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tls: send SNI in the client hello

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2017-01-20 22:48:41 +01:00
parent 0af5265180
commit dd2577f21a
1 changed files with 50 additions and 17 deletions
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67
networking/tls.c
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@ -228,6 +228,8 @@ struct record_hdr {
typedef struct tls_state {
int fd;
//TODO: store just the DER key here, parse/use/delete it when sending client key
//this way it will stay key type agnostic here.
psRsaKey_t server_rsa_pub_key;
sha256_ctx_t handshake_sha256_ctx;
@ -1066,7 +1068,7 @@ static void find_key_in_der_cert(tls_state_t *tls, uint8_t *der, int len)
/*
* TLS Handshake routines
*/
static int xread_tls_handshake_block(tls_state_t *tls, int min_len)
static int tls_xread_handshake_block(tls_state_t *tls, int min_len)
{
struct record_hdr *xhdr;
int len = tls_xread_record(tls);
@ -1098,7 +1100,7 @@ static ALWAYS_INLINE void fill_handshake_record_hdr(void *buf, unsigned type, un
}
//TODO: implement RFC 5746 (Renegotiation Indication Extension) - some servers will refuse to work with us otherwise
static void send_client_hello(tls_state_t *tls)
static void send_client_hello(tls_state_t *tls, const char *sni)
{
struct client_hello {
uint8_t type;
@ -1111,28 +1113,58 @@ static void send_client_hello(tls_state_t *tls)
uint8_t cipherid[2 * 1]; /* actually variable */
uint8_t comprtypes_len;
uint8_t comprtypes[1]; /* actually variable */
/* Extensions (SNI shown):
* hi,lo // len of all extensions
* 0x00,0x00 // extension_type: "Server Name"
* 0x00,0x0e // list len (there can be more than one SNI)
* 0x00,0x0c // len of 1st Server Name Indication
* 0x00 // name type: host_name
* 0x00,0x09 // name len
* "localhost" // name
*/
};
struct client_hello *record = tls_get_outbuf(tls, sizeof(*record));
struct client_hello *record;
int len;
int sni_len = sni ? strnlen(sni, 127) : 0;
fill_handshake_record_hdr(record, HANDSHAKE_CLIENT_HELLO, sizeof(*record));
len = sizeof(*record);
if (sni_len)
len += 11 + strlen(sni);
record = tls_get_outbuf(tls, len);
memset(record, 0, len);
fill_handshake_record_hdr(record, HANDSHAKE_CLIENT_HELLO, len);
record->proto_maj = TLS_MAJ; /* the "requested" version of the protocol, */
record->proto_min = TLS_MIN; /* can be higher than one in record headers */
tls_get_random(record->rand32, sizeof(record->rand32));
if (TLS_DEBUG_FIXED_SECRETS)
memset(record->rand32, 0x11, sizeof(record->rand32));
memcpy(tls->client_and_server_rand32, record->rand32, sizeof(record->rand32));
record->session_id_len = 0;
record->cipherid_len16_hi = 0;
/* record->session_id_len = 0; - already is */
/* record->cipherid_len16_hi = 0; */
record->cipherid_len16_lo = 2 * 1;
record->cipherid[0] = CIPHER_ID >> 8;
record->cipherid[1] = CIPHER_ID & 0xff;
record->comprtypes_len = 1;
record->comprtypes[0] = 0;
/* record->comprtypes[0] = 0; */
//TODO: send options, at least SNI.
