[or-cvs] r12385: Function to process link auth cells; stub function for cert (in tor/trunk: . doc src/or)
nickm at seul.org
nickm at seul.org
Mon Nov 5 18:15:56 UTC 2007
Author: nickm
Date: 2007-11-05 13:15:56 -0500 (Mon, 05 Nov 2007)
New Revision: 12385
Modified:
tor/trunk/
tor/trunk/doc/TODO
tor/trunk/src/or/command.c
tor/trunk/src/or/connection_or.c
tor/trunk/src/or/or.h
Log:
r16414 at catbus: nickm | 2007-11-05 13:14:46 -0500
Function to process link auth cells; stub function for cert cell processing
Property changes on: tor/trunk
___________________________________________________________________
svk:merge ticket from /tor/trunk [r16414] on 8246c3cf-6607-4228-993b-4d95d33730f1
Modified: tor/trunk/doc/TODO
===================================================================
--- tor/trunk/doc/TODO 2007-11-05 18:15:54 UTC (rev 12384)
+++ tor/trunk/doc/TODO 2007-11-05 18:15:56 UTC (rev 12385)
@@ -37,14 +37,15 @@
- functions to parse x509 certs
- functions to validate a single x509 cert against a TLS connection
- functions to validate a chain of x509 certs, and extract a PK.
+ o function to encode x509 certs
- Parse CERT cells
- Generate CERT cells
o Keep copies of X509 certs around, not necessarily associated with
connection.
- LINK_AUTH cells
- - Code to generate
+ . Code to generate
o Remember certificate digests from TLS
- - Code to parse and check
+ o Code to parse and check
- Unit tests
- Revised handshake: TLS
- Server checks for new cipher types, and if it finds them, sends
@@ -53,7 +54,7 @@
- Client sends new cipher list.
- Client sends correct extension list.
- Revised handshake: post-TLS.
- - If in 'handshaking' state (since v2+ conn is in use), accept
+ o If in 'handshaking' state (since v2+ conn is in use), accept
VERSIONS and NETINFO and CERT and LINK_AUTH.
- After we send NETINFO, send CERT and LINK_AUTH if needed.
- Once we get a good LINK_AUTH, the connection is OPEN.
Modified: tor/trunk/src/or/command.c
===================================================================
--- tor/trunk/src/or/command.c 2007-11-05 18:15:54 UTC (rev 12384)
+++ tor/trunk/src/or/command.c 2007-11-05 18:15:56 UTC (rev 12385)
@@ -27,6 +27,8 @@
uint64_t stats_n_destroy_cells_processed = 0;
uint64_t stats_n_versions_cells_processed = 0;
uint64_t stats_n_netinfo_cells_processed = 0;
+uint64_t stats_n_cert_cells_processed = 0;
+uint64_t stats_n_link_auth_cells_processed = 0;
/* These are the main functions for processing cells */
static void command_process_create_cell(cell_t *cell, or_connection_t *conn);
@@ -35,6 +37,8 @@
static void command_process_destroy_cell(cell_t *cell, or_connection_t *conn);
static void command_process_versions_cell(cell_t *cell, or_connection_t *conn);
static void command_process_netinfo_cell(cell_t *cell, or_connection_t *conn);
+static void command_process_cert_cell(cell_t *cell, or_connection_t *conn);
+static void command_process_link_auth_cell(cell_t *cell,or_connection_t *conn);
#ifdef KEEP_TIMING_STATS
/** This is a wrapper function around the actual function that processes the
@@ -113,6 +117,8 @@
#define PROCESS_CELL(tp, cl, cn) command_process_ ## tp ## _cell(cl, cn)
#endif
+ /*XXXX020 reject all but VERSIONS, NETINFO, CERT, LINK_AUTH when
+ * handshaking. */
switch (cell->command) {
case CELL_PADDING:
++stats_n_padding_cells_processed;
@@ -144,6 +150,14 @@
++stats_n_netinfo_cells_processed;
PROCESS_CELL(netinfo, cell, conn);
break;
+ case CELL_CERT:
+ ++stats_n_cert_cells_processed;
+ PROCESS_CELL(cert, cell, conn);
+ break;
+ case CELL_LINK_AUTH:
+ ++stats_n_link_auth_cells_processed;
+ PROCESS_CELL(link_auth, cell, conn);
+ break;
default:
log_fn(LOG_INFO, LD_PROTOCOL,
"Cell of unknown type (%d) received. Dropping.", cell->command);
@@ -500,6 +514,7 @@
conn->handshake_state->received_netinfo = 1;
}
+/*XXXX020 move to connection_or.c */
/** DOCDOC Called when we're done authenticating; act on stuff we
* learned in netinfo. */
void
@@ -536,3 +551,92 @@
conn->is_canonical = 1;
}
}
+
+static void
+command_process_cert_cell(cell_t *cell, or_connection_t *conn)
+{
+ (void) cell;
+ (void) conn;
+
+ /* Parse certs. */
+ /* Verify that identity cert has signed peer cert in SSL, or
+ * peer cert in the cell. */
+ /* Verify that identity cert is self-signed. */
+ /* Learn ID digest. */
+ /* Learn cert digests. */
+ /* Remember peer cert public key. */
+ /* set received_certs. */
