiet_shutdown_ptr
 #define SSL_CTX_set_security_level SSL_CTX_set_security_level_ptr
 #define SSL_CTX_set_session_id_context SSL_CTX_set_session_id_context_ptr
@@ -1268,6 +1270,7 @@ FOR_ALL_OPENSSL_FUNCTIONS
 #define X509_get_X509_PUBKEY local_X509_get_X509_PUBKEY
 #define X509_get_version local_X509_get_version
 #define X509_up_ref local_X509_up_ref
+#define SSL_CTX_set_keylog_callback local_SSL_CTX_set_keylog_callback
 
 #if OPENSSL_VERSION_NUMBER < OPENSSL_VERSION_1_0_2_RTM
 

src/native/libs/System.Security.Cryptography.Native/osslcompat_111.h

@@ -86,6 +86,7 @@ int X509_set1_notBefore(X509* x509, const ASN1_TIME*);
 int32_t X509_up_ref(X509* x509);
 const char *SSL_SESSION_get0_hostname(const SSL_SESSION *s);
 int SSL_SESSION_set1_hostname(SSL_SESSION *s, const char *hostname);
+void SSL_CTX_set_keylog_callback(SSL_CTX *ctx, SSL_CTX_keylog_cb_func cb);
 
 #if OPENSSL_VERSION_NUMBER < OPENSSL_VERSION_1_0_2_RTM
 int32_t X509_check_host(X509* x509, const char* name, size_t namelen, unsigned int flags, char** peername);

src/native/libs/System.Security.Cryptography.Native/pal_ssl.c

@@ -1005,6 +1005,13 @@ void CryptoNative_SslSetClientCertCallback(SSL* ssl, int set)
     SSL_set_cert_cb(ssl, set ? client_certificate_cb : NULL, NULL);
 }
 
+void CryptoNative_SslCtxSetKeylogCallback(SSL_CTX* ctx, SslCtxSetKeylogCallback cb)
+{
+    // void shim functions don't lead to exceptions, so skip the unconditional error clearing.
+
+    SSL_CTX_set_keylog_callback(ctx, cb);
+}
+
 void CryptoNative_SslSetPostHandshakeAuth(SSL* ssl, int32_t val)
 {
 #if defined NEED_OPENSSL_1_1 || defined NEED_OPENSSL_3_0

src/native/libs/System.Security.Cryptography.Native/pal_ssl.h

@@ -124,6 +124,9 @@ typedef int32_t (*SslCtxNewSessionCallback)(SSL* ssl, SSL_SESSION* session);
 // the function pointer used for new  session
 typedef void (*SslCtxRemoveSessionCallback)(SSL_CTX* ctx, SSL_SESSION* session);
 
+// the function pointer for keylog
+typedef void (*SslCtxSetKeylogCallback)(const SSL* ssl, const char *line);
+
 /*
 Ensures that libssl is correctly initialized and ready to use.
 */
@@ -164,6 +167,11 @@ Sets session caching. 0 is disabled.
 */
 PALEXPORT int CryptoNative_SslCtxSetCaching(SSL_CTX* ctx, int mode, int cacheSize, int contextIdLength, uint8_t* contextId, SslCtxNewSessionCallback newSessionCb, SslCtxRemoveSessionCallback removeSessionCb);
 
+/*
+Sets callback to log TLS session keys
+*/
+PALEXPORT void CryptoNative_SslCtxSetKeylogCallback(SSL_CTX* ctx, SslCtxSetKeylogCallback callback);
+
 /*
 Returns name associated with given ssl session.
 OpenSSL holds reference to it and it must not be freed.