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Rfc5746 #181

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merged 2 commits into from
Jul 27, 2023
Merged

Rfc5746 #181

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4ea6312
dtls.c: add RFC5746 minimal version implementation.
boaks Nov 28, 2022
70f7bd4
Add renegotiation info to test clients.
boaks Jan 24, 2023
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2 changes: 2 additions & 0 deletions crypto.h
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Original file line number Diff line number Diff line change
Expand Up @@ -140,6 +140,7 @@ typedef struct dtls_user_parameters_t {
*/
dtls_cipher_t cipher_suites[DTLS_MAX_CIPHER_SUITES + 1];
unsigned int force_extended_master_secret:1; /** force extended master secret extension (RFC7627) */
unsigned int force_renegotiation_info:1; /** force renegotiation info extension (RFC5746) */
} dtls_user_parameters_t;

typedef struct {
Expand All @@ -159,6 +160,7 @@ typedef struct {
dtls_cipher_index_t cipher_index; /**< internal index for cipher_suite_params, DTLS_CIPHER_INDEX_NULL for TLS_NULL_WITH_NULL_NULL */
unsigned int do_client_auth:1;
unsigned int extended_master_secret:1;
unsigned int renegotiation_info:1;
union {
#ifdef DTLS_ECC
dtls_handshake_parameters_ecdsa_t ecdsa;
Expand Down
50 changes: 46 additions & 4 deletions dtls.c
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Expand Up @@ -140,6 +140,9 @@ memarray_t dtlscontext_storage;
* ec point format := 6 bytes => 26
* sign. and hash algos := 8 bytes
* extended master secret := 4 bytes => 12
*
* (The ClientHello uses TLS_EMPTY_RENEGOTIATION_INFO_SCSV
* instead of renegotiation info)
*/
#define DTLS_CH_LENGTH sizeof(dtls_client_hello_t) /* no variable length fields! */
#define DTLS_COOKIE_LENGTH_MAX 32
Expand Down Expand Up @@ -660,6 +663,7 @@ static const dtls_user_parameters_t default_user_parameters = {
},
#endif /* DTLS_DEFAULT_CIPHER_SUITES */
.force_extended_master_secret = 1,
.force_renegotiation_info = 1,
};

/** only one compression method is currently defined */
Expand Down Expand Up @@ -1260,6 +1264,15 @@ dtls_check_tls_extension(dtls_peer_t *peer,
if (verify_ext_sig_hash_algo(data, j))
goto error;
break;
case TLS_EXT_RENEGOTIATION_INFO:
/* RFC 5746, minimal version, only empty info is supported */
if (j == 1 && *data == 0) {
config->renegotiation_info = 1;
} else {
dtls_warn("only empty renegotiation info is supported.\n");
goto error;
}
break;
default:
dtls_notice("unsupported tls extension: %i\n", i);
break;
Expand Down Expand Up @@ -1288,6 +1301,11 @@ dtls_check_tls_extension(dtls_peer_t *peer,
goto error;
}
}
if (config->user_parameters.force_renegotiation_info) {
if (!config->renegotiation_info) {
goto error;
}
}
return 0;

error:
Expand Down Expand Up @@ -1366,9 +1384,13 @@ dtls_update_parameters(dtls_context_t *ctx,
}

ok = 0;
while ((i >= (int)sizeof(uint16)) && !ok) {
config->cipher_index = get_cipher_index(config->user_parameters.cipher_suites, dtls_uint16_to_int(data));
ok = known_cipher(ctx, config->cipher_index, 0);
while ((i >= (int)sizeof(uint16)) && (!ok || !config->renegotiation_info)) {
if (dtls_uint16_to_int(data) == TLS_EMPTY_RENEGOTIATION_INFO_SCSV) {
config->renegotiation_info = 1;
} else if (!ok) {
config->cipher_index = get_cipher_index(config->user_parameters.cipher_suites, dtls_uint16_to_int(data));
ok = known_cipher(ctx, config->cipher_index, 0);
}
i -= sizeof(uint16);
data += sizeof(uint16);
}
Expand Down Expand Up @@ -2435,17 +2457,19 @@ dtls_send_server_hello(dtls_context_t *ctx, dtls_peer_t *peer)
* server certificate type := 5 bytes
* ec_point_formats := 6 bytes
* extended master secret := 4 bytes
* renegotiation info := 5 bytes
*
* (no elliptic_curves in ServerHello.)
*/
uint8 buf[DTLS_SH_LENGTH + 2 + 5 + 5 + 6 + 4];
uint8 buf[DTLS_SH_LENGTH + 2 + 5 + 5 + 6 + 4 + 5];
uint8 *p;
uint8 extension_size;
dtls_handshake_parameters_t * const handshake = peer->handshake_params;
const dtls_cipher_t cipher_suite = get_cipher_suite(handshake->cipher_index);
const int ecdsa = is_key_exchange_ecdhe_ecdsa(handshake->cipher_index);

extension_size = (handshake->extended_master_secret ? 4 : 0) +
(handshake->renegotiation_info ? 5 : 0) +
(ecdsa ? 5 + 5 + 6 : 0);

