Introduce macros for constants in SSL ticket implementation
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 8492c19..25eab49 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -54,6 +54,19 @@
#define MAX_KEY_BYTES 32 /* 256 bits */
+#define TICKET_KEY_NAME_BYTES 4
+#define TICKET_IV_BYTES 12
+#define TICKET_CRYPT_LEN_BYTES 2
+#define TICKET_AUTH_TAG_BYTES 16
+
+#define TICKET_MIN_LEN ( TICKET_KEY_NAME_BYTES + \
+ TICKET_IV_BYTES + \
+ TICKET_CRYPT_LEN_BYTES + \
+ TICKET_AUTH_TAG_BYTES )
+#define TICKET_ADD_DATA_LEN ( TICKET_KEY_NAME_BYTES + \
+ TICKET_IV_BYTES + \
+ TICKET_CRYPT_LEN_BYTES )
+
/*
* Generate/update a key
*/
@@ -278,6 +291,7 @@
* The key_name, iv, and length of encrypted_state are the additional
* authenticated data.
*/
+
int mbedtls_ssl_ticket_write( void *p_ticket,
const mbedtls_ssl_session *session,
unsigned char *start,
@@ -289,9 +303,9 @@
mbedtls_ssl_ticket_context *ctx = p_ticket;
mbedtls_ssl_ticket_key *key;
unsigned char *key_name = start;
- unsigned char *iv = start + 4;
- unsigned char *state_len_bytes = iv + 12;
- unsigned char *state = state_len_bytes + 2;
+ unsigned char *iv = start + TICKET_KEY_NAME_BYTES;
+ unsigned char *state_len_bytes = iv + TICKET_IV_BYTES;
+ unsigned char *state = state_len_bytes + TICKET_CRYPT_LEN_BYTES;
unsigned char *tag;
size_t clear_len, ciph_len;
@@ -302,7 +316,7 @@
/* We need at least 4 bytes for key_name, 12 for IV, 2 for len 16 for tag,
* in addition to session itself, that will be checked when writing it. */
- if( end - start < 4 + 12 + 2 + 16 )
+ if( end - start < TICKET_MIN_LEN )
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
#if defined(MBEDTLS_THREADING_C)
@@ -317,9 +331,9 @@
*ticket_lifetime = ctx->ticket_lifetime;
- memcpy( key_name, key->name, 4 );
+ memcpy( key_name, key->name, TICKET_KEY_NAME_BYTES );
- if( ( ret = ctx->f_rng( ctx->p_rng, iv, 12 ) ) != 0 )
+ if( ( ret = ctx->f_rng( ctx->p_rng, iv, TICKET_IV_BYTES ) ) != 0 )
goto cleanup;
/* Dump session state */
@@ -335,8 +349,11 @@
/* Encrypt and authenticate */
tag = state + clear_len;
if( ( ret = mbedtls_cipher_auth_encrypt( &key->ctx,
- iv, 12, key_name, 4 + 12 + 2,
- state, clear_len, state, &ciph_len, tag, 16 ) ) != 0 )
+ iv, TICKET_IV_BYTES,
+ /* Additional data: key name, IV and length */
+ key_name, TICKET_ADD_DATA_LEN,
+ state, clear_len, state, &ciph_len,
+ tag, TICKET_AUTH_TAG_BYTES ) ) != 0 )
{
goto cleanup;
}
@@ -346,7 +363,7 @@
goto cleanup;
}
- *tlen = 4 + 12 + 2 + 16 + ciph_len;
+ *tlen = TICKET_MIN_LEN + ciph_len;
cleanup:
#if defined(MBEDTLS_THREADING_C)
@@ -385,17 +402,16 @@
mbedtls_ssl_ticket_context *ctx = p_ticket;
mbedtls_ssl_ticket_key *key;
unsigned char *key_name = buf;
- unsigned char *iv = buf + 4;
- unsigned char *enc_len_p = iv + 12;
- unsigned char *ticket = enc_len_p + 2;
+ unsigned char *iv = buf + TICKET_KEY_NAME_BYTES;
+ unsigned char *enc_len_p = iv + TICKET_IV_BYTES;
+ unsigned char *ticket = enc_len_p + TICKET_CRYPT_LEN_BYTES;
unsigned char *tag;
size_t enc_len, clear_len;
if( ctx == NULL || ctx->f_rng == NULL )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
- /* See mbedtls_ssl_ticket_write() */
- if( len < 4 + 12 + 2 + 16 )
+ if( len < TICKET_MIN_LEN )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
#if defined(MBEDTLS_THREADING_C)
@@ -409,7 +425,7 @@
enc_len = ( enc_len_p[0] << 8 ) | enc_len_p[1];
tag = ticket + enc_len;
- if( len != 4 + 12 + 2 + enc_len + 16 )
+ if( len != TICKET_MIN_LEN + enc_len )
{
ret = MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
goto cleanup;
@@ -425,9 +441,13 @@
}
/* Decrypt and authenticate */
- if( ( ret = mbedtls_cipher_auth_decrypt( &key->ctx, iv, 12,
- key_name, 4 + 12 + 2, ticket, enc_len,
- ticket, &clear_len, tag, 16 ) ) != 0 )
+ if( ( ret = mbedtls_cipher_auth_decrypt( &key->ctx,
+ iv, TICKET_IV_BYTES,
+ /* Additional data: key name, IV and length */
+ key_name, TICKET_ADD_DATA_LEN,
+ ticket, enc_len,
+ ticket, &clear_len,
+ tag, TICKET_AUTH_TAG_BYTES ) ) != 0 )
{
if( ret == MBEDTLS_ERR_CIPHER_AUTH_FAILED )
ret = MBEDTLS_ERR_SSL_INVALID_MAC;