env_ami.c

SIP（Session Initiation Protocol）是由IETF定义

 * Accepts: user name string
 *	    password string
 *	    authenticating user name string
 *	    argument count
 *	    argument vector
 * Returns: T if password validated, NIL otherwise
 */

long server_login (char *user,char *pwd,char *authuser,int argc,char *argv[])
{
  char *s,usr[MAILTMPLEN],ausr[MAILTMPLEN];
  struct passwd *pw;
  struct passwd *logpw = NIL;
				/* cretins still haven't given up */
  if ((strlen (user) >= MAILTMPLEN) ||
      (authuser && (strlen (authuser) >= MAILTMPLEN))) {
    syslog (LOG_ALERT|LOG_AUTH,"SYSTEM BREAK-IN ATTEMPT, host=%.80s",
	    tcp_clienthost ());
    logtry = 0;			/* render this session useless */
  }
  else {
    strcpy (usr,user);		/* make writeable copy of user */
    if (auth_md5.server) {	/* using CRAM-MD5 authentication? */
				/* make sure user exists */
      if ((pw = getpwnam (usr)) || (pw = getpwnam (lcase (usr)))) {
				/* default authentication identity */
	if (!(authuser && *authuser))
	  s = auth_md5_pwd (strcpy (ausr,pw->pw_name));
				/* otherwise use given authentication id */
	else if (!(s = auth_md5_pwd (strcpy (ausr,authuser))))
	  s = auth_md5_pwd (lcase (ausr));
	if (s) {		/* have a CRAM-MD5 password? */
	  if (!strcmp (s,pwd) && strcmp (s,pwd+1)) logpw = pw;
				/* erase sensitive information */
	  memset (s,0,strlen (s));
	  fs_give ((void **) &s);
	}
	else syslog (LOG_NOTICE|LOG_AUTH,
		     "Login %s failed: %s has no CRAM-MD5 password host=%.80s",
		     usr,ausr,tcp_clienthost ());
      }
    }
				/* ordinary password authentication */
    else if ((authuser && *authuser) ?
	     (((pw = getpwnam (strcpy (ausr,authuser))) ||
	       (pw = getpwnam (lcase (ausr)))) &&
	      (checkpw (pw,pwd,argc,argv) ||
	       ((*pwd == ' ') && checkpw (getpwnam (ausr),pwd+1,argc,argv))) &&
	      ((pw = getpwnam (strcpy (usr,user))) ||
	       (pw = getpwnam (lcase (usr))))) :
	     (((pw = getpwnam (strcpy (ausr,user))) ||
	       (pw = getpwnam (lcase (ausr)))) &&
	      ((pw = checkpw (pw,pwd,argc,argv)) ||
	       ((*pwd == ' ') &&
		(pw = checkpw (getpwnam(ausr),pwd+1,argc,argv))))))
      logpw = pw;

    if (logtry <= 0)
      syslog (LOG_NOTICE|LOG_AUTH,
	      "Login attempt after lockout user=%.80s host=%.80s",
	      user,tcp_clienthost ());
#ifndef PLAINTEXT_DISABLED
    else if (logpw) {		/* have logpw, validate authentication ID */
      if (pw_login (pw,ausr,pw->pw_name,pw->pw_dir,argc,argv)) return T;
    }
#endif
    else syslog (LOG_NOTICE|LOG_AUTH,"%s user=%.80s host=%.80s",
		 (logtry-- > 0) ? "Login failure" : "Excessive login attempts",
		 user,tcp_clienthost ());
  }
  sleep (3);			/* slow down possible cracker */
  return NIL;
}

/* Authenticated server log in
 * Accepts: user name string
 *	    authenticating user name string
 *	    argument count
 *	    argument vector
 * Returns: T if password validated, NIL otherwise
 */

long authserver_login (char *user,char *authuser,int argc,char *argv[])
{
  struct passwd *pw = getpwnam (user);
  return pw ? pw_login (pw,authuser,pw->pw_name,pw->pw_dir,argc,argv) : NIL;
}


