EAP-FAST: Moved common peer/server functionality into a shared file

2 files changed, 283 insertions, 0 deletions

diff --git a/src/eap_common/eap_fast_common.c b/src/eap_common/eap_fast_common.c
index 039c40e..7b9207f 100644
--- a/src/eap_common/eap_fast_common.c
+++ b/src/eap_common/eap_fast_common.c
@@ -15,6 +15,10 @@
 #include "includes.h"
 
 #include "common.h"
+#include "sha1.h"
+#include "tls.h"
+#include "eap_defs.h"
+#include "eap_tlv_common.h"
 #include "eap_fast_common.h"
 
 
@@ -41,3 +45,260 @@ void eap_fast_put_tlv_buf(struct wpabuf *buf, u16 type,
 	eap_fast_put_tlv_hdr(buf, type, wpabuf_len(data));
 	wpabuf_put_buf(buf, data);
 }
+
+
+struct wpabuf * eap_fast_tlv_eap_payload(struct wpabuf *buf)
+{
+	struct wpabuf *e;
+
+	if (buf == NULL)
+		return NULL;
+
+	/* Encapsulate EAP packet in EAP-Payload TLV */
+	wpa_printf(MSG_DEBUG, "EAP-FAST: Add EAP-Payload TLV");
+	e = wpabuf_alloc(sizeof(struct pac_tlv_hdr) + wpabuf_len(buf));
+	if (e == NULL) {
+		wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to allocate memory "
+			   "for TLV encapsulation");
+		wpabuf_free(buf);
+		return NULL;
+	}
+	eap_fast_put_tlv_buf(e,
+			     EAP_TLV_TYPE_MANDATORY | EAP_TLV_EAP_PAYLOAD_TLV,
+			     buf);
+	wpabuf_free(buf);
+	return e;
+}
+
+
+void eap_fast_derive_master_secret(const u8 *pac_key, const u8 *server_random,
+				   const u8 *client_random, u8 *master_secret)
+{
+#define TLS_RANDOM_LEN 32
+#define TLS_MASTER_SECRET_LEN 48
+	u8 seed[2 * TLS_RANDOM_LEN];
+
+	wpa_hexdump(MSG_DEBUG, "EAP-FAST: client_random",
+		    client_random, TLS_RANDOM_LEN);
+	wpa_hexdump(MSG_DEBUG, "EAP-FAST: server_random",
+		    server_random, TLS_RANDOM_LEN);
+
+	/*
+	 * RFC 4851, Section 5.1:
+	 * master_secret = T-PRF(PAC-Key, "PAC to master secret label hash", 
+	 *                       server_random + client_random, 48)
+	 */
+	os_memcpy(seed, server_random, TLS_RANDOM_LEN);
+	os_memcpy(seed + TLS_RANDOM_LEN, client_random, TLS_RANDOM_LEN);
+	sha1_t_prf(pac_key, EAP_FAST_PAC_KEY_LEN,
+		   "PAC to master secret label hash",
+		   seed, sizeof(seed), master_secret, TLS_MASTER_SECRET_LEN);
+
+	wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: master_secret",
+			master_secret, TLS_MASTER_SECRET_LEN);
+}
+
+
+u8 * eap_fast_derive_key(void *ssl_ctx, struct tls_connection *conn,
+			 const char *label, size_t len)
+{
+	struct tls_keys keys;
+	u8 *rnd = NULL, *out;
+	int block_size;
+
+	block_size = tls_connection_get_keyblock_size(ssl_ctx, conn);
+	if (block_size < 0)
+		return NULL;
+
+	out = os_malloc(block_size + len);
+	if (out == NULL)
+		return NULL;
+
+	if (tls_connection_prf(ssl_ctx, conn, label, 1, out, block_size + len)
+	    == 0) {
+		os_memmove(out, out + block_size, len);
+		return out;
+	}
+
+	if (tls_connection_get_keys(ssl_ctx, conn, &keys))
+		goto fail;
+
+	rnd = os_malloc(keys.client_random_len + keys.server_random_len);
+	if (rnd == NULL)
+		goto fail;
+
+	os_memcpy(rnd, keys.server_random, keys.server_random_len);
+	os_memcpy(rnd + keys.server_random_len, keys.client_random,
+		  keys.client_random_len);
+
+	wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: master_secret for key "
+			"expansion", keys.master_key, keys.master_key_len);
+	if (tls_prf(keys.master_key, keys.master_key_len,
+		    label, rnd, keys.client_random_len +
+		    keys.server_random_len, out, block_size + len))
+		goto fail;
+	os_free(rnd);
+	os_memmove(out, out + block_size, len);
+	return out;
+
+fail:
+	os_free(rnd);
+	os_free(out);
+	return NULL;
+}
+
+
+void eap_fast_derive_eap_msk(const u8 *simck, u8 *msk)
+{
+	/*
+	 * RFC 4851, Section 5.4: EAP Master Session Key Generation
+	 * MSK = T-PRF(S-IMCK[j], "Session Key Generating Function", 64)
+	 */
+
+	sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
+		   "Session Key Generating Function", (u8 *) "", 0,
+		   msk, EAP_FAST_KEY_LEN);
+	wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (MSK)",
+			msk, EAP_FAST_KEY_LEN);
+}
+
+
+void eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk)
+{
+	/*
+	 * RFC 4851, Section 5.4: EAP Master Session Key Genreration
+	 * EMSK = T-PRF(S-IMCK[j],
+	 *        "Extended Session Key Generating Function", 64)
+	 */
+
+	sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
+		   "Extended Session Key Generating Function", (u8 *) "", 0,
+		   emsk, EAP_EMSK_LEN);
+	wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (EMSK)",
+			emsk, EAP_EMSK_LEN);
+}
+
+
+int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv,
+		       int tlv_type, u8 *pos, int len)
+{
+	switch (tlv_type) {
+	case EAP_TLV_EAP_PAYLOAD_TLV:
+		wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: EAP-Payload TLV",
+			    pos, len);
+		if (tlv->eap_payload_tlv) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
+				   "EAP-Payload TLV in the message");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			return -2;
+		}
+		tlv->eap_payload_tlv = pos;
+		tlv->eap_payload_tlv_len = len;
+		break;
+	case EAP_TLV_RESULT_TLV:
+		wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Result TLV", pos, len);
+		if (tlv->result) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
+				   "Result TLV in the message");
+			tlv->result = EAP_TLV_RESULT_FAILURE;
+			return -2;
+		}
+		if (len < 2) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
+				   "Result TLV");
+			tlv->result = EAP_TLV_RESULT_FAILURE;
+			break;
+		}
+		tlv->result = WPA_GET_BE16(pos);
+		if (tlv->result != EAP_TLV_RESULT_SUCCESS &&
+		    tlv->result != EAP_TLV_RESULT_FAILURE) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Result %d",
+				   tlv->result);
+			tlv->result = EAP_TLV_RESULT_FAILURE;
+		}
+		wpa_printf(MSG_DEBUG, "EAP-FAST: Result: %s",
+			   tlv->result == EAP_TLV_RESULT_SUCCESS ?
+			   "Success" : "Failure");
+		break;
+	case EAP_TLV_INTERMEDIATE_RESULT_TLV:
+		wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Intermediate Result TLV",
+			    pos, len);
+		if (len < 2) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
+				   "Intermediate-Result TLV");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			break;
+		}
+		if (tlv->iresult) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
+				   "Intermediate-Result TLV in the message");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			return -2;
+		}
+		tlv->iresult = WPA_GET_BE16(pos);
+		if (tlv->iresult != EAP_TLV_RESULT_SUCCESS &&
+		    tlv->iresult != EAP_TLV_RESULT_FAILURE) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Intermediate "
+				   "Result %d", tlv->iresult);
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+		}
+		wpa_printf(MSG_DEBUG, "EAP-FAST: Intermediate Result: %s",
+			   tlv->iresult == EAP_TLV_RESULT_SUCCESS ?
+			   "Success" : "Failure");
+		break;
+	case EAP_TLV_CRYPTO_BINDING_TLV:
+		wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV",
+			    pos, len);
+		if (tlv->crypto_binding) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
+				   "Crypto-Binding TLV in the message");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			return -2;
+		}
+		tlv->crypto_binding_len = sizeof(struct eap_tlv_hdr) + len;
+		if (tlv->crypto_binding_len < sizeof(*tlv->crypto_binding)) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
+				   "Crypto-Binding TLV");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			return -2;
+		}
+		tlv->crypto_binding = (struct eap_tlv_crypto_binding__tlv *)
+			(pos - sizeof(struct eap_tlv_hdr));
+		break;
+	case EAP_TLV_REQUEST_ACTION_TLV:
+		wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Request-Action TLV",
+			    pos, len);
+		if (tlv->request_action) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
+				   "Request-Action TLV in the message");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			return -2;
+		}
+		if (len < 2) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
+				   "Request-Action TLV");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			break;
+		}
+		tlv->request_action = WPA_GET_BE16(pos);
+		wpa_printf(MSG_DEBUG, "EAP-FAST: Request-Action: %d",
+			   tlv->request_action);
+		break;
+	case EAP_TLV_PAC_TLV:
+		wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: PAC TLV", pos, len);
+		if (tlv->pac) {
+			wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
+				   "PAC TLV in the message");
+			tlv->iresult = EAP_TLV_RESULT_FAILURE;
+			return -2;
+		}
+		tlv->pac = pos;
+		tlv->pac_len = len;
+		break;
+	default:
+		/* Unknown TLV */
+		return -1;
+	}
+
+	return 0;
+}
diff --git a/src/eap_common/eap_fast_common.h b/src/eap_common/eap_fast_common.h
index e69b7a0..8bb767b 100644
--- a/src/eap_common/eap_fast_common.h
+++ b/src/eap_common/eap_fast_common.h
@@ -84,11 +84,33 @@ struct eap_fast_key_block_provisioning {
 
