tls_misc.c

/*++
 * NAME
 *	tls_misc 3
 * SUMMARY
 *	miscellaneous TLS support routines
 * SYNOPSIS
 *	#include <tls.h>
 *	#include <tls_private.h>
 *
 *	char	*var_tls_high_clist;
 *	char	*var_tls_medium_clist;
 *	char	*var_tls_low_clist;
 *	char	*var_tls_export_clist;
 *	char	*var_tls_null_clist;
 *	char	*var_tls_eecdh_strong;
 *	char	*var_tls_eecdh_ultra;
 *	int	var_tls_daemon_rand_bytes;
 *
 *	TLS_APPL_STATE *tls_alloc_app_context(ssl_ctx)
 *	SSL_CTX	*ssl_ctx;
 *
 *	void	tls_free_app_context(app_ctx)
 *	void	*app_ctx;
 *
 *	TLS_SESS_STATE *tls_alloc_sess_context(log_level, namaddr)
 *	int	log_level;
 *	const char *namaddr;
 *
 *	void	tls_free_context(TLScontext)
 *	TLS_SESS_STATE *TLScontext;
 *
 *	void	tls_check_version()
 *
 *	long	tls_bug_bits()
 *
 *	void	tls_param_init()
 *
 *	int	tls_protocol_mask(plist)
 *	const char *plist;
 *
 *	int	tls_cipher_grade(name)
 *	const char *name;
 *
 *	const char *str_tls_cipher_grade(grade)
 *	int	grade;
 *
 *	const char *tls_set_ciphers(app_ctx, context, grade, exclusions)
 *	TLS_APPL_STATE *app_ctx;
 *	const char *context;
 *	int	grade;
 *	const char *exclusions;
 *
 *	void	tls_print_errors()
 *
 *	void	tls_info_callback(ssl, where, ret)
 *	const SSL *ssl; #unused 
 *	int	where;
 *	int	ret;
 *
 *	long	tls_bio_dump_cb(bio, cmd, argp, argi, argl, ret)
 *	BIO	*bio;
 *	int	cmd;
 *	const char *argp;
 *	int	argi;
 *	long	argl; #unused
 *	long	ret;
 * DESCRIPTION
 *	This module implements routines that support the TLS client
 *	and server internals.
 *
 *	tls_alloc_app_context() creates an application context that
 *	holds the SSL context for the application and related cached state.
 *
 *	tls_free_app_context() deallocates the application context and its
 *	contents (the application context is stored outside the TLS library).
 *
 *	tls_alloc_sess_context() creates an initialized TLS session context
 *	structure with the specified log mask and peer name[addr].
 *
 *	tls_free_context() destroys a TLScontext structure
 *	together with OpenSSL structures that are attached to it.
 *
 *	tls_check_version() logs a warning when the run-time OpenSSL
 *	library differs in its major, minor or micro number from
 *	the compile-time OpenSSL headers.
 *
 *	tls_bug_bits() returns the bug compatibility mask appropriate
 *	for the run-time library. Some of the bug work-arounds are
 *	not appropriate for some library versions.
 *
 *	tls_param_init() loads main.cf parameters used internally in
 *	TLS library. Any errors are fatal.
 *
 *	tls_protocol_mask() returns a bitmask of excluded protocols, given
 *	a list (plist) of protocols to include or (preceded by a '!') exclude.
 *	If "plist" contains invalid protocol names, TLS_PROTOCOL_INVALID is
 *	returned and no warning is logged.
 *
 *	tls_cipher_grade() converts a case-insensitive cipher grade
 *	name (high, medium, low, export, null) to the corresponding
 *	TLS_CIPHER_ constant.  When the input specifies an unrecognized
 *	grade, tls_cipher_grade() logs no warning, and returns
 *	TLS_CIPHER_NONE.
 *
 *	str_tls_cipher_grade() converts a cipher grade to a name.
 *	When the input specifies an undefined grade, str_tls_cipher_grade()
 *	logs no warning, returns a null pointer.
 *
 *	tls_set_ciphers() generates a cipher list from the specified
 *	grade, minus any ciphers specified via a list of exclusions.
 *	The cipherlist is applied to the supplied SSL context if it
 *	is different from the most recently applied value. The return
 *	value is the cipherlist used and is overwritten upon each call.
 *	When the input is invalid, tls_set_ciphers() logs a warning with
 *	the specified context, and returns a null pointer result.
 *
 *	tls_print_errors() queries the OpenSSL error stack,
 *	logs the error messages, and clears the error stack.
 *
 *	tls_info_callback() is a call-back routine for the
 *	SSL_CTX_set_info_callback() routine. It logs SSL events
 *	to the Postfix logfile.
 *
 *	tls_bio_dump_cb() is a call-back routine for the
 *	BIO_set_callback() routine. It logs SSL content to the
 *	Postfix logfile.
 * LICENSE
 * .ad
 * .fi
 *	This software is free. You can do with it whatever you want.
 *	The original author kindly requests that you acknowledge
 *	the use of his software.
 * AUTHOR(S)
 *	Originally written by:
 *	Lutz Jaenicke
 *	BTU Cottbus
 *	Allgemeine Elektrotechnik
 *	Universitaetsplatz 3-4
 *	D-03044 Cottbus, Germany
 *
 *	Updated by:
 *	Wietse Venema
 *	IBM T.J. Watson Research
 *	P.O. Box 704
 *	Yorktown Heights, NY 10598, USA
 *
 *	Victor Duchovni
 *	Morgan Stanley
 *--*/

