/*
 * Copyright (C) 1997-1999 Matt Newman <[email protected]>
 * some modifications:
 *	Copyright (C) 2000 Ajuba Solutions
 *	Copyright (C) 2002 ActiveState Corporation
 *	Copyright (C) 2004 Starfish Systems
 *	Copyright (C) 2023 Brian O'Hagan
 *
 * TLS (aka SSL) Channel - can be layered on any bi-directional
 * Tcl_Channel (Note: Requires Trf Core Patch)
 *
 * This was built (almost) from scratch based upon observation of
 * OpenSSL 0.9.2B
 *
 * Addition credit is due for Andreas Kupries ([email protected]), for
 * providing the Tcl_ReplaceChannel mechanism and working closely with me
 * to enhance it to support full fileevent semantics.
 *
 * Also work done by the follow people provided the impetus to do this "right":
 *	tclSSL (Colin McCormack, Shared Technology)
 *	SSLtcl (Peter Antman)
 *
 */

#include "tlsInt.h"
#include "tclOpts.h"
#include <stdlib.h>

/* Min OpenSSL version */
#if !defined(LIBRESSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER < 0x10101000L
#error "Only OpenSSL v1.1.1 or later is supported"
#endif

/*
 * External functions
 */

/*
 * Forward declarations

    State *statePtr	= (State*)SSL_get_app_data(ssl);
    int depth		= X509_STORE_CTX_get_error_depth(ctx);
    int err		= X509_STORE_CTX_get_error(ctx);

    dprintf("Verify: %d", ok);

    if (!ok) {
	errStr = (char*)X509_verify_cert_error_string(err);
	errStr = (char *)X509_verify_cert_error_string(err);
    } else {
	errStr = (char *)0;
    }

    if (statePtr->callback == (Tcl_Obj*)NULL) {
    if (statePtr->callback == NULL) {
	if (statePtr->vflags & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) {
	    return ok;
	} else {
	    return 1;
	}
    }
    cmdPtr = Tcl_DuplicateObj(statePtr->callback);

 */
#ifdef PRE_OPENSSL_0_9_4
/*
 * No way to handle user-data therefore no way without a global
 * variable to access the Tcl interpreter.
*/
static int
PasswordCallback(char *buf, int size, int verify)
PasswordCallback(
    TCL_UNUSED(char *) /* buf */,
    TCL_UNUSED(int) /* size */,
    TCL_UNUSED(int) /* verify */)
{
    return -1;
    	buf = buf;
	size = size;
	verify = verify;
}
#else
static int
PasswordCallback(char *buf, int size, TCL_UNUSED(int) /* verify */, void *udata)
{
    State *statePtr	= (State *) udata;
    Tcl_Interp *interp	= statePtr->interp;

    }
    if (objc > 2 && Tcl_GetBooleanFromObj( interp, objv[2],
	&verbose) != TCL_OK) {
	return TCL_ERROR;
    }
    switch ((enum protocol)index) {
    case TLS_SSL2:
#if defined(NO_SSL2)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(SSLv2_method()); break;
#endif
    case TLS_SSL3:
#if defined(NO_SSL3)
#if defined(NO_SSL3) || defined(OPENSSL_NO_SSL3) || defined(OPENSSL_NO_SSL3_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(SSLv3_method()); break;
#endif
    case TLS_TLS1:
#if defined(NO_TLS1)
#if defined(NO_TLS1) || defined(OPENSSL_NO_TLS1) || defined(OPENSSL_NO_TLS1_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLSv1_method()); break;
#endif
    case TLS_TLS1_1:
#if defined(NO_TLS1_1)
#if defined(NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLSv1_1_method()); break;
#endif
    case TLS_TLS1_2:
#if defined(NO_TLS1_2)
#if defined(NO_TLS1_2) || defined(OPENSSL_NO_TLS1_2) || defined(OPENSSL_NO_TLS1_2_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLSv1_2_method()); break;
#endif
    case TLS_TLS1_3:
#if defined(NO_TLS1_3)
#if defined(NO_TLS1_3) || defined(OPENSSL_NO_TLS1_3) || defined(OPENSSL_NO_TLS1_3_METHOD)
		Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
		return TCL_ERROR;
#else
		ctx = SSL_CTX_new(TLS_method()); break;
                SSL_CTX_set_min_proto_version (ctx, TLS1_3_VERSION);
                SSL_CTX_set_max_proto_version (ctx, TLS1_3_VERSION);
		SSL_CTX_set_min_proto_version (ctx, TLS1_3_VERSION);
		SSL_CTX_set_max_proto_version (ctx, TLS1_3_VERSION);
#endif
    default:
		break;
    }
    if (ctx == NULL) {
	Tcl_AppendResult(interp, REASON(), (char *) NULL);
	return TCL_ERROR;

