[exim.git] / src / src / tls.c

/* $Cambridge: exim/src/src/tls.c,v 1.1 2004/10/07 10:39:01 ph10 Exp $ */

/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) University of Cambridge 1995 - 2004 */
/* See the file NOTICE for conditions of use and distribution. */

/* This module provides TLS (aka SSL) support for Exim. The code for OpenSSL is
based on a patch that was originally contributed by Steve Haslam. It was
adapted from stunnel, a GPL program by Michal Trojnara. The code for GNU TLS is
based on a patch contributed by Nikos Mavroyanopoulos. Because these packages
are so very different, the functions for each are kept in separate files. The
relevant file is #included as required, after any any common functions.

No cryptographic code is included in Exim. All this module does is to call
functions from the OpenSSL or GNU TLS libraries. */


#include "exim.h"

/* This module is compiled only when it is specifically requested in the
build-time configuration. However, some compilers don't like compiling empty
modules, so keep them happy with a dummy when skipping the rest. Make it
reference itself to stop picky compilers complaining that it is unused, and put
in a dummy argument to stop even pickier compilers complaining about infinite
loops. */

#ifndef SUPPORT_TLS
static void dummy(int x) { dummy(x-1); }
#else

/* Static variables that are used for buffering data by both sets of
functions and the common functions below. */


static uschar *ssl_xfer_buffer = NULL;
static int ssl_xfer_buffer_size = 4096;
static int ssl_xfer_buffer_lwm = 0;
static int ssl_xfer_buffer_hwm = 0;
static int ssl_xfer_eof = 0;
static int ssl_xfer_error = 0;


/*************************************************
*       Expand string; give error on failure     *
*************************************************/

/* If expansion is forced to fail, set the result NULL and return TRUE.
Other failures return FALSE. For a server, an SMTP response is given.

Arguments:
  s         the string to expand; if NULL just return TRUE
  name      name of string being expanded (for error)
  result    where to put the result

Returns:    TRUE if OK; result may still be NULL after forced failure
*/

static BOOL
expand_check(uschar *s, uschar *name, uschar **result)
{
if (s == NULL) *result = NULL; else
  {
  *result = expand_string(s);
  if (*result == NULL && !expand_string_forcedfail)
    {
    log_write(0, LOG_MAIN|LOG_PANIC, "expansion of %s failed: %s", name,
      expand_string_message);
    return FALSE;
    }
  }
return TRUE;
}


/*************************************************
*        Many functions are package-specific     *
*************************************************/

#ifdef USE_GNUTLS
#include "tls-gnu.c"
#else
#include "tls-openssl.c"
#endif


/*************************************************
*           TLS version of ungetc                *
*************************************************/

/* Puts a character back in the input buffer. Only ever
called once.

Arguments:
  ch           the character

Returns:       the character
*/

int
tls_ungetc(int ch)
{
ssl_xfer_buffer[--ssl_xfer_buffer_lwm] = ch;
return ch;
}


/*************************************************
*           TLS version of feof                  *
*************************************************/

/* Tests for a previous EOF

Arguments:     none
Returns:       non-zero if the eof flag is set
*/

int
tls_feof(void)
{
return ssl_xfer_eof;
}


/*************************************************
*              TLS version of ferror             *
*************************************************/

/* Tests for a previous read error, and returns with errno
restored to what it was when the error was detected.