/* System library. */

#include "StdAfx.h"
#include <ctype.h>
#include <string.h>

#ifdef USE_TLS

 /*
  * TLS library.
  */
#include "tls.h"
#include "tls_params.h"
#include "tls_private.h"

 /* Application-specific. */

 /*
  * Index to attach TLScontext pointers to SSL objects, so that they can be
  * accessed by call-back routines.
  */
int     TLScontext_index = -1;

 /*
  * Protocol name <=> mask conversion.
  */
static const NAME_CODE protocol_table[] = {
    { SSL_TXT_SSLV2, TLS_PROTOCOL_SSLv2 },
    { SSL_TXT_SSLV3, TLS_PROTOCOL_SSLv3 },
    { SSL_TXT_TLSV1, TLS_PROTOCOL_TLSv1 },
    { 0, TLS_PROTOCOL_INVALID },
};

 /*
  * Ciphersuite name <=> code conversion.
  */
const NAME_CODE tls_cipher_grade_table[] = {
    { "high", TLS_CIPHER_HIGH },
    { "medium", TLS_CIPHER_MEDIUM },
    { "low", TLS_CIPHER_LOW },
    { "export", TLS_CIPHER_EXPORT },
    { "null", TLS_CIPHER_NULL },
    { "invalid", TLS_CIPHER_NONE },
    { 0, TLS_CIPHER_NONE },
};

 /*
  * Parsed OpenSSL version number.
  */
typedef struct {
    int     major;
    int     minor;
    int     micro;
    int     patch;
    int     status;
} TLS_VINFO;

 /*
  * OpenSSL adopted the cipher selection patch, so we don't expect any more
  * broken ciphers other than AES and CAMELLIA.
  */
typedef struct {
    const char *ssl_name;
    const int alg_bits;
    const char *evp_name;
} cipher_probe_t;

static const cipher_probe_t cipher_probes[] = {
    { "AES", 256, "AES-256-CBC" },
    { "CAMELLIA", 256, "CAMELLIA-256-CBC" },
    { 0, 0, 0 },
};

static void free_argv_fn(void *arg)
{
    ACL_ARGV *argv = (ACL_ARGV*) arg;
    acl_argv_free(argv);
}

