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Commit 7142f3e4 authored by Nick Mathewson's avatar Nick Mathewson 🥄

Merge branch 'trove_2020_001_035' into maint-0.3.5

parents 3e08dd9d 7b2d1070
o Major bugfixes (NSS):
- Fix out-of-bound memory access in `tor_tls_cert_matches_key()` when Tor is
compiled with NSS support. Fixes bug 33119; bugfix on 0.3.5.1-alpha. This
issue is also tracked as TROVE-2020-001.
......@@ -713,23 +713,58 @@ MOCK_IMPL(int,
tor_tls_cert_matches_key,(const tor_tls_t *tls,
const struct tor_x509_cert_t *cert))
{
tor_assert(tls);
tor_assert(cert);
tor_assert(cert->cert);
int rv = 0;
CERTCertificate *peercert = SSL_PeerCertificate(tls->ssl);
if (!peercert)
tor_x509_cert_t *peercert = tor_tls_get_peer_cert((tor_tls_t *)tls);
if (!peercert || !peercert->cert)
goto done;
CERTSubjectPublicKeyInfo *peer_info = &peercert->subjectPublicKeyInfo;
CERTSubjectPublicKeyInfo *peer_info = &peercert->cert->subjectPublicKeyInfo;
CERTSubjectPublicKeyInfo *cert_info = &cert->cert->subjectPublicKeyInfo;
/* NSS stores the `len` field in bits, instead of bytes, for the
* `subjectPublicKey` field in CERTSubjectPublicKeyInfo, but
* `SECITEM_ItemsAreEqual()` compares the two bitstrings using a length field
* defined in bytes.
*
* We convert the `len` field from bits to bytes, do our comparison with
* `SECITEM_ItemsAreEqual()`, and reset the length field from bytes to bits
* again.
*
* See also NSS's own implementation of `SECKEY_CopySubjectPublicKeyInfo()`
* in seckey.c in the NSS source tree. This function also does the conversion
* between bits and bytes.
*/
const unsigned int peer_info_orig_len = peer_info->subjectPublicKey.len;
const unsigned int cert_info_orig_len = cert_info->subjectPublicKey.len;
/* We convert the length from bits to bytes, but instead of using NSS's
* `DER_ConvertBitString()` macro on both of peer_info->subjectPublicKey and
* cert_info->subjectPublicKey, we have to do the conversion explicitly since
* both of the two subjectPublicKey fields are allowed to point to the same
* memory address. Otherwise, the bits to bytes conversion would potentially
* be applied twice, which would lead to us comparing too few of the bytes
* when we call SECITEM_ItemsAreEqual(), which would be catastrophic.
*/
peer_info->subjectPublicKey.len = ((peer_info_orig_len + 7) >> 3);
cert_info->subjectPublicKey.len = ((cert_info_orig_len + 7) >> 3);
rv = SECOID_CompareAlgorithmID(&peer_info->algorithm,
&cert_info->algorithm) == 0 &&
SECITEM_ItemsAreEqual(&peer_info->subjectPublicKey,
&cert_info->subjectPublicKey);
/* Convert from bytes back to bits. */
peer_info->subjectPublicKey.len = peer_info_orig_len;
cert_info->subjectPublicKey.len = cert_info_orig_len;
done:
if (peercert)
CERT_DestroyCertificate(peercert);
tor_x509_cert_free(peercert);
return rv;
}
......
......@@ -105,6 +105,17 @@ const char* caCertString = "-----BEGIN CERTIFICATE-----\n"
"Yy1RT69d0rwYc5u/vnqODz1IjvT90smsrkBumGt791FAFeg=\n"
"-----END CERTIFICATE-----\n";
static tor_x509_cert_t *fixed_x509_cert = NULL;
static tor_x509_cert_t *
get_peer_cert_mock_return_fixed(tor_tls_t *tls)
{
(void)tls;
if (fixed_x509_cert)
return tor_x509_cert_dup(fixed_x509_cert);
else
return NULL;
}
tor_x509_cert_impl_t *
read_cert_from(const char *str)
{
......@@ -513,6 +524,67 @@ test_tortls_verify(void *ignored)
crypto_pk_free(k);
}
static void
test_tortls_cert_matches_key(void *ignored)
{
(void)ignored;
tor_x509_cert_impl_t *cert1 = NULL,
*cert2 = NULL,
*cert3 = NULL,
*cert4 = NULL;
tor_x509_cert_t *c1 = NULL, *c2 = NULL, *c3 = NULL, *c4 = NULL;
crypto_pk_t *k1 = NULL, *k2 = NULL, *k3 = NULL;
k1 = pk_generate(1);
k2 = pk_generate(2);
k3 = pk_generate(3);
cert1 = tor_tls_create_certificate(k1, k2, "A", "B", 1000);
cert2 = tor_tls_create_certificate(k1, k3, "C", "D", 1000);
cert3 = tor_tls_create_certificate(k2, k3, "C", "D", 1000);
cert4 = tor_tls_create_certificate(k3, k2, "E", "F", 1000);
tt_assert(cert1 && cert2 && cert3 && cert4);
c1 = tor_x509_cert_new(cert1); cert1 = NULL;
c2 = tor_x509_cert_new(cert2); cert2 = NULL;