>>>>> Hmm. Errno not handled yet. Where do we get it from?  >>>>>

Arguments:     none
Returns:       non-zero if the error flag is set
*/

int
tls_ferror(void)
{
return ssl_xfer_error;
}

#endif  /* SUPPORT_TLS */

/* End of tls.c */
Commit	Line	Data
059ec3d9 PH	1	/* $Cambridge: exim/src/src/tls.c,v 1.1 2004/10/07 10:39:01 ph10 Exp $ */
	2
	3	/*************************************************
	4	* Exim - an Internet mail transport agent *
	5	*************************************************/
	6
	7	/* Copyright (c) University of Cambridge 1995 - 2004 */
	8	/* See the file NOTICE for conditions of use and distribution. */
	9
	10	/* This module provides TLS (aka SSL) support for Exim. The code for OpenSSL is
	11	based on a patch that was originally contributed by Steve Haslam. It was
	12	adapted from stunnel, a GPL program by Michal Trojnara. The code for GNU TLS is
	13	based on a patch contributed by Nikos Mavroyanopoulos. Because these packages
	14	are so very different, the functions for each are kept in separate files. The
	15	relevant file is #included as required, after any any common functions.
	16
	17	No cryptographic code is included in Exim. All this module does is to call
	18	functions from the OpenSSL or GNU TLS libraries. */
	19
	20
	21	#include "exim.h"
	22
	23	/* This module is compiled only when it is specifically requested in the
	24	build-time configuration. However, some compilers don't like compiling empty
	25	modules, so keep them happy with a dummy when skipping the rest. Make it
	26	reference itself to stop picky compilers complaining that it is unused, and put
	27	in a dummy argument to stop even pickier compilers complaining about infinite
	28	loops. */
	29
	30	#ifndef SUPPORT_TLS
	31	static void dummy(int x) { dummy(x-1); }
	32	#else
	33
	34	/* Static variables that are used for buffering data by both sets of
	35	functions and the common functions below. */
	36
	37
	38	static uschar *ssl_xfer_buffer = NULL;
	39	static int ssl_xfer_buffer_size = 4096;
	40	static int ssl_xfer_buffer_lwm = 0;
	41	static int ssl_xfer_buffer_hwm = 0;
	42	static int ssl_xfer_eof = 0;
	43	static int ssl_xfer_error = 0;
	44
	45
	46
	47	/*************************************************
	48	* Expand string; give error on failure *
	49	*************************************************/
	50
	51	/* If expansion is forced to fail, set the result NULL and return TRUE.
	52	Other failures return FALSE. For a server, an SMTP response is given.
	53
	54	Arguments:
	55	s the string to expand; if NULL just return TRUE
	56	name name of string being expanded (for error)
	57	result where to put the result
	58
	59	Returns: TRUE if OK; result may still be NULL after forced failure
	60	*/
	61
	62	static BOOL
	63	expand_check(uschar s, uschar name, uschar **result)
	64	{
65	if (s == NULL) *result = NULL; else
66	{
67	*result = expand_string(s);
68	if (*result == NULL && !expand_string_forcedfail)
69	{
70	log_write(0, LOG_MAIN\|LOG_PANIC, "expansion of %s failed: %s", name,
71	expand_string_message);
72	return FALSE;
73	}
74	}
75	return TRUE;
76	}
77
78
79	/*************************************************
80	* Many functions are package-specific *
81	*************************************************/
82
83	#ifdef USE_GNUTLS
84	#include "tls-gnu.c"
85	#else
86	#include "tls-openssl.c"
87	#endif
88
89
90
91	/*************************************************
92	* TLS version of ungetc *
93	*************************************************/
94
95	/* Puts a character back in the input buffer. Only ever
96	called once.
97
98	Arguments:
99	ch the character
100
101	Returns: the character
102	*/
103
104	int
105	tls_ungetc(int ch)
106	{
107	ssl_xfer_buffer[--ssl_xfer_buffer_lwm] = ch;
108	return ch;
109	}
110
111
112
113	/*************************************************
114	* TLS version of feof *
115	*************************************************/
116
117	/* Tests for a previous EOF
118
119	Arguments: none
120	Returns: non-zero if the eof flag is set
121	*/
122
123	int
124	tls_feof(void)
125	{
126	return ssl_xfer_eof;
127	}
128
129
130
131	/*************************************************
132	* TLS version of ferror *
133	*************************************************/
134
135	/* Tests for a previous read error, and returns with errno
136	restored to what it was when the error was detected.
137
138	>>>>> Hmm. Errno not handled yet. Where do we get it from? >>>>>
139
140	Arguments: none
141	Returns: non-zero if the error flag is set
142	*/
143
144	int
145	tls_ferror(void)
146	{
147	return ssl_xfer_error;
148	}
149
150	#endif /* SUPPORT_TLS */
151
152	/* End of tls.c */