/* tls_exclude_missing - Append exclusions for missing ciphers */

static const char *tls_exclude_missing(SSL_CTX *ctx, ACL_VSTRING *buf)
{
    const char *myname = "tls_exclude_missing";
    static __thread ACL_ARGV *exclude;		/* Cached */
    SSL    *s = 0;

    STACK_OF(SSL_CIPHER) * ciphers;
    SSL_CIPHER *c;
    const cipher_probe_t *probe;
    int     alg_bits;
    int     num;
    int     i;

    /*
     * Process a list of probes which specify:
     * 
     * An SSL cipher-suite name for a family of ciphers that use the same
     * symmetric algorithm at two or more key sizes, typically 128/256 bits.
     * 
     * The key size (typically 256) that OpenSSL fails to check, and assumes
     * available when another key size (typically 128) is usable.
     * 
     * The OpenSSL name of the symmetric algorithm associated with the SSL
     * cipher-suite. Typically, this is MUMBLE-256-CBC, where "MUMBLE" is the
     * name of the SSL cipher-suite that use the MUMBLE symmetric algorithm.
     * On systems that support the required encryption algorithm, the name is
     * listed in the output of "openssl list-cipher-algorithms".
     * 
     * When an encryption algorithm is not available at the given key size but
     * the corresponding OpenSSL cipher-suite contains ciphers that have have
     * this key size, the problem ciphers are explicitly disabled in Postfix.
     * The list is cached in the static "exclude" array.
     */
    if (exclude == 0) {
	exclude = acl_argv_alloc(1);
	acl_pthread_atexit_add(exclude, free_argv_fn);

	/*
	 * Iterate over the probe list
	 */
	for (probe = cipher_probes; probe->ssl_name; ++probe) {
	    /* No exclusions if evp_name is a valid algorithm */
	    if (EVP_get_cipherbyname(probe->evp_name))
		continue;

	    /*
	     * Sadly there is no SSL_CTX_get_ciphers() interface, so we are
	     * forced to allocate and free an SSL object. Fatal error if we
	     * can't allocate the SSL object.
	     */
	    ERR_clear_error();
	    if (s == 0 && (s = SSL_new(ctx)) == 0) {
		tls_print_errors();
		acl_msg_fatal("%s: error allocating SSL object", myname);
	    }

	    /*
	     * Cipher is not supported by libcrypto, nothing to do if also
	     * not supported by libssl. Flush the OpenSSL error stack.
	     * 
	     * XXX: There may be additional places in pre-existing code where
	     * SSL errors are generated and ignored, that require a similar
	     * "flush". Better yet, is to always flush before calls that run
	     * tls_print_errors() on failure.
	     * 
	     * Contrary to documentation, on SunOS 5.10 SSL_set_cipher_list()
	     * returns success with no ciphers selected, when this happens
	     * SSL_get_ciphers() produces a stack with 0 elements!
	     */
	    if (SSL_set_cipher_list(s, probe->ssl_name) == 0
		|| (ciphers = SSL_get_ciphers(s)) == 0
		|| (num = sk_SSL_CIPHER_num(ciphers)) == 0) {
		ERR_clear_error();		/* flush any generated errors */
		continue;
	    }
	    for (i = 0; i < num; ++i) {
		c = sk_SSL_CIPHER_value(ciphers, i);
		(void) SSL_CIPHER_get_bits(c, &alg_bits);
		if (alg_bits == probe->alg_bits)
		    acl_argv_add(exclude, SSL_CIPHER_get_name(c), ACL_ARGV_END);
	    }
	}
	if (s != 0)
	    SSL_free(s);
    }
    for (i = 0; i < exclude->argc; ++i)
	acl_vstring_sprintf_append(buf, ":!%s", exclude->argv[i]);
    return (acl_vstring_str(buf));
}

/* tls_apply_cipher_list - update SSL_CTX cipher list */

static const char *tls_apply_cipher_list(TLS_APPL_STATE *app_ctx,
	const char *context, ACL_VSTRING *spec)
{
    const char *new = tls_exclude_missing(app_ctx->ssl_ctx, spec);