if (sni_len) {
uint8_t *p = (void*)(record + 1);
//p[0] = 0; //
p[1] = sni_len + 9; //ext_len
//p[2] = 0; //
//p[3] = 0; //extension_type
//p[4] = 0; //
p[5] = sni_len + 5; //list len
//p[6] = 0; //
p[7] = sni_len + 3; //len of 1st SNI
//p[8] = 0; //name type
//p[9] = 0; //
p[10] = sni_len; //name len
memcpy(&p[11], sni, sni_len);
}
dbg(">> CLIENT_HELLO\n");
xwrite_and_update_handshake_hash(tls, sizeof(*record));
xwrite_and_update_handshake_hash(tls, len);
}
static void get_server_hello(tls_state_t *tls)
@ -1149,10 +1181,11 @@ static void get_server_hello(tls_state_t *tls)
uint8_t comprtype;
/* extensions may follow, but only those which client offered in its Hello */
};
struct server_hello *hp;
uint8_t *cipherid;
xread_tls_handshake_block(tls, 74);
tls_xread_handshake_block(tls, 74);
hp = (void*)tls->inbuf;
// 74 bytes:
@ -1199,7 +1232,7 @@ static void get_server_cert(tls_state_t *tls)
uint8_t *certbuf;
int len, len1;
len = xread_tls_handshake_block(tls, 10);
len = tls_xread_handshake_block(tls, 10);
xhdr = (void*)tls->inbuf;
certbuf = (void*)(xhdr + 1);
@ -1416,7 +1449,7 @@ static void send_client_finished(tls_state_t *tls)
xwrite_encrypted(tls, sizeof(*record), RECORD_TYPE_HANDSHAKE);
}
static void tls_handshake(tls_state_t *tls)
static void tls_handshake(tls_state_t *tls, const char *sni)
{
// Client RFC 5246 Server
// (*) - optional messages, not always sent
@ -1437,7 +1470,7 @@ static void tls_handshake(tls_state_t *tls)
// Application Data <------> Application Data
int len;
send_client_hello(tls);
send_client_hello(tls, sni);
get_server_hello(tls);
// RFC 5246
@ -1451,7 +1484,7 @@ static void tls_handshake(tls_state_t *tls)
// (for example, kernel.org does not even accept DH_anon cipher id)
get_server_cert(tls);
len = xread_tls_handshake_block(tls, 4);
len = tls_xread_handshake_block(tls, 4);
if (tls->inbuf[RECHDR_LEN] == HANDSHAKE_SERVER_KEY_EXCHANGE) {
// 459 bytes:
// 0c 00|01|c7 03|00|17|41|04|87|94|2e|2f|68|d0|c9|f4|97|a8|2d|ef|ed|67|ea|c6|f3|b3|56|47|5d|27|b6|bd|ee|70|25|30|5e|b0|8e|f6|21|5a...
@ -1460,7 +1493,7 @@ static void tls_handshake(tls_state_t *tls)
// 0c 00|01|c9 03|00|17|41|04|cd|9b|b4|29|1f|f6|b0|c2|84|82|7f|29|6a|47|4e|ec|87|0b|c1|9c|69|e1|f8|c6|d0|53|e9|27|90|a5|c8|02|15|75...
dbg("<< SERVER_KEY_EXCHANGE len:%u\n", len);
//probably need to save it
xread_tls_handshake_block(tls, 4);
tls_xread_handshake_block(tls, 4);
}
// if (tls->inbuf[RECHDR_LEN] == HANDSHAKE_CERTIFICATE_REQUEST) {
@ -1472,7 +1505,7 @@ static void tls_handshake(tls_state_t *tls)
// Client certificates are sent using the Certificate structure
// defined in Section 7.4.2."
// (i.e. the same format as server certs)
// xread_tls_handshake_block(tls, 4);
// tls_xread_handshake_block(tls, 4);
// }
if (tls->inbuf[RECHDR_LEN] != HANDSHAKE_SERVER_HELLO_DONE)
@ -1546,7 +1579,7 @@ int tls_main(int argc UNUSED_PARAM, char **argv)
tls = new_tls_state();
tls->fd = cfd;
tls_handshake(tls);
tls_handshake(tls, argv[1]);
/* Select loop copying stdin to cfd, and cfd to stdout */
FD_ZERO(&readfds);