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simplified ciphersuite selection method and select ciphers based on server's desire.

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This commit is contained in:
Nikos Mavrogiannopoulos
2014-01-19 11:43:10 +01:00
parent 404d831c35
commit b500de2ec0
2 changed files with 87 additions and 68 deletions
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140
src/worker-vpn.c
View File

@@ -184,9 +184,65 @@ int url_cb(http_parser * parser, const char *at, size_t length)
#define CS_AES128_GCM "OC-DTLS1_2-AES128-GCM"
#define CS_AES256_GCM "OC-DTLS1_2-AES256-GCM"
/* Consider switching to gperf when this table grows significantly.
*/
static const dtls_ciphersuite_st ciphersuites[] =
{
#if GNUTLS_VERSION_NUMBER >= 0x030207
{
.oc_name = CS_ESALSA20,
.gnutls_name = "NONE:+VERS-DTLS1.2:+COMP-NULL:+ESTREAM-SALSA20-256:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION",
.gnutls_version = GNUTLS_DTLS1_2,
.gnutls_mac = GNUTLS_MAC_SHA1,
.gnutls_cipher = GNUTLS_CIPHER_ESTREAM_SALSA20_256,
.server_prio = 100
},
{
.oc_name = CS_SALSA20,
.gnutls_name = "NONE:+VERS-DTLS1.2:+COMP-NULL:+SALSA20-256:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION",
.gnutls_version = GNUTLS_DTLS1_2,
.gnutls_mac = GNUTLS_MAC_SHA1,
.gnutls_cipher = GNUTLS_CIPHER_SALSA20_256,
.server_prio = 100
},
{
.oc_name = CS_AES128_GCM,
.gnutls_name = "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-128-GCM:+AEAD:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION:+SIGN-ALL",
.gnutls_version = GNUTLS_DTLS1_2,
.gnutls_mac = GNUTLS_MAC_AEAD,
.gnutls_cipher = GNUTLS_CIPHER_AES_128_GCM,
.server_prio = 90
},
{
.oc_name = CS_AES256_GCM,
.gnutls_name = "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-256-GCM:+AEAD:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION:+SIGN-ALL",
.gnutls_version = GNUTLS_DTLS1_2,
.gnutls_mac = GNUTLS_MAC_AEAD,
.gnutls_cipher = GNUTLS_CIPHER_AES_256_GCM,
.server_prio = 80,
},
#endif
{
.oc_name = "AES128-SHA",
.gnutls_name = "NONE:+VERS-DTLS0.9:+COMP-NULL:+AES-128-CBC:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION",
.gnutls_version = GNUTLS_DTLS0_9,
.gnutls_mac = GNUTLS_MAC_SHA1,
.gnutls_cipher = GNUTLS_CIPHER_AES_128_CBC,
.server_prio = 50,
},
{
.oc_name = "DES-CBC3-SHA",
.gnutls_name = "NONE:+VERS-DTLS0.9:+COMP-NULL:+3DES-CBC:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION",
.gnutls_version = GNUTLS_DTLS0_9,
.gnutls_mac = GNUTLS_MAC_SHA1,
.gnutls_cipher = GNUTLS_CIPHER_3DES_CBC,
.server_prio = 1,
},
};
static void value_check(struct worker_st *ws, struct http_req_st *req)
{
unsigned length;
unsigned length, i;
int ret;
size_t nlen;
uint8_t *p;
@@ -232,60 +288,18 @@ static void value_check(struct worker_st *ws, struct http_req_st *req)
break;
case HEADER_DTLS_CIPHERSUITE:
req->selected_ciphersuite = NULL;
str = (char *)req->value.data;
while ((token = strtok(str, ":")) != NULL) {
#if GNUTLS_VERSION_NUMBER >= 0x030207
if (strcmp(token, CS_ESALSA20) == 0) {
req->selected_ciphersuite = CS_ESALSA20;
req->gnutls_ciphersuite =
"NONE:+VERS-DTLS1.2:+COMP-NULL:+ESTREAM-SALSA20-256:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION";
req->gnutls_cipher =
GNUTLS_CIPHER_ESTREAM_SALSA20_256;
req->gnutls_mac = GNUTLS_MAC_SHA1;
req->gnutls_version = GNUTLS_DTLS1_2;
break;
} else if (strcmp(token, CS_SALSA20) == 0) {
req->selected_ciphersuite = CS_SALSA20;
req->gnutls_ciphersuite =
"NONE:+VERS-DTLS1.2:+COMP-NULL:+SALSA20-256:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION";
req->gnutls_cipher = GNUTLS_CIPHER_SALSA20_256;
req->gnutls_mac = GNUTLS_MAC_SHA1;
req->gnutls_version = GNUTLS_DTLS1_2;
break;
} else if (strcmp(token, CS_AES128_GCM) == 0) {
req->selected_ciphersuite = CS_AES128_GCM;
req->gnutls_ciphersuite =
"NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-128-GCM:+AEAD:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION:+SIGN-ALL";
req->gnutls_cipher = GNUTLS_CIPHER_AES_128_GCM;
req->gnutls_mac = GNUTLS_MAC_AEAD;
req->gnutls_version = GNUTLS_DTLS1_2;
break;
} else if (strcmp(token, CS_AES256_GCM) == 0) {
req->selected_ciphersuite = CS_AES256_GCM;
req->gnutls_ciphersuite =
"NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-256-GCM:+AEAD:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION:+SIGN-ALL";
req->gnutls_cipher = GNUTLS_CIPHER_AES_256_GCM;
req->gnutls_mac = GNUTLS_MAC_AEAD;
req->gnutls_version = GNUTLS_DTLS1_2;
break;
} else
#endif
if (strcmp(token, "AES128-SHA") == 0) {
req->gnutls_ciphersuite =
"NONE:+VERS-DTLS0.9:+COMP-NULL:+AES-128-CBC:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION";
req->selected_ciphersuite = "AES128-SHA";
req->gnutls_cipher = GNUTLS_CIPHER_AES_128_CBC;
req->gnutls_mac = GNUTLS_MAC_SHA1;
req->gnutls_version = GNUTLS_DTLS0_9;
break;
} else if (strcmp(token, "DES-CBC3-SHA") == 0) {
req->gnutls_ciphersuite =
"NONE:+VERS-DTLS0.9:+COMP-NULL:+3DES-CBC:+SHA1:+RSA:%COMPAT:%DISABLE_SAFE_RENEGOTIATION";
req->selected_ciphersuite = "DES-CBC3-SHA";
req->gnutls_cipher = GNUTLS_CIPHER_3DES_CBC;
req->gnutls_mac = GNUTLS_MAC_SHA1;
req->gnutls_version = GNUTLS_DTLS0_9;
break;
for (i=0;i<sizeof(ciphersuites)/sizeof(ciphersuites[0]);i++) {
if (strcmp(token, ciphersuites[i].oc_name) == 0) {
if (req->selected_ciphersuite == NULL ||
req->selected_ciphersuite->server_prio < ciphersuites[i].server_prio) {
req->selected_ciphersuite = &ciphersuites[i];
}
}
}
str = NULL;
}
@@ -476,7 +490,7 @@ static int setup_dtls_connection(struct worker_st *ws)
{ ws->master_secret, sizeof(ws->master_secret) };
gnutls_datum_t sid = { ws->session_id, sizeof(ws->session_id) };
if (ws->req.gnutls_ciphersuite == NULL) {
if (ws->req.selected_ciphersuite == NULL) {
oclog(ws, LOG_ERR, "no DTLS ciphersuite negotiated");
return -1;
}
@@ -493,7 +507,7 @@ static int setup_dtls_connection(struct worker_st *ws)
}
ret =
gnutls_priority_set_direct(session, ws->req.gnutls_ciphersuite,
gnutls_priority_set_direct(session, ws->req.selected_ciphersuite->gnutls_name,
NULL);
if (ret < 0) {
oclog(ws, LOG_ERR, "could not set TLS priority: %s",
@@ -502,9 +516,9 @@ static int setup_dtls_connection(struct worker_st *ws)
}
ret = gnutls_session_set_premaster(session, GNUTLS_SERVER,
ws->req.gnutls_version,
GNUTLS_KX_RSA, ws->req.gnutls_cipher,
ws->req.gnutls_mac, GNUTLS_COMP_NULL,
ws->req.selected_ciphersuite->gnutls_version,
GNUTLS_KX_RSA, ws->req.selected_ciphersuite->gnutls_cipher,
ws->req.selected_ciphersuite->gnutls_mac, GNUTLS_COMP_NULL,
&master, &sid);
if (ret < 0) {
oclog(ws, LOG_ERR, "could not set TLS premaster: %s",
@@ -776,7 +790,7 @@ void session_info_send(worker_st * ws)
}
if (ws->udp_state != UP_DISABLED) {
msg.dtls_ciphersuite = ws->req.selected_ciphersuite;
msg.dtls_ciphersuite = (char*)ws->req.selected_ciphersuite->oc_name;
}
if (ws->req.user_agent[0] != 0) {
@@ -1264,10 +1278,10 @@ static int connect_handler(worker_st * ws)
SEND_ERR(ret);
oclog(ws, LOG_INFO, "DTLS ciphersuite: %s",
ws->req.selected_ciphersuite);
ws->req.selected_ciphersuite->oc_name);
ret =
tls_printf(ws->session, "X-DTLS-CipherSuite: %s\r\n",
ws->req.selected_ciphersuite);
ws->req.selected_ciphersuite->oc_name);
SEND_ERR(ret);
/* assume that if IPv6 is used over TCP then the same would be used over UDP */
@@ -1287,8 +1301,8 @@ static int connect_handler(worker_st * ws)
overhead =
CSTP_DTLS_OVERHEAD +
tls_get_overhead(ws->req.gnutls_version,
ws->req.gnutls_cipher, ws->req.gnutls_mac);
tls_get_overhead(ws->req.selected_ciphersuite->gnutls_version,
ws->req.selected_ciphersuite->gnutls_cipher, ws->req.selected_ciphersuite->gnutls_mac);
dtls_mtu = ws->conn_mtu - overhead;
tls_printf(ws->session, "X-DTLS-MTU: %u\r\n", dtls_mtu);

15
src/worker.h
View File

@@ -67,6 +67,15 @@ enum {
S_AUTH_COMPLETE
};
typedef struct dtls_ciphersuite_st {
const char* oc_name;
const char* gnutls_name; /* the gnutls priority string to set */
unsigned server_prio; /* the highest the more we want to negotiate that */
unsigned gnutls_cipher;
unsigned gnutls_mac;
unsigned gnutls_version;
} dtls_ciphersuite_st;
struct http_req_st {
char url[256];
@@ -87,11 +96,7 @@ struct http_req_st {
char *body;
unsigned int body_length;
char *gnutls_ciphersuite; /* static string */
char *selected_ciphersuite; /* static string */
int gnutls_cipher;
int gnutls_mac;
int gnutls_version;
const dtls_ciphersuite_st *selected_ciphersuite;
unsigned int headers_complete;
unsigned int message_complete;