/* Log in as anonymous daemon
 * Accepts: argument count
 *	    argument vector
 * Returns: T if successful, NIL if error
 */

long anonymous_login (int argc,char *argv[])
{
  struct passwd *pw = getpwnam ((char *) anonymous_user);
				/* log in Mr. A. N. Onymous */
  return pw ? pw_login (pw,NIL,NIL,ANONYMOUSHOME,argc,argv) : NIL;
}


/* Finish log in and environment initialization
 * Accepts: passwd struct for loginpw()
 *	    authentication user name
 *	    user name (NIL for anonymous)
 *	    home directory (NIL for anonymous)
 *	    argument count
 *	    argument vector
 * Returns: T if successful, NIL if error
 */

long pw_login (struct passwd *pw,char *authuser,char *user,char *home,int argc,
	       char *argv[])
{
  long ret = NIL;
				/* OK if matches authorization ID */
  if (authuser && strcmp (authuser,pw->pw_name)) {
    struct group *gr = getgrnam ((char *) admin_grp);
    char **t;
				/* scan list of mail administrators */
    for (t = gr ? gr->gr_mem : NIL; t; t++) if (!strcmp (authuser,*t)) {
      syslog (LOG_NOTICE|LOG_AUTH,"Admin %s override of user=%s host=%.80s",
	      authuser,pw->pw_name,tcp_clienthost ());
      return pw_login (pw,NIL,user,home,argc,argv);
    }
    syslog (LOG_NOTICE|LOG_AUTH,
	    "Login %s failed: invalid authentication ID %s host=%.80s",
	    pw->pw_name,authuser,tcp_clienthost ());
  }
  else if (!pw->pw_uid);	/* disallow UID 0 */
				/* if same as EUID, treat as application */
  else if (pw->pw_uid == geteuid ()) ret = env_init (user,home);
  else {			/* in case loginpw() smashes these */
    char *u = user ? cpystr (user) : NIL;
    char *h = home ? cpystr (home) : NIL;
#ifdef CHROOT_SERVER
				/* paranoid site, lock out other directories */
    if (chdir (home ? home : ANONYMOUSHOME) &&
	chroot (home ? home : ANONYMOUSHOME)) return NIL;
    home = "/";			/* home directory now root */
    closedBox = T;		/* flag that this is a closed box */
#endif
				/* log the user in */
    if (loginpw (pw,argc,argv)) ret = env_init (u,h);
    if (h) fs_give ((void **) &h);
    if (u) fs_give ((void **) &u);
  }
  if (ret) chdir (myhomedir ());/* make sure at home directory */
  return ret;			/* return status */
}

/* Initialize environment
 * Accepts: user name
 *	    home directory name
 * Returns: T, always
 */

long env_init (char *user,char *home)
{
  extern MAILSTREAM CREATEPROTO;
  extern MAILSTREAM EMPTYPROTO;
  struct passwd *pw;
  struct stat sbuf;
  char *s,tmp[MAILTMPLEN];
  if (myUserName) fatal ("env_init called twice!");
				/* myUserName must be set before dorc() call */
  myUserName = cpystr (user ? user : (char *) anonymous_user);
  if (closedBox) {		/* closed box server */
				/* standard user can only reference home */
    if (user) nslist[0] = &nshome;
    else {			/* anonymous user */
      nslist[0] = &nsblackother; /* set root */
      anonymous = T;		/* flag as anonymous */
    }
    nslist[1] = nslist[2] = NIL;/* can't reference anything else */
    anonymousHome = "";		/* make sure user rc files don't try these */
    sysInbox = cpystr ("INBOX");/* make system INBOX */
  }

