Reinstate support for TPM2 'TSS2 KEY BLOB' support with GnuTLS

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

gnutls.c

@@ -1320,7 +1320,8 @@ static int load_certificate(struct openconnect_info *vpninfo)
 	}
 
 	/* Is it a PEM file with a TPM key blob? */
-	if (strstr((char *)fdata.data, "-----BEGIN TSS2 PRIVATE KEY-----")) {
+	if (strstr((char *)fdata.data, "-----BEGIN TSS2 PRIVATE KEY-----") ||
+	    strstr((char *)fdata.data, "-----BEGIN TSS2 KEY BLOB-----")) {
 #ifndef HAVE_TSS2
 		vpn_progress(vpninfo, PRG_ERR,
 			     _("This version of OpenConnect was built without TPM2 support\n"));

gnutls.h

@@ -32,7 +32,8 @@ int load_tpm2_key(struct openconnect_info *vpninfo, gnutls_datum_t *fdata,
 		 gnutls_privkey_t *pkey, gnutls_datum_t *pkey_sig);
 void release_tpm2_ctx(struct openconnect_info *info);
 int install_tpm2_key(struct openconnect_info *vpninfo, gnutls_privkey_t *pkey, gnutls_datum_t *pkey_sig,
-		     unsigned int parent, int emptyauth, gnutls_datum_t *privdata, gnutls_datum_t *pubdata);
+		     unsigned int parent, int emptyauth, int legacy,
+		     gnutls_datum_t *privdata, gnutls_datum_t *pubdata);
 
 int tpm2_rsa_sign_hash_fn(gnutls_privkey_t key, gnutls_sign_algorithm_t algo,
 			  void *_vpninfo, unsigned int flags,

gnutls_tpm2.c

@@ -51,6 +51,21 @@ const asn1_static_node tpmkey_asn1_tab[] = {
   { NULL, 0, NULL }
 };
 
+const asn1_static_node tpmkey_asn1_tab_old[] = {
+  { "TPMKey", 536875024, NULL },
+  { NULL, 1073741836, NULL },
+  { "TPMKey", 536870917, NULL },
+  { "type", 1073741836, NULL },
+  { "emptyAuth", 1610637316, NULL },
+  { NULL, 2056, "0"},
+  { "parent", 1610637315, NULL },
+  { NULL, 2056, "1"},
+  { "pubkey", 1610637319, NULL },
+  { NULL, 2056, "2"},
+  { "privkey", 7, NULL },
+  { NULL, 0, NULL }
+};
+
 
 #if GNUTLS_VERSION_NUMBER < 0x030600
 static int tpm2_rsa_sign_fn(gnutls_privkey_t key, void *_vpninfo,
@@ -168,16 +183,22 @@ int load_tpm2_key(struct openconnect_info *vpninfo, gnutls_datum_t *fdata,
 	int emptyauth = 0;
 	unsigned int parent;
 	int err, ret = -EINVAL;
+	const asn1_static_node *asn1tab;
 
 	err = gnutls_pem_base64_decode_alloc("TSS2 PRIVATE KEY", fdata, &asn1);
-	if (err) {
-		vpn_progress(vpninfo, PRG_ERR,
-			     _("Error decoding TSS2 key blob: %s\n"),
-			     gnutls_strerror(err));
-		return -EINVAL;
+	if (!err) {
+		asn1tab = tpmkey_asn1_tab;
+	} else {
+		if (gnutls_pem_base64_decode_alloc("TSS2 KEY BLOB", fdata, &asn1)) {
+			/* Report the first error */
+			vpn_progress(vpninfo, PRG_ERR,
+				     _("Error decoding TSS2 key blob: %s\n"),
+				     gnutls_strerror(err));
+			return -EINVAL;
+		}
+		asn1tab = tpmkey_asn1_tab_old;
 	}
-
-	err = asn1_array2tree(tpmkey_asn1_tab, &tpmkey_def, NULL);
+	err = asn1_array2tree(asn1tab, &tpmkey_def, NULL);
 	if (err != ASN1_SUCCESS) {
 		vpn_progress(vpninfo, PRG_ERR,
 			     _("Failed to create ASN.1 type for TPM2: %s\n"),
@@ -243,7 +264,8 @@ int load_tpm2_key(struct openconnect_info *vpninfo, gnutls_datum_t *fdata,
 
