sendmail/src/tls.c

	tls.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * Copyright (c) 2000-2005 Sendmail, Inc. and its suppliers.
 *  All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 *
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sendmail.h>

SM_RCSID("@(#)$Id: tls.c,v 8.97 2005/03/08 22:20:52 ca Exp $")

#if STARTTLS
#  include <openssl/err.h>
#  include <openssl/bio.h>
#  include <openssl/pem.h>
#  ifndef HASURANDOMDEV
#   include <openssl/rand.h>
#  endif /* ! HASURANDOMDEV */
# if !TLS_NO_RSA
static RSA *rsa_tmp = NULL; /* temporary RSA key */
static RSA *tmp_rsa_key __P((SSL *, int, int));
# endif /* !TLS_NO_RSA */
#  if !defined(OPENSSL_VERSION_NUMBER) || OPENSSL_VERSION_NUMBER < 0x00907000L
static int  tls_verify_cb __P((X509_STORE_CTX *));
#  else /* !defined() || OPENSSL_VERSION_NUMBER < 0x00907000L */
static int  tls_verify_cb __P((X509_STORE_CTX *, void *));
#  endif /* !defined() || OPENSSL_VERSION_NUMBER < 0x00907000L */

# if OPENSSL_VERSION_NUMBER > 0x00907000L
static int x509_verify_cb __P((int, X509_STORE_CTX *));
# endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */

# if !defined(OPENSSL_VERSION_NUMBER) || OPENSSL_VERSION_NUMBER < 0x00907000L
#  define CONST097
# else /* !defined() || OPENSSL_VERSION_NUMBER < 0x00907000L */
#  define CONST097 const
# endif /* !defined() || OPENSSL_VERSION_NUMBER < 0x00907000L */
static void apps_ssl_info_cb __P((CONST097 SSL *, int , int));
static bool tls_ok_f __P((char *, char *, int));
static bool tls_safe_f __P((char *, long, bool));
static int  tls_verify_log __P((int, X509_STORE_CTX *, char *));

# if !NO_DH
static DH *get_dh512 __P((void));

static unsigned char dh512_p[] =
{
    0xDA,0x58,0x3C,0x16,0xD9,0x85,0x22,0x89,0xD0,0xE4,0xAF,0x75,
    0x6F,0x4C,0xCA,0x92,0xDD,0x4B,0xE5,0x33,0xB8,0x04,0xFB,0x0F,
    0xED,0x94,0xEF,0x9C,0x8A,0x44,0x03,0xED,0x57,0x46,0x50,0xD3,
    0x69,0x99,0xDB,0x29,0xD7,0x76,0x27,0x6B,0xA2,0xD3,0xD4,0x12,
    0xE2,0x18,0xF4,0xDD,0x1E,0x08,0x4C,0xF6,0xD8,0x00,0x3E,0x7C,
    0x47,0x74,0xE8,0x33
};
static unsigned char dh512_g[] =
{
    0x02
};

static DH *
get_dh512()
{
    DH *dh = NULL;

    if ((dh = DH_new()) == NULL)
        return NULL;
    dh->p = BN_bin2bn(dh512_p, sizeof(dh512_p), NULL);
    dh->g = BN_bin2bn(dh512_g, sizeof(dh512_g), NULL);
    if ((dh->p == NULL) || (dh->g == NULL))
        return NULL;
    return dh;
}
# endif /* !NO_DH */


/*
**  TLS_RAND_INIT -- initialize STARTTLS random generator
**
**  Parameters:
**      randfile -- name of file with random data
**      logl -- loglevel
**
**  Returns:
**      success/failure
**
**  Side Effects:
**      initializes PRNG for tls library.
*/

# define MIN_RAND_BYTES 128 /* 1024 bits */

# define RF_OK      0   /* randfile OK */
# define RF_MISS    1   /* randfile == NULL || *randfile == '\0' */
# define RF_UNKNOWN 2   /* unknown prefix for randfile */

# define RI_NONE    0   /* no init yet */
# define RI_SUCCESS 1   /* init was successful */
# define RI_FAIL    2   /* init failed */

static bool tls_rand_init __P((char *, int));

static bool
tls_rand_init(randfile, logl)
    char *randfile;
    int logl;
{
# ifndef HASURANDOMDEV
    /* not required if /dev/urandom exists, OpenSSL does it internally */

    bool ok;
    int randdef;
    static int done = RI_NONE;

    /*
    **  initialize PRNG
    */

    /* did we try this before? if yes: return old value */
    if (done != RI_NONE)
        return done == RI_SUCCESS;

    /* set default values */
    ok = false;
    done = RI_FAIL;
    randdef = (randfile == NULL || *randfile == '\0') ? RF_MISS : RF_OK;
#   if EGD
    if (randdef == RF_OK && sm_strncasecmp(randfile, "egd:", 4) == 0)
    {
        randfile += 4;
        if (RAND_egd(randfile) < 0)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS: RAND_egd(%s) failed: random number generator not seeded",
                   randfile);
        }
        else
            ok = true;
    }
    else
#   endif /* EGD */
    if (randdef == RF_OK && sm_strncasecmp(randfile, "file:", 5) == 0)
    {
        int fd;
        long sff;
        struct stat st;

        randfile += 5;
        sff = SFF_SAFEDIRPATH | SFF_NOWLINK
              | SFF_NOGWFILES | SFF_NOWWFILES
              | SFF_NOGRFILES | SFF_NOWRFILES
              | SFF_MUSTOWN | SFF_ROOTOK | SFF_OPENASROOT;
        if (DontLockReadFiles)
            sff |= SFF_NOLOCK;
        if ((fd = safeopen(randfile, O_RDONLY, 0, sff)) >= 0)
        {
            if (fstat(fd, &st) < 0)
            {
                if (LogLevel > logl)
                    sm_syslog(LOG_ERR, NOQID,
                          "STARTTLS: can't fstat(%s)",
                          randfile);
            }
            else
            {
                bool use, problem;

                use = true;
                problem = false;

