tls_mgr.c

[詳解]

/*++
/* NAME
/*  tls_mgr 3
/* SUMMARY
/*  tlsmgr client interface
/* SYNOPSIS
/*  #include <tls_mgr.h>
/*
/*  int tls_mgr_seed(buf, len)
/*  VSTRING *buf;
/*  int len;
/*
/*  int tls_mgr_policy(cache_type, cachable, timeout)
/*  const char *cache_type;
/*  int *cachable;
/*  int *timeout;
/*
/*  int tls_mgr_update(cache_type, cache_id, buf, len)
/*  const char *cache_type;
/*  const char *cache_id;
/*  const char *buf;
/*  ssize_t len;
/*
/*  int tls_mgr_lookup(cache_type, cache_id, buf)
/*  const char *cache_type;
/*  const char *cache_id;
/*  VSTRING *buf;
/*
/*  int tls_mgr_delete(cache_type, cache_id)
/*  const char *cache_type;
/*  const char *cache_id;
/*
/*  TLS_TICKET_KEY *tls_mgr_key(keyname, timeout)
/*  unsigned char *keyname;
/*  int timeout;
/* DESCRIPTION
/*  These routines communicate with the tlsmgr(8) server for
/*  entropy and session cache management. Since these are
/*  non-critical services, requests are allowed to fail without
/*  disrupting Postfix.
/*
/*  tls_mgr_seed() requests entropy from the tlsmgr(8)
/*  Pseudo Random Number Generator (PRNG) pool.
/*
/*  tls_mgr_policy() requests the session caching policy.
/*
/*  tls_mgr_lookup() loads the specified session from
/*  the specified session cache.
/*
/*  tls_mgr_update() saves the specified session to
/*  the specified session cache.
/*
/*  tls_mgr_delete() removes specified session from
/*  the specified session cache.
/*
/*  tls_mgr_key() is used to retrieve the current TLS session ticket
/*  encryption or decryption keys.
/*
/*  Arguments:
/* .IP cache_type
/*  One of TLS_MGR_SCACHE_SMTPD, TLS_MGR_SCACHE_SMTP or
/*  TLS_MGR_SCACHE_LMTP.
/* .IP cachable
/*  Pointer to int, set non-zero if the requested cache_type
/*  is enabled.
/* .IP timeout
/*  Pointer to int, returns the cache entry timeout.
/* .IP cache_id
/*  The session cache lookup key.
/* .IP buf
/*  The result or input buffer.
/* .IP len
/*  The length of the input buffer, or the amount of data requested.
/* .IP keyname
/*  Is null when requesting the current encryption keys.  Otherwise,
/*  keyname is a pointer to an array of TLS_TICKET_NAMELEN unsigned
/*  chars (not NUL terminated) that is an identifier for a key
/*  previously used to encrypt a session ticket.  When encrypting
/*  a null result indicates that session tickets are not supported, when
/*  decrypting it indicates that no matching keys were found.
/* .IP timeout
/*  The encryption key timeout.  Once a key has been active for this many
/*  seconds it is retired and used only for decrypting previously issued
/*  session tickets for another timeout seconds, and is then destroyed.
/*  The timeout must not be longer than half the SSL session lifetime.
/* DIAGNOSTICS
/*  All client functions return one of the following status codes:
/* .IP TLS_MGR_STAT_OK
/*  The request completed, and the requested operation was
/*  successful (for example, the requested session was found,
/*  or the specified session was saved or removed).
/* .IP TLS_MGR_STAT_ERR
/*  The request completed, but the requested operation failed
/*  (for example, the requested object was not found or the
/*  specified session was not saved or removed).
/* .IP TLS_MGR_STAT_FAIL
/*  The request could not complete (the client could not
/*  communicate with the tlsmgr(8) server).
/* SEE ALSO
/*  tlsmgr(8) TLS session and PRNG management
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*--*/