 	/* Now we've extracted what we need from the ASN.1, invoke the
 	 * actual TPM2 code (whichever implementation we end up with */
-	ret = install_tpm2_key(vpninfo, pkey, pkey_sig, parent, emptyauth, &privdata, &pubdata);
+	ret = install_tpm2_key(vpninfo, pkey, pkey_sig, parent, emptyauth,
+			       asn1tab == tpmkey_asn1_tab_old, &privdata, &pubdata);
 	if (ret < 0)
 		goto out_tpmkey;
 

gnutls_tpm2_esys.c

@@ -66,6 +66,7 @@ struct oc_tpm2_ctx {
 	TPM2B_DIGEST ownerauth;
 	unsigned int need_userauth:1;
 	unsigned int need_ownerauth:1;
+	unsigned int legacy_srk:1;
 	unsigned int parent;
 };
 
@@ -106,6 +107,41 @@ static TPM2B_PUBLIC primaryTemplate = {
 	}
 };
 
+static TPM2B_PUBLIC primaryTemplate_legacy = {
+	.publicArea = {
+		.type = TPM2_ALG_ECC,
+		.nameAlg = TPM2_ALG_SHA256,
+		.objectAttributes = (TPMA_OBJECT_USERWITHAUTH |
+				     TPMA_OBJECT_RESTRICTED |
+				     TPMA_OBJECT_DECRYPT |
+				     TPMA_OBJECT_NODA |
+				     TPMA_OBJECT_SENSITIVEDATAORIGIN),
+		.authPolicy = {
+			.size = 0,
+		},
+		.parameters.eccDetail = {
+			.symmetric = {
+				.algorithm = TPM2_ALG_AES,
+				.keyBits.aes = 128,
+				.mode.aes = TPM2_ALG_CFB,
+			},
+			.scheme = {
+				.scheme = TPM2_ALG_NULL,
+				.details = {}
+			},
+			.curveID = TPM2_ECC_NIST_P256,
+			.kdf = {
+				.scheme = TPM2_ALG_NULL,
+				.details = {}
+			},
+		},
+		.unique.ecc = {
+			.x.size = 0,
+			.y.size = 0
+		}
+	}
+};
+
 static TPM2B_SENSITIVE_CREATE primarySensitive = {
 	.sensitive = {
 		.userAuth = {
@@ -175,7 +211,8 @@ static int init_tpm2_primary(struct openconnect_info *vpninfo,
 	}
 	r = Esys_CreatePrimary(ctx, hierarchy,
 			       ESYS_TR_PASSWORD, ESYS_TR_NONE, ESYS_TR_NONE,
-			       &primarySensitive, &primaryTemplate,
+			       &primarySensitive,
+			       vpninfo->tpm2->legacy_srk ? &primaryTemplate_legacy : &primaryTemplate,
 			       &allOutsideInfo, &allCreationPCR,
 			       primaryHandle, NULL, NULL, NULL, NULL);
 	if (r == KEY_AUTH_FAILED) {
@@ -480,7 +517,7 @@ int tpm2_ec_sign_hash_fn(gnutls_privkey_t key, gnutls_sign_algorithm_t algo,
 }
 
 int install_tpm2_key(struct openconnect_info *vpninfo, gnutls_privkey_t *pkey, gnutls_datum_t *pkey_sig,
-		     unsigned int parent, int emptyauth, gnutls_datum_t *privdata, gnutls_datum_t *pubdata)
+		     unsigned int parent, int emptyauth, int legacy, gnutls_datum_t *privdata, gnutls_datum_t *pubdata)
 {
 	TSS2_RC r;
 