                /* max. age of file: 10 minutes */
                if (st.st_mtime + 600 < curtime())
                {
                    use = bitnset(DBS_INSUFFICIENTENTROPY,
                              DontBlameSendmail);
                    problem = true;
                    if (LogLevel > logl)
                        sm_syslog(LOG_ERR, NOQID,
                              "STARTTLS: RandFile %s too old: %s",
                              randfile,
                              use ? "unsafe" :
                                "unusable");
                }
                if (use && st.st_size < MIN_RAND_BYTES)
                {
                    use = bitnset(DBS_INSUFFICIENTENTROPY,
                              DontBlameSendmail);
                    problem = true;
                    if (LogLevel > logl)
                        sm_syslog(LOG_ERR, NOQID,
                              "STARTTLS: size(%s) < %d: %s",
                              randfile,
                              MIN_RAND_BYTES,
                              use ? "unsafe" :
                                "unusable");
                }
                if (use)
                    ok = RAND_load_file(randfile, -1) >=
                         MIN_RAND_BYTES;
                if (use && !ok)
                {
                    if (LogLevel > logl)
                        sm_syslog(LOG_WARNING, NOQID,
                              "STARTTLS: RAND_load_file(%s) failed: random number generator not seeded",
                              randfile);
                }
                if (problem)
                    ok = false;
            }
            if (ok || bitnset(DBS_INSUFFICIENTENTROPY,
                      DontBlameSendmail))
            {
                /* add this even if fstat() failed */
                RAND_seed((void *) &st, sizeof st);
            }
            (void) close(fd);
        }
        else
        {
            if (LogLevel > logl)
                sm_syslog(LOG_WARNING, NOQID,
                      "STARTTLS: Warning: safeopen(%s) failed",
                      randfile);
        }
    }
    else if (randdef == RF_OK)
    {
        if (LogLevel > logl)
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS: Error: no proper random file definition %s",
                  randfile);
        randdef = RF_UNKNOWN;
    }
    if (randdef == RF_MISS)
    {
        if (LogLevel > logl)
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS: Error: missing random file definition");
    }
    if (!ok && bitnset(DBS_INSUFFICIENTENTROPY, DontBlameSendmail))
    {
        int i;
        long r;
        unsigned char buf[MIN_RAND_BYTES];

        /* assert((MIN_RAND_BYTES % sizeof(long)) == 0); */
        for (i = 0; i <= sizeof(buf) - sizeof(long); i += sizeof(long))
        {
            r = get_random();
            (void) memcpy(buf + i, (void *) &r, sizeof(long));
        }
        RAND_seed(buf, sizeof buf);
        if (LogLevel > logl)
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS: Warning: random number generator not properly seeded");
        ok = true;
    }
    done = ok ? RI_SUCCESS : RI_FAIL;
    return ok;
# else /* ! HASURANDOMDEV */
    return true;
# endif /* ! HASURANDOMDEV */
}
/*
**  INIT_TLS_LIBRARY -- Calls functions which setup TLS library for global use.
**
**  Parameters:
**      none.
**
**  Returns:
**      succeeded?
*/

bool
init_tls_library()
{
    /* basic TLS initialization, ignore result for now */
    SSL_library_init();
    SSL_load_error_strings();
# if 0
    /* this is currently a macro for SSL_library_init */
    SSLeay_add_ssl_algorithms();
# endif /* 0 */

    return tls_rand_init(RandFile, 7);
}
/*
**  TLS_SET_VERIFY -- request client certificate?
**
**  Parameters:
**      ctx -- TLS context
**      ssl -- TLS structure
**      vrfy -- require certificate?
**
**  Returns:
**      none.
**
**  Side Effects:
**      Sets verification state for TLS
**
# if TLS_VRFY_PER_CTX
**  Notice:
**      This is per TLS context, not per TLS structure;
**      the former is global, the latter per connection.
**      It would be nice to do this per connection, but this
**      doesn't work in the current TLS libraries :-(
# endif * TLS_VRFY_PER_CTX *
*/

void
tls_set_verify(ctx, ssl, vrfy)
    SSL_CTX *ctx;
    SSL *ssl;
    bool vrfy;
{
# if !TLS_VRFY_PER_CTX
    SSL_set_verify(ssl, vrfy ? SSL_VERIFY_PEER : SSL_VERIFY_NONE, NULL);
# else /* !TLS_VRFY_PER_CTX */
    SSL_CTX_set_verify(ctx, vrfy ? SSL_VERIFY_PEER : SSL_VERIFY_NONE,
            NULL);
# endif /* !TLS_VRFY_PER_CTX */
}

/*
**  status in initialization
**  these flags keep track of the status of the initialization
**  i.e., whether a file exists (_EX) and whether it can be used (_OK)
**  [due to permissions]
*/

# define TLS_S_NONE 0x00000000  /* none yet */
# define TLS_S_CERT_EX  0x00000001  /* cert file exists */
# define TLS_S_CERT_OK  0x00000002  /* cert file is ok */
# define TLS_S_KEY_EX   0x00000004  /* key file exists */
# define TLS_S_KEY_OK   0x00000008  /* key file is ok */
# define TLS_S_CERTP_EX 0x00000010  /* CA cert path exists */
# define TLS_S_CERTP_OK 0x00000020  /* CA cert path is ok */
# define TLS_S_CERTF_EX 0x00000040  /* CA cert file exists */
# define TLS_S_CERTF_OK 0x00000080  /* CA cert file is ok */
# define TLS_S_CRLF_EX  0x00000100  /* CRL file exists */
# define TLS_S_CRLF_OK  0x00000200  /* CRL file is ok */

# if _FFR_TLS_1
#  define TLS_S_CERT2_EX    0x00001000  /* 2nd cert file exists */
#  define TLS_S_CERT2_OK    0x00002000  /* 2nd cert file is ok */
#  define TLS_S_KEY2_EX 0x00004000  /* 2nd key file exists */
#  define TLS_S_KEY2_OK 0x00008000  /* 2nd key file is ok */
# endif /* _FFR_TLS_1 */

# define TLS_S_DH_OK    0x00200000  /* DH cert is ok */
# define TLS_S_DHPAR_EX 0x00400000  /* DH param file exists */
# define TLS_S_DHPAR_OK 0x00800000  /* DH param file is ok to use */

/* Type of variable */
# define TLS_T_OTHER    0
# define TLS_T_SRV  1
# define TLS_T_CLT  2

/*
**  TLS_OK_F -- can var be an absolute filename?
**
**  Parameters:
**      var -- filename
**      fn -- what is the filename used for?
**      type -- type of variable
**
**  Returns:
**      ok?
*/

static bool
tls_ok_f(var, fn, type)
    char *var;
    char *fn;
    int type;
{
    /* must be absolute pathname */
    if (var != NULL && *var == '/')
        return true;
    if (LogLevel > 12)
        sm_syslog(LOG_WARNING, NOQID, "STARTTLS: %s%s missing",
              type == TLS_T_SRV ? "Server" :
              (type == TLS_T_CLT ? "Client" : ""), fn);
    return false;
}
/*
**  TLS_SAFE_F -- is a file safe to use?
**
**  Parameters:
**      var -- filename
**      sff -- flags for safefile()
**      srv -- server side?
**
**  Returns:
**      ok?
*/

static bool
tls_safe_f(var, sff, srv)
    char *var;
    long sff;
    bool srv;
{
    int ret;

    if ((ret = safefile(var, RunAsUid, RunAsGid, RunAsUserName, sff,
                S_IRUSR, NULL)) == 0)
        return true;
    if (LogLevel > 7)
        sm_syslog(LOG_WARNING, NOQID, "STARTTLS=%s: file %s unsafe: %s",
              srv ? "server" : "client", var, sm_errstring(ret));
    return false;
}

