Add TLS-PRF using HMAC with P_SHA384 for TEAP

This version of TLS PRF is needed when using TEAP with TLS ciphersuites
that are defined to use SHA384 instead of SHA256.

Signed-off-by: Jouni Malinen <j@w1.fi>

hostapd/Android.mk

@@ -494,6 +494,8 @@ OBJS += src/eap_common/eap_teap_common.c
 TLS_FUNCS=y
 NEED_T_PRF=y
 NEED_SHA384=y
+NEED_TLS_PRF_SHA256=y
+NEED_TLS_PRF_SHA384=y
 NEED_AES_UNWRAP=y
 endif
 
@@ -923,6 +925,9 @@ endif
 ifdef NEED_TLS_PRF_SHA256
 OBJS += src/crypto/sha256-tlsprf.c
 endif
+ifdef NEED_TLS_PRF_SHA384
+OBJS += src/crypto/sha384-tlsprf.c
+endif
 ifdef NEED_HMAC_SHA256_KDF
 OBJS += src/crypto/sha256-kdf.c
 endif

hostapd/Makefile

@@ -533,6 +533,8 @@ OBJS += ../src/eap_common/eap_teap_common.o
 TLS_FUNCS=y
 NEED_T_PRF=y
 NEED_SHA384=y
+NEED_TLS_PRF_SHA256=y
+NEED_TLS_PRF_SHA384=y
 NEED_AES_UNWRAP=y
 endif
 
@@ -1068,6 +1070,9 @@ endif
 ifdef NEED_TLS_PRF_SHA256
 OBJS += ../src/crypto/sha256-tlsprf.o
 endif
+ifdef NEED_TLS_PRF_SHA384
+OBJS += ../src/crypto/sha384-tlsprf.o
+endif
 ifdef NEED_HMAC_SHA256_KDF
 OBJS += ../src/crypto/sha256-kdf.o
 endif

src/crypto/sha384-tlsprf.c

@@ -0,0 +1,71 @@
+/*
+ * TLS PRF P_SHA384
+ * Copyright (c) 2011-2019, Jouni Malinen <j@w1.fi>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "sha384.h"
+
+
+/**
+ * tls_prf_sha384 - Pseudo-Random Function for TLS v1.2 (P_SHA384, RFC 5246)
+ * @secret: Key for PRF
+ * @secret_len: Length of the key in bytes
+ * @label: A unique label for each purpose of the PRF
+ * @seed: Seed value to bind into the key
+ * @seed_len: Length of the seed
+ * @out: Buffer for the generated pseudo-random key
+ * @outlen: Number of bytes of key to generate
+ * Returns: 0 on success, -1 on failure.
+ *
+ * This function is used to derive new, cryptographically separate keys from a
+ * given key in TLS. This PRF is defined in RFC 5246, Chapter 5.
+ */
+int tls_prf_sha384(const u8 *secret, size_t secret_len, const char *label,
+		   const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
+{
+	size_t clen;
+	u8 A[SHA384_MAC_LEN];
+	u8 P[SHA384_MAC_LEN];
+	size_t pos;
+	const unsigned char *addr[3];
+	size_t len[3];
+
+	addr[0] = A;
+	len[0] = SHA384_MAC_LEN;
+	addr[1] = (unsigned char *) label;
+	len[1] = os_strlen(label);
+	addr[2] = seed;
+	len[2] = seed_len;
+
+	/*
+	 * RFC 5246, Chapter 5
+	 * A(0) = seed, A(i) = HMAC(secret, A(i-1))
+	 * P_hash = HMAC(secret, A(1) + seed) + HMAC(secret, A(2) + seed) + ..
+	 * PRF(secret, label, seed) = P_SHA384(secret, label + seed)
+	 */
+
+	if (hmac_sha384_vector(secret, secret_len, 2, &addr[1], &len[1], A) < 0)
+		return -1;
+
+	pos = 0;
+	while (pos < outlen) {
+		if (hmac_sha384_vector(secret, secret_len, 3, addr, len, P) <
+		    0 ||
+		    hmac_sha384(secret, secret_len, A, SHA384_MAC_LEN, A) < 0)
+			return -1;
+
+		clen = outlen - pos;
+		if (clen > SHA384_MAC_LEN)
+			clen = SHA384_MAC_LEN;
+		os_memcpy(out + pos, P, clen);
+		pos += clen;
+	}
+
+	return 0;
+}

src/crypto/sha384.h

@@ -20,6 +20,9 @@ int sha384_prf(const u8 *key, size_t key_len, const char *label,
 int sha384_prf_bits(const u8 *key, size_t key_len, const char *label,
 		    const u8 *data, size_t data_len, u8 *buf,
 		    size_t buf_len_bits);
+int tls_prf_sha384(const u8 *secret, size_t secret_len,
+		   const char *label, const u8 *seed, size_t seed_len,
+		   u8 *out, size_t outlen);
 int hmac_sha384_kdf(const u8 *secret, size_t secret_len,
 		    const char *label, const u8 *seed, size_t seed_len,
 		    u8 *out, size_t outlen);

wpa_supplicant/Android.mk

@@ -659,6 +659,8 @@ TLS_FUNCS=y
 CONFIG_IEEE8021X_EAPOL=y
 NEED_T_PRF=y
 NEED_SHA384=y
+NEED_TLS_PRF_SHA256=y
+NEED_TLS_PRF_SHA384=y
 endif
 
 ifdef CONFIG_EAP_PAX
@@ -1366,6 +1368,9 @@ endif
 ifdef NEED_TLS_PRF_SHA256
 SHA256OBJS += src/crypto/sha256-tlsprf.c
 endif
+ifdef NEED_TLS_PRF_SHA384
+SHA256OBJS += src/crypto/sha384-tlsprf.c
+endif
 ifdef NEED_HMAC_SHA256_KDF
 L_CFLAGS += -DCONFIG_HMAC_SHA256_KDF
 SHA256OBJS += src/crypto/sha256-kdf.c

wpa_supplicant/Makefile

@@ -686,6 +686,8 @@ TLS_FUNCS=y
 CONFIG_IEEE8021X_EAPOL=y
 NEED_T_PRF=y
 NEED_SHA384=y
+NEED_TLS_PRF_SHA256=y
+NEED_TLS_PRF_SHA384=y
 endif
 
 ifdef CONFIG_EAP_PAX
@@ -1501,6 +1503,9 @@ endif
 ifdef NEED_TLS_PRF_SHA256
 SHA256OBJS += ../src/crypto/sha256-tlsprf.o
 endif
+ifdef NEED_TLS_PRF_SHA384
+SHA256OBJS += ../src/crypto/sha384-tlsprf.o
+endif
 ifdef NEED_HMAC_SHA256_KDF
 CFLAGS += -DCONFIG_HMAC_SHA256_KDF
 OBJS += ../src/crypto/sha256-kdf.o