/* System library. */

#include <sys_defs.h>

#ifdef USE_TLS

#ifdef STRCASECMP_IN_STRINGS_H
#include <strings.h>
#endif

/* Utility library. */

#include <msg.h>
#include <vstream.h>
#include <vstring.h>
#include <attr.h>
#include <attr_clnt.h>
#include <mymalloc.h>
#include <stringops.h>

/* Global library. */

#include <mail_params.h>
#include <mail_proto.h>

/* TLS library. */
#include <tls_mgr.h>

/* Application-specific. */

#define STR(x) vstring_str(x)
#define LEN(x) VSTRING_LEN(x)

static ATTR_CLNT *tls_mgr;

/* tls_mgr_open - create client handle */

static void tls_mgr_open(void)
{
    char   *service;

    /*
     * Sanity check.
     */
    if (tls_mgr != 0)
    msg_panic("tls_mgr_open: multiple initialization");

    /*
     * Use whatever IPC is preferred for internal use: UNIX-domain sockets or
     * Solaris streams.
     */
    service = concatenate("local:" TLS_MGR_CLASS "/", var_tls_mgr_service,
              (char *) 0);
    tls_mgr = attr_clnt_create(service, var_ipc_timeout,
                   var_ipc_idle_limit, var_ipc_ttl_limit);
    myfree(service);

    attr_clnt_control(tls_mgr,
              ATTR_CLNT_CTL_PROTO, attr_vprint, attr_vscan,
              ATTR_CLNT_CTL_END);
}

/* tls_mgr_seed - request PRNG seed */

int     tls_mgr_seed(VSTRING *buf, int len)
{
    int     status;

    /*
     * Create the tlsmgr client handle.
     */
    if (tls_mgr == 0)
    tls_mgr_open();

    /*
     * Request seed.
     */
    if (attr_clnt_request(tls_mgr,
              ATTR_FLAG_NONE,   /* Request attributes */
              SEND_ATTR_STR(TLS_MGR_ATTR_REQ, TLS_MGR_REQ_SEED),
              SEND_ATTR_INT(TLS_MGR_ATTR_SIZE, len),
              ATTR_TYPE_END,
              ATTR_FLAG_MISSING,    /* Reply attributes */
              RECV_ATTR_INT(TLS_MGR_ATTR_STATUS, &status),
              RECV_ATTR_DATA(TLS_MGR_ATTR_SEED, buf),
              ATTR_TYPE_END) != 2)
    status = TLS_MGR_STAT_FAIL;
    return (status);
}

/* tls_mgr_policy - request caching policy */

int     tls_mgr_policy(const char *cache_type, int *cachable, int *timeout)
{
    int     status;

    /*
     * Create the tlsmgr client handle.
     */
    if (tls_mgr == 0)
    tls_mgr_open();

    /*
     * Request policy.
     */
    if (attr_clnt_request(tls_mgr,
              ATTR_FLAG_NONE,   /* Request attributes */
            SEND_ATTR_STR(TLS_MGR_ATTR_REQ, TLS_MGR_REQ_POLICY),
              SEND_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
              ATTR_TYPE_END,
              ATTR_FLAG_MISSING,    /* Reply attributes */
              RECV_ATTR_INT(TLS_MGR_ATTR_STATUS, &status),
              RECV_ATTR_INT(TLS_MGR_ATTR_CACHABLE, cachable),
              RECV_ATTR_INT(TLS_MGR_ATTR_SESSTOUT, timeout),
              ATTR_TYPE_END) != 3)
    status = TLS_MGR_STAT_FAIL;
    return (status);
}

/* tls_mgr_lookup - request cached session */

int     tls_mgr_lookup(const char *cache_type, const char *cache_id,
                       VSTRING *buf)
{
    int     status;

    /*
     * Create the tlsmgr client handle.
     */
    if (tls_mgr == 0)
    tls_mgr_open();