/*
**  TLS_OK_F -- macro to simplify calls to tls_ok_f
**
**  Parameters:
**      var -- filename
**      fn -- what is the filename used for?
**      req -- is the file required?
**      st -- status bit to set if ok
**      type -- type of variable
**
**  Side Effects:
**      uses r, ok; may change ok and status.
**
*/

# define TLS_OK_F(var, fn, req, st, type) if (ok) \
    { \
        r = tls_ok_f(var, fn, type); \
        if (r) \
            status |= st; \
        else if (req) \
            ok = false; \
    }

/*
**  TLS_UNR -- macro to return whether a file should be unreadable
**
**  Parameters:
**      bit -- flag to test
**      req -- flags
**
**  Returns:
**      0/SFF_NORFILES
*/
# define TLS_UNR(bit, req)  (bitset(bit, req) ? SFF_NORFILES : 0)
# define TLS_OUNR(bit, req) (bitset(bit, req) ? SFF_NOWRFILES : 0)
# define TLS_KEYSFF(req)    \
    (bitnset(DBS_GROUPREADABLEKEYFILE, DontBlameSendmail) ? \
        TLS_OUNR(TLS_I_KEY_OUNR, req) :         \
        TLS_UNR(TLS_I_KEY_UNR, req))

/*
**  TLS_SAFE_F -- macro to simplify calls to tls_safe_f
**
**  Parameters:
**      var -- filename
**      sff -- flags for safefile()
**      req -- is the file required?
**      ex -- does the file exist?
**      st -- status bit to set if ok
**      srv -- server side?
**
**  Side Effects:
**      uses r, ok, ex; may change ok and status.
**
*/

# define TLS_SAFE_F(var, sff, req, ex, st, srv) if (ex && ok) \
    { \
        r = tls_safe_f(var, sff, srv); \
        if (r) \
            status |= st;   \
        else if (req) \
            ok = false; \
    }

/*
**  INITTLS -- initialize TLS
**
**  Parameters:
**      ctx -- pointer to context
**      req -- requirements for initialization (see sendmail.h)
**      srv -- server side?
**      certfile -- filename of certificate
**      keyfile -- filename of private key
**      cacertpath -- path to CAs
**      cacertfile -- file with CA(s)
**      dhparam -- parameters for DH
**
**  Returns:
**      succeeded?
*/

bool
inittls(ctx, req, srv, certfile, keyfile, cacertpath, cacertfile, dhparam)
    SSL_CTX **ctx;
    unsigned long req;
    bool srv;
    char *certfile, *keyfile, *cacertpath, *cacertfile, *dhparam;
{
# if !NO_DH
    static DH *dh = NULL;
# endif /* !NO_DH */
    int r;
    bool ok;
    long sff, status;
    char *who;
# if _FFR_TLS_1
    char *cf2, *kf2;
# endif /* _FFR_TLS_1 */
#  if SM_CONF_SHM
    extern int ShmId;
#  endif /* SM_CONF_SHM */
# if OPENSSL_VERSION_NUMBER > 0x00907000L
    BIO *crl_file;
    X509_CRL *crl;
    X509_STORE *store;
# endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */

    status = TLS_S_NONE;
    who = srv ? "server" : "client";
    if (ctx == NULL)
        syserr("STARTTLS=%s, inittls: ctx == NULL", who);

    /* already initialized? (we could re-init...) */
    if (*ctx != NULL)
        return true;
    ok = true;

# if _FFR_TLS_1
    /*
    **  look for a second filename: it must be separated by a ','
    **  no blanks allowed (they won't be skipped).
    **  we change a global variable here! this change will be undone
    **  before return from the function but only if it returns true.
    **  this isn't a problem since in a failure case this function
    **  won't be called again with the same (overwritten) values.
    **  otherwise each return must be replaced with a goto endinittls.
    */

    cf2 = NULL;
    kf2 = NULL;
    if (certfile != NULL && (cf2 = strchr(certfile, ',')) != NULL)
    {
        *cf2++ = '\0';
        if (keyfile != NULL && (kf2 = strchr(keyfile, ',')) != NULL)
            *kf2++ = '\0';
    }
# endif /* _FFR_TLS_1 */

    /*
    **  Check whether files/paths are defined
    */

    TLS_OK_F(certfile, "CertFile", bitset(TLS_I_CERT_EX, req),
         TLS_S_CERT_EX, srv ? TLS_T_SRV : TLS_T_CLT);
    TLS_OK_F(keyfile, "KeyFile", bitset(TLS_I_KEY_EX, req),
         TLS_S_KEY_EX, srv ? TLS_T_SRV : TLS_T_CLT);
    TLS_OK_F(cacertpath, "CACertPath", bitset(TLS_I_CERTP_EX, req),
         TLS_S_CERTP_EX, TLS_T_OTHER);
    TLS_OK_F(cacertfile, "CACertFile", bitset(TLS_I_CERTF_EX, req),
         TLS_S_CERTF_EX, TLS_T_OTHER);

# if OPENSSL_VERSION_NUMBER > 0x00907000L
    TLS_OK_F(CRLFile, "CRLFile", bitset(TLS_I_CRLF_EX, req),
         TLS_S_CRLF_EX, TLS_T_OTHER);
# endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */

# if _FFR_TLS_1
    /*
    **  if the second file is specified it must exist
    **  XXX: it is possible here to define only one of those files
    */

    if (cf2 != NULL)
    {
        TLS_OK_F(cf2, "CertFile", bitset(TLS_I_CERT_EX, req),
             TLS_S_CERT2_EX, srv ? TLS_T_SRV : TLS_T_CLT);
    }
    if (kf2 != NULL)
    {
        TLS_OK_F(kf2, "KeyFile", bitset(TLS_I_KEY_EX, req),
             TLS_S_KEY2_EX, srv ? TLS_T_SRV : TLS_T_CLT);
    }
# endif /* _FFR_TLS_1 */

