diff options
Diffstat (limited to 'crypto/kerberosIV/lib/krb/recvauth.c')
-rw-r--r-- | crypto/kerberosIV/lib/krb/recvauth.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/crypto/kerberosIV/lib/krb/recvauth.c b/crypto/kerberosIV/lib/krb/recvauth.c new file mode 100644 index 0000000..6c96897 --- /dev/null +++ b/crypto/kerberosIV/lib/krb/recvauth.c @@ -0,0 +1,190 @@ +/* + Copyright (C) 1989 by the Massachusetts Institute of Technology + + Export of this software from the United States of America is assumed + to require a specific license from the United States Government. + It is the responsibility of any person or organization contemplating + export to obtain such a license before exporting. + +WITHIN THAT CONSTRAINT, permission to use, copy, modify, and +distribute this software and its documentation for any purpose and +without fee is hereby granted, provided that the above copyright +notice appear in all copies and that both that copyright notice and +this permission notice appear in supporting documentation, and that +the name of M.I.T. not be used in advertising or publicity pertaining +to distribution of the software without specific, written prior +permission. M.I.T. makes no representations about the suitability of +this software for any purpose. It is provided "as is" without express +or implied warranty. + + */ + +#include "krb_locl.h" + +RCSID("$Id: recvauth.c,v 1.17 1997/03/23 03:53:16 joda Exp $"); + +/* + * krb_recvauth() reads (and optionally responds to) a message sent + * using krb_sendauth(). The "options" argument is a bit-field of + * selected options (see "sendauth.c" for options description). + * The only option relevant to krb_recvauth() is KOPT_DO_MUTUAL + * (mutual authentication requested). The "fd" argument supplies + * a file descriptor to read from (and write to, if mutual authenti- + * cation is requested). + * + * Part of the received message will be a Kerberos ticket sent by the + * client; this is read into the "ticket" argument. The "service" and + * "instance" arguments supply the server's Kerberos name. If the + * "instance" argument is the string "*", it is treated as a wild card + * and filled in during the krb_rd_req() call (see read_service_key()). + * + * The "faddr" and "laddr" give the sending (client) and receiving + * (local server) network addresses. ("laddr" may be left NULL unless + * mutual authentication is requested, in which case it must be set.) + * + * The authentication information extracted from the message is returned + * in "kdata". The "filename" argument indicates the file where the + * server's key can be found. (It is passed on to krb_rd_req().) If + * left null, the default "/etc/srvtab" will be used. + * + * If mutual authentication is requested, the session key schedule must + * be computed in order to reply; this schedule is returned in the + * "schedule" argument. A string containing the application version + * number from the received message is returned in "version", which + * should be large enough to hold a KRB_SENDAUTH_VLEN-character string. + * + * See krb_sendauth() for the format of the received client message. + * + * krb_recvauth() first reads the protocol version string from the + * given file descriptor. If it doesn't match the current protocol + * version (KRB_SENDAUTH_VERS), the old-style format is assumed. In + * that case, the string of characters up to the first space is read + * and interpreted as the ticket length, then the ticket is read. + * + * If the first string did match KRB_SENDAUTH_VERS, krb_recvauth() + * next reads the application protocol version string. Then the + * ticket length and ticket itself are read. + * + * The ticket is decrypted and checked by the call to krb_rd_req(). + * If no mutual authentication is required, the result of the + * krb_rd_req() call is retured by this routine. If mutual authenti- + * cation is required, a message in the following format is returned + * on "fd": + * + * Size Variable Field + * ---- -------- ----- + * + * 4 bytes tkt_len length of ticket or -1 + * if error occurred + * + * priv_len tmp_buf "private" message created + * by krb_mk_priv() which + * contains the incremented + * checksum sent by the client + * encrypted in the session + * key. (This field is not + * present in case of error.) + * + * If all goes well, KSUCCESS is returned; otherwise KFAILURE or some + * other error code is returned. + */ + +static int +send_error_reply(int fd) +{ + unsigned char tmp[4] = { 255, 255, 255, 255 }; + if(krb_net_write(fd, tmp, sizeof(tmp)) != sizeof(tmp)) + return -1; + return 0; +} + +int +krb_recvauth(int32_t options, /* bit-pattern of options */ + int fd, /* file descr. to read from */ + KTEXT ticket, /* storage for client's ticket */ + char *service, /* service expected */ + char *instance, /* inst expected (may be filled in) */ + struct sockaddr_in *faddr, /* address of foreign host on fd */ + struct sockaddr_in *laddr, /* local address */ + AUTH_DAT *kdata, /* kerberos data (returned) */ + char *filename, /* name of file with service keys */ + struct des_ks_struct *schedule, /* key schedule (return) */ + char *version) /* version string (filled in) */ +{ + int cc; + char krb_vers[KRB_SENDAUTH_VLEN + 1]; /* + 1 for the null terminator */ + int rem; + int32_t priv_len; + u_char tmp_buf[MAX_KTXT_LEN+max(KRB_SENDAUTH_VLEN+1,21)]; + + /* read the protocol version number */ + if (krb_net_read(fd, krb_vers, KRB_SENDAUTH_VLEN) != KRB_SENDAUTH_VLEN) + return(errno); + krb_vers[KRB_SENDAUTH_VLEN] = '\0'; + + /* read the application version string */ + if (krb_net_read(fd, version, KRB_SENDAUTH_VLEN) != KRB_SENDAUTH_VLEN) + return(errno); + version[KRB_SENDAUTH_VLEN] = '\0'; + + /* get the length of the ticket */ + { + char tmp[4]; + if (krb_net_read(fd, tmp, 4) != 4) + return -1; + krb_get_int(tmp, &ticket->length, 4, 0); + } + + /* sanity check */ + if (ticket->length <= 0 || ticket->length > MAX_KTXT_LEN) { + if (options & KOPT_DO_MUTUAL) { + if(send_error_reply(fd)) + return -1; + return KFAILURE; + } else + return KFAILURE; /* XXX there may still be junk on the fd? */ + } + + /* read the ticket */ + if (krb_net_read(fd, ticket->dat, ticket->length) != ticket->length) + return -1; + /* + * now have the ticket. decrypt it to get the authenticated + * data. + */ + rem = krb_rd_req(ticket, service, instance, faddr->sin_addr.s_addr, + kdata, filename); + + /* if we are doing mutual auth, compose a response */ + if (options & KOPT_DO_MUTUAL) { + if (rem != KSUCCESS){ + /* the krb_rd_req failed */ + if(send_error_reply(fd)) + return -1; + return rem; + } + + /* add one to the (formerly) sealed checksum, and re-seal it + for return to the client */ + { + unsigned char cs[4]; + krb_put_int(kdata->checksum + 1, cs, 4); +#ifndef NOENCRYPTION + des_key_sched(&kdata->session,schedule); +#endif + priv_len = krb_mk_priv(cs, + tmp_buf+4, + 4, + schedule, + &kdata->session, + laddr, + faddr); + } + /* mk_priv will never fail */ + priv_len += krb_put_int(priv_len, tmp_buf, 4); + + if((cc = krb_net_write(fd, tmp_buf, priv_len)) != priv_len) + return -1; + } + return rem; +} |