    ERR_clear_error();
    if (SSL_CTX_set_cipher_list(app_ctx->ssl_ctx, new) == 0) {
	tls_print_errors();
	acl_vstring_sprintf(app_ctx->why, "invalid %s cipher list: \"%s\"",
			context, new);
	return (0);
    }
    return (new);
}

/* tls_protocol_mask - Bitmask of protocols to exclude */

int     tls_protocol_mask(const char *plist)
{
    char   *save;
    char   *tok;
    char   *cp;
    int     code;
    int     exclude = 0;
    int     include = 0;

    save = cp = acl_mystrdup(plist);
    while ((tok = acl_mystrtok(&cp, "\t\n\r ,:")) != 0) {
	if (*tok == '!')
	    exclude |= code =
		name_code(protocol_table, NAME_CODE_FLAG_NONE, ++tok);
	else
	    include |= code =
		name_code(protocol_table, NAME_CODE_FLAG_NONE, tok);
	if (code == TLS_PROTOCOL_INVALID)
	    return TLS_PROTOCOL_INVALID;
    }
    acl_myfree(save);

    /*
     * When the include list is empty, use only the explicit exclusions.
     * Otherwise, also exclude the complement of the include list from the
     * built-in list of known protocols. There is no way to exclude protocols
     * we don't know about at compile time, and this is unavoidable because
     * the OpenSSL API works with compile-time *exclusion* bit-masks.
     */
    return (include ? (exclude | (TLS_KNOWN_PROTOCOLS & ~include)) : exclude);
}

static void free_vstring_fn(void *arg)
{
    ACL_VSTRING *s = (ACL_VSTRING*) arg;

    acl_vstring_free(s);
}

/* tls_set_ciphers - Set SSL context cipher list */

const char *tls_set_ciphers(TLS_APPL_STATE *app_ctx, const char *context,
	const char *grade, const char *exclusions)
{
    const char *myname = "tls_set_ciphers";
    static __thread ACL_VSTRING *buf;
    int     new_grade;
    char   *save;
    char   *cp;
    char   *tok;
    const char *new_list;

    new_grade = tls_cipher_grade(grade);
    if (new_grade == TLS_CIPHER_NONE) {
	acl_vstring_sprintf(app_ctx->why, "invalid %s cipher grade: \"%s\"",
			context, grade);
	return (0);
    }
    if (buf == 0) {
	buf = acl_vstring_alloc(10);
	acl_pthread_atexit_add(buf, free_vstring_fn);
    }
    ACL_VSTRING_RESET(buf);

    /*
     * Given cached state and identical input, we return the same result.
     */
    if (app_ctx->cipher_list) {
	if (new_grade == app_ctx->cipher_grade
	    && strcmp(app_ctx->cipher_exclusions, exclusions) == 0)
	    return (app_ctx->cipher_list);

	/* Change required, flush cached state */
	app_ctx->cipher_grade = TLS_CIPHER_NONE;

	acl_myfree(app_ctx->cipher_exclusions);
	app_ctx->cipher_exclusions = 0;

	acl_myfree(app_ctx->cipher_list);
	app_ctx->cipher_list = 0;
    }
    switch (new_grade) {
    case TLS_CIPHER_HIGH:
	acl_vstring_strcpy(buf, var_tls_high_clist);
	break;
    case TLS_CIPHER_MEDIUM:
	acl_vstring_strcpy(buf, var_tls_medium_clist);
	break;
    case TLS_CIPHER_LOW:
	acl_vstring_strcpy(buf, var_tls_low_clist);
	break;
    case TLS_CIPHER_EXPORT:
	acl_vstring_strcpy(buf, var_tls_export_clist);
	break;
    case TLS_CIPHER_NULL:
	acl_vstring_strcpy(buf, var_tls_null_clist);
	break;
    default:

