1 | /* |
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2 | * $Header: /afs/dev.mit.edu/source/repository/athena/bin/rkinit/rkinitd/krb.c,v 1.1 1989-11-12 19:35:48 qjb Exp $ |
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3 | * $Source: /afs/dev.mit.edu/source/repository/athena/bin/rkinit/rkinitd/krb.c,v $ |
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4 | * $Author: qjb $ |
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5 | * |
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6 | * This file contains all of the kerberos part of rkinitd. |
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7 | */ |
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8 | |
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9 | #if !defined(lint) && !defined(SABER) |
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10 | static char *rcsid = "$Header: /afs/dev.mit.edu/source/repository/athena/bin/rkinit/rkinitd/krb.c,v 1.1 1989-11-12 19:35:48 qjb Exp $"; |
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11 | #endif lint || SABER |
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12 | |
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13 | #include <stdio.h> |
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14 | #include <sys/types.h> |
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15 | #include <errno.h> |
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16 | #include <syslog.h> |
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17 | #include <netinet/in.h> |
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18 | #include <setjmp.h> |
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19 | #include <pwd.h> |
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20 | #include <krb.h> |
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21 | #include <des.h> |
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22 | |
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23 | #include <rkinit.h> |
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24 | #include <rkinit_private.h> |
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25 | #include <rkinit_err.h> |
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26 | |
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27 | #define FAILURE (!RKINIT_SUCCESS) |
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28 | |
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29 | extern int errno; |
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30 | extern char *sys_errlist[]; |
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31 | |
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32 | static char errbuf[BUFSIZ]; |
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33 | |
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34 | typedef struct { |
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35 | jmp_buf env; |
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36 | } rkinitd_intkt_info; |
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37 | |
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38 | static void this_phost(host, hostlen) |
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39 | char *host; |
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40 | int hostlen; |
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41 | { |
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42 | char this_host[MAXHOSTNAMELEN + 1]; |
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43 | |
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44 | BCLEAR(this_host); |
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45 | |
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46 | if (gethostname(this_host, sizeof(this_host)) < 0) { |
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47 | sprintf(errbuf, "gethostname: %s", sys_errlist[errno]); |
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48 | rkinit_errmsg(errbuf); |
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49 | error(); |
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50 | exit(1); |
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51 | } |
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52 | |
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53 | strncpy(host, krb_get_phost(this_host), hostlen - 1); |
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54 | } |
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55 | |
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56 | static int decrypt_tkt(user, instance, realm, arg, key_proc, cipp) |
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57 | char *user; |
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58 | char *instance; |
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59 | char *realm; |
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60 | char *arg; |
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61 | int (*key_proc)(); |
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62 | KTEXT *cipp; |
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63 | { |
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64 | MSG_DAT msg_data; /* Message data containing decrypted data */ |
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65 | KTEXT_ST auth; /* Authenticator */ |
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66 | AUTH_DAT auth_dat; /* Authentication data */ |
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67 | KTEXT cip = *cipp; |
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68 | MSG_DAT scip; |
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69 | int status = 0; |
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70 | des_cblock key; |
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71 | des_key_schedule sched; |
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72 | char phost[MAXHOSTNAMELEN + 1]; |
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73 | struct sockaddr_in caddr; /* client internet address */ |
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74 | struct sockaddr_in saddr; /* server internet address */ |
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75 | |
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76 | rkinitd_intkt_info *rii = (rkinitd_intkt_info *)arg; |
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77 | |
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78 | u_char enc_data[MAX_KTXT_LEN]; |
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79 | |
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80 | SBCLEAR(auth); |
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81 | SBCLEAR(auth_dat); |
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82 | SBCLEAR(scip); |
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83 | BCLEAR(enc_data); |
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84 | |
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85 | scip.app_data = enc_data; |
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86 | |
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87 | /* |
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88 | * Exchange with the client our response from the KDC (ticket encrypted |
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89 | * in user's private key) for the same ticket encrypted in our |
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90 | * (not yet known) session key. |
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91 | */ |
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92 | |
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93 | rpc_exchange_tkt(cip, &scip); |
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94 | |
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95 | /* |
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96 | * Get the authenticator |
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97 | */ |
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98 | |
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99 | SBCLEAR(auth); |
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100 | |
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101 | rpc_getauth(&auth, &caddr, &saddr); |
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102 | |
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103 | /* |
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104 | * Decode authenticator and extract session key. The first zero |
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105 | * means we don't care what host this comes from. This needs to |
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106 | * be done with euid of root so that /etc/srvtab can be read. |
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107 | */ |
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108 | |
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109 | BCLEAR(phost); |
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110 | this_phost(phost, sizeof(phost)); |
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111 | |
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112 | /* |
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113 | * This function has to use longjmp to return to the caller |
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114 | * because the kerberos library routine that calls it doesn't |
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115 | * pay attention to the return value it gives. That means that |
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116 | * if any of these routines failed, the error returned to the client |
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117 | * would be "password incorrect". |
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118 | */ |
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119 | |
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120 | if (status = krb_rd_req(&auth, KEY, phost, caddr.sin_addr.s_addr, |
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121 | &auth_dat, KEYFILE)) { |
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122 | sprintf(errbuf, "krb_rd_req: %s", krb_err_txt[status]); |
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123 | rkinit_errmsg(errbuf); |