    /*
     * Send the request and receive the reply.
     */
    if (attr_clnt_request(tls_mgr,
              ATTR_FLAG_NONE,   /* Request */
            SEND_ATTR_STR(TLS_MGR_ATTR_REQ, TLS_MGR_REQ_LOOKUP),
              SEND_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
              SEND_ATTR_STR(TLS_MGR_ATTR_CACHE_ID, cache_id),
              ATTR_TYPE_END,
              ATTR_FLAG_MISSING,    /* Reply */
              RECV_ATTR_INT(TLS_MGR_ATTR_STATUS, &status),
              RECV_ATTR_DATA(TLS_MGR_ATTR_SESSION, buf),
              ATTR_TYPE_END) != 2)
    status = TLS_MGR_STAT_FAIL;
    return (status);
}

/* tls_mgr_update - save session to cache */

int     tls_mgr_update(const char *cache_type, const char *cache_id,
                       const char *buf, ssize_t len)
{
    int     status;

    /*
     * Create the tlsmgr client handle.
     */
    if (tls_mgr == 0)
    tls_mgr_open();

    /*
     * Send the request and receive the reply.
     */
    if (attr_clnt_request(tls_mgr,
              ATTR_FLAG_NONE,   /* Request */
            SEND_ATTR_STR(TLS_MGR_ATTR_REQ, TLS_MGR_REQ_UPDATE),
              SEND_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
              SEND_ATTR_STR(TLS_MGR_ATTR_CACHE_ID, cache_id),
              SEND_ATTR_DATA(TLS_MGR_ATTR_SESSION, len, buf),
              ATTR_TYPE_END,
              ATTR_FLAG_MISSING,    /* Reply */
              RECV_ATTR_INT(TLS_MGR_ATTR_STATUS, &status),
              ATTR_TYPE_END) != 1)
    status = TLS_MGR_STAT_FAIL;
    return (status);
}

/* tls_mgr_delete - remove cached session */

int     tls_mgr_delete(const char *cache_type, const char *cache_id)
{
    int     status;

    /*
     * Create the tlsmgr client handle.
     */
    if (tls_mgr == 0)
    tls_mgr_open();

    /*
     * Send the request and receive the reply.
     */
    if (attr_clnt_request(tls_mgr,
              ATTR_FLAG_NONE,   /* Request */
            SEND_ATTR_STR(TLS_MGR_ATTR_REQ, TLS_MGR_REQ_DELETE),
              SEND_ATTR_STR(TLS_MGR_ATTR_CACHE_TYPE, cache_type),
              SEND_ATTR_STR(TLS_MGR_ATTR_CACHE_ID, cache_id),
              ATTR_TYPE_END,
              ATTR_FLAG_MISSING,    /* Reply */
              RECV_ATTR_INT(TLS_MGR_ATTR_STATUS, &status),
              ATTR_TYPE_END) != 1)
    status = TLS_MGR_STAT_FAIL;
    return (status);
}

/* request_scache_key - ask tlsmgr(8) for matching key */

static TLS_TICKET_KEY *request_scache_key(unsigned char *keyname)
{
    TLS_TICKET_KEY tmp;
    static VSTRING *keybuf;
    char   *name;
    size_t  len;
    int     status;

    /*
     * Create the tlsmgr client handle.
     */
    if (tls_mgr == 0)
    tls_mgr_open();

    if (keybuf == 0)
    keybuf = vstring_alloc(sizeof(tmp));

    /* In tlsmgr requests we encode null key names as empty strings. */
    name = keyname ? (char *) keyname : "";
    len = keyname ? TLS_TICKET_NAMELEN : 0;

    /*
     * Send the request and receive the reply.
     */
    if (attr_clnt_request(tls_mgr,
              ATTR_FLAG_NONE,   /* Request */
            SEND_ATTR_STR(TLS_MGR_ATTR_REQ, TLS_MGR_REQ_TKTKEY),
              SEND_ATTR_DATA(TLS_MGR_ATTR_KEYNAME, len, name),
              ATTR_TYPE_END,
              ATTR_FLAG_MISSING,    /* Reply */
              RECV_ATTR_INT(TLS_MGR_ATTR_STATUS, &status),
              RECV_ATTR_DATA(TLS_MGR_ATTR_KEYBUF, keybuf),
              ATTR_TYPE_END) != 2
    || status != TLS_MGR_STAT_OK
    || LEN(keybuf) != sizeof(tmp))
    return (0);

    memcpy((void *) &tmp, STR(keybuf), sizeof(tmp));
    return (tls_scache_key_rotate(&tmp));
}