	/*
	 * The caller MUST provide a valid cipher grade
	 */
	acl_msg_panic("invalid %s cipher grade: %d", context, new_grade);
    }

    /*
     * The base lists for each grade can't be empty.
     */
    if (ACL_VSTRING_LEN(buf) == 0)
	acl_msg_panic("%s: empty \"%s\" cipherlist", myname, grade);

    /*
     * Apply locally-specified exclusions.
     */
#define CIPHER_SEP "\t\n\r ,:"
    if (exclusions != 0) {
	cp = save = acl_mystrdup(exclusions);
	while ((tok = acl_mystrtok(&cp, CIPHER_SEP)) != 0) {

	    /*
	     * Can't exclude ciphers that start with modifiers.
	     */
	    if (strchr("!+-@", *tok)) {
		acl_vstring_sprintf(app_ctx->why,
				"invalid unary '!+-@' in %s cipher "
				"exclusion: \"%s\"", context, tok);
		return (0);
	    }
	    acl_vstring_sprintf_append(buf, ":!%s", tok);
	}
	acl_myfree(save);
    }
    if ((new_list = tls_apply_cipher_list(app_ctx, context, buf)) == 0)
	return (0);

    /* Cache new state */
    app_ctx->cipher_grade = new_grade;
    app_ctx->cipher_exclusions = acl_mystrdup(exclusions);

    return (app_ctx->cipher_list = acl_mystrdup(new_list));
}

/* tls_alloc_app_context - allocate TLS application context */

TLS_APPL_STATE *tls_alloc_app_context(SSL_CTX *ssl_ctx)
{
    TLS_APPL_STATE *app_ctx;

    app_ctx = (TLS_APPL_STATE *) acl_mymalloc(sizeof(*app_ctx));

    memset((char *) app_ctx, 0, sizeof(*app_ctx));
    app_ctx->ssl_ctx = ssl_ctx;

    /* See also: cache purging code in tls_set_ciphers(). */
    app_ctx->cipher_grade = TLS_CIPHER_NONE;
    app_ctx->cipher_exclusions = 0;
    app_ctx->cipher_list = 0;
    app_ctx->cache_type = 0;
    app_ctx->why = acl_vstring_alloc(1);

    return (app_ctx);
}

/* tls_free_app_context - Free TLS application context */

void    tls_free_app_context(TLS_APPL_STATE *app_ctx)
{
    if (app_ctx->ssl_ctx)
	SSL_CTX_free(app_ctx->ssl_ctx);
    if (app_ctx->cache_type)
	acl_myfree(app_ctx->cache_type);
    /* See also: cache purging code in tls_set_ciphers(). */
    if (app_ctx->cipher_exclusions)
	acl_myfree(app_ctx->cipher_exclusions);
    if (app_ctx->cipher_list)
	acl_myfree(app_ctx->cipher_list);
    if (app_ctx->why)
	acl_vstring_free(app_ctx->why);
    acl_myfree(app_ctx);
}

/* tls_alloc_sess_context - allocate TLS session context */

TLS_SESS_STATE *tls_alloc_sess_context(int log_level, const char *namaddr)
{
    TLS_SESS_STATE *TLScontext;

    /*
     * PORTABILITY: Do not assume that null pointers are all-zero bits. Use
     * explicit assignments to initialize pointers.
     * 
     * See the C language FAQ item 5.17, or if you have time to burn,
     * http://www.google.com/search?q=zero+bit+null+pointer
     * 
     * However, it's OK to use memset() to zero integer values.
     */
    TLScontext = (TLS_SESS_STATE *) acl_mymalloc(sizeof(TLS_SESS_STATE));
    memset((char *) TLScontext, 0, sizeof(*TLScontext));
    TLScontext->con = 0;
    TLScontext->internal_bio = 0;
    TLScontext->network_bio = 0;
    TLScontext->cache_type = 0;
    TLScontext->serverid = 0;
    TLScontext->peer_CN = 0;
    TLScontext->issuer_CN = 0;
    TLScontext->peer_fingerprint = 0;
    TLScontext->protocol = 0;
    TLScontext->cipher_name = 0;
    TLScontext->log_level = log_level;
    TLScontext->namaddr = acl_lowercase(acl_mystrdup(namaddr));