    int ssl2 = 0, ssl3 = 0;
    int tls1 = 1, tls1_1 = 1, tls1_2 = 1, tls1_3 = 1;
    int proto = 0;
    int verify = 0, require = 0, request = 1;

    dprintf("Called");

#if defined(NO_TLS1) && defined(NO_TLS1_1) && defined(NO_TLS1_2) && defined(NO_SSL3) && !defined(NO_SSL2)
#if defined(NO_TLS1) && defined(NO_TLS1_1) && defined(NO_TLS1_2) && !defined(NO_SSL3)
    ssl2 = 1;
#endif
#if defined(NO_TLS1) && defined(NO_TLS1_1) && defined(NO_TLS1_2) && defined(NO_SSL2) && !defined(NO_SSL3)
    ssl3 = 1;
#endif
#if defined(NO_TLS1)
    tls1 = 0;
#endif
#if defined(NO_TLS1_1)
    tls1_1 = 0;

    int load_private_key;
    const SSL_METHOD *method;

    dprintf("Called");

    if (!proto) {
	Tcl_AppendResult(interp, "no valid protocol selected", (char *)NULL);
	return (SSL_CTX *)0;
	return NULL;
    }

    /* create SSL context */
#if defined(NO_SSL2)
    if (ENABLED(proto, TLS_PROTO_SSL2)) {
	Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
	return (SSL_CTX *)0;
	return NULL;
    }
#endif
#if defined(NO_SSL3)
#if defined(NO_SSL3) || defined(OPENSSL_NO_SSL3) || defined(OPENSSL_NO_SSL3_METHOD)
    if (ENABLED(proto, TLS_PROTO_SSL3)) {
	Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
	return (SSL_CTX *)0;
	return NULL;
    }
#endif
#if defined(NO_TLS1)
#if defined(NO_TLS1) || defined(OPENSSL_NO_TLS1) || defined(OPENSSL_NO_TLS1_METHOD)
    if (ENABLED(proto, TLS_PROTO_TLS1)) {
	Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
	return (SSL_CTX *)0;
	return NULL;
    }
#endif
#if defined(NO_TLS1_1)
#if defined(NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1_METHOD)
    if (ENABLED(proto, TLS_PROTO_TLS1_1)) {
	Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
	return (SSL_CTX *)0;
	return NULL;
    }
#endif
#if defined(NO_TLS1_2)
#if defined(NO_TLS1_2) || defined(OPENSSL_NO_TLS1_2) || defined(OPENSSL_NO_TLS1_2_METHOD)
    if (ENABLED(proto, TLS_PROTO_TLS1_2)) {
	Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
	return (SSL_CTX *)0;
	return NULL;
    }
#endif
#if defined(NO_TLS1_3)
#if defined(NO_TLS1_3) || defined(OPENSSL_NO_TLS1_3) || defined(OPENSSL_NO_TLS1_3_METHOD)
    if (ENABLED(proto, TLS_PROTO_TLS1_3)) {
	Tcl_AppendResult(interp, "protocol not supported", (char *)NULL);
	return (SSL_CTX *)0;
	return NULL;
    }
#endif