    /*
    **  valid values for dhparam are (only the first char is checked)
    **  none    no parameters: don't use DH
    **  512     generate 512 bit parameters (fixed)
    **  1024    generate 1024 bit parameters
    **  /file/name  read parameters from /file/name
    **  default is: 1024 for server, 512 for client (OK? XXX)
    */

    if (bitset(TLS_I_TRY_DH, req))
    {
        if (dhparam != NULL)
        {
            char c = *dhparam;

            if (c == '1')
                req |= TLS_I_DH1024;
            else if (c == '5')
                req |= TLS_I_DH512;
            else if (c != 'n' && c != 'N' && c != '/')
            {
                if (LogLevel > 12)
                    sm_syslog(LOG_WARNING, NOQID,
                          "STARTTLS=%s, error: illegal value '%s' for DHParam",
                          who, dhparam);
                dhparam = NULL;
            }
        }
        if (dhparam == NULL)
            dhparam = srv ? "1" : "5";
        else if (*dhparam == '/')
        {
            TLS_OK_F(dhparam, "DHParameters",
                 bitset(TLS_I_DHPAR_EX, req),
                 TLS_S_DHPAR_EX, TLS_T_OTHER);
        }
    }
    if (!ok)
        return ok;

    /* certfile etc. must be "safe". */
    sff = SFF_REGONLY | SFF_SAFEDIRPATH | SFF_NOWLINK
         | SFF_NOGWFILES | SFF_NOWWFILES
         | SFF_MUSTOWN | SFF_ROOTOK | SFF_OPENASROOT;
    if (DontLockReadFiles)
        sff |= SFF_NOLOCK;

    TLS_SAFE_F(certfile, sff | TLS_UNR(TLS_I_CERT_UNR, req),
           bitset(TLS_I_CERT_EX, req),
           bitset(TLS_S_CERT_EX, status), TLS_S_CERT_OK, srv);
    TLS_SAFE_F(keyfile, sff | TLS_KEYSFF(req),
           bitset(TLS_I_KEY_EX, req),
           bitset(TLS_S_KEY_EX, status), TLS_S_KEY_OK, srv);
    TLS_SAFE_F(cacertfile, sff | TLS_UNR(TLS_I_CERTF_UNR, req),
           bitset(TLS_I_CERTF_EX, req),
           bitset(TLS_S_CERTF_EX, status), TLS_S_CERTF_OK, srv);
    TLS_SAFE_F(dhparam, sff | TLS_UNR(TLS_I_DHPAR_UNR, req),
           bitset(TLS_I_DHPAR_EX, req),
           bitset(TLS_S_DHPAR_EX, status), TLS_S_DHPAR_OK, srv);
# if OPENSSL_VERSION_NUMBER > 0x00907000L
    TLS_SAFE_F(CRLFile, sff | TLS_UNR(TLS_I_CRLF_UNR, req),
           bitset(TLS_I_CRLF_EX, req),
           bitset(TLS_S_CRLF_EX, status), TLS_S_CRLF_OK, srv);
# endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
    if (!ok)
        return ok;
# if _FFR_TLS_1
    if (cf2 != NULL)
    {
        TLS_SAFE_F(cf2, sff | TLS_UNR(TLS_I_CERT_UNR, req),
               bitset(TLS_I_CERT_EX, req),
               bitset(TLS_S_CERT2_EX, status), TLS_S_CERT2_OK, srv);
    }
    if (kf2 != NULL)
    {
        TLS_SAFE_F(kf2, sff | TLS_KEYSFF(req),
               bitset(TLS_I_KEY_EX, req),
               bitset(TLS_S_KEY2_EX, status), TLS_S_KEY2_OK, srv);
    }
# endif /* _FFR_TLS_1 */

    /* create a method and a new context */
    if ((*ctx = SSL_CTX_new(srv ? SSLv23_server_method() :
                      SSLv23_client_method())) == NULL)
    {
        if (LogLevel > 7)
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: SSL_CTX_new(SSLv23_%s_method()) failed",
                  who, who);
        if (LogLevel > 9)
            tlslogerr(who);
        return false;
    }

# if OPENSSL_VERSION_NUMBER > 0x00907000L
    if (CRLFile != NULL)
    {
        /* get a pointer to the current certificate validation store */
        store = SSL_CTX_get_cert_store(*ctx);   /* does not fail */
        crl_file = BIO_new(BIO_s_file_internal());
        if (crl_file != NULL)
        {
            if (BIO_read_filename(crl_file, CRLFile) >= 0)
            {
                crl = PEM_read_bio_X509_CRL(crl_file, NULL,
                            NULL, NULL);
                BIO_free(crl_file);
                X509_STORE_add_crl(store, crl);
                X509_CRL_free(crl);
                X509_STORE_set_flags(store,
                    X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
                X509_STORE_set_verify_cb_func(store,
                        x509_verify_cb);
            }
            else
            {
                if (LogLevel > 9)
                {
                    sm_syslog(LOG_WARNING, NOQID,
                          "STARTTLS=%s, error: PEM_read_bio_X509_CRL(%s)=failed",
                          who, CRLFile);
                }

                /* avoid memory leaks */
                BIO_free(crl_file);
                return false;
            }

        }
        else if (LogLevel > 9)
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: BIO_new=failed", who);
    }
#  if _FFR_CRLPATH
    if (CRLPath != NULL)
    {
        X509_LOOKUP *lookup;

        lookup = X509_STORE_add_lookup(store, X509_LOOKUP_hash_dir());
        if (lookup == NULL)
        {
            if (LogLevel > 9)
            {
                sm_syslog(LOG_WARNING, NOQID,
                      "STARTTLS=%s, error: X509_STORE_add_lookup(hash)=failed",
                      who, CRLFile);
            }
            return false;
        }
        X509_LOOKUP_add_dir(lookup, CRLPath, X509_FILETYPE_PEM);
        X509_STORE_set_flags(store,
            X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
    }
#  endif /* _FFR_CRLPATH */
# endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */

# if TLS_NO_RSA
    /* turn off backward compatibility, required for no-rsa */
    SSL_CTX_set_options(*ctx, SSL_OP_NO_SSLv2);
# endif /* TLS_NO_RSA */


# if !TLS_NO_RSA
    /*
    **  Create a temporary RSA key
    **  XXX  Maybe we shouldn't create this always (even though it
    **  is only at startup).
    **  It is a time-consuming operation and it is not always necessary.
    **  maybe we should do it only on demand...
    */

    if (bitset(TLS_I_RSA_TMP, req)
#   if SM_CONF_SHM
        && ShmId != SM_SHM_NO_ID &&
        (rsa_tmp = RSA_generate_key(RSA_KEYLENGTH, RSA_F4, NULL,
                    NULL)) == NULL
#   else /* SM_CONF_SHM */
        && 0    /* no shared memory: no need to generate key now */
#   endif /* SM_CONF_SHM */
       )
    {
        if (LogLevel > 7)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: RSA_generate_key failed",
                  who);
            if (LogLevel > 9)
                tlslogerr(who);
        }
        return false;
    }
# endif /* !TLS_NO_RSA */