    return (TLScontext);
}

/* tls_free_context - deallocate TLScontext and members */

void    tls_free_context(TLS_SESS_STATE *TLScontext)
{
    /*
     * Free the SSL structure and the BIOs. Warning: the internal_bio is
     * connected to the SSL structure and is automatically freed with it. Do
     * not free it again (core dump)!! Only free the network_bio.
     */
    if (TLScontext->con != 0)
	SSL_free(TLScontext->con);
    if (TLScontext->network_bio)
	BIO_free(TLScontext->network_bio);

    if (TLScontext->namaddr)
	acl_myfree(TLScontext->namaddr);
    if (TLScontext->serverid)
	acl_myfree(TLScontext->serverid);

    if (TLScontext->peer_CN)
	acl_myfree(TLScontext->peer_CN);
    if (TLScontext->issuer_CN)
	acl_myfree(TLScontext->issuer_CN);
    if (TLScontext->peer_fingerprint)
	acl_myfree(TLScontext->peer_fingerprint);

    acl_myfree(TLScontext);
}

/* tls_version_split - Split OpenSSL version number into major, minor, ... */

static void tls_version_split(long version, TLS_VINFO *info)
{

    /*
     * OPENSSL_VERSION_NUMBER(3):
     * 
     * OPENSSL_VERSION_NUMBER is a numeric release version identifier:
     * 
     * MMNNFFPPS: major minor fix patch status
     * 
     * The status nibble has one of the values 0 for development, 1 to e for
     * betas 1 to 14, and f for release. Parsed OpenSSL version number. for
     * example
     * 
     * 0x000906000 == 0.9.6 dev 0x000906023 == 0.9.6b beta 3 0x00090605f ==
     * 0.9.6e release
     * 
     * Versions prior to 0.9.3 have identifiers < 0x0930.  Versions between
     * 0.9.3 and 0.9.5 had a version identifier with this interpretation:
     * 
     * MMNNFFRBB major minor fix final beta/patch
     * 
     * for example
     * 
     * 0x000904100 == 0.9.4 release 0x000905000 == 0.9.5 dev
     * 
     * Version 0.9.5a had an interim interpretation that is like the current
     * one, except the patch level got the highest bit set, to keep continu-
     * ity.  The number was therefore 0x0090581f.
     */

    if (version < 0x0930) {
	info->status = 0;
	info->patch = version & 0x0f;
	version >>= 4;
	info->micro = version & 0x0f;
	version >>= 4;
	info->minor = version & 0x0f;
	version >>= 4;
	info->major = version & 0x0f;
    } else if (version < 0x00905800L) {
	info->patch = version & 0xff;
	version >>= 8;
	info->status = version & 0xf;
	version >>= 4;
	info->micro = version & 0xff;
	version >>= 8;
	info->minor = version & 0xff;
	version >>= 8;
	info->major = version & 0xff;
    } else {
	info->status = version & 0xf;
	version >>= 4;
	info->patch = version & 0xff;
	version >>= 8;
	info->micro = version & 0xff;
	version >>= 8;
	info->minor = version & 0xff;
	version >>= 8;
	info->major = version & 0xff;
	if (version < 0x00906000L)
	    info->patch &= ~0x80;
    }
}

