return *n == '\0';
}
-/* Check that the identity of the remote host, as presented by its
- server certificate, corresponds to HOST, which is the host name the
- user thinks he's connecting to. This assumes that FD has been
- connected to an SSL context using ssl_connect. Return 1 if the
- identity checks out, 0 otherwise.
+/* Verify the validity of the certificate presented by the server.
+ Also check that the "common name" of the server, as presented by
+ its certificate, corresponds to HOST. (HOST typically comes from
+ the URL and is what the user thinks he's connecting to.)
- If opt.check_cert is 0, this always returns 1, but still warns the
- user about the mismatches, if any. */
+ This assumes that ssl_connect has successfully finished, i.e. that
+ the SSL handshake has been performed and that FD is connected to an
+ SSL handle.
+
+ If opt.check_cert is non-zero (the default), this returns 1 if the
+ certificate is valid, 0 otherwise. If opt.check_cert is 0, the
+ function always returns 1, but should still be called because it
+ warns the user about any problems with the certificate. */
int
-ssl_check_server_identity (int fd, const char *host)
+ssl_check_certificate (int fd, const char *host)
{
- X509 *peer_cert;
- char peer_CN[256];
+ X509 *cert;
+ char common_name[256];
long vresult;
- int retval;
+ int success;
/* If the user has specified --no-check-cert, we still want to warn
him about problems with the server's certificate. */
SSL *ssl = (SSL *) fd_transport_context (fd);
assert (ssl != NULL);
- peer_cert = SSL_get_peer_certificate (ssl);
- if (!peer_cert)
+ cert = SSL_get_peer_certificate (ssl);
+ if (!cert)
{
logprintf (LOG_NOTQUIET, _("%s: No certificate presented by %s.\n"),
severity, escnonprint (host));
- retval = 0;
+ success = 0;
goto out;
}
#ifdef ENABLE_DEBUG
if (opt.debug)
{
- char *subject = X509_NAME_oneline (X509_get_subject_name (peer_cert), 0, 0);
- char *issuer = X509_NAME_oneline (X509_get_issuer_name (peer_cert), 0, 0);
+ char *subject = X509_NAME_oneline (X509_get_subject_name (cert), 0, 0);
+ char *issuer = X509_NAME_oneline (X509_get_issuer_name (cert), 0, 0);
DEBUGP (("certificate:\n subject: %s\n issuer: %s\n",
escnonprint (subject), escnonprint (issuer)));
OPENSSL_free (subject);
_("%s: Certificate verification error for %s: %s\n"),
severity, escnonprint (host),
X509_verify_cert_error_string (vresult));
- retval = 0;
+ success = 0;
goto out;
}
- /* Check that the common name in the presented certificate matches
- HOST. This should be improved in the following ways:
+ /* Check that HOST matches the common name in the certificate. ####
+ The remains to be done:
- It should use dNSName/ipAddress subjectAltName extensions if
available; according to rfc2818: "If a subjectAltName extension
- When matching against common names, it should loop over all
common names and choose the most specific one, i.e. the last
- one, not the first one, which the current code picks. */
+ one, not the first one, which the current code picks.
+
+ - Make sure that the names are encoded as UTF-8 which, being
+ ASCII-compatible, can be easily compared against HOST. */
- peer_CN[0] = '\0';
- X509_NAME_get_text_by_NID (X509_get_subject_name (peer_cert),
- NID_commonName, peer_CN, sizeof (peer_CN));
- if (!pattern_match (peer_CN, host))
+ common_name[0] = '\0';
+ X509_NAME_get_text_by_NID (X509_get_subject_name (cert),
+ NID_commonName, common_name, sizeof (common_name));
+ if (!pattern_match (common_name, host))
{
logprintf (LOG_NOTQUIET, _("\
%s: certificate common name `%s' doesn't match requested host name `%s'.\n"),
- severity, escnonprint (peer_CN), escnonprint (host));
- retval = 0;
+ severity, escnonprint (common_name), escnonprint (host));
+ success = 0;
goto out;
}
/* The certificate was found, verified, and matched HOST. */
- retval = 1;
+ success = 1;
out:
- if (peer_cert)
- X509_free (peer_cert);
+ if (cert)
+ X509_free (cert);
+
+ if (opt.check_cert && !success)
+ logprintf (LOG_NOTQUIET, _("\
+To connect to %s insecurely, use `--no-check-certificate'.\n"),
+ escnonprint (host));
/* Allow --no-check-cert to disable certificate checking. */
- return opt.check_cert ? retval : 1;
+ return opt.check_cert ? success : 1;
}