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dd2577f21

Denys Vlasenko
Denys Vlasenko
2017-01-20
SUCCESS Duration: 187s

Subject

tls: send SNI in the client hello

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

networking/tls.c +52 -19
networking/tls.c+52 -19
@@ -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));
-
- fill_handshake_record_hdr(record, HANDSHAKE_CLIENT_HELLO, sizeof(*record));
+ struct client_hello *record;
+ int len;
+ int sni_len = sni ? strnlen(sni, 127) : 0;
+
+ 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;
-
-//TODO: send options, at least SNI.
+ /* record->comprtypes[0] = 0; */
+
+ 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);