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When parsing certs cells, allow more certs types

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Implements the parsing part of #19157
This commit is contained in:
Nick Mathewson 2015-03-05 10:59:04 +01:00
parent 77e2be06f6
commit 986695fb74
1 changed files with 114 additions and 23 deletions
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123
src/or/channeltls.c
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@ -33,6 +33,7 @@
#include "router.h"
#include "routerlist.h"
#include "scheduler.h"
#include "torcert.h"
/** How many CELL_PADDING cells have we received, ever? */
uint64_t stats_n_padding_cells_processed = 0;
@ -1722,6 +1723,41 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
assert_connection_ok(TO_CONN(chan->conn),time(NULL));
}
/** Types of certificates that we know how to parse from CERTS cells. Each
* type corresponds to a different encoding format. */
typedef enum cert_encoding_t {
CERT_ENCODING_UNKNOWN, /**< We don't recognize this. */
CERT_ENCODING_X509, /**< It's an RSA key, signed with RSA, encoded in x509.
* (Actually, it might not be RSA. We test that later.) */
CERT_ENCODING_ED25519, /**< It's something signed with an Ed25519 key,
* encoded asa a tor_cert_t.*/
CERT_ENCODING_RSA_CROSSCERT, /**< It's an Ed key signed with an RSA key. */
} cert_encoding_t;
/**
* Given one of the certificate type codes used in a CERTS cell,
* return the corresponding cert_encoding_t that we should use to parse
* the certificate.
*/
static cert_encoding_t
certs_cell_typenum_to_cert_type(int typenum)
{
switch (typenum) {
case CERTTYPE_RSA1024_ID_LINK:
case CERTTYPE_RSA1024_ID_ID:
case CERTTYPE_RSA1024_ID_AUTH:
return CERT_ENCODING_X509;
case CERTTYPE_ED_ID_SIGN:
case CERTTYPE_ED_SIGN_LINK:
case CERTTYPE_ED_SIGN_AUTH:
return CERT_ENCODING_ED25519;
case CERTTYPE_RSA1024_ID_EDID:
return CERT_ENCODING_RSA_CROSSCERT;
default:
return CERT_ENCODING_UNKNOWN;
}
}
/**
* Process a CERTS cell from a channel.
*
@ -1741,14 +1777,20 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
STATIC void
channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan)
{
#define MAX_CERT_TYPE_WANTED OR_CERT_TYPE_AUTH_1024
tor_x509_cert_t *certs[MAX_CERT_TYPE_WANTED + 1];
#define MAX_CERT_TYPE_WANTED CERTTYPE_RSA1024_ID_EDID
/* These arrays will be sparse, since a cert type can be at most one
* of ed/x509 */
tor_x509_cert_t *x509_certs[MAX_CERT_TYPE_WANTED + 1];
tor_cert_t *ed_certs[MAX_CERT_TYPE_WANTED + 1];
rsa_ed_crosscert_t *rsa_crosscert = NULL;
int n_certs, i;
certs_cell_t *cc = NULL;
int send_netinfo = 0;
memset(certs, 0, sizeof(certs));
memset(x509_certs, 0, sizeof(x509_certs));
memset(ed_certs, 0, sizeof(ed_certs));
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
@ -1792,26 +1834,70 @@ channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan)
if (cert_type > MAX_CERT_TYPE_WANTED)
continue;
tor_x509_cert_t *cert = tor_x509_cert_decode(cert_body, cert_len);
if (!cert) {
const cert_encoding_t ct = certs_cell_typenum_to_cert_type(cert_type);
switch (ct) {
default:
case CERT_ENCODING_UNKNOWN:
break;
case CERT_ENCODING_X509: {
tor_x509_cert_t *x509_cert = tor_x509_cert_decode(cert_body, cert_len);
if (!x509_cert) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received undecodable certificate in CERTS cell from %s:%d",
safe_str(chan->conn->base_.address),
chan->conn->base_.port);
} else {
if (certs[cert_type]) {
tor_x509_cert_free(cert);
if (x509_certs[cert_type]) {
tor_x509_cert_free(x509_cert);
ERR("Duplicate x509 certificate");
} else {
certs[cert_type] = cert;
x509_certs[cert_type] = x509_cert;
}
}
break;
}
case CERT_ENCODING_ED25519: {
tor_cert_t *ed_cert = tor_cert_parse(cert_body, cert_len);
if (!ed_cert) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received undecodable Ed certificate in CERTS cell from %s:%d",
safe_str(chan->conn->base_.address),
chan->conn->base_.port);
} else {
if (ed_certs[cert_type]) {
tor_cert_free(ed_cert);
ERR("Duplicate Ed25519 certificate");
} else {
ed_certs[cert_type] = ed_cert;
}
}
break;
}
case CERT_ENCODING_RSA_CROSSCERT: {
rsa_ed_crosscert_t *cc_cert = NULL;
ssize_t n = rsa_ed_crosscert_parse(&cc_cert, cert_body, cert_len);
if (n != cert_len) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received unparseable RS1024-Ed25519 crosscert "
" in CERTS cell from %s:%d",
safe_str(chan->conn->base_.address),
chan->conn->base_.port);
} else {
if (rsa_crosscert) {
rsa_ed_crosscert_free(cc_cert);
ERR("Duplicate RSA->Ed25519 crosscert");
} else {
rsa_crosscert = cc_cert;
}
}
break;
}
}
}
tor_x509_cert_t *id_cert = certs[OR_CERT_TYPE_ID_1024];
tor_x509_cert_t *auth_cert = certs[OR_CERT_TYPE_AUTH_1024];
tor_x509_cert_t *link_cert = certs[OR_CERT_TYPE_TLS_LINK];
tor_x509_cert_t *id_cert = x509_certs[OR_CERT_TYPE_ID_1024];
tor_x509_cert_t *auth_cert = x509_certs[OR_CERT_TYPE_AUTH_1024];
tor_x509_cert_t *link_cert = x509_certs[OR_CERT_TYPE_TLS_LINK];
if (chan->conn->handshake_state->started_here) {
int severity;
@ -1862,7 +1948,7 @@ channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan)
safe_str(chan->conn->base_.address), chan->conn->base_.port);
chan->conn->handshake_state->id_cert = id_cert;
certs[OR_CERT_TYPE_ID_1024] = NULL;
x509_certs[OR_CERT_TYPE_ID_1024] = NULL;
if (!public_server_mode(get_options())) {
/* If we initiated the connection and we are not a public server, we
@ -1889,7 +1975,8 @@ channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan)
chan->conn->handshake_state->id_cert = id_cert;
chan->conn->handshake_state->auth_cert = auth_cert;
certs[OR_CERT_TYPE_ID_1024] = certs[OR_CERT_TYPE_AUTH_1024] = NULL;
x509_certs[OR_CERT_TYPE_ID_1024] = x509_certs[OR_CERT_TYPE_AUTH_1024]
= NULL;
}
chan->conn->handshake_state->received_certs_cell = 1;
@ -1903,9 +1990,13 @@ channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan)
}
err:
for (unsigned u = 0; u < ARRAY_LENGTH(certs); ++u) {
tor_x509_cert_free(certs[u]);
for (unsigned u = 0; u < ARRAY_LENGTH(x509_certs); ++u) {
tor_x509_cert_free(x509_certs[u]);
}
for (unsigned u = 0; u < ARRAY_LENGTH(ed_certs); ++u) {
tor_cert_free(ed_certs[u]);
}
rsa_ed_crosscert_free(rsa_crosscert);
certs_cell_free(cc);
#undef ERR
}