    /*
    **  load private key
    **  XXX change this for DSA-only version
    */

    if (bitset(TLS_S_KEY_OK, status) &&
        SSL_CTX_use_PrivateKey_file(*ctx, keyfile,
                     SSL_FILETYPE_PEM) <= 0)
    {
        if (LogLevel > 7)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: SSL_CTX_use_PrivateKey_file(%s) failed",
                  who, keyfile);
            if (LogLevel > 9)
                tlslogerr(who);
        }
        if (bitset(TLS_I_USE_KEY, req))
            return false;
    }

    /* get the certificate file */
    if (bitset(TLS_S_CERT_OK, status) &&
        SSL_CTX_use_certificate_file(*ctx, certfile,
                     SSL_FILETYPE_PEM) <= 0)
    {
        if (LogLevel > 7)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: SSL_CTX_use_certificate_file(%s) failed",
                  who, certfile);
            if (LogLevel > 9)
                tlslogerr(who);
        }
        if (bitset(TLS_I_USE_CERT, req))
            return false;
    }

    /* check the private key */
    if (bitset(TLS_S_KEY_OK, status) &&
        (r = SSL_CTX_check_private_key(*ctx)) <= 0)
    {
        /* Private key does not match the certificate public key */
        if (LogLevel > 5)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: SSL_CTX_check_private_key failed(%s): %d",
                  who, keyfile, r);
            if (LogLevel > 9)
                tlslogerr(who);
        }
        if (bitset(TLS_I_USE_KEY, req))
            return false;
    }

# if _FFR_TLS_1
    /* XXX this code is pretty much duplicated from above! */

    /* load private key */
    if (bitset(TLS_S_KEY2_OK, status) &&
        SSL_CTX_use_PrivateKey_file(*ctx, kf2, SSL_FILETYPE_PEM) <= 0)
    {
        if (LogLevel > 7)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: SSL_CTX_use_PrivateKey_file(%s) failed",
                  who, kf2);
            if (LogLevel > 9)
                tlslogerr(who);
        }
    }

    /* get the certificate file */
    if (bitset(TLS_S_CERT2_OK, status) &&
        SSL_CTX_use_certificate_file(*ctx, cf2, SSL_FILETYPE_PEM) <= 0)
    {
        if (LogLevel > 7)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: SSL_CTX_use_certificate_file(%s) failed",
                  who, cf2);
            if (LogLevel > 9)
                tlslogerr(who);
        }
    }

    /* also check the private key */
    if (bitset(TLS_S_KEY2_OK, status) &&
        (r = SSL_CTX_check_private_key(*ctx)) <= 0)
    {
        /* Private key does not match the certificate public key */
        if (LogLevel > 5)
        {
            sm_syslog(LOG_WARNING, NOQID,
                  "STARTTLS=%s, error: SSL_CTX_check_private_key 2 failed: %d",
                  who, r);
            if (LogLevel > 9)
                tlslogerr(who);
        }
    }
# endif /* _FFR_TLS_1 */

    /* SSL_CTX_set_quiet_shutdown(*ctx, 1); violation of standard? */
    SSL_CTX_set_options(*ctx, SSL_OP_ALL);  /* XXX bug compatibility? */

# if !NO_DH
    /* Diffie-Hellman initialization */
    if (bitset(TLS_I_TRY_DH, req))
    {
        if (bitset(TLS_S_DHPAR_OK, status))
        {
            BIO *bio;

            if ((bio = BIO_new_file(dhparam, "r")) != NULL)
            {
                dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
                BIO_free(bio);
                if (dh == NULL && LogLevel > 7)
                {
                    unsigned long err;

                    err = ERR_get_error();
                    sm_syslog(LOG_WARNING, NOQID,
                          "STARTTLS=%s, error: cannot read DH parameters(%s): %s",
                          who, dhparam,
                          ERR_error_string(err, NULL));
                    if (LogLevel > 9)
                        tlslogerr(who);
                }
            }
            else
            {
                if (LogLevel > 5)
                {
                    sm_syslog(LOG_WARNING, NOQID,
                          "STARTTLS=%s, error: BIO_new_file(%s) failed",
                          who, dhparam);
                    if (LogLevel > 9)
                        tlslogerr(who);
                }
            }
        }
        if (dh == NULL && bitset(TLS_I_DH1024, req))
        {
            DSA *dsa;

            /* this takes a while! (7-130s on a 450MHz AMD K6-2) */
            dsa = DSA_generate_parameters(1024, NULL, 0, NULL,
                              NULL, 0, NULL);
            dh = DSA_dup_DH(dsa);
            DSA_free(dsa);
        }
        else
        if (dh == NULL && bitset(TLS_I_DH512, req))
            dh = get_dh512();

        if (dh == NULL)
        {
            if (LogLevel > 9)
            {
                unsigned long err;

                err = ERR_get_error();
                sm_syslog(LOG_WARNING, NOQID,
                      "STARTTLS=%s, error: cannot read or set DH parameters(%s): %s",
                      who, dhparam,
                      ERR_error_string(err, NULL));
            }
            if (bitset(TLS_I_REQ_DH, req))
                return false;
        }
        else
        {
            SSL_CTX_set_tmp_dh(*ctx, dh);

            /* important to avoid small subgroup attacks */
            SSL_CTX_set_options(*ctx, SSL_OP_SINGLE_DH_USE);
            if (LogLevel > 13)
                sm_syslog(LOG_INFO, NOQID,
                      "STARTTLS=%s, Diffie-Hellman init, key=%d bit (%c)",
                      who, 8 * DH_size(dh), *dhparam);
            DH_free(dh);
        }
    }
# endif /* !NO_DH */


    /* XXX do we need this cache here? */
    if (bitset(TLS_I_CACHE, req))
        SSL_CTX_sess_set_cache_size(*ctx, 128);
    /* timeout? SSL_CTX_set_timeout(*ctx, TimeOut...); */

    /* load certificate locations and default CA paths */
    if (bitset(TLS_S_CERTP_EX, status) && bitset(TLS_S_CERTF_EX, status))
    {
        if ((r = SSL_CTX_load_verify_locations(*ctx, cacertfile,
                               cacertpath)) == 1)
        {
# if !TLS_NO_RSA
            if (bitset(TLS_I_RSA_TMP, req))
                SSL_CTX_set_tmp_rsa_callback(*ctx, tmp_rsa_key);
# endif /* !TLS_NO_RSA */

            /*
            **  We have to install our own verify callback:
            **  SSL_VERIFY_PEER requests a client cert but even
            **  though *FAIL_IF* isn't set, the connection
            **  will be aborted if the client presents a cert
            **  that is not "liked" (can't be verified?) by
            **  the TLS library :-(
            */

