Use tls_connection_prf() for all EAP TLS-based key derivation
tls_openssl.c is the only remaining TLS/crypto wrapper that needs the
internal PRF implementation for EAP-FAST (since
SSL_export_keying_material() is not available in older versions and does
not support server-random-before-client case). As such, it is cleaner to
assume that TLS libraries support tls_connection_prf() and move the
additional support code for the otherwise unsupported cases into
tls_openssl.c.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
diff --git a/src/crypto/tls_openssl.c b/src/crypto/tls_openssl.c
index 52db8fc..8f9bea6 100644
--- a/src/crypto/tls_openssl.c
+++ b/src/crypto/tls_openssl.c
@@ -26,6 +26,7 @@
#include "common.h"
#include "crypto.h"
+#include "sha1.h"
#include "tls.h"
#if defined(SSL_CTX_get_app_data) && defined(SSL_CTX_set_app_data)
@@ -2644,6 +2645,60 @@
}
+static int openssl_tls_prf(void *tls_ctx, struct tls_connection *conn,
+ const char *label, int server_random_first,
+ u8 *out, size_t out_len)
+{
+#ifdef CONFIG_FIPS
+ wpa_printf(MSG_ERROR, "OpenSSL: TLS keys cannot be exported in FIPS "
+ "mode");
+ return -1;
+#else /* CONFIG_FIPS */
+ SSL *ssl;
+ u8 *rnd;
+ int ret = -1;
+
+ /*
+ * TLS library did not support key generation, so get the needed TLS
+ * session parameters and use an internal implementation of TLS PRF to
+ * derive the key.
+ */
+
+ if (conn == NULL)
+ return -1;
+ ssl = conn->ssl;
+ if (ssl == NULL || ssl->s3 == NULL || ssl->session == NULL ||
+ ssl->s3->client_random == NULL || ssl->s3->server_random == NULL ||
+ ssl->session->master_key == NULL)
+ return -1;
+
+ rnd = os_malloc(2 * SSL3_RANDOM_SIZE);
+ if (rnd == NULL)
+ return -1;
+ if (server_random_first) {
+ os_memcpy(rnd, ssl->s3->server_random, SSL3_RANDOM_SIZE);
+ os_memcpy(rnd + SSL3_RANDOM_SIZE, ssl->s3->client_random,
+ SSL3_RANDOM_SIZE);
+ } else {
+ os_memcpy(rnd, ssl->s3->client_random, SSL3_RANDOM_SIZE);
+ os_memcpy(rnd + SSL3_RANDOM_SIZE, ssl->s3->server_random,
+ SSL3_RANDOM_SIZE);
+ }
+
+ /* TODO: TLSv1.2 may need another PRF. This could use something closer
+ * to SSL_export_keying_material() design. */
+ if (tls_prf_sha1_md5(ssl->session->master_key,
+ ssl->session->master_key_length,
+ label, rnd, 2 * SSL3_RANDOM_SIZE,
+ out, out_len) == 0)
+ ret = 0;
+ os_free(rnd);
+
+ return ret;
+#endif /* CONFIG_FIPS */
+}
+
+
int tls_connection_prf(void *tls_ctx, struct tls_connection *conn,
const char *label, int server_random_first,
u8 *out, size_t out_len)
@@ -2653,7 +2708,8 @@
if (conn == NULL)
return -1;
if (server_random_first)
- return -1;
+ return openssl_tls_prf(tls_ctx, conn, label,
+ server_random_first, out, out_len);
ssl = conn->ssl;
if (SSL_export_keying_material(ssl, out, out_len, label,
os_strlen(label), NULL, 0, 0) == 1) {
@@ -2661,7 +2717,8 @@
return 0;
}
#endif
- return -1;
+ return openssl_tls_prf(tls_ctx, conn, label, server_random_first,
+ out, out_len);
}
diff --git a/src/eap_common/eap_fast_common.c b/src/eap_common/eap_fast_common.c
index fceb1b0..5b41189 100644
--- a/src/eap_common/eap_fast_common.c
+++ b/src/eap_common/eap_fast_common.c
@@ -96,8 +96,7 @@
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;
+ u8 *out;
int block_size;
block_size = tls_connection_get_keyblock_size(ssl_ctx, conn);
@@ -108,37 +107,15 @@