+}
+
+#define LINK_AUTH_STRING "Tor initiator certificate verification"
+
+/** DOCDOC */
+static void
+command_process_link_auth_cell(cell_t *cell, or_connection_t *conn)
+{
+ or_handshake_state_t *s;
+ char hmac[DIGEST_LEN];
+ size_t sig_len;
+ const char *sig;
+ char *checked = NULL;
+ int checked_len;
+ tor_assert(conn);
+ if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING) {
+ log_fn(LOG_PROTOCOL_WARN, LD_OR,
+ "Received a LINK_AUTH cell on connection in the wrong state; "
+ "dropping.");
+ return;
+ }
+ s = conn->handshake_state;
+ tor_assert(s);
+ if (s->started_here) {
+ log_fn(LOG_PROTOCOL_WARN, LD_OR,
+ "Got a LINK_AUTH cell from a server; closing the connection.");
+ goto err;
+ }
+ if (!s->received_netinfo || !s->received_versions || !s->received_certs) {
+ log_fn(LOG_PROTOCOL_WARN, LD_OR, "Got a LINK_AUTH cell too early; "
+ "closing the connection");
+ goto err;
+ }
+ if (cell->payload[0] != 0x00) {
+ log_fn(LOG_PROTOCOL_WARN, LD_OR, "Unrecognized LINK_AUTH signature "
+ "version; closing the connection");
+ goto err;
+ }
+ connection_or_compute_link_auth_hmac(conn, hmac);
+
+ tor_assert(s->signing_key);
+
+ /*XXXX020 these two are wrong; fix when protocol is revised. */
+ sig = cell->payload+1;
+ sig_len = 128;
+ checked = tor_malloc(crypto_pk_keysize(s->signing_key));
+ checked_len = crypto_pk_public_checksig(s->signing_key,checked,sig,sig_len);
+ if (checked_len < 0) {
+ log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad signature on LINK_AUTH cell; "
+ "closing the connection");
+ goto err;
+ }
+ if (checked_len != DIGEST_LEN) {
+ log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad length (%d) of signed material in "
+ "LINK_AUTH cell; closing the connection", checked_len);
+ goto err;
+ }
+ if (memcmp(checked, hmac, DIGEST_LEN) != 0) {
+ log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad signed data in LINK_AUTH cell; "
+ "closing the connection.");
+ goto err;
+ }
+
+ /* Okay, we're authenticated. */
+ s->authenticated = 1;
+
+ /* XXXX020 act on being authenticated: */
+
+ return;
+ err:
+ tor_free(checked);
+ connection_mark_for_close(TO_CONN(conn));
+}
+
Modified: tor/trunk/src/or/connection_or.c
===================================================================
--- tor/trunk/src/or/connection_or.c 2007-11-05 18:15:54 UTC (rev 12384)
+++ tor/trunk/src/or/connection_or.c 2007-11-05 18:15:56 UTC (rev 12385)
@@ -947,3 +947,37 @@
return 0;
}
+#define LINK_AUTH_STRING "Tor initiator certificate verification"
+/** DOCDOC */
+int
+connection_or_compute_link_auth_hmac(or_connection_t *conn,
+ char *hmac_out)
+{
+ char buf[64 + 2*TOR_TLS_RANDOM_LEN + 2*DIGEST_LEN];
+ char *cp;
+ or_handshake_state_t *s;
+ tor_assert(conn);
+ tor_assert(conn->handshake_state);
+ tor_assert(conn->tls);
+ s = conn->handshake_state;
+
+ /* Fill the buffer. */
+ strlcpy(buf, LINK_AUTH_STRING, sizeof(buf));
+ cp = buf+strlen(buf);
+ ++cp; /* Skip the NUL */
+ memcpy(cp, s->client_random, TOR_TLS_RANDOM_LEN);
+ cp += TOR_TLS_RANDOM_LEN;
+ memcpy(cp, s->server_random, TOR_TLS_RANDOM_LEN);
+ cp += TOR_TLS_RANDOM_LEN;
+ memcpy(cp, s->client_cert_digest, DIGEST_LEN);
+ cp += DIGEST_LEN;
+ memcpy(cp, s->server_cert_digest, DIGEST_LEN);
+ cp += DIGEST_LEN;
+ tor_assert(cp < buf+sizeof(buf));
+
+ if (tor_tls_hmac_with_master_secret(conn->tls, hmac_out, buf, cp-buf) < 0)
+ return -1;
+ return 0;
+}
+
+
Modified: tor/trunk/src/or/or.h
===================================================================
--- tor/trunk/src/or/or.h 2007-11-05 18:15:54 UTC (rev 12384)
+++ tor/trunk/src/or/or.h 2007-11-05 18:15:56 UTC (rev 12385)
@@ -657,6 +657,8 @@
#define CELL_CREATED_FAST 6
#define CELL_VERSIONS 7
#define CELL_NETINFO 8
+#define CELL_CERT 9
+#define CELL_LINK_AUTH 10
/** How long to test reachability before complaining to the user. */
#define TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT (20*60)
@@ -2778,6 +2780,10 @@
int connection_or_send_destroy(uint16_t circ_id, or_connection_t *conn,
int reason);
int connection_or_send_netinfo(or_connection_t *conn);
+int connection_or_send_certs(or_connection_t *conn);
+int connection_or_send_link_auth(or_connection_t *conn);
+int connection_or_compute_link_auth_hmac(or_connection_t *conn,
+ char *hmac_out);
void cell_pack(packed_cell_t *dest, const cell_t *src);
More information about the tor-commits
mailing list