From 32f4760664c53db6312a425e73bac41d1e88f366 Mon Sep 17 00:00:00 2001
From: Jouni Malinen <j@w1.fi>
Date: Sat, 16 Mar 2019 18:40:49 +0200
Subject: [PATCH] TLS: Add support for RFC 5705 TLS exporter context with
internal TLS
Use the provided context, if any, to generate the seed for TLS PRF.
Signed-off-by: Jouni Malinen <j@w1.fi>
---
src/crypto/tls_internal.c | 22 +++++++++++-----------
src/tls/tlsv1_client.c | 34 +++++++++++++++++++++++++++++-----
src/tls/tlsv1_client.h | 3 ++-
src/tls/tlsv1_server.c | 34 +++++++++++++++++++++++++++++-----
src/tls/tlsv1_server.h | 3 ++-
5 files changed, 73 insertions(+), 23 deletions(-)
diff --git a/src/crypto/tls_internal.c b/src/crypto/tls_internal.c
index 50a7b300d..8095b43bd 100644
--- a/src/crypto/tls_internal.c
+++ b/src/crypto/tls_internal.c
@@ -1,6 +1,6 @@
/*
* TLS interface functions and an internal TLS implementation
- * Copyright (c) 2004-2011, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2004-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@@ -412,7 +412,8 @@ static int tls_get_keyblock_size(struct tls_connection *conn)
static int tls_connection_prf(void *tls_ctx, struct tls_connection *conn,
- const char *label, int server_random_first,
+ const char *label, const u8 *context,
+ size_t context_len, int server_random_first,
int skip_keyblock, u8 *out, size_t out_len)
{
int ret = -1, skip = 0;
@@ -431,15 +432,15 @@ static int tls_connection_prf(void *tls_ctx, struct tls_connection *conn,
#ifdef CONFIG_TLS_INTERNAL_CLIENT
if (conn->client) {
- ret = tlsv1_client_prf(conn->client, label,
- server_random_first,
+ ret = tlsv1_client_prf(conn->client, label, context,
+ context_len, server_random_first,
_out, skip + out_len);
}
#endif /* CONFIG_TLS_INTERNAL_CLIENT */
#ifdef CONFIG_TLS_INTERNAL_SERVER
if (conn->server) {
- ret = tlsv1_server_prf(conn->server, label,
- server_random_first,
+ ret = tlsv1_server_prf(conn->server, label, context,
+ context_len, server_random_first,
_out, skip + out_len);
}
#endif /* CONFIG_TLS_INTERNAL_SERVER */
@@ -455,17 +456,16 @@ int tls_connection_export_key(void *tls_ctx, struct tls_connection *conn,
const char *label, const u8 *context,
size_t context_len, u8 *out, size_t out_len)
{
- if (context)
- return -1;
- return tls_connection_prf(tls_ctx, conn, label, 0, 0, out, out_len);
+ return tls_connection_prf(tls_ctx, conn, label, context, context_len,
+ 0, 0, out, out_len);
}
int tls_connection_get_eap_fast_key(void *tls_ctx, struct tls_connection *conn,
u8 *out, size_t out_len)
{
- return tls_connection_prf(tls_ctx, conn, "key expansion", 1, 1, out,
- out_len);
+ return tls_connection_prf(tls_ctx, conn, "key expansion", NULL, 0,
+ 1, 1, out, out_len);
}
diff --git a/src/tls/tlsv1_client.c b/src/tls/tlsv1_client.c
index 76e19746b..a147a54a3 100644
--- a/src/tls/tlsv1_client.c
+++ b/src/tls/tlsv1_client.c
@@ -1,6 +1,6 @@
/*
* TLS v1.0/v1.1/v1.2 client (RFC 2246, RFC 4346, RFC 5246)
- * Copyright (c) 2006-2015, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2006-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@@ -514,6 +514,8 @@ int tlsv1_client_established(struct tlsv1_client *conn)
* tlsv1_client_prf - Use TLS-PRF to derive keying material
* @conn: TLSv1 client connection data from tlsv1_client_init()
* @label: Label (e.g., description of the key) for PRF
+ * @context: Optional extra upper-layer context (max len 2^16)
+ * @context_len: The length of the context value
* @server_random_first: seed is 0 = client_random|server_random,
* 1 = server_random|client_random
* @out: Buffer for output data from TLS-PRF
@@ -521,13 +523,26 @@ int tlsv1_client_established(struct tlsv1_client *conn)
* Returns: 0 on success, -1 on failure
*/
int tlsv1_client_prf(struct tlsv1_client *conn, const char *label,
+ const u8 *context, size_t context_len,
int server_random_first, u8 *out, size_t out_len)
{
- u8 seed[2 * TLS_RANDOM_LEN];
+ u8 *seed, *pos;
+ size_t seed_len = 2 * TLS_RANDOM_LEN;
+ int res;
if (conn->state != ESTABLISHED)
return -1;
+ if (context_len > 65535)
+ return -1;
+
+ if (context)
+ seed_len += 2 + context_len;
+
+ seed = os_malloc(seed_len);
+ if (!seed)
+ return -1;
+
if (server_random_first) {
os_memcpy(seed, conn->server_random, TLS_RANDOM_LEN);
os_memcpy(seed + TLS_RANDOM_LEN, conn->client_random,