            /*
            **  XXX currently we could call tls_set_verify()
            **  but we hope that that function will later on
            **  only set the mode per connection.
            */
            SSL_CTX_set_verify(*ctx,
                bitset(TLS_I_NO_VRFY, req) ? SSL_VERIFY_NONE
                               : SSL_VERIFY_PEER,
                NULL);

            /* install verify callback */
            SSL_CTX_set_cert_verify_callback(*ctx, tls_verify_cb,
                             NULL);
            SSL_CTX_set_client_CA_list(*ctx,
                SSL_load_client_CA_file(cacertfile));
        }
        else
        {
            /*
            **  can't load CA data; do we care?
            **  the data is necessary to authenticate the client,
            **  which in turn would be necessary
            **  if we want to allow relaying based on it.
            */
            if (LogLevel > 5)
            {
                sm_syslog(LOG_WARNING, NOQID,
                      "STARTTLS=%s, error: load verify locs %s, %s failed: %d",
                      who, cacertpath, cacertfile, r);
                if (LogLevel > 9)
                    tlslogerr(who);
            }
            if (bitset(TLS_I_VRFY_LOC, req))
                return false;
        }
    }

    /* XXX: make this dependent on an option? */
    if (tTd(96, 9))
        SSL_CTX_set_info_callback(*ctx, apps_ssl_info_cb);

# if _FFR_TLS_1
    /* install our own cipher list */
    if (CipherList != NULL && *CipherList != '\0')
    {
        if (SSL_CTX_set_cipher_list(*ctx, CipherList) <= 0)
        {
            if (LogLevel > 7)
            {
                sm_syslog(LOG_WARNING, NOQID,
                      "STARTTLS=%s, error: SSL_CTX_set_cipher_list(%s) failed, list ignored",
                      who, CipherList);

                if (LogLevel > 9)
                    tlslogerr(who);
            }
            /* failure if setting to this list is required? */
        }
    }
# endif /* _FFR_TLS_1 */
    if (LogLevel > 12)
        sm_syslog(LOG_INFO, NOQID, "STARTTLS=%s, init=%d", who, ok);

# if _FFR_TLS_1
#  if 0
    /*
    **  this label is required if we want to have a "clean" exit
    **  see the comments above at the initialization of cf2
    */

    endinittls:
#  endif /* 0 */

    /* undo damage to global variables */
    if (cf2 != NULL)
        *--cf2 = ',';
    if (kf2 != NULL)
        *--kf2 = ',';
# endif /* _FFR_TLS_1 */

    return ok;
}
/*
**  TLS_GET_INFO -- get information about TLS connection
**
**  Parameters:
**      ssl -- TLS connection structure
**      srv -- server or client
**      host -- hostname of other side
**      mac -- macro storage
**      certreq -- did we ask for a cert?
**
**  Returns:
**      result of authentication.
**
**  Side Effects:
**      sets macros: {cipher}, {tls_version}, {verify},
**      {cipher_bits}, {alg_bits}, {cert}, {cert_subject},
**      {cert_issuer}, {cn_subject}, {cn_issuer}
*/

int
tls_get_info(ssl, srv, host, mac, certreq)
    SSL *ssl;
    bool srv;
    char *host;
    MACROS_T *mac;
    bool certreq;
{
    SSL_CIPHER *c;
    int b, r;
    long verifyok;
    char *s, *who;
    char bitstr[16];
    X509 *cert;

    c = SSL_get_current_cipher(ssl);

    /* cast is just workaround for compiler warning */
    macdefine(mac, A_TEMP, macid("{cipher}"),
          (char *) SSL_CIPHER_get_name(c));
    b = SSL_CIPHER_get_bits(c, &r);
    (void) sm_snprintf(bitstr, sizeof bitstr, "%d", b);
    macdefine(mac, A_TEMP, macid("{cipher_bits}"), bitstr);
    (void) sm_snprintf(bitstr, sizeof bitstr, "%d", r);
    macdefine(mac, A_TEMP, macid("{alg_bits}"), bitstr);
    s = SSL_CIPHER_get_version(c);
    if (s == NULL)
        s = "UNKNOWN";
    macdefine(mac, A_TEMP, macid("{tls_version}"), s);

    who = srv ? "server" : "client";
    cert = SSL_get_peer_certificate(ssl);
    verifyok = SSL_get_verify_result(ssl);
    if (LogLevel > 14)
        sm_syslog(LOG_INFO, NOQID,
              "STARTTLS=%s, get_verify: %ld get_peer: 0x%lx",
              who, verifyok, (unsigned long) cert);
    if (cert != NULL)
    {
        unsigned int n;
        unsigned char md[EVP_MAX_MD_SIZE];
        char buf[MAXNAME];

        X509_NAME_oneline(X509_get_subject_name(cert),
                  buf, sizeof buf);
        macdefine(mac, A_TEMP, macid("{cert_subject}"),
             xtextify(buf, "<>\")"));
        X509_NAME_oneline(X509_get_issuer_name(cert),
                  buf, sizeof buf);
        macdefine(mac, A_TEMP, macid("{cert_issuer}"),
             xtextify(buf, "<>\")"));
        X509_NAME_get_text_by_NID(X509_get_subject_name(cert),
                      NID_commonName, buf, sizeof buf);
        macdefine(mac, A_TEMP, macid("{cn_subject}"),
             xtextify(buf, "<>\")"));
        X509_NAME_get_text_by_NID(X509_get_issuer_name(cert),
                      NID_commonName, buf, sizeof buf);
        macdefine(mac, A_TEMP, macid("{cn_issuer}"),
             xtextify(buf, "<>\")"));
        n = 0;
        if (X509_digest(cert, EVP_md5(), md, &n) != 0 && n > 0)
        {
            char md5h[EVP_MAX_MD_SIZE * 3];
            static const char hexcodes[] = "0123456789ABCDEF";