/* tls_mgr_key - session ticket key lookup, local cache, then tlsmgr(8) */

TLS_TICKET_KEY *tls_mgr_key(unsigned char *keyname, int timeout)
{
    TLS_TICKET_KEY *key = 0;
    time_t  now = time((time_t *) 0);

    /* A zero timeout disables session tickets. */
    if (timeout <= 0)
    return (0);

    if ((key = tls_scache_key(keyname, now, timeout)) == 0)
    key = request_scache_key(keyname);
    return (key);
}

#ifdef TEST

/* System library. */

#include <stdlib.h>

/* Utility library. */

#include <argv.h>
#include <msg_vstream.h>
#include <vstring_vstream.h>
#include <hex_code.h>

/* Global library. */

#include <config.h>

/* Application-specific. */

int     main(int unused_ac, char **av)
{
    VSTRING *inbuf = vstring_alloc(10);
    int     status;
    ARGV   *argv = 0;

    msg_vstream_init(av[0], VSTREAM_ERR);

    msg_verbose = 3;

    mail_conf_read();
    msg_info("using config files in %s", var_config_dir);

    if (chdir(var_queue_dir) < 0)
    msg_fatal("chdir %s: %m", var_queue_dir);

    while (vstring_fgets_nonl(inbuf, VSTREAM_IN)) {
    argv = argv_split(STR(inbuf), CHARS_SPACE);
    if (argv->argc == 0) {
        argv_free(argv);
        continue;
    }
#define COMMAND(argv, str, len) \
    (strcasecmp(argv->argv[0], str) == 0 && argv->argc == len)

    if (COMMAND(argv, "policy", 2)) {
        int     cachable;
        int     timeout;

        status = tls_mgr_policy(argv->argv[1], &cachable, &timeout);
        vstream_printf("status=%d cachable=%d timeout=%d\n",
               status, cachable, timeout);
    } else if (COMMAND(argv, "seed", 2)) {
        VSTRING *buf = vstring_alloc(10);
        VSTRING *hex = vstring_alloc(10);
        int     len = atoi(argv->argv[1]);

        status = tls_mgr_seed(buf, len);
        hex_encode(hex, STR(buf), LEN(buf));
        vstream_printf("status=%d seed=%s\n", status, STR(hex));
        vstring_free(hex);
        vstring_free(buf);
    } else if (COMMAND(argv, "lookup", 3)) {
        VSTRING *buf = vstring_alloc(10);

        status = tls_mgr_lookup(argv->argv[1], argv->argv[2], buf);
        vstream_printf("status=%d session=%.*s\n",
               status, LEN(buf), STR(buf));
        vstring_free(buf);
    } else if (COMMAND(argv, "update", 4)) {
        status = tls_mgr_update(argv->argv[1], argv->argv[2],
                    argv->argv[3], strlen(argv->argv[3]));
        vstream_printf("status=%d\n", status);
    } else if (COMMAND(argv, "delete", 3)) {
        status = tls_mgr_delete(argv->argv[1], argv->argv[2]);
        vstream_printf("status=%d\n", status);
    } else {
        vstream_printf("usage:\n"
               "seed byte_count\n"
               "policy smtpd|smtp|lmtp\n"
               "lookup smtpd|smtp|lmtp cache_id\n"
               "update smtpd|smtp|lmtp cache_id session\n"
               "delete smtpd|smtp|lmtp cache_id\n");
    }
    vstream_fflush(VSTREAM_OUT);
    argv_free(argv);
    }

    vstring_free(inbuf);
    return (0);
}

#endif                  /* TEST */

#endif                  /* USE_TLS */