    switch (proto) {
#if !defined(NO_SSL2)
    case TLS_PROTO_SSL2:
	method = SSLv2_method ();
	break;
#endif
#if !defined(NO_SSL3)
#if !defined(NO_SSL3) && !defined(OPENSSL_NO_SSL3) && !defined(OPENSSL_NO_SSL3_METHOD)
    case TLS_PROTO_SSL3:
	method = SSLv3_method ();
	break;
#endif
#if !defined(NO_TLS1)
#if !defined(NO_TLS1) && !defined(OPENSSL_NO_TLS1) && !defined(OPENSSL_NO_TLS1_METHOD)
    case TLS_PROTO_TLS1:
	method = TLSv1_method ();
	break;
#endif
#if !defined(NO_TLS1_1)
#if !defined(NO_TLS1_1) && !defined(OPENSSL_NO_TLS1_1) && !defined(OPENSSL_NO_TLS1_1_METHOD)
    case TLS_PROTO_TLS1_1:
	method = TLSv1_1_method ();
	break;
#endif
#if !defined(NO_TLS1_2)
#if !defined(NO_TLS1_2) && !defined(OPENSSL_NO_TLS1_2) && !defined(OPENSSL_NO_TLS1_2_METHOD)
    case TLS_PROTO_TLS1_2:
	method = TLSv1_2_method ();
	break;
#endif
#if !defined(NO_TLS1_3)
#if !defined(NO_TLS1_3) && !defined(OPENSSL_NO_TLS1_3) && !defined(OPENSSL_NO_TLS1_3_METHOD)
    case TLS_PROTO_TLS1_3:
        /*
         * The version range is constrained below,
         * after the context is created.  Use the
         * generic method here.
         */
	method = TLS_method ();
	break;
#endif
    default:
#ifdef HAVE_TLS_METHOD
        method = TLS_method ();
#else
        method = SSLv23_method ();
#endif
#if !defined(NO_SSL2)
	off |= (ENABLED(proto, TLS_PROTO_SSL2)   ? 0 : SSL_OP_NO_SSLv2);
#endif
#if !defined(NO_SSL3)
#if !defined(NO_SSL3) && !defined(OPENSSL_NO_SSL3) && !defined(OPENSSL_NO_SSL3_METHOD)
	off |= (ENABLED(proto, TLS_PROTO_SSL3)   ? 0 : SSL_OP_NO_SSLv3);
#endif
#if !defined(NO_TLS1)
#if !defined(NO_TLS1) && !defined(OPENSSL_NO_TLS1) && !defined(OPENSSL_NO_TLS1_METHOD)
	off |= (ENABLED(proto, TLS_PROTO_TLS1)   ? 0 : SSL_OP_NO_TLSv1);
#endif
#if !defined(NO_TLS1_1)
#if !defined(NO_TLS1_1) && !defined(OPENSSL_NO_TLS1_1) && !defined(OPENSSL_NO_TLS1_1_METHOD)
	off |= (ENABLED(proto, TLS_PROTO_TLS1_1) ? 0 : SSL_OP_NO_TLSv1_1);
#endif
#if !defined(NO_TLS1_2)
#if !defined(NO_TLS1_2) && !defined(OPENSSL_NO_TLS1_2) && !defined(OPENSSL_NO_TLS1_2_METHOD)
	off |= (ENABLED(proto, TLS_PROTO_TLS1_2) ? 0 : SSL_OP_NO_TLSv1_2);
#endif
#if !defined(NO_TLS1_3)
#if !defined(NO_TLS1_3) && !defined(OPENSSL_NO_TLS1_3) && !defined(OPENSSL_NO_TLS1_3_METHOD)
	off |= (ENABLED(proto, TLS_PROTO_TLS1_3) ? 0 : SSL_OP_NO_TLSv1_3);
#endif
	break;
    }

    ctx = SSL_CTX_new (method);

