/*
* Verify established TLS connections.
*
- * Copyright (C) 2011-2013 Simon Ruderich
+ * Copyright (C) 2011-2014 Simon Ruderich
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#include "tlsproxy.h"
#include "verify.h"
+#include <assert.h>
#include <errno.h>
#include <gnutls/x509.h>
+/* Compatibility for older GnuTLS versions. Define the constants in a way
+ * which doesn't affect the status check below. */
+#ifndef GNUTLS_CERT_SIGNER_NOT_CA
+# define GNUTLS_CERT_SIGNER_NOT_CA 0
+#endif
+#ifndef GNUTLS_CERT_SIGNATURE_FAILURE
+# define GNUTLS_CERT_SIGNATURE_FAILURE 0
+#endif
+#ifndef GNUTLS_CERT_REVOCATION_DATA_SUPERSEDED
+# define GNUTLS_CERT_REVOCATION_DATA_SUPERSEDED 0
+#endif
+#ifndef GNUTLS_CERT_UNEXPECTED_OWNER
+# define GNUTLS_CERT_UNEXPECTED_OWNER 0
+#endif
+#ifndef GNUTLS_CERT_REVOCATION_DATA_ISSUED_IN_FUTURE
+# define GNUTLS_CERT_REVOCATION_DATA_ISSUED_IN_FUTURE 0
+#endif
+#ifndef GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE
+# define GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE 0
+#endif
+#ifndef GNUTLS_CERT_MISMATCH
+# define GNUTLS_CERT_MISMATCH 0
+#endif
+
+
static int get_certificate_path(const char *format,
const char *hostname, char *buffer, size_t size);
/* Verification failed (!= invalid certificate but worse), no need for any
* more checks. */
if (result < 0) {
- LOG(LOG_WARNING,
- "verify_tls_connection(): gnutls_certificate_verify_peers2() failed: %s",
+ LOG(WARNING,
+ "verify_tls_connection(): "
+ "gnutls_certificate_verify_peers2() failed: %s",
gnutls_strerror(result));
return -1;
}
- /* Definitely an invalid certificate, abort. */
- if (status & GNUTLS_CERT_EXPIRED
- || status & GNUTLS_CERT_REVOKED
+ /* Definitely an invalid certificate, abort. We don't perform any CA
+ * verification so don't check for GNUTLS_CERT_INVALID. */
+ if (status & GNUTLS_CERT_REVOKED
+ || status & GNUTLS_CERT_SIGNER_NOT_CA
+ || status & GNUTLS_CERT_INSECURE_ALGORITHM
|| status & GNUTLS_CERT_NOT_ACTIVATED
- || status & GNUTLS_CERT_INSECURE_ALGORITHM) {
- LOG(LOG_WARNING,
- "verify_tls_connection(): invalid server certificate");
+ || status & GNUTLS_CERT_EXPIRED
+ || status & GNUTLS_CERT_SIGNATURE_FAILURE
+ || status & GNUTLS_CERT_REVOCATION_DATA_SUPERSEDED
+ || status & GNUTLS_CERT_UNEXPECTED_OWNER
+ || status & GNUTLS_CERT_REVOCATION_DATA_ISSUED_IN_FUTURE
+ || status & GNUTLS_CERT_SIGNER_CONSTRAINTS_FAILURE
+ || status & GNUTLS_CERT_MISMATCH) {
+ LOG(WARNING, "verify_tls_connection(): invalid server certificate");
return -1;
}
* prevent an attacker from changing the certificate type to prevent
* detection. */
if (gnutls_certificate_type_get(session) != GNUTLS_CRT_X509) {
- LOG(LOG_WARNING,
- "verify_tls_connection(): no X509 server certificate");
+ LOG(WARNING, "verify_tls_connection(): no X509 server certificate");
return -1;
}
result = gnutls_x509_crt_init(&cert);
if (result < 0) {
- LOG(LOG_WARNING,
+ LOG(WARNING,
"verify_tls_connection(): gnutls_x509_crt_init() failed: %s",
gnutls_strerror(result));
return -1;
cert_list = gnutls_certificate_get_peers(session, &cert_list_size);
if (cert_list == NULL) {
- LOG(LOG_WARNING,
+ LOG(WARNING,
"verify_tls_connection(): gnutls_certificate_get_peers() failed");
gnutls_x509_crt_deinit(cert);
return -1;
result = gnutls_x509_crt_import(cert, &cert_list[0], GNUTLS_X509_FMT_DER);
if (result < 0) {
- LOG(LOG_WARNING,
+ LOG(WARNING,
"verify_tls_connection(): gnutls_x509_crt_import() failed: %s",
gnutls_strerror(result));
gnutls_x509_crt_deinit(cert);
result = gnutls_x509_crt_export(cert, GNUTLS_X509_FMT_PEM,
server_cert, &size);
if (result != GNUTLS_E_SUCCESS) {
- LOG(LOG_WARNING,
+ LOG(WARNING,
"verify_tls_connection(): gnutls_x509_crt_export() failed: %s",
gnutls_strerror(result));
gnutls_x509_crt_deinit(cert);
/* Open stored server certificate file. */
if (server_certificate_file(&file, hostname, path, sizeof(path)) != 0) {
- LOG(LOG_DEBUG, "server certificate:\n%s", server_cert);
+ LOG(DEBUG1, "server certificate:\n%s", server_cert);
return -1;
}
size += strlen(buffer);
/* Make sure the buffer is big enough. */
if (size >= sizeof(stored_cert)) {
- LOG(LOG_WARNING, "verify_tls_connection(): '%s' too big", path);