            SM_ASSERT((n * 3) + 2 < sizeof(md5h));
            for (r = 0; r < (int) n; r++)
            {
                md5h[r * 3] = hexcodes[(md[r] & 0xf0) >> 4];
                md5h[(r * 3) + 1] = hexcodes[(md[r] & 0x0f)];
                md5h[(r * 3) + 2] = ':';
            }
            md5h[(n * 3) - 1] = '\0';
            macdefine(mac, A_TEMP, macid("{cert_md5}"), md5h);
        }
        else
            macdefine(mac, A_TEMP, macid("{cert_md5}"), "");
    }
    else
    {
        macdefine(mac, A_PERM, macid("{cert_subject}"), "");
        macdefine(mac, A_PERM, macid("{cert_issuer}"), "");
        macdefine(mac, A_PERM, macid("{cn_subject}"), "");
        macdefine(mac, A_PERM, macid("{cn_issuer}"), "");
        macdefine(mac, A_TEMP, macid("{cert_md5}"), "");
    }
    switch (verifyok)
    {
      case X509_V_OK:
        if (cert != NULL)
        {
            s = "OK";
            r = TLS_AUTH_OK;
        }
        else
        {
            s = certreq ? "NO" : "NOT",
            r = TLS_AUTH_NO;
        }
        break;
      default:
        s = "FAIL";
        r = TLS_AUTH_FAIL;
        break;
    }
    macdefine(mac, A_PERM, macid("{verify}"), s);
    if (cert != NULL)
        X509_free(cert);

    /* do some logging */
    if (LogLevel > 8)
    {
        char *vers, *s1, *s2, *cbits, *algbits;

        vers = macget(mac, macid("{tls_version}"));
        cbits = macget(mac, macid("{cipher_bits}"));
        algbits = macget(mac, macid("{alg_bits}"));
        s1 = macget(mac, macid("{verify}"));
        s2 = macget(mac, macid("{cipher}"));

        /* XXX: maybe cut off ident info? */
        sm_syslog(LOG_INFO, NOQID,
              "STARTTLS=%s, relay=%.100s, version=%.16s, verify=%.16s, cipher=%.64s, bits=%.6s/%.6s",
              who,
              host == NULL ? "local" : host,
              vers, s1, s2, /* sm_snprintf() can deal with NULL */
              algbits == NULL ? "0" : algbits,
              cbits == NULL ? "0" : cbits);
        if (LogLevel > 11)
        {
            /*
            **  Maybe run xuntextify on the strings?
            **  That is easier to read but makes it maybe a bit
            **  more complicated to figure out the right values
            **  for the access map...
            */

            s1 = macget(mac, macid("{cert_subject}"));
            s2 = macget(mac, macid("{cert_issuer}"));
            sm_syslog(LOG_INFO, NOQID,
                  "STARTTLS=%s, cert-subject=%.256s, cert-issuer=%.256s, verifymsg=%s",
                  who, s1, s2,
                  X509_verify_cert_error_string(verifyok));
        }
    }
    return r;
}
/*
**  ENDTLS -- shutdown secure connection
**
**  Parameters:
**      ssl -- SSL connection information.
**      side -- server/client (for logging).
**
**  Returns:
**      success? (EX_* code)
*/

int
endtls(ssl, side)
    SSL *ssl;
    char *side;
{
    int ret = EX_OK;

    if (ssl != NULL)
    {
        int r;

        if ((r = SSL_shutdown(ssl)) < 0)
        {
            if (LogLevel > 11)
            {
                sm_syslog(LOG_WARNING, NOQID,
                      "STARTTLS=%s, SSL_shutdown failed: %d",
                      side, r);
                tlslogerr(side);
            }
            ret = EX_SOFTWARE;
        }
# if !defined(OPENSSL_VERSION_NUMBER) || OPENSSL_VERSION_NUMBER > 0x0090602fL

        /*
        **  Bug in OpenSSL (at least up to 0.9.6b):
        **  From: Lutz.Jaenicke@aet.TU-Cottbus.DE
        **  Message-ID: <20010723152244.A13122@serv01.aet.tu-cottbus.de>
        **  To: openssl-users@openssl.org
        **  Subject: Re: SSL_shutdown() woes (fwd)
        **
        **  The side sending the shutdown alert first will
        **  not care about the answer of the peer but will
        **  immediately return with a return value of "0"
        **  (ssl/s3_lib.c:ssl3_shutdown()). SSL_get_error will evaluate
        **  the value of "0" and as the shutdown alert of the peer was
        **  not received (actually, the program did not even wait for
        **  the answer), an SSL_ERROR_SYSCALL is flagged, because this
        **  is the default rule in case everything else does not apply.
        **
        **  For your server the problem is different, because it
        **  receives the shutdown first (setting SSL_RECEIVED_SHUTDOWN),
        **  then sends its response (SSL_SENT_SHUTDOWN), so for the
        **  server the shutdown was successfull.
        **
        **  As is by know, you would have to call SSL_shutdown() once
        **  and ignore an SSL_ERROR_SYSCALL returned. Then call
        **  SSL_shutdown() again to actually get the server's response.
        **
        **  In the last discussion, Bodo Moeller concluded that a
        **  rewrite of the shutdown code would be necessary, but
        **  probably with another API, as the change would not be
        **  compatible to the way it is now.  Things do not become
        **  easier as other programs do not follow the shutdown
        **  guidelines anyway, so that a lot error conditions and
        **  compitibility issues would have to be caught.
        **
        **  For now the recommondation is to ignore the error message.
        */

        else if (r == 0)
        {
            if (LogLevel > 15)
            {
                sm_syslog(LOG_WARNING, NOQID,
                      "STARTTLS=%s, SSL_shutdown not done",
                      side);
                tlslogerr(side);
            }
            ret = EX_SOFTWARE;
        }
# endif /* !defined(OPENSSL_VERSION_NUMBER) || OPENSSL_VERSION_NUMBER > 0x0090602fL */
        SSL_free(ssl);
        ssl = NULL;
    }
    return ret;
}

# if !TLS_NO_RSA
/*
**  TMP_RSA_KEY -- return temporary RSA key
**
**  Parameters:
**      s -- TLS connection structure
**      export --
**      keylength --
**
**  Returns:
**      temporary RSA key.
*/

#   ifndef MAX_RSA_TMP_CNT
#    define MAX_RSA_TMP_CNT 1000    /* XXX better value? */
#   endif /* ! MAX_RSA_TMP_CNT */

/* ARGUSED0 */
static RSA *
tmp_rsa_key(s, export, keylength)
    SSL *s;
    int export;
    int keylength;
{
#   if SM_CONF_SHM
    extern int ShmId;
    extern int *PRSATmpCnt;

    if (ShmId != SM_SHM_NO_ID && rsa_tmp != NULL &&
        ++(*PRSATmpCnt) < MAX_RSA_TMP_CNT)
        return rsa_tmp;
#   endif /* SM_CONF_SHM */

    if (rsa_tmp != NULL)
        RSA_free(rsa_tmp);
    rsa_tmp = RSA_generate_key(RSA_KEYLENGTH, RSA_F4, NULL, NULL);
    if (rsa_tmp == NULL)
    {
        if (LogLevel > 0)
            sm_syslog(LOG_ERR, NOQID,
                  "STARTTLS=server, tmp_rsa_key: RSA_generate_key failed!");
    }
    else
    {
#   if SM_CONF_SHM
#    if 0
        /*
        **  XXX we can't (yet) share the new key...
        **  The RSA structure contains pointers hence it can't be
        **  easily kept in shared memory.  It must be transformed
        **  into a continous memory region first, then stored,
        **  and later read out again (each time re-transformed).
        */

