-/* $Cambridge: exim/src/src/tls-openssl.c,v 1.14 2009/06/10 07:34:04 tom Exp $ */
+/* $Cambridge: exim/src/src/tls-openssl.c,v 1.22 2009/11/16 19:50:37 nm4 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2007 */
+/* Copyright (c) University of Cambridge 1995 - 2009 */
/* See the file NOTICE for conditions of use and distribution. */
/* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
/* Structure for collecting random data for seeding. */
typedef struct randstuff {
- time_t t;
- pid_t p;
+ struct timeval tv;
+ pid_t p;
} randstuff;
/* Local static variables */
if (msg == NULL)
{
ERR_error_string(ERR_get_error(), ssl_errstring);
- msg = ssl_errstring;
+ msg = (uschar *)ssl_errstring;
}
if (host == NULL)
{
uschar *conn_info = smtp_get_connection_info();
- if (strncmp(conn_info, "SMTP ", 5) == 0)
+ if (Ustrncmp(conn_info, US"SMTP ", 5) == 0)
conn_info += 5;
log_write(0, LOG_MAIN, "TLS error on %s (%s): %s",
conn_info, prefix, msg);
if ((bio = BIO_new_file(CS dhexpanded, "r")) == NULL)
{
tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
- host, strerror(errno));
+ host, (uschar *)strerror(errno));
yield = FALSE;
}
else
SSL_load_error_strings(); /* basic set up */
OpenSSL_add_ssl_algorithms();
+#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
+/* SHA256 is becoming ever moar popular. This makes sure it gets added to the
+list of available digests. */
+EVP_add_digest(EVP_sha256());
+#endif
+
/* Create a context */
ctx = SSL_CTX_new((host == NULL)?
if (!RAND_status())
{
randstuff r;
- r.t = time(NULL);
+ gettimeofday(&r.tv, NULL);
r.p = getpid();
RAND_seed((uschar *)(&r), sizeof(r));
if (!RAND_status())
return tls_error(US"RAND_status", host,
- "unable to seed random number generator");
+ US"unable to seed random number generator");
}
/* Set up the information callback, which outputs if debugging is at a suitable
if (tls_active >= 0)
{
- tls_error("STARTTLS received after TLS started", NULL, "");
+ tls_error(US"STARTTLS received after TLS started", NULL, US"");
smtp_printf("554 Already in TLS\r\n");
return FAIL;
}
tls_active = -1;
}
+
+
+
+/*************************************************
+* Report the library versions. *
+*************************************************/
+
+/* There have historically been some issues with binary compatibility in
+OpenSSL libraries; if Exim (like many other applications) is built against
+one version of OpenSSL but the run-time linker picks up another version,
+it can result in serious failures, including crashing with a SIGSEGV. So
+report the version found by the compiler and the run-time version.
+
+Arguments: a FILE* to print the results to
+Returns: nothing
+*/
+
+void
+tls_version_report(FILE *f)
+{
+fprintf(f, "OpenSSL compile-time version: %s\n", OPENSSL_VERSION_TEXT);
+fprintf(f, "OpenSSL runtime version: %s\n", SSLeay_version(SSLEAY_VERSION));
+}
+
+
+
+
+/*************************************************
+* Pseudo-random number generation *
+*************************************************/
+
+/* Pseudo-random number generation. The result is not expected to be
+cryptographically strong but not so weak that someone will shoot themselves
+in the foot using it as a nonce in input in some email header scheme or
+whatever weirdness they'll twist this into. The result should handle fork()
+and avoid repeating sequences. OpenSSL handles that for us.
+
+Arguments:
+ max range maximum
+Returns a random number in range [0, max-1]
+*/
+
+int
+pseudo_random_number(int max)
+{
+unsigned int r;
+int i, needed_len;
+uschar *p;
+uschar smallbuf[sizeof(r)];
+
+if (max <= 1)
+ return 0;
+
+/* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */
+if (!RAND_status())
+ {
+ randstuff r;
+ gettimeofday(&r.tv, NULL);
+ r.p = getpid();
+
+ RAND_seed((uschar *)(&r), sizeof(r));
+ }
+/* We're after pseudo-random, not random; if we still don't have enough data
+in the internal PRNG then our options are limited. We could sleep and hope
+for entropy to come along (prayer technique) but if the system is so depleted
+in the first place then something is likely to just keep taking it. Instead,
+we'll just take whatever little bit of pseudo-random we can still manage to
+get. */
+
+needed_len = sizeof(r);
+/* Don't take 8 times more entropy than needed if int is 8 octets and we were
+asked for a number less than 10. */
+for (r = max, i = 0; r; ++i)
+ r >>= 1;
+i = (i + 7) / 8;
+if (i < needed_len)
+ needed_len = i;
+
+/* We do not care if crypto-strong */
+(void) RAND_pseudo_bytes(smallbuf, needed_len);
+r = 0;
+for (p = smallbuf; needed_len; --needed_len, ++p)
+ {
+ r *= 256;
+ r += *p;
+ }
+
+/* We don't particularly care about weighted results; if someone wants
+smooth distribution and cares enough then they should submit a patch then. */
+return r % max;
+}
+
/* End of tls-openssl.c */
git://git.exim.org / exim.git / blobdiff