    /* read a Diffie-Hellman parameters file, or use the built-in one */
#ifdef OPENSSL_NO_DH
    if (DHparams != NULL) {
	Tcl_AppendResult(interp,
	    "DH parameter support not available", (char *) NULL);
	SSL_CTX_free(ctx);
	return (SSL_CTX *)0;
	return NULL;
    }
#else
    {
	DH* dh;
	if (DHparams != NULL) {
	    BIO *bio;
	    Tcl_DStringInit(&ds);
	    bio = BIO_new_file(F2N(DHparams, &ds), "r");
	    if (!bio) {
		Tcl_DStringFree(&ds);
		Tcl_AppendResult(interp,
		    "Could not find DH parameters file", (char *) NULL);
		SSL_CTX_free(ctx);
		return (SSL_CTX *)0;
		return NULL;
	    }

	    dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
	    BIO_free(bio);
	    Tcl_DStringFree(&ds);
	    if (!dh) {
		Tcl_AppendResult(interp,
		    "Could not read DH parameters from file", (char *) NULL);
		SSL_CTX_free(ctx);
		return (SSL_CTX *)0;
		return NULL;
	    }
	} else {
	    dh = get_dhParams();
	}
	SSL_CTX_set_tmp_dh(ctx, dh);
	DH_free(dh);
    }

	if (SSL_CTX_use_certificate_file(ctx, F2N( certfile, &ds),
					SSL_FILETYPE_PEM) <= 0) {
	    Tcl_DStringFree(&ds);
	    Tcl_AppendResult(interp,
			     "unable to set certificate file ", certfile, ": ",
			     REASON(), (char *) NULL);
	    SSL_CTX_free(ctx);
	    return (SSL_CTX *)0;
	    return NULL;
	}
    } else if (cert != NULL) {
	load_private_key = 1;
	if (SSL_CTX_use_certificate_ASN1(ctx, cert_len, cert) <= 0) {
	    Tcl_DStringFree(&ds);
	    Tcl_AppendResult(interp,
			     "unable to set certificate: ",
			     REASON(), (char *) NULL);
	    SSL_CTX_free(ctx);
	    return (SSL_CTX *)0;
	    return NULL;
	}
    } else {
	certfile = (char*)X509_get_default_cert_file();

	if (SSL_CTX_use_certificate_file(ctx, certfile,
					SSL_FILETYPE_PEM) <= 0) {
#if 0
	    Tcl_DStringFree(&ds);
	    Tcl_AppendResult(interp,
			     "unable to use default certificate file ", certfile, ": ",
			     REASON(), (char *) NULL);
	    SSL_CTX_free(ctx);
	    return (SSL_CTX *)0;
	    return NULL;
#endif
	}
    }

    /* set our private key */
    if (load_private_key) {
	if (keyfile == NULL && key == NULL) {

		Tcl_DStringFree(&ds);
		/* flush the passphrase which might be left in the result */
		Tcl_SetResult(interp, NULL, TCL_STATIC);
		Tcl_AppendResult(interp,
			         "unable to set public key file ", keyfile, " ",
			         REASON(), (char *) NULL);
		SSL_CTX_free(ctx);
		return (SSL_CTX *)0;
		return NULL;
	    }

	    Tcl_DStringFree(&ds);
	} else if (key != NULL) {
	    if (SSL_CTX_use_PrivateKey_ASN1(EVP_PKEY_RSA, ctx, key,key_len) <= 0) {
		Tcl_DStringFree(&ds);
		/* flush the passphrase which might be left in the result */
		Tcl_SetResult(interp, NULL, TCL_STATIC);
		Tcl_AppendResult(interp,
		                 "unable to set public key: ",
		                 REASON(), (char *) NULL);
		SSL_CTX_free(ctx);
		return (SSL_CTX *)0;
		return NULL;
	    }
	}
	/* Now we know that a key and cert have been set against
	 * the SSL context */
	if (!SSL_CTX_check_private_key(ctx)) {
	    Tcl_AppendResult(interp,
			     "private key does not match the certificate public key",
			     (char *) NULL);
	    SSL_CTX_free(ctx);
	    return (SSL_CTX *)0;
	    return NULL;
	}
    }