        if (ShmId != SM_SHM_NO_ID)
            *PRSATmpCnt = 0;
#    endif /* 0 */
#   endif /* SM_CONF_SHM */
        if (LogLevel > 9)
            sm_syslog(LOG_ERR, NOQID,
                  "STARTTLS=server, tmp_rsa_key: new temp RSA key");
    }
    return rsa_tmp;
}
# endif /* !TLS_NO_RSA */
/*
**  APPS_SSL_INFO_CB -- info callback for TLS connections
**
**  Parameters:
**      s -- TLS connection structure
**      where -- state in handshake
**      ret -- return code of last operation
**
**  Returns:
**      none.
*/

static void
apps_ssl_info_cb(s, where, ret)
    CONST097 SSL *s;
    int where;
    int ret;
{
    int w;
    char *str;
    BIO *bio_err = NULL;

    if (LogLevel > 14)
        sm_syslog(LOG_INFO, NOQID,
              "STARTTLS: info_callback where=0x%x, ret=%d",
              where, ret);

    w = where & ~SSL_ST_MASK;
    if (bio_err == NULL)
        bio_err = BIO_new_fp(stderr, BIO_NOCLOSE);

    if (bitset(SSL_ST_CONNECT, w))
        str = "SSL_connect";
    else if (bitset(SSL_ST_ACCEPT, w))
        str = "SSL_accept";
    else
        str = "undefined";

    if (bitset(SSL_CB_LOOP, where))
    {
        if (LogLevel > 12)
            sm_syslog(LOG_NOTICE, NOQID,
                "STARTTLS: %s:%s",
                str, SSL_state_string_long(s));
    }
    else if (bitset(SSL_CB_ALERT, where))
    {
        str = bitset(SSL_CB_READ, where) ? "read" : "write";
        if (LogLevel > 12)
            sm_syslog(LOG_NOTICE, NOQID,
                "STARTTLS: SSL3 alert %s:%s:%s",
                str, SSL_alert_type_string_long(ret),
                SSL_alert_desc_string_long(ret));
    }
    else if (bitset(SSL_CB_EXIT, where))
    {
        if (ret == 0)
        {
            if (LogLevel > 7)
                sm_syslog(LOG_WARNING, NOQID,
                    "STARTTLS: %s:failed in %s",
                    str, SSL_state_string_long(s));
        }
        else if (ret < 0)
        {
            if (LogLevel > 7)
                sm_syslog(LOG_WARNING, NOQID,
                    "STARTTLS: %s:error in %s",
                    str, SSL_state_string_long(s));
        }
    }
}
/*
**  TLS_VERIFY_LOG -- log verify error for TLS certificates
**
**  Parameters:
**      ok -- verify ok?
**      ctx -- x509 context
**
**  Returns:
**      0 -- fatal error
**      1 -- ok
*/

static int
tls_verify_log(ok, ctx, name)
    int ok;
    X509_STORE_CTX *ctx;
    char *name;
{
    SSL *ssl;
    X509 *cert;
    int reason, depth;
    char buf[512];

    cert = X509_STORE_CTX_get_current_cert(ctx);
    reason = X509_STORE_CTX_get_error(ctx);
    depth = X509_STORE_CTX_get_error_depth(ctx);
    ssl = (SSL *) X509_STORE_CTX_get_ex_data(ctx,
            SSL_get_ex_data_X509_STORE_CTX_idx());

    if (ssl == NULL)
    {
        /* internal error */
        sm_syslog(LOG_ERR, NOQID,
              "STARTTLS: internal error: tls_verify_cb: ssl == NULL");
        return 0;
    }

    X509_NAME_oneline(X509_get_subject_name(cert), buf, sizeof buf);
    sm_syslog(LOG_INFO, NOQID,
          "STARTTLS: %s cert verify: depth=%d %s, state=%d, reason=%s",
          name, depth, buf, ok, X509_verify_cert_error_string(reason));
    return 1;
}

/*
**  TLS_VERIFY_CB -- verify callback for TLS certificates
**
**  Parameters:
**      ctx -- x509 context
**
**  Returns:
**      accept connection?
**      currently: always yes.
*/

static int
#  if !defined(OPENSSL_VERSION_NUMBER) || OPENSSL_VERSION_NUMBER < 0x00907000L
tls_verify_cb(ctx)
    X509_STORE_CTX *ctx;
#  else /* !defined() || OPENSSL_VERSION_NUMBER < 0x00907000L */
tls_verify_cb(ctx, unused)
    X509_STORE_CTX *ctx;
    void *unused;
#  endif /* !defined() || OPENSSL_VERSION_NUMBER < 0x00907000L */
{
    int ok;

    ok = X509_verify_cert(ctx);
    if (ok == 0)
    {
        if (LogLevel > 13)
            return tls_verify_log(ok, ctx, "TLS");
        return 1;   /* override it */
    }
    return ok;
}
/*
**  TLSLOGERR -- log the errors from the TLS error stack
**
**  Parameters:
**      who -- server/client (for logging).
**
**  Returns:
**      none.
*/

void
tlslogerr(who)
    char *who;
{
    unsigned long l;
    int line, flags;
    unsigned long es;
    char *file, *data;
    char buf[256];
#  define CP (const char **)

    es = CRYPTO_thread_id();
    while ((l = ERR_get_error_line_data(CP &file, &line, CP &data, &flags))
        != 0)
    {
        sm_syslog(LOG_WARNING, NOQID,
              "STARTTLS=%s: %lu:%s:%s:%d:%s", who, es,
              ERR_error_string(l, buf),
              file, line,
              bitset(ERR_TXT_STRING, flags) ? data : "");
    }
}

# if OPENSSL_VERSION_NUMBER > 0x00907000L
/*
**  X509_VERIFY_CB -- verify callback
**
**  Parameters:
**      ctx -- x509 context
**
**  Returns:
**      accept connection?
**      currently: always yes.
*/

static int
x509_verify_cb(ok, ctx)
    int ok;
    X509_STORE_CTX *ctx;
{
    if (ok == 0)
    {
        if (LogLevel > 13)
            tls_verify_log(ok, ctx, "x509");
        if (ctx->error == X509_V_ERR_UNABLE_TO_GET_CRL)
        {
            ctx->error = 0;
            return 1;   /* override it */
        }
    }
    return ok;
}
# endif /* OPENSSL_VERSION_NUMBER > 0x00907000L */
#endif /* STARTTLS */