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_prf(ssl_ctx, conn, label, 1, out, block_size + len))
+ {
+ os_free(out);
+ return NULL;
}
- 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_sha1_md5(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);
+ os_memset(out + len, 0, block_size);
return out;
-
-fail:
- os_free(rnd);
- os_free(out);
- return NULL;
}
diff --git a/src/eap_peer/eap_tls_common.c b/src/eap_peer/eap_tls_common.c
index 8710781..e5a6ee5 100644
--- a/src/eap_peer/eap_tls_common.c
+++ b/src/eap_peer/eap_tls_common.c
@@ -313,53 +313,18 @@
u8 * eap_peer_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
const char *label, size_t len)
{
-#ifndef CONFIG_FIPS
- struct tls_keys keys;
-#endif /* CONFIG_FIPS */
- u8 *rnd = NULL, *out;
+ u8 *out;
out = os_malloc(len);
if (out == NULL)
return NULL;
- /* First, try to use TLS library function for PRF, if available. */
- if (tls_connection_prf(data->ssl_ctx, data->conn, label, 0, out, len)
- == 0)
- return out;
+ if (tls_connection_prf(data->ssl_ctx, data->conn, label, 0, out, len)) {
+ os_free(out);
+ return NULL;
+ }
-#ifndef CONFIG_FIPS
- /*
- * TLS library did not support key generation, so get the needed TLS
- * session parameters and use an internal implementation of TLS PRF to
- * derive the key.
- */
- if (tls_connection_get_keys(data->ssl_ctx, data->conn, &keys))
- goto fail;
-
- if (keys.client_random == NULL || keys.server_random == NULL ||
- keys.master_key == NULL)
- goto fail;
-
- rnd = os_malloc(keys.client_random_len + keys.server_random_len);
- if (rnd == NULL)
- goto fail;
- os_memcpy(rnd, keys.client_random, keys.client_random_len);
- os_memcpy(rnd + keys.client_random_len, keys.server_random,
- keys.server_random_len);
-
- if (tls_prf_sha1_md5(keys.master_key, keys.master_key_len,
- label, rnd, keys.client_random_len +
- keys.server_random_len, out, len))
- goto fail;
-
- os_free(rnd);
return out;
-
-fail:
-#endif /* CONFIG_FIPS */
- os_free(out);
- os_free(rnd);
- return NULL;
}
diff --git a/src/eap_server/eap_server_tls_common.c b/src/eap_server/eap_server_tls_common.c
index 56916c4..09f2a82 100644
--- a/src/eap_server/eap_server_tls_common.c
+++ b/src/eap_server/eap_server_tls_common.c
@@ -100,43 +100,18 @@
u8 * eap_server_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
char *label, size_t len)
{
- struct tls_keys keys;
- u8 *rnd = NULL, *out;
+ u8 *out;
out = os_malloc(len);
if (out == NULL)
return NULL;
- if (tls_connection_prf(sm->ssl_ctx, data->conn, label, 0, out, len) ==
- 0)
- return out;
+ if (tls_connection_prf(sm->ssl_ctx, data->conn, label, 0, out, len)) {
+ os_free(out);
+ return NULL;
+ }
- if (tls_connection_get_keys(sm->ssl_ctx, data->conn, &keys))
- goto fail;
-
- if (keys.client_random == NULL || keys.server_random == NULL ||
- keys.master_key == NULL)
- goto fail;
-
- rnd = os_malloc(keys.client_random_len + keys.server_random_len);
- if (rnd == NULL)
- goto fail;
- os_memcpy(rnd, keys.client_random, keys.client_random_len);
- os_memcpy(rnd + keys.client_random_len, keys.server_random,
- keys.server_random_len);
-
- if (tls_prf_sha1_md5(keys.master_key, keys.master_key_len,
- label, rnd, keys.client_random_len +
- keys.server_random_len, out, len))
- goto fail;
-
- os_free(rnd);
return out;
-
-fail:
- os_free(out);
- os_free(rnd);
- return NULL;
}