  else {			/* open or black box */
				/* do systemwide configuration */
    dorc ("/etc/c-client.cf",NIL);
    if (!anonymousHome) anonymousHome = cpystr (ANONYMOUSHOME);
    if (user) {			/* remember user name and home directory */
      nslist[0] = &nshome;	/* home directory */
				/* other users */
      nslist[1] = &nsamigaother;
#ifdef ADVERTISE_THE_WORLD
      nslist[2] = &nsworld;	/* you probably don't want to do this! */
#else
      nslist[2] = &nsshared;	/* what, me paranoid? */
#endif
    }
    else {			/* anonymous user */
      nslist[0] = nslist[1] = NIL,nslist[2] = &nsftp;
      sprintf (tmp,"%s/INBOX",home = anonymousHome);
      sysInbox = cpystr (tmp);	/* make system INBOX */
      anonymous = T;		/* flag as anonymous */
    }
  }

  myHomeDir = cpystr (home);	/* use real home directory */
  dorc (strcat (strcpy (tmp,myHomeDir),"/.mminit"),T);
  dorc (strcat (strcpy (tmp,myHomeDir),"/.imaprc"),NIL);
  if (!closedBox) {		/* can't do this on closed server */
				/* #ftp namespace */
    if (!ftpHome && (pw = getpwnam ("ftp"))) ftpHome = cpystr (pw->pw_dir);
				/* #public namespace */
    if (!publicHome && (pw = getpwnam ("imappublic")))
      publicHome = cpystr (pw->pw_dir);
				/* #shared namespace */
    if (!anonymous && !sharedHome && (pw = getpwnam ("imapshared")))
      sharedHome = cpystr (pw->pw_dir);
  }
  if (!myLocalHost) mylocalhost ();
  if (!myNewsrc) myNewsrc = cpystr(strcat (strcpy (tmp,myHomeDir),"/.newsrc"));
  if (!newsActive) newsActive = cpystr (ACTIVEFILE);
  if (!newsSpool) newsSpool = cpystr (NEWSSPOOL);
				/* force default prototype to be set */
  if (!createProto) createProto = &CREATEPROTO;
  if (!appendProto) appendProto = &EMPTYPROTO;
				/* re-do open action to get flags */
  (*createProto->dtb->open) (NIL);
  endpwent ();			/* close pw database */
  return T;
}
 
/* Return my user name
 * Accepts: pointer to optional flags
 * Returns: my user name
 */

char *myusername_full (unsigned long *flags)
{
  char *ret = (char *) unlogged_user;
  if (!myUserName) {		/* get user name if don't have it yet */
    struct passwd *pw;
    unsigned long euid = geteuid ();
    char *s = (char *) (euid ? getlogin () : NIL);
				/* look up getlogin() user name or EUID */
    if (!((s && *s && (strlen (s) < NETMAXUSER) && (pw = getpwnam (s)) &&
	   (pw->pw_uid == euid)) || (pw = getpwuid (euid))))
      fatal ("Unable to look up user name");
				/* init environment if not root */
    if (euid) env_init (pw->pw_name,((s = getenv ("HOME")) && *s &&
				     (strlen (s) < NETMAXMBX) &&
				     !stat (s,&sbuf) &&
				     ((sbuf.st_mode & S_IFMT) == S_IFDIR)) ?
			s : pw->pw_dir);
    else ret = pw->pw_name;	/* in case UID 0 user is other than root */
  }
  if (myUserName) {		/* logged in? */
    if (flags) *flags = anonymous ? MU_ANONYMOUS : MU_LOGGEDIN;
    ret = myUserName;		/* return user name */
  }
  else if (flags) *flags = MU_NOTLOGGEDIN;
  return ret;
}


/* Return my local host name
 * Returns: my local host name
 */

char *mylocalhost ()
{
  char tmp[MAILTMPLEN];
  struct hostent *host_name;
  if (!myLocalHost) {
    gethostname(tmp,MAILTMPLEN);/* get local host name */
    myLocalHost = cpystr ((host_name = gethostbyname (tmp)) ?
			  host_name->h_name : tmp);
  }
  return myLocalHost;
}

/* Return my home directory name
 * Returns: my home directory name
 */

char *myhomedir ()
{
  if (!myHomeDir) myusername ();/* initialize if first time */
  return myHomeDir ? myHomeDir : "";
}