/* tls_check_version - Detect mismatch between headers and library. */

void    tls_check_version(void)
{
    const char *myname = "tls_check_version";
    TLS_VINFO hdr_info;
    TLS_VINFO lib_info;

    tls_version_split(OPENSSL_VERSION_NUMBER, &hdr_info);
    tls_version_split(SSLeay(), &lib_info);

    if (lib_info.major != hdr_info.major
	|| lib_info.minor != hdr_info.minor
	|| lib_info.micro != hdr_info.micro)
	acl_msg_warn("%s: run-time library vs. compile-time header version mismatch: "
	     "OpenSSL %d.%d.%d may not be compatible with OpenSSL %d.%d.%d",
		 myname, lib_info.major, lib_info.minor, lib_info.micro,
		 hdr_info.major, hdr_info.minor, hdr_info.micro);
}

/* tls_bug_bits - SSL bug compatibility bits for this OpenSSL version */

long    tls_bug_bits(void)
{
    long    bits = SSL_OP_ALL;		/* Work around all known bugs */

#if OPENSSL_VERSION_NUMBER >= 0x00908000L
    long    lib_version = SSLeay();

    /*
     * In OpenSSL 0.9.8[ab], enabling zlib compression breaks the padding bug
     * work-around, leading to false positives and failed connections. We may
     * not interoperate with systems with the bug, but this is better than
     * breaking on all 0.9.8[ab] systems that have zlib support enabled.
     */
    if (lib_version >= 0x00908000L && lib_version <= 0x0090802fL) {
	STACK_OF(SSL_COMP) * comp_methods;

	comp_methods = SSL_COMP_get_compression_methods();
	if (comp_methods != 0 && sk_SSL_COMP_num(comp_methods) > 0)
	    bits &= ~SSL_OP_TLS_BLOCK_PADDING_BUG;
    }
#endif
    return (bits);
}

/* tls_print_errors - print and clear the error stack */

void    tls_print_errors(void)
{
    const char *myname = "tls_print_errors";
    unsigned long err;
    char    buffer[1024];		/* XXX */
    const char *file;
    const char *data;
    int     line;
    int     flags;
    unsigned long thread;

    /*
    while ((err = ERR_get_error()) != 0) {
	ERR_error_string(err, buffer);
	acl_msg_warn("%s: TLS library warning: %lu|%s", __FUNCTION__, err, buffer);
    }
    */

    thread = CRYPTO_thread_id();
    while ((err = ERR_get_error_line_data(&file, &line, &data, &flags)) != 0) {
	ERR_error_string_n(err, buffer, sizeof(buffer));
	if (flags & ERR_TXT_STRING)
	    acl_msg_warn("%s: TLS library problem: %lu|%s|%s|%d|%s|",
		     myname, thread, buffer, file, line, data);
	else
	    acl_msg_warn("%s: TLS library problem: %lu|%s|%s|%d|",
		     myname, thread, buffer, file, line);
    }
}

/* tls_info_callback - callback for logging SSL events via Postfix */

void    tls_info_callback(const SSL *s, int where, int ret)
{
    char   *str;
    int     w;

    /* Adapted from OpenSSL apps/s_cb.c. */

    w = where & ~SSL_ST_MASK;

    if (w & SSL_ST_CONNECT)
	str = "SSL_connect";
    else if (w & SSL_ST_ACCEPT)
	str = "SSL_accept";
    else
	str = "unknown";

    if (where & SSL_CB_LOOP) {
	acl_msg_info("%s:%s", str, SSL_state_string_long((const SSL *) s));
    } else if (where & SSL_CB_ALERT) {
	str = (where & SSL_CB_READ) ? "read" : "write";
	if ((ret & 0xff) != SSL3_AD_CLOSE_NOTIFY)
	    acl_msg_info("SSL3 alert %s:%s:%s", str,
		     SSL_alert_type_string_long(ret),
		     SSL_alert_desc_string_long(ret));
    } else if (where & SSL_CB_EXIT) {
	if (ret == 0)
	    acl_msg_info("%s:failed in %s",
		     str, SSL_state_string_long((const SSL *) s));
	else if (ret < 0) {
#ifndef LOG_NON_ERROR_STATES
	    switch (SSL_get_error((SSL *) s, ret)) {
	    case SSL_ERROR_WANT_READ:
	    case SSL_ERROR_WANT_WRITE:
		/* Don't log non-error states. */
		break;
	    default:
#endif
		acl_msg_info("%s:error in %s",
			 str, SSL_state_string_long((SSL *) s));
#ifndef LOG_NON_ERROR_STATES
	    }
#endif
	}
    }
}