/* Handshake header */
Expand Down Expand Up @@ -2527,6 +2551,19 @@ dtls_send_server_hello(dtls_context_t *ctx, dtls_peer_t *peer)
p += sizeof(uint16);
}

if (handshake->renegotiation_info) {
/* RFC5746 minimal version, empty renegotiation info, 5 bytes */
dtls_int_to_uint16(p, TLS_EXT_RENEGOTIATION_INFO);
p += sizeof(uint16);

/* length of this extension type */
dtls_int_to_uint16(p, 1);
p += sizeof(uint16);

/* empty renegotiation info */
*p++ = 0;
}

assert((buf <= p) && ((unsigned int)(p - buf) <= sizeof(buf)));

/* TODO use the same record sequence number as in the ClientHello,
Expand Down Expand Up @@ -3098,6 +3135,11 @@ dtls_send_client_hello(dtls_context_t *ctx, dtls_peer_t *peer,
return dtls_alert_fatal_create(DTLS_ALERT_HANDSHAKE_FAILURE);
}

/* RFC5746 add RENEGOTIATION_INFO_SCSV */
dtls_int_to_uint16(p, TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
p += sizeof(uint16);
cipher_suites_size += sizeof(uint16);

/* set size of known cipher suites */
dtls_int_to_uint16(p_cipher_suites_size, cipher_suites_size);

Expand Down
4 changes: 3 additions & 1 deletion global.h
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Original file line number Diff line number Diff line change
Expand Up @@ -74,10 +74,11 @@ typedef unsigned char uint48[6];
/** Known cipher suites.*/
typedef enum {
TLS_NULL_WITH_NULL_NULL = 0x0000, /**< NULL cipher */
TLS_EMPTY_RENEGOTIATION_INFO_SCSV = 0x00FF, /**< see RFC 5746 */
TLS_PSK_WITH_AES_128_CCM = 0xC0A4, /**< see RFC 6655 */
TLS_PSK_WITH_AES_128_CCM_8 = 0xC0A8, /**< see RFC 6655 */
TLS_ECDHE_ECDSA_WITH_AES_128_CCM = 0xC0AC, /**< see RFC 7251 */
TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 = 0xC0AE /**< see RFC 7251 */
TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 = 0xC0AE, /**< see RFC 7251 */
} dtls_cipher_t;

/** Known compression suites.*/
Expand All @@ -92,6 +93,7 @@ typedef enum {
#define TLS_EXT_SERVER_CERTIFICATE_TYPE 20 /* see RFC 7250 */
#define TLS_EXT_ENCRYPT_THEN_MAC 22 /* see RFC 7366 */
#define TLS_EXT_EXTENDED_MASTER_SECRET 23 /* see RFC 7627 */
#define TLS_EXT_RENEGOTIATION_INFO 65281 /* see RFC 5746 */

#define TLS_CERT_TYPE_RAW_PUBLIC_KEY 2 /* see RFC 7250 */

Expand Down
19 changes: 14 additions & 5 deletions tests/dtls-client.c
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Expand Up @@ -62,6 +62,7 @@ static dtls_context_t *orig_dtls_context = NULL;

static const dtls_cipher_t* ciphers = NULL;
static unsigned int force_extended_master_secret = 0;
static unsigned int force_renegotiation_info = 0;


