Move cookie callbacks implementation to own module
diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
new file mode 100644
index 0000000..5b6a79a
--- /dev/null
+++ b/library/ssl_cookie.c
@@ -0,0 +1,157 @@
+/*
+ * DTLS cookie callbacks implementation
+ *
+ * Copyright (C) 2014, Brainspark B.V.
+ *
+ * This file is part of PolarSSL (http://www.polarssl.org)
+ * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+/*
+ * These session callbacks use a simple chained list
+ * to store and retrieve the session information.
+ */
+
+#if !defined(POLARSSL_CONFIG_FILE)
+#include "polarssl/config.h"
+#else
+#include POLARSSL_CONFIG_FILE
+#endif
+
+#if defined(POLARSSL_SSL_DTLS_HELLO_VERIFY)
+
+#include "polarssl/ssl_cookie.h"
+
+#if defined(POLARSSL_PLATFORM_C)
+#include "polarssl/platform.h"
+#else
+#define polarssl_malloc malloc
+#define polarssl_free free
+#endif
+
+/* Implementation that should never be optimized out by the compiler */
+static void polarssl_zeroize( void *v, size_t n ) {
+ volatile unsigned char *p = v; while( n-- ) *p++ = 0;
+}
+
+/*
+ * If DTLS is in use, then at least one of SHA-1, SHA-256, SHA-512 is
+ * available. Try SHA-256 first, 512 wastes resources since we need to stay
+ * with max 32 bytes of cookie for DTLS 1.0
+ */
+#if defined(POLARSSL_SHA256_C)
+#define HVR_MD POLARSSL_MD_SHA256
+#define HVR_MD_LEN 32
+#define HVR_MD_USE 32
+#elif defined(POLARSSL_SHA512_C)
+#define HVR_MD POLARSSL_MD_SHA384
+#define HVR_MD_LEN 48
+#define HVR_MD_USE 32
+#elif defined(POLARSSL_SHA1_C)
+#define HVR_MD POLARSSL_MD_SHA1
+#define HVR_MD_LEN 20
+#define HVR_MD_USE 20
+#else
+#error "DTLS hello verify needs SHA-1 or SHA-2"
+#endif
+
+void ssl_cookie_init( ssl_cookie_ctx *ctx )
+{
+ md_init( &ctx->hmac_ctx );
+}
+
+void ssl_cookie_free( ssl_cookie_ctx *ctx )
+{
+ md_free( &ctx->hmac_ctx );
+}
+
+int ssl_cookie_setup( ssl_cookie_ctx *ctx,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng )
+{
+ int ret;
+ unsigned char key[HVR_MD_LEN];
+
+ if( ( ret = f_rng( p_rng, key, sizeof( key ) ) ) != 0 )
+ return( ret );
+
+ ret = md_init_ctx( &ctx->hmac_ctx, md_info_from_type( HVR_MD ) );
+ if( ret != 0 )
+ return( ret );
+
+ ret = md_hmac_starts( &ctx->hmac_ctx, key, sizeof( key ) );
+ if( ret != 0 )
+ return( ret );
+
+ polarssl_zeroize( key, sizeof( key ) );
+
+ return( 0 );
+}
+
+/*
+ * Generate cookie for DTLS ClientHello verification
+ */
+int ssl_cookie_write( void *ctx,
+ unsigned char **p, unsigned char *end,
+ const unsigned char *cli_id, size_t cli_id_len )
+{
+ int ret;
+ unsigned char hmac_out[HVR_MD_LEN];
+ md_context_t *hmac_ctx = (md_context_t *) ctx;
+
+ if( (size_t)( end - *p ) < HVR_MD_USE )
+ return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
+
+ if( ( ret = md_hmac_reset( hmac_ctx ) ) != 0 ||
+ ( ret = md_hmac_update( hmac_ctx, cli_id, cli_id_len ) ) != 0 ||
+ ( ret = md_hmac_finish( hmac_ctx, hmac_out ) ) != 0 )
+ {
+ return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ memcpy( *p, hmac_out, HVR_MD_USE );
+ *p += HVR_MD_USE;
+
+ return( 0 );
+}
+
+/*
+ * Check a cookie
+ */
+int ssl_cookie_check( void *ctx,
+ const unsigned char *cookie, size_t cookie_len,
+ const unsigned char *cli_id, size_t cli_id_len )
+{
+ unsigned char ref_cookie[HVR_MD_USE];
+ unsigned char *p = ref_cookie;
+ md_context_t *hmac_ctx = (md_context_t *) ctx;
+
+ if( cookie_len != HVR_MD_USE )
+ return( -1 );
+
+ if( ssl_cookie_write( hmac_ctx,
+ &p, p + sizeof( ref_cookie ),
+ cli_id, cli_id_len ) != 0 )
+ return( -1 );
+
+ if( safer_memcmp( cookie, ref_cookie, sizeof( ref_cookie ) ) != 0 )
+ return( -1 );
+
+ return( 0 );
+}
+#endif /* POLARSSL_SSL_COOKIE_C */