 /*
  * taken from OpenSSL crypto/bio/b_dump.c.
  * 
  * Modified to save a lot of strcpy and strcat by Matti Aarnio.
  * 
  * Rewritten by Wietse to elimate fixed-size stack buffer, array index
  * multiplication and division, sprintf() and strcpy(), and lots of strlen()
  * calls. We could make it a little faster by using a fixed-size stack-based
  * buffer.
  * 
  * 200412 - use %lx to print pointers, after casting them to unsigned long.
  */

#define TRUNCATE_SPACE_NULL
#define DUMP_WIDTH	16
#define VERT_SPLIT	7

static void tls_dump_buffer(const unsigned char *start, int len)
{
    ACL_VSTRING *buf = acl_vstring_alloc(100);
    const unsigned char *last = start + len - 1;
    const unsigned char *row;
    const unsigned char *col;
    int     ch;

#ifdef TRUNCATE_SPACE_NULL
    while (last >= start && (*last == ' ' || *last == 0))
	last--;
#endif

    for (row = start; row <= last; row += DUMP_WIDTH) {
	ACL_VSTRING_RESET(buf);
	acl_vstring_sprintf(buf, "%04lx ", (unsigned long) (row - start));
	for (col = row; col < row + DUMP_WIDTH; col++) {
	    if (col > last) {
		acl_vstring_strcat(buf, "   ");
	    } else {
		ch = *col;
		acl_vstring_sprintf_append(buf, "%02x%c",
				   ch, col - row == VERT_SPLIT ? '|' : ' ');
	    }
	}
	ACL_VSTRING_ADDCH(buf, ' ');
	for (col = row; col < row + DUMP_WIDTH; col++) {
	    if (col > last)
		break;
	    ch = *col;
	    if (!ACL_ISPRINT(ch))
		ch = '.';
	    ACL_VSTRING_ADDCH(buf, ch);
	    if (col - row == VERT_SPLIT)
		ACL_VSTRING_ADDCH(buf, ' ');
	}
	ACL_VSTRING_TERMINATE(buf);
	acl_msg_info("%s", acl_vstring_str(buf));
    }
#ifdef TRUNCATE_SPACE_NULL
    if ((last + 1) - start < len)
	acl_msg_info("%04lx - <SPACES/NULLS>",
		 (unsigned long) ((last + 1) - start));
#endif
    acl_vstring_free(buf);
}

/* taken from OpenSSL apps/s_cb.c */

long    tls_bio_dump_cb(BIO *bio, int cmd, const char *argp, int argi,
			        long unused_argl acl_unused, long ret)
{
    if (cmd == (BIO_CB_READ | BIO_CB_RETURN)) {
	acl_msg_info("read from %08lX [%08lX] (%d bytes => %ld (0x%lX))",
		 (unsigned long) bio, (unsigned long) argp, argi,
		 ret, (unsigned long) ret);
	tls_dump_buffer((const unsigned char *) argp, (int) ret);
    } else if (cmd == (BIO_CB_WRITE | BIO_CB_RETURN)) {
	acl_msg_info("write to %08lX [%08lX] (%d bytes => %ld (0x%lX))",
		 (unsigned long) bio, (unsigned long) argp, argi,
		 ret, (unsigned long) ret);
	tls_dump_buffer((const unsigned char *) argp, (int) ret);
    }
    return (ret);
}

#else

 /*
  * Broken linker workaround.
  */
int     tls_dummy_for_broken_linkers;

#endif