/* Return my home mailbox name
 * Returns: my home directory name
 */

static char *mymailboxdir ()
{
				/* initialize if first time */
#ifdef MAILSUBDIR
  if (!myMailboxDir) {
    char tmp[MAILTMPLEN];
    sprintf (tmp,"%s/%s",myhomedir (),MAILSUBDIR);
    myHomeDir = cpystr (tmp);	/* use pre-defined subdirectory of home */
  }
#else
  if (!myMailboxDir && myHomeDir) myMailboxDir = cpystr (myhomedir ());
#endif
  return myMailboxDir ? myMailboxDir : "";
}


/* Return system standard INBOX
 * Accepts: buffer string
 */

char *sysinbox ()
{
  char tmp[MAILTMPLEN];
  if (!sysInbox) {		/* initialize if first time */
    sprintf (tmp,"%s/%s",MAILSPOOL,myusername ());
    sysInbox = cpystr (tmp);	/* system inbox is from mail spool */
  }
  return sysInbox;
}

/* Return mailbox directory name
 * Accepts: destination buffer
 *	    directory prefix
 *	    name in directory
 * Returns: file name or NIL if error
 */

char *mailboxdir (char *dst,char *dir,char *name)
{
  char tmp[MAILTMPLEN];
  if (dir || name) {		/* if either argument provided */
    if (dir) {
      if (strlen (dir) > NETMAXMBX) return NIL;
      strcpy (tmp,dir);		/* write directory prefix */
    }
    else tmp[0] = '\0';		/* otherwise null string */
    if (name) {
      if (strlen (name) > NETMAXMBX) return NIL;
      strcat (tmp,name);	/* write name in directory */
    }
				/* validate name, return its name */
    if (!mailboxfile (dst,tmp)) return NIL;
  }
				/* no arguments, wants mailbox directory */
  else strcpy (dst,mymailboxdir ());
  return dst;			/* return the name */
}

/* Return mailbox file name
 * Accepts: destination buffer
 *	    mailbox name
 * Returns: file name or empty string for driver-selected INBOX or NIL if error
 */

char *mailboxfile (char *dst,char *name)
{
  struct passwd *pw;
  char *dir = mymailboxdir ();
  *dst = '\0';			/* default to empty string */
				/* check invalid name */
  if (!name || !*name || (*name == '{') || (strlen (name) > NETMAXMBX))
    return NIL;
				/* check for INBOX */
  if (((name[0] == 'I') || (name[0] == 'i')) &&
      ((name[1] == 'N') || (name[1] == 'n')) &&
      ((name[2] == 'B') || (name[2] == 'b')) &&
      ((name[3] == 'O') || (name[3] == 'o')) &&
      ((name[4] == 'X') || (name[4] == 'x')) && !name[5]) {
				/* if restricted, canonicalize name of INBOX */
    if (anonymous || closedBox) name = "INBOX";
    else return dst;		/* else driver selects the INBOX name */
  }
				/* restricted name? */
  else if ((*name == '#') || anonymous) {
    if (strstr (name,"..") || strstr (name,"//") || strstr (name,"/~"))
      return NIL;		/* none of these allowed when restricted */
    switch (*name) {		/* what kind of restricted name? */
    case '#':			/* namespace name */
      if (((name[1] == 'f') || (name[1] == 'F')) &&
	  ((name[2] == 't') || (name[2] == 'T')) &&
	  ((name[3] == 'p') || (name[3] == 'P')) &&
	  (name[4] == '/') && (dir = ftpHome)) name += 5;
      else if (((name[1] == 'p') || (name[1] == 'P')) &&
	       ((name[2] == 'u') || (name[2] == 'U')) &&
	       ((name[3] == 'b') || (name[3] == 'B')) &&
	       ((name[4] == 'l') || (name[4] == 'L')) &&
	       ((name[5] == 'i') || (name[5] == 'I')) &&
	       ((name[6] == 'c') || (name[6] == 'C')) &&
	       (name[7] == '/') && (dir = publicHome)) name += 8;
      else if (!anonymous && ((name[1] == 's') || (name[1] == 'S')) &&
	       ((name[2] == 'h') || (name[2] == 'H')) &&