c3 = tor_x509_cert_new(cert3); cert3 = NULL;
c4 = tor_x509_cert_new(cert4); cert4 = NULL;
tt_assert(c1 && c2 && c3 && c4);
MOCK(tor_tls_get_peer_cert, get_peer_cert_mock_return_fixed);
fixed_x509_cert = NULL;
/* If the peer has no certificate, it shouldn't match anything. */
tt_assert(! tor_tls_cert_matches_key(NULL, c1));
tt_assert(! tor_tls_cert_matches_key(NULL, c2));
tt_assert(! tor_tls_cert_matches_key(NULL, c3));
tt_assert(! tor_tls_cert_matches_key(NULL, c4));
fixed_x509_cert = c1;
/* If the peer has a certificate, it should match every cert with the same
* subject key. */
tt_assert(tor_tls_cert_matches_key(NULL, c1));
tt_assert(tor_tls_cert_matches_key(NULL, c2));
tt_assert(! tor_tls_cert_matches_key(NULL, c3));
tt_assert(! tor_tls_cert_matches_key(NULL, c4));
done:
tor_x509_cert_free(c1);
tor_x509_cert_free(c2);
tor_x509_cert_free(c3);
tor_x509_cert_free(c4);
if (cert1) tor_x509_cert_impl_free(cert1);
if (cert2) tor_x509_cert_impl_free(cert2);
if (cert3) tor_x509_cert_impl_free(cert3);
if (cert4) tor_x509_cert_impl_free(cert4);
crypto_pk_free(k1);
crypto_pk_free(k2);
crypto_pk_free(k3);
UNMOCK(tor_tls_get_peer_cert);
}
#define LOCAL_TEST_CASE(name, flags) \
{ #name, test_tortls_##name, (flags|TT_FORK), NULL, NULL }
......@@ -533,5 +605,6 @@ struct testcase_t tortls_tests[] = {
LOCAL_TEST_CASE(is_server, 0),
LOCAL_TEST_CASE(bridge_init, TT_FORK),
LOCAL_TEST_CASE(verify, TT_FORK),
LOCAL_TEST_CASE(cert_matches_key, 0),
END_OF_TESTCASES
};
......@@ -479,75 +479,6 @@ fake_x509_free(X509 *cert)
}
#endif
static tor_x509_cert_t *fixed_x509_cert = NULL;
static tor_x509_cert_t *
get_peer_cert_mock_return_fixed(tor_tls_t *tls)
{
(void)tls;
if (fixed_x509_cert)
return tor_x509_cert_dup(fixed_x509_cert);
else
return NULL;
}
static void
test_tortls_cert_matches_key(void *ignored)
{
(void)ignored;
X509 *cert1 = NULL, *cert2 = NULL, *cert3 = NULL, *cert4 = NULL;
tor_x509_cert_t *c1 = NULL, *c2 = NULL, *c3 = NULL, *c4 = NULL;
crypto_pk_t *k1 = NULL, *k2 = NULL, *k3 = NULL;
k1 = pk_generate(1);
k2 = pk_generate(2);
k3 = pk_generate(3);
cert1 = tor_tls_create_certificate(k1, k2, "A", "B", 1000);
cert2 = tor_tls_create_certificate(k1, k3, "C", "D", 1000);
cert3 = tor_tls_create_certificate(k2, k3, "C", "D", 1000);
cert4 = tor_tls_create_certificate(k3, k2, "E", "F", 1000);
tt_assert(cert1 && cert2 && cert3 && cert4);
c1 = tor_x509_cert_new(cert1); cert1 = NULL;
c2 = tor_x509_cert_new(cert2); cert2 = NULL;
c3 = tor_x509_cert_new(cert3); cert3 = NULL;
c4 = tor_x509_cert_new(cert4); cert4 = NULL;
tt_assert(c1 && c2 && c3 && c4);
MOCK(tor_tls_get_peer_cert, get_peer_cert_mock_return_fixed);
fixed_x509_cert = NULL;
/* If the peer has no certificate, it shouldn't match anything. */
tt_assert(! tor_tls_cert_matches_key(NULL, c1));
tt_assert(! tor_tls_cert_matches_key(NULL, c2));
tt_assert(! tor_tls_cert_matches_key(NULL, c3));
tt_assert(! tor_tls_cert_matches_key(NULL, c4));
fixed_x509_cert = c1;
/* If the peer has a certificate, it should match every cert with the same
* subject key. */
tt_assert(tor_tls_cert_matches_key(NULL, c1));
tt_assert(tor_tls_cert_matches_key(NULL, c2));
tt_assert(! tor_tls_cert_matches_key(NULL, c3));
tt_assert(! tor_tls_cert_matches_key(NULL, c4));
done:
tor_x509_cert_free(c1);
tor_x509_cert_free(c2);
tor_x509_cert_free(c3);
tor_x509_cert_free(c4);
if (cert1) X509_free(cert1);
if (cert2) X509_free(cert2);
if (cert3) X509_free(cert3);
if (cert4) X509_free(cert4);
crypto_pk_free(k1);
crypto_pk_free(k2);
crypto_pk_free(k3);
UNMOCK(tor_tls_get_peer_cert);
}
#ifndef OPENSSL_OPAQUE
static void
test_tortls_cert_get_key(void *ignored)
......@@ -2279,7 +2210,6 @@ struct testcase_t tortls_openssl_tests[] = {
INTRUSIVE_TEST_CASE(get_error, TT_FORK),
LOCAL_TEST_CASE(always_accept_verify_cb, 0),
INTRUSIVE_TEST_CASE(x509_cert_free, 0),
LOCAL_TEST_CASE(cert_matches_key, 0),
INTRUSIVE_TEST_CASE(cert_get_key, 0),
LOCAL_TEST_CASE(get_my_client_auth_key, TT_FORK),
INTRUSIVE_TEST_CASE(get_ciphersuite_name, 0),
......
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