Make PSK_LEN configurable and adjust PMS size
diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index e83518a..d43365f 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -2154,6 +2154,7 @@
/* SSL options */
//#define SSL_MAX_CONTENT_LEN 16384 /**< Size of the input / output buffer */
//#define SSL_DEFAULT_TICKET_LIFETIME 86400 /**< Lifetime of session tickets (if enabled) */
+//#define POLARSSL_PSK_MAX_LEN 32 /**< Max size of TLS pre-shared keys, in bytes (default 256 bits) */
/**
* Complete list of ciphersuites to use, in order of preference.
diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index 9db0fc6..f1de499 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -34,6 +34,7 @@
#endif
#include "net.h"
#include "bignum.h"
+#include "ecp.h"
#include "ssl_ciphersuites.h"
@@ -409,12 +410,43 @@
/*
* Size defines
*/
-#if !defined(POLARSSL_MPI_MAX_SIZE)
-#define POLARSSL_PREMASTER_SIZE 512
-#else
-#define POLARSSL_PREMASTER_SIZE POLARSSL_MPI_MAX_SIZE
+#if !defined(POLARSSL_PSK_MAX_LEN)
+#define POLARSSL_PSK_MAX_LEN 32 /* 256 bits */
#endif
+/* Dummy type used only for its size */
+union _ssl_premaster_secret
+{
+#if defined(POLARSSL_KEY_EXCHANGE_RSA_ENABLED)
+ unsigned char _pms_rsa[48]; /* RFC 5246 8.1.1 */
+#endif
+#if defined(POLARSSL_KEY_EXCHANGE_DHE_RSA_ENABLED)
+ unsigned char _pms_dhm[POLARSSL_MPI_MAX_SIZE]; /* RFC 5246 8.1.2 */
+#endif
+#if defined(POLARSSL_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
+ defined(POLARSSL_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
+ defined(POLARSSL_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
+ defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+ unsigned char _pms_ecdh[POLARSSL_ECP_MAX_BYTES]; /* RFC 4492 5.10 */
+#endif
+#if defined(POLARSSL_KEY_EXCHANGE_PSK_ENABLED)
+ unsigned char _pms_psk[4 + 2 * POLARSSL_PSK_MAX_LEN]; /* RFC 4279 2 */
+#endif
+#if defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED)
+ unsigned char _pms_dhe_psk[4 + POLARSSL_MPI_MAX_SIZE
+ + POLARSSL_PSK_MAX_LEN]; /* RFC 4279 3 */
+#endif
+#if defined(POLARSSL_KEY_EXCHANGE_RSA_PSK_ENABLED)
+ unsigned char _pms_rsa_psk[52 + POLARSSL_PSK_MAX_LEN]; /* RFC 4279 4 */
+#endif
+#if defined(POLARSSL_KEY_EXCHANGE_DHE_PSK_ENABLED)
+ unsigned char _pms_ecdhe_psk[4 + POLARSSL_ECP_MAX_BYTES
+ + POLARSSL_PSK_MAX_LEN]; /* RFC 5489 2 */
+#endif
+};
+
+#define POLARSSL_PREMASTER_SIZE sizeof( union _ssl_premaster_secret )
+
#ifdef __cplusplus
extern "C" {
#endif
diff --git a/include/polarssl/ssl_ciphersuites.h b/include/polarssl/ssl_ciphersuites.h
index 5ecd5fe..c4f1ffe 100644
--- a/include/polarssl/ssl_ciphersuites.h
+++ b/include/polarssl/ssl_ciphersuites.h
@@ -233,6 +233,7 @@
#define TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 0xC0AE /**< TLS 1.2 */
#define TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8 0xC0AF /**< TLS 1.2 */
+/* Reminder: update _ssl_premaster_secret when adding a new key exchange */
typedef enum {
POLARSSL_KEY_EXCHANGE_NONE = 0,
POLARSSL_KEY_EXCHANGE_RSA,
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index a1428dc..373a1f5 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3740,12 +3740,7 @@
if( psk == NULL || psk_identity == NULL )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
- /*
- * The length will be check later anyway, but in case it is obviously
- * too large, better abort now. The PMS is as follows:
- * other_len (2 bytes) + other + psk_len (2 bytes) + psk
- */
- if( psk_len + 4 > POLARSSL_PREMASTER_SIZE )
+ if( psk_len > POLARSSL_PSK_MAX_LEN )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
if( ssl->psk != NULL )
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 3af54f9..4682ee5 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -325,7 +325,7 @@
int ret = 0, len, server_fd, i, written, frags;
unsigned char buf[SSL_MAX_CONTENT_LEN + 1];
#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
- unsigned char psk[256];
+ unsigned char psk[POLARSSL_PSK_MAX_LEN];
size_t psk_len = 0;
#endif
#if defined(POLARSSL_SSL_ALPN)
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index d5f01bc..935a7a5 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -126,8 +126,6 @@
"<h2>PolarSSL Test Server</h2>\r\n" \
"<p>Successful connection using: %s</p>\r\n" // LONG_RESPONSE
-#define MAX_PSK_LEN 256
-
/*
* Size of the basic I/O buffer. Able to hold our default response.
*
@@ -460,7 +458,7 @@
size_t j;
*olen = strlen( input );
- if( *olen % 2 != 0 || *olen / 2 > MAX_PSK_LEN )
+ if( *olen % 2 != 0 || *olen / 2 > POLARSSL_PSK_MAX_LEN )
return( -1 );
*olen /= 2;
@@ -484,7 +482,7 @@
{
const char *name;
size_t key_len;
- unsigned char key[MAX_PSK_LEN];
+ unsigned char key[POLARSSL_PSK_MAX_LEN];
psk_entry *next;
};
@@ -573,7 +571,7 @@
int version_suites[4][2];
unsigned char buf[IO_BUF_LEN];
#if defined(POLARSSL_KEY_EXCHANGE__SOME__PSK_ENABLED)
- unsigned char psk[MAX_PSK_LEN];
+ unsigned char psk[POLARSSL_PSK_MAX_LEN];
size_t psk_len = 0;
psk_entry *psk_info = NULL;
#endif