 
 struct wpabuf;
+struct tls_connection;
+
+struct eap_fast_tlv_parse {
+	u8 *eap_payload_tlv;
+	size_t eap_payload_tlv_len;
+	struct eap_tlv_crypto_binding__tlv *crypto_binding;
+	size_t crypto_binding_len;
+	int iresult;
+	int result;
+	int request_action;
+	u8 *pac;
+	size_t pac_len;
+};
 
 void eap_fast_put_tlv_hdr(struct wpabuf *buf, u16 type, u16 len);
 void eap_fast_put_tlv(struct wpabuf *buf, u16 type, const void *data,
 		      u16 len);
 void eap_fast_put_tlv_buf(struct wpabuf *buf, u16 type,
 			  const struct wpabuf *data);
+struct wpabuf * eap_fast_tlv_eap_payload(struct wpabuf *buf);
+void eap_fast_derive_master_secret(const u8 *pac_key, const u8 *server_random,
+				   const u8 *client_random, u8 *master_secret);
+u8 * eap_fast_derive_key(void *ssl_ctx, struct tls_connection *conn,
+			 const char *label, size_t len);
+void eap_fast_derive_eap_msk(const u8 *simck, u8 *msk);
+void eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk);
+int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv,
+		       int tlv_type, u8 *pos, int len);
 
 #endif /* EAP_FAST_H */