#ifdef DTLS_ECC
Expand Down Expand Up @@ -238,6 +239,7 @@ get_user_parameters(struct dtls_context_t *ctx,
(void) ctx;
(void) session;
user_parameters->force_extended_master_secret = force_extended_master_secret;
user_parameters->force_renegotiation_info = force_renegotiation_info;
if (ciphers) {
int i = 0;
while (i < DTLS_MAX_CIPHER_SUITES) {
Expand Down Expand Up @@ -353,19 +355,23 @@ usage( const char *program, const char *version) {
fprintf(stderr, "%s v%s -- DTLS client implementation\n"
"(c) 2011-2014 Olaf Bergmann <bergmann@tzi.org>\n\n"
#ifdef DTLS_PSK
"usage: %s [-c cipher suites] [-e] [-i file] [-k file] [-o file] [-p port] [-v num] addr [port]\n",
"usage: %s [-c cipher suites] [-e] [-i file] [-k file] [-o file]\n"
" %*s [-p port] [-r] [-v num] addr [port]\n",
#else /* DTLS_PSK */
"usage: %s [-c cipher suites] [-e] [-o file] [-p port] [-v num] addr [port]\n",
"usage: %s [-c cipher suites] [-e] [-o file] [-p port] [-r]\n"
" %*s [-v num] addr [port]\n",
#endif /* DTLS_PSK */
program, version, program);
program, version, program, (int)strlen(program), "");
cipher_suites_usage(stderr, "\t");
fprintf(stderr, "\t-e\t\tforce extended master secret (RFC7627)\n"
#ifdef DTLS_PSK
"\t-i file\t\tread PSK identity from file\n"
"\t-k file\t\tread pre-shared key from file\n"
#endif /* DTLS_PSK */
"\t-o file\t\toutput received data to this file (use '-' for STDOUT)\n"
"\t-o file\t\toutput received data to this file\n"
"\t \t\t(use '-' for STDOUT)\n"
"\t-p port\t\tlisten on specified port (default is %d)\n"
"\t-r\t\tforce renegotiation info (RFC5746)\n"
"\t-v num\t\tverbosity level (default: 3)\n",
DEFAULT_PORT);
}
Expand Down Expand Up @@ -422,7 +428,7 @@ main(int argc, char **argv) {
memcpy(psk_key, PSK_DEFAULT_KEY, psk_key_length);
#endif /* DTLS_PSK */

while ((opt = getopt(argc, argv, "c:eo:p:v:" PSK_OPTIONS)) != -1) {
while ((opt = getopt(argc, argv, "c:eo:p:rv:" PSK_OPTIONS)) != -1) {
switch (opt) {
#ifdef DTLS_PSK
case 'i' :
Expand Down Expand Up @@ -464,6 +470,9 @@ main(int argc, char **argv) {
strncpy(port_str, optarg, NI_MAXSERV-1);
port_str[NI_MAXSERV - 1] = '\0';
break;
case 'r' :
force_renegotiation_info = 1;
break;
case 'v' :
log_level = strtol(optarg, NULL, 10);
break;
Expand Down
10 changes: 8 additions & 2 deletions tests/dtls-server.c
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ static dtls_context_t *the_context = NULL;
static volatile int cmd_exit = 0;
static const dtls_cipher_t* ciphers = NULL;
static unsigned int force_extended_master_secret = 0;
static unsigned int force_renegotiation_info = 0;

#ifdef DTLS_ECC
static const unsigned char ecdsa_priv_key[] = {
Expand Down Expand Up @@ -199,6 +200,7 @@ get_user_parameters(struct dtls_context_t *ctx,
(void) ctx;
(void) session;
user_parameters->force_extended_master_secret = force_extended_master_secret;
user_parameters->force_renegotiation_info = force_renegotiation_info;
if (ciphers) {
int i = 0;
while (i < DTLS_MAX_CIPHER_SUITES) {
Expand Down Expand Up @@ -307,12 +309,13 @@ usage(const char *program, const char *version) {

fprintf(stderr, "%s v%s -- DTLS server implementation\n"
"(c) 2011-2014 Olaf Bergmann <bergmann@tzi.org>\n\n"
"usage: %s [-A address] [-c cipher suites] [-e] [-p port] [-v num]\n"
"usage: %s [-A address] [-c cipher suites] [-e] [-p port] [-r] [-v num]\n"
"\t-A address\t\tlisten on specified address (default is ::)\n",
program, version, program);
cipher_suites_usage(stderr, "\t");
fprintf(stderr, "\t-e\t\tforce extended master secret (RFC7627)\n"
"\t-p port\t\tlisten on specified port (default is %d)\n"
"\t-r\t\tforce renegotiation info (RFC5746)\n"
"\t-v num\t\tverbosity level (default: 3)\n",
DEFAULT_PORT);
}
Expand Down Expand Up @@ -355,7 +358,7 @@ main(int argc, char **argv) {
listen_addr.sin6_family = AF_INET6;
listen_addr.sin6_addr = in6addr_any;

while ((opt = getopt(argc, argv, "A:c:ep:v:")) != -1) {
while ((opt = getopt(argc, argv, "A:c:ep:rv:")) != -1) {
switch (opt) {
case 'A' :
if (resolve_address(optarg, (struct sockaddr *)&listen_addr) < 0) {
Expand All @@ -372,6 +375,9 @@ main(int argc, char **argv) {
case 'p' :
port = htons(atoi(optarg));
break;
case 'r' :
force_renegotiation_info = 1;
break;
case 'v' :
log_level = strtol(optarg, NULL, 10);
break;
Expand Down