* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2009 */
+/* Copyright (c) University of Cambridge 1995 - 2012 */
/* See the file NOTICE for conditions of use and distribution. */
/* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
#define EXIM_OCSP_MAX_AGE (-1L)
#endif
+#if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
+#define EXIM_HAVE_OPENSSL_TLSEXT
+#endif
+
/* Structure for collecting random data for seeding. */
typedef struct randstuff {
static const uschar *sid_ctx = US"exim";
static SSL_CTX *ctx = NULL;
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
static SSL_CTX *ctx_sni = NULL;
+#endif
static SSL *ssl = NULL;
static char ssl_errstring[256];
setup_certs(SSL_CTX *sctx, uschar *certs, uschar *crl, host_item *host, BOOL optional);
/* Callbacks */
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
static int tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg);
+#endif
#ifdef EXPERIMENTAL_OCSP
static int tls_stapling_cb(SSL *s, void *arg);
#endif
}
else
{
- SSL_CTX_set_tmp_dh(ctx, dh);
- DEBUG(D_tls)
- debug_printf("Diffie-Hellman initialized from %s with %d-bit key\n",
- dhexpanded, 8*DH_size(dh));
+ if ((8*DH_size(dh)) > tls_dh_max_bits)
+ {
+ DEBUG(D_tls)
+ debug_printf("dhparams file %d bits, is > tls_dh_max_bits limit of %d",
+ 8*DH_size(dh), tls_dh_max_bits);
+ }
+ else
+ {
+ SSL_CTX_set_tmp_dh(ctx, dh);
+ DEBUG(D_tls)
+ debug_printf("Diffie-Hellman initialized from %s with %d-bit key\n",
+ dhexpanded, 8*DH_size(dh));
+ }
DH_free(dh);
}
BIO_free(bio);
Returns: SSL_TLSEXT_ERR_{OK,ALERT_WARNING,ALERT_FATAL,NOACK}
*/
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
static int
tls_servername_cb(SSL *s, int *ad ARG_UNUSED, void *arg)
{
return SSL_TLSEXT_ERR_OK;
}
+#endif /* EXIM_HAVE_OPENSSL_TLSEXT */
if (rc != OK) return rc;
/* If we need to handle SNI, do so */
-#if OPENSSL_VERSION_NUMBER >= 0x0090806fL && !defined(OPENSSL_NO_TLSEXT)
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
if (host == NULL)
{
#ifdef EXPERIMENTAL_OCSP
Arguments:
require_ciphers allowed ciphers
- ------------------------------------------------------
- require_mac list of allowed MACs ) Not used
- require_kx list of allowed key_exchange methods ) for
- require_proto list of allowed protocols ) OpenSSL
- ------------------------------------------------------
Returns: OK on success
DEFER for errors before the start of the negotiation
*/
int
-tls_server_start(uschar *require_ciphers, uschar *require_mac,
- uschar *require_kx, uschar *require_proto)
+tls_server_start(const uschar *require_ciphers)
{
int rc;
uschar *expciphers;
return FAIL;
/* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they
-are separated by underscores. So that I can use either form in my tests, and
-also for general convenience, we turn underscores into hyphens here. */
+were historically separated by underscores. So that I can use either form in my
+tests, and also for general convenience, we turn underscores into hyphens here.
+*/
if (expciphers != NULL)
{
verify_certs file for certificate verify
crl file containing CRL
require_ciphers list of allowed ciphers
- ------------------------------------------------------
- require_mac list of allowed MACs ) Not used
- require_kx list of allowed key_exchange methods ) for
- require_proto list of allowed protocols ) OpenSSL
- ------------------------------------------------------
timeout startup timeout
Returns: OK on success
tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam,
uschar *certificate, uschar *privatekey, uschar *sni,
uschar *verify_certs, uschar *crl,
- uschar *require_ciphers, uschar *require_mac, uschar *require_kx,
- uschar *require_proto, int timeout)
+ uschar *require_ciphers, int timeout)
{
static uschar txt[256];
uschar *expciphers;
tls_sni = NULL;
else
{
+#ifdef EXIM_HAVE_OPENSSL_TLSEXT
DEBUG(D_tls) debug_printf("Setting TLS SNI \"%s\"\n", tls_sni);
SSL_set_tlsext_host_name(ssl, tls_sni);
+#else
+ DEBUG(D_tls)
+ debug_printf("OpenSSL at build-time lacked SNI support, ignoring \"%s\"\n",
+ tls_sni);
+#endif
}
}
+/*************************************************
+* Let tls_require_ciphers be checked at startup *
+*************************************************/
+
+/* The tls_require_ciphers option, if set, must be something which the
+library can parse.
+
+Returns: NULL on success, or error message
+*/
+
+uschar *
+tls_validate_require_cipher(void)
+{
+SSL_CTX *ctx;
+uschar *s, *expciphers, *err;
+
+/* this duplicates from tls_init(), we need a better "init just global
+state, for no specific purpose" singleton function of our own */
+
+SSL_load_error_strings();
+OpenSSL_add_ssl_algorithms();
+#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
+/* SHA256 is becoming ever more popular. This makes sure it gets added to the
+list of available digests. */
+EVP_add_digest(EVP_sha256());
+#endif
+
+if (!(tls_require_ciphers && *tls_require_ciphers))
+ return NULL;
+
+if (!expand_check(tls_require_ciphers, US"tls_require_ciphers", &expciphers))
+ return US"failed to expand tls_require_ciphers";
+
+if (!(expciphers && *expciphers))
+ return NULL;
+
+/* normalisation ripped from above */
+s = expciphers;
+while (*s != 0) { if (*s == '_') *s = '-'; s++; }
+
+err = NULL;
+
+ctx = SSL_CTX_new(SSLv23_server_method());
+if (!ctx)
+ {
+ ERR_error_string(ERR_get_error(), ssl_errstring);
+ return string_sprintf("SSL_CTX_new() failed: %s", ssl_errstring);
+ }
+
+DEBUG(D_tls)
+ debug_printf("tls_require_ciphers expands to \"%s\"\n", expciphers);
+
+if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
+ {
+ ERR_error_string(ERR_get_error(), ssl_errstring);
+ err = string_sprintf("SSL_CTX_set_cipher_list(%s) failed", expciphers);
+ }
+
+SSL_CTX_free(ctx);
+
+return err;
+}
+
+
+
+
/*************************************************
* Report the library versions. *
*************************************************/
/*************************************************
-* Pseudo-random number generation *
+* Random number generation *
*************************************************/
/* Pseudo-random number generation. The result is not expected to be
*/
int
-pseudo_random_number(int max)
+vaguely_random_number(int max)
{
unsigned int r;
int i, needed_len;
needed_len = i;
/* We do not care if crypto-strong */
-(void) RAND_pseudo_bytes(smallbuf, needed_len);
+i = RAND_pseudo_bytes(smallbuf, needed_len);
+if (i < 0)
+ {
+ DEBUG(D_all)
+ debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n");
+ return vaguely_random_number_fallback(max);
+ }
+
r = 0;
for (p = smallbuf; needed_len; --needed_len, ++p)
{
BOOL adding, item_parsed;
result = 0L;
-/* Prior to 4.78 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
+/* Prior to 4.80 we or'd in SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; removed
* from default because it increases BEAST susceptibility. */
if (option_spec == NULL)
git://git.exim.org / exim.git / blobdiff