@@ -517,6 +554,7 @@ int install_tpm2_key(struct openconnect_info *vpninfo, gnutls_privkey_t *pkey, g
 	}
 
 	vpninfo->tpm2->need_userauth = !emptyauth;
+	vpninfo->tpm2->legacy_srk = legacy;
 
 	switch(vpninfo->tpm2->pub.publicArea.type) {
 	case TPM2_ALG_RSA: return GNUTLS_PK_RSA;

gnutls_tpm2_ibm.c

@@ -40,6 +40,7 @@ struct oc_tpm2_ctx {
 	TPM2B_PRIVATE priv;
 	char *parent_pass, *key_pass;
 	unsigned int need_userauth:1;
+	unsigned int legacy_srk:1;
 	unsigned int parent;
 };
 
@@ -188,7 +189,8 @@ static void tpm2_flush_srk(TSS_CONTEXT *tssContext, TPM_HANDLE hSRK)
 
 
 static TPM_RC tpm2_load_srk(TSS_CONTEXT *tssContext, TPM_HANDLE *h,
-			    const char *auth, TPM_HANDLE hierarchy)
+			    const char *auth, TPM_HANDLE hierarchy,
+			    int legacy_srk)
 {
 	TPM_RC rc;
 	CreatePrimary_In in;
@@ -215,13 +217,15 @@ static TPM_RC tpm2_load_srk(TSS_CONTEXT *tssContext, TPM_HANDLE *h,
 	in.inPublic.publicArea.type = TPM_ALG_ECC;
 	in.inPublic.publicArea.nameAlg = TPM_ALG_SHA256;
 	in.inPublic.publicArea.objectAttributes.val =
-		TPMA_OBJECT_FIXEDPARENT |
-		TPMA_OBJECT_FIXEDTPM |
 		TPMA_OBJECT_NODA |
 		TPMA_OBJECT_SENSITIVEDATAORIGIN |
 		TPMA_OBJECT_USERWITHAUTH |
 		TPMA_OBJECT_DECRYPT |
 		TPMA_OBJECT_RESTRICTED;
+	if (!legacy_srk)
+		in.inPublic.publicArea.objectAttributes.val |=
+			TPMA_OBJECT_FIXEDPARENT | TPMA_OBJECT_FIXEDTPM;
+
 	in.inPublic.publicArea.parameters.eccDetail.symmetric.algorithm = TPM_ALG_AES;
 	in.inPublic.publicArea.parameters.eccDetail.symmetric.keyBits.aes = 128;
 	in.inPublic.publicArea.parameters.eccDetail.symmetric.mode.aes = TPM_ALG_CFB;
@@ -295,7 +299,7 @@ static TPM_HANDLE tpm2_load_key(struct openconnect_info *vpninfo, TSS_CONTEXT **
 		in.parentHandle = vpninfo->tpm2->parent;
 	} else {
 	reauth_srk:
-		rc = tpm2_load_srk(tssContext, &in.parentHandle, pass, vpninfo->tpm2->parent);
+		rc = tpm2_load_srk(tssContext, &in.parentHandle, pass, vpninfo->tpm2->parent, vpninfo->tpm2->legacy_srk);
 		if (rc == KEY_AUTH_FAILED) {
 			free_pass(&pass);
 			if (!request_passphrase(vpninfo, "openconnect_tpm2_hierarchy", &pass,
@@ -511,7 +515,8 @@ int tpm2_ec_sign_hash_fn(gnutls_privkey_t key, gnutls_sign_algorithm_t algo,
 }
 
 int install_tpm2_key(struct openconnect_info *vpninfo, gnutls_privkey_t *pkey, gnutls_datum_t *pkey_sig,
-		     unsigned int parent, int emptyauth, gnutls_datum_t *privdata, gnutls_datum_t *pubdata)
+		     unsigned int parent, int emptyauth, int legacy,
+		     gnutls_datum_t *privdata, gnutls_datum_t *pubdata)
 {
 	TPM_RC rc;
 	BYTE *der;
@@ -531,6 +536,7 @@ int install_tpm2_key(struct openconnect_info *vpninfo, gnutls_privkey_t *pkey, g
 
 	vpninfo->tpm2->parent = parent;
 	vpninfo->tpm2->need_userauth = !emptyauth;
+	vpninfo->tpm2->legacy_srk = legacy;
 
 	der = privdata->data;
 	dersize = privdata->size;