@@ -538,9 +553,18 @@ int tlsv1_client_prf(struct tlsv1_client *conn, const char *label,
TLS_RANDOM_LEN);
}
- return tls_prf(conn->rl.tls_version,
- conn->master_secret, TLS_MASTER_SECRET_LEN,
- label, seed, 2 * TLS_RANDOM_LEN, out, out_len);
+ if (context) {
+ pos = seed + 2 * TLS_RANDOM_LEN;
+ WPA_PUT_BE16(pos, context_len);
+ pos += 2;
+ os_memcpy(pos, context, context_len);
+ }
+
+ res = tls_prf(conn->rl.tls_version,
+ conn->master_secret, TLS_MASTER_SECRET_LEN,
+ label, seed, seed_len, out, out_len);
+ os_free(seed);
+ return res;
}
diff --git a/src/tls/tlsv1_client.h b/src/tls/tlsv1_client.h
index 40fa6c7fb..7fcc256f1 100644
--- a/src/tls/tlsv1_client.h
+++ b/src/tls/tlsv1_client.h
@@ -1,6 +1,6 @@
/*
* TLS v1.0/v1.1/v1.2 client (RFC 2246, RFC 4346, RFC 5246)
- * Copyright (c) 2006-2011, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2006-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@@ -19,6 +19,7 @@ struct tlsv1_client * tlsv1_client_init(void);
void tlsv1_client_deinit(struct tlsv1_client *conn);
int tlsv1_client_established(struct tlsv1_client *conn);
int tlsv1_client_prf(struct tlsv1_client *conn, const char *label,
+ const u8 *context, size_t context_len,
int server_random_first, u8 *out, size_t out_len);
u8 * tlsv1_client_handshake(struct tlsv1_client *conn,
const u8 *in_data, size_t in_len,
diff --git a/src/tls/tlsv1_server.c b/src/tls/tlsv1_server.c
index 4759509e5..12dcc859a 100644
--- a/src/tls/tlsv1_server.c
+++ b/src/tls/tlsv1_server.c
@@ -1,6 +1,6 @@
/*
* TLS v1.0/v1.1/v1.2 server (RFC 2246, RFC 4346, RFC 5246)
- * Copyright (c) 2006-2014, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2006-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@@ -462,6 +462,8 @@ int tlsv1_server_established(struct tlsv1_server *conn)
* tlsv1_server_prf - Use TLS-PRF to derive keying material
* @conn: TLSv1 server connection data from tlsv1_server_init()
* @label: Label (e.g., description of the key) for PRF
+ * @context: Optional extra upper-layer context (max len 2^16)
+ * @context_len: The length of the context value
* @server_random_first: seed is 0 = client_random|server_random,
* 1 = server_random|client_random
* @out: Buffer for output data from TLS-PRF
@@ -469,13 +471,26 @@ int tlsv1_server_established(struct tlsv1_server *conn)
* Returns: 0 on success, -1 on failure
*/
int tlsv1_server_prf(struct tlsv1_server *conn, const char *label,
+ const u8 *context, size_t context_len,
int server_random_first, u8 *out, size_t out_len)
{
- u8 seed[2 * TLS_RANDOM_LEN];
+ u8 *seed, *pos;
+ size_t seed_len = 2 * TLS_RANDOM_LEN;
+ int res;
if (conn->state != ESTABLISHED)
return -1;
+ if (context_len > 65535)
+ return -1;
+
+ if (context)
+ seed_len += 2 + context_len;
+
+ seed = os_malloc(seed_len);
+ if (!seed)
+ return -1;
+
if (server_random_first) {
os_memcpy(seed, conn->server_random, TLS_RANDOM_LEN);
os_memcpy(seed + TLS_RANDOM_LEN, conn->client_random,
@@ -486,9 +501,18 @@ int tlsv1_server_prf(struct tlsv1_server *conn, const char *label,
TLS_RANDOM_LEN);
}
- return tls_prf(conn->rl.tls_version,
- conn->master_secret, TLS_MASTER_SECRET_LEN,
- label, seed, 2 * TLS_RANDOM_LEN, out, out_len);
+ if (context) {
+ pos = seed + 2 * TLS_RANDOM_LEN;
+ WPA_PUT_BE16(pos, context_len);
+ pos += 2;
+ os_memcpy(pos, context, context_len);
+ }
+
+ res = tls_prf(conn->rl.tls_version,
+ conn->master_secret, TLS_MASTER_SECRET_LEN,
+ label, seed, seed_len, out, out_len);
+ os_free(seed);
+ return res;
}
diff --git a/src/tls/tlsv1_server.h b/src/tls/tlsv1_server.h
index c3fd37eb0..c9c0875ca 100644
--- a/src/tls/tlsv1_server.h
+++ b/src/tls/tlsv1_server.h
@@ -1,6 +1,6 @@
/*
* TLS v1.0/v1.1/v1.2 server (RFC 2246, RFC 4346, RFC 5246)
- * Copyright (c) 2006-2011, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2006-2019, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@@ -19,6 +19,7 @@ struct tlsv1_server * tlsv1_server_init(struct tlsv1_credentials *cred);
void tlsv1_server_deinit(struct tlsv1_server *conn);
int tlsv1_server_established(struct tlsv1_server *conn);
int tlsv1_server_prf(struct tlsv1_server *conn, const char *label,
+ const u8 *context, size_t context_len,
int server_random_first, u8 *out, size_t out_len);
u8 * tlsv1_server_handshake(struct tlsv1_server *conn,
const u8 *in_data, size_t in_len, size_t *out_len);