    /* Set verification CAs */
    Tcl_DStringInit(&ds);
    Tcl_DStringInit(&ds1);
    if (!SSL_CTX_load_verify_locations(ctx, F2N(CAfile, &ds), F2N(CAdir, &ds1)) ||
	!SSL_CTX_set_default_verify_paths(ctx)) {
#if 0
	Tcl_DStringFree(&ds);
	Tcl_DStringFree(&ds1);
	/* Don't currently care if this fails */
	Tcl_AppendResult(interp, "SSL default verify paths: ",
		REASON(), (char *) NULL);
	SSL_CTX_free(ctx);
	return (SSL_CTX *)0;
	return NULL;
#endif
    }

    /* https://sourceforge.net/p/tls/bugs/57/ */
    /* XXX:TODO: Let the user supply values here instead of something that exists on the filesystem */
    if ( CAfile != NULL ) {
        STACK_OF(X509_NAME) *certNames = SSL_load_client_CA_file( F2N(CAfile, &ds) );

#include "tls.tcl.h"
            0x00
	};

        dprintf("Called");

	/*
	 * We only support Tcl 8.4 or newer
	 * We only support Tcl 8.6 or newer
	 */
	if (
#ifdef USE_TCL_STUBS
	    Tcl_InitStubs(interp, "8.6-", 0)
#else
	    Tcl_PkgRequire(interp, "Tcl", "8.6-", 0)
#endif
	     == NULL) {
		return TCL_ERROR;
	}

	if (TlsLibInit(0) != TCL_OK) {
		Tcl_AppendResult(interp, "could not initialize SSL library", (char *)NULL);
		return TCL_ERROR;
	}

	Tcl_CreateObjCommand(interp, "tls::ciphers", CiphersObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
	Tcl_CreateObjCommand(interp, "tls::handshake", HandshakeObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
	Tcl_CreateObjCommand(interp, "tls::import", ImportObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
	Tcl_CreateObjCommand(interp, "tls::unimport", UnimportObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
	Tcl_CreateObjCommand(interp, "tls::status", StatusObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
	Tcl_CreateObjCommand(interp, "tls::version", VersionObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
	Tcl_CreateObjCommand(interp, "tls::misc", MiscObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
	Tcl_CreateObjCommand(interp, "tls::ciphers", CiphersObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::handshake", HandshakeObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::import", ImportObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::unimport", UnimportObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::status", StatusObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::version", VersionObjCmd, NULL, 0);
	Tcl_CreateObjCommand(interp, "tls::misc", MiscObjCmd, NULL, 0);

	if (interp) {
		Tcl_Eval(interp, tlsTclInitScript);
	}

	return(Tcl_PkgProvide(interp, "tls", PACKAGE_VERSION));
}

	}

	SSL_load_error_strings();
	ERR_load_crypto_strings();

	BIO_new_tcl(NULL, 0);

#if 0
	/*
	 * XXX:TODO: Remove this code and replace it with a check
	 * for enough entropy and do not try to create our own
	 * terrible entropy
	 */
    /*
     * Seed the random number generator in the SSL library,
     * using the do/while construct because of the bug note in the
     * OpenSSL FAQ at http://www.openssl.org/support/faq.html#USER1
     *
     * The crux of the problem is that Solaris 7 does not have a
     * /dev/random or /dev/urandom device so it cannot gather enough
     * entropy from the RAND_seed() when TLS initializes and refuses
     * to go further. Earlier versions of OpenSSL carried on regardless.
     */
    srand((unsigned int) time((time_t *) NULL));
    do {
	for (i = 0; i < 16; i++) {
	    rnd_seed[i] = 1 + (char) (255.0 * rand()/(RAND_MAX+1.0));
	}
	RAND_seed(rnd_seed, sizeof(rnd_seed));
    } while (RAND_status() != 1);
#endif

done:
#if defined(OPENSSL_THREADS) && defined(TCL_THREADS)
	Tcl_MutexUnlock(&init_mx);
#endif

	return(status);
}