+ LOG(WARNING, "verify_tls_connection(): '%s' too big", path);
fclose(file);
- LOG(LOG_DEBUG, "server certificate:\n%s", server_cert);
+ LOG(DEBUG1, "server certificate:\n%s", server_cert);
return -1;
}
strcat(stored_cert, buffer);
}
if (ferror(file)) {
+ LOG(WARNING, "verify_tls_connection(): failed to read from '%s': %s",
+ path, strerror(errno));
fclose(file);
- LOG(LOG_WARNING,
- "verify_tls_connection(): failed to read from '%s': %s",
- path, strerror(errno));
- LOG(LOG_DEBUG, "server certificate:\n%s", server_cert);
+ LOG(DEBUG1, "server certificate:\n%s", server_cert);
return -1;
}
fclose(file);
/* Check if the server certificate matches our stored certificate. */
if (strcmp(stored_cert, server_cert)) {
- LOG(LOG_ERROR,
- "verify_tls_connection(): server certificate changed!",
- path, strerror(errno));
+ LOG(ERROR, "verify_tls_connection(): server certificate changed!",
+ path, strerror(errno));
- LOG(LOG_WARNING, "server certificate:\n%s", server_cert);
+ LOG(WARNING, "server certificate:\n%s", server_cert);
return -2;
}
- /* Check that the proxy certificate file exists and is readable for this
- * domain. This ensures we send an "invalid" certificate even if the proxy
- * certificate doesn't exist. */
+ /* Check that the proxy certificate file for this domain exists and is
+ * readable. This ensures we send an "invalid" certificate if the proxy
+ * certificate doesn't exist.
+ *
+ * If the file gets removed or becomes unreadable after the check we won't
+ * be able to establish a connection to the real server so this
+ * race-condition has no security issues and is only a convenience for the
+ * user. */
if (proxy_certificate_path(hostname, path, sizeof(path)) != 0) {
return -1;
}
file = fopen(path, "r");
if (file == NULL) {
- LOG(LOG_WARNING,
+ LOG(WARNING,
"verify_tls_connection(): proxy certificate doesn't exist: '%s'",
path);
return -1;
int result;
/* Hostname too long. */
+ assert(size > strlen(format));
if (size - strlen(format) <= strlen(hostname)) {
- LOG(LOG_WARNING,
- "get_certificate_path(): hostname too long: '%s'",
- hostname);
+ LOG(WARNING, "get_certificate_path(): hostname too long: '%s'",
+ hostname);
return -1;
}
/* Try to prevent path traversals in hostnames. */
if (strstr(hostname, "..") != NULL) {
- LOG(LOG_WARNING,
- "get_certificate_path(): possible path traversal: '%s'",
- hostname);
+ LOG(WARNING, "get_certificate_path(): possible path traversal: '%s'",
+ hostname);
return -1;
}
/* Safe as format is no user input. */
result = snprintf(buffer, size, format, hostname);
if (result < 0) {
- LOG_PERROR(LOG_ERROR, "get_certificate_path(): snprintf failed");
+ LOG_PERROR(ERROR, "get_certificate_path(): snprintf failed");
return -1;
} else if ((size_t)result >= size) {
- LOG(LOG_ERROR, "get_certificate_path(): snprintf buffer too short");
+ LOG(ERROR, "get_certificate_path(): snprintf buffer too short");
return -1;
}
}
int proxy_certificate_path(const char *hostname, char *path, size_t size) {
- return get_certificate_path(PROXY_SERVER_CERT_FORMAT,
+ return get_certificate_path(PROXY_SERVER_CERT_FILE_FORMAT,
hostname, path, size);
}
int server_certificate_file(FILE **file, const char *hostname,
char *path, size_t size) {
- if (get_certificate_path(STORED_SERVER_CERT_FORMAT,
+ if (get_certificate_path(STORED_SERVER_CERT_FILE_FORMAT,
hostname, path, size) != 0) {
- LOG_PERROR(LOG_ERROR,
- "server_certificate_file(): failed to get path");
+ LOG_PERROR(ERROR, "server_certificate_file(): failed to get path");
return -1;
}
*file = fopen(path, "rb");
if (*file == NULL) {
if (global_passthrough_unknown) {
- LOG(LOG_DEBUG,
- "server_certificate_file(): failed to open '%s': %s",
- path, strerror(errno));
+ LOG(DEBUG1, "server_certificate_file(): failed to open '%s': %s",
+ path, strerror(errno));
} else {
- LOG(LOG_WARNING,
- "server_certificate_file(): failed to open '%s': %s",
- path, strerror(errno));
+ LOG(WARNING, "server_certificate_file(): failed to open '%s': %s",
+ path, strerror(errno));
}
/* Couldn't open the file, special case. */
return -2;
ruderich.org/simon / tlsproxy / tlsproxy.git / blobdiff