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124 | longjmp(rii->env, status); |
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125 | } |
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126 | |
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127 | bcopy(auth_dat.session, key, sizeof(key)); |
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128 | if (des_key_sched(key, sched)) { |
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129 | sprintf(errbuf, "Error in des_key_sched"); |
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130 | rkinit_errmsg(errbuf); |
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131 | longjmp(rii->env, RKINIT_DES); |
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132 | } |
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133 | |
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134 | /* Decrypt the data. */ |
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135 | if ((status = |
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136 | krb_rd_priv((u_char *)scip.app_data, scip.app_length, |
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137 | sched, key, &caddr, &saddr, &msg_data)) == KSUCCESS) { |
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138 | cip->length = msg_data.app_length; |
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139 | bcopy(msg_data.app_data, cip->dat, msg_data.app_length); |
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140 | cip->dat[cip->length] = 0; |
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141 | } |
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142 | else { |
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143 | sprintf(errbuf, "krb_rd_priv: %s", krb_err_txt[status]); |
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144 | rkinit_errmsg(errbuf); |
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145 | longjmp(rii->env, status); |
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146 | } |
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147 | |
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148 | return(status); |
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149 | } |
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150 | |
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151 | static int validate_user(aname, inst, realm, username, errmsg) |
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152 | char *aname; |
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153 | char *inst; |
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154 | char *realm; |
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155 | char *username; |
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156 | char *errmsg; |
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157 | { |
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158 | struct passwd *pwnam; /* For access_check and uid */ |
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159 | AUTH_DAT auth_dat; |
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160 | |
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161 | SBCLEAR(auth_dat); |
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162 | |
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163 | if ((pwnam = getpwnam(username)) == NULL) { |
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164 | sprintf(errmsg, "%s does not exist on the remote host.", username); |
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165 | return(FAILURE); |
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166 | } |
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167 | |
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168 | strcpy(auth_dat.pname, aname); |
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169 | strcpy(auth_dat.pinst, inst); |
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170 | strcpy(auth_dat.prealm, realm); |
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171 | |
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172 | if (kuserok(&auth_dat, username) != KSUCCESS) { |
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173 | sprintf(errmsg, "%s has not allowed you to log in with", username); |
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174 | if (strlen(auth_dat.pinst)) |
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175 | sprintf(errmsg, "%s %s.%s", errmsg, auth_dat.pname, |
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176 | auth_dat.pinst); |
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177 | else |
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178 | sprintf(errmsg, "%s %s", errmsg, auth_dat.pname); |
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179 | sprintf(errmsg, "%s@%s tickets.", errmsg, auth_dat.prealm); |
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180 | return(FAILURE); |
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181 | } |
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182 | |
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183 | /* |
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184 | * Set real uid to owner of ticket file. The library takes care |
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185 | * of making the appropriate change. |
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186 | */ |
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187 | if (setruid(pwnam->pw_uid) < 0) { |
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188 | sprintf(errmsg, |
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189 | "Failure setting ruid to %d: %s\n", sys_errlist[errno]); |
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190 | strcpy(errbuf, errmsg); |
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191 | error(); |
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192 | return(FAILURE); |
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193 | } |
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194 | |
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195 | return(RKINIT_SUCCESS); |
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196 | } |
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197 | |
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198 | int get_tickets(version) |
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199 | int version; |
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200 | { |
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201 | rkinit_info info; |
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202 | AUTH_DAT auth_dat; |
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203 | |
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204 | int status; |
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205 | char errmsg[BUFSIZ]; /* error message for client */ |
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206 | |
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207 | rkinitd_intkt_info rii; |
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208 | |
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209 | SBCLEAR(info); |
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210 | SBCLEAR(auth_dat); |
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211 | BCLEAR(errmsg); |
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212 | SBCLEAR(rii); |
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213 | |
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214 | rpc_get_rkinit_info(&info); |
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215 | |
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216 | /* |
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217 | * The validate_user routine makes sure that the principal in question |
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218 | * is allowed to log in as username, and if so, does a setuid(localuid). |
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219 | * If there is an access violation or an error in setting the uid, |
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220 | * an error is returned and the string errmsg is initialized with |
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221 | * an error message that will be sent back to the client. |
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222 | */ |
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223 | if ((status = validate_user(info.aname, info.inst, info.realm, |
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224 | info.username, errmsg)) != RKINIT_SUCCESS) { |
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225 | rpc_send_error(errmsg); |
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226 | exit(0); |
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227 | } |
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228 | else |
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229 | rpc_send_success(); |
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230 | |
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231 | /* |
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232 | * If the name of a ticket file was specified, set it; otherwise, |
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233 | * just use the default. |
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234 | */ |
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235 | if (strlen(info.tktfilename)) |
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236 | krb_set_tkt_string(info.tktfilename); |
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237 | |
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238 | /* |
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239 | * Call internal kerberos library routine so that we can supply |
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240 | * our own ticket decryption routine. |
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241 | */ |
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242 | |
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243 | /* |
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244 | * We need a setjmp here because krb_get_in_tkt ignores the |
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245 | * return value of decrypt_