diff options
Diffstat (limited to 'libtac/lib/authen_s.c')
| -rw-r--r-- | libtac/lib/authen_s.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/libtac/lib/authen_s.c b/libtac/lib/authen_s.c new file mode 100644 index 0000000..4a7e55a --- /dev/null +++ b/libtac/lib/authen_s.c @@ -0,0 +1,143 @@ +/* authen_s.c - Send authentication request to the server. + * + * Copyright (C) 2010, Pawel Krawczyk <kravietz@ceti.pl> and + * Jeroen Nijhof <jeroen@nijhofnet.nl> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program - see the file COPYING. + * + * See `CHANGES' file for revision history. + */ + +#include "tacplus.h" +#include "libtac.h" +#include "md5.h" + +/* this function sends a packet do TACACS+ server, asking + * for validation of given username and password + */ +int tac_authen_send(int fd, const char *user, char *pass, char *tty) +{ + HDR *th; /* TACACS+ packet header */ + struct authen_start tb; /* message body */ + int user_len, port_len, chal_len, mdp_len, token_len, bodylength, w; + int pkt_len=0; + int ret=0; + char *chal = "1234123412341234"; + char digest[MD5_LEN]; + char *token; + u_char *pkt, *mdp; + MD5_CTX mdcontext; + + th=_tac_req_header(TAC_PLUS_AUTHEN); + + /* set some header options */ + if(strcmp(tac_login,"login") == 0) { + th->version=TAC_PLUS_VER_0; + } else { + th->version=TAC_PLUS_VER_1; + } + th->encryption=tac_encryption ? TAC_PLUS_ENCRYPTED : TAC_PLUS_CLEAR; + + TACDEBUG((LOG_DEBUG, "%s: user '%s', tty '%s', encrypt: %s", \ + __FUNCTION__, user, tty, \ + (tac_encryption) ? "yes" : "no")) + + if(strcmp(tac_login,"chap") == 0) { + chal_len = strlen(chal); + mdp_len = sizeof(u_char) + strlen(pass) + chal_len; + mdp = (u_char *) xcalloc(1, mdp_len); + mdp[0] = 5; + memcpy(&mdp[1], pass, strlen(pass)); + memcpy(mdp + strlen(pass) + 1, chal, chal_len); + MD5Init(&mdcontext); + MD5Update(&mdcontext, mdp, mdp_len); + MD5Final((u_char *) digest, &mdcontext); + free(mdp); + token = xcalloc(1, sizeof(u_char) + 1 + chal_len + MD5_LEN); + token[0] = 5; + memcpy(&token[1], chal, chal_len); + memcpy(token + chal_len + 1, digest, MD5_LEN); + } else { + token = pass; + } + + /* get size of submitted data */ + user_len=strlen(user); + port_len=strlen(tty); + token_len=strlen(token); + + /* fill the body of message */ + tb.action=TAC_PLUS_AUTHEN_LOGIN; + tb.priv_lvl=TAC_PLUS_PRIV_LVL_MIN; + if(strcmp(tac_login,"chap") == 0) { + tb.authen_type=TAC_PLUS_AUTHEN_TYPE_CHAP; + } else if(strcmp(tac_login,"login") == 0) { + tb.authen_type=TAC_PLUS_AUTHEN_TYPE_ASCII; + } else { + tb.authen_type=TAC_PLUS_AUTHEN_TYPE_PAP; + } + tb.service=TAC_PLUS_AUTHEN_SVC_PPP; + tb.user_len=user_len; + tb.port_len=port_len; + tb.rem_addr_len=0; /* may be e.g Caller-ID in future */ + tb.data_len=token_len; + + /* fill body length in header */ + bodylength=sizeof(tb) + user_len + + port_len + token_len; /* + rem_addr_len */ + + th->datalength= htonl(bodylength); + + /* we can now write the header */ + w=write(fd, th, TAC_PLUS_HDR_SIZE); + if(w < 0 || w < TAC_PLUS_HDR_SIZE) { + syslog(LOG_ERR, "%s: short write on header: wrote %d of %d: %m", + __FUNCTION__, w, TAC_PLUS_HDR_SIZE); + ret=-1; + } + + /* build the packet */ + pkt=(u_char *) xcalloc(1, bodylength+10); + + bcopy(&tb, pkt+pkt_len, sizeof(tb)); /* packet body beginning */ + pkt_len+=sizeof(tb); + bcopy(user, pkt+pkt_len, user_len); /* user */ + pkt_len+=user_len; + bcopy(tty, pkt+pkt_len, port_len); /* tty */ + pkt_len+=port_len; + bcopy(token, pkt+pkt_len, token_len); /* password */ + pkt_len+=token_len; + + /* pkt_len == bodylength ? */ + if(pkt_len != bodylength) { + syslog(LOG_ERR, "%s: bodylength %d != pkt_len %d", + __FUNCTION__, bodylength, pkt_len); + ret=-1; + } + + /* encrypt the body */ + _tac_crypt(pkt, th, bodylength); + + w=write(fd, pkt, pkt_len); + if(w < 0 || w < pkt_len) { + syslog(LOG_ERR, "%s: short write on body: wrote %d of %d: %m", + __FUNCTION__, w, pkt_len); + ret=-1; + } + + free(pkt); + free(th); + + return(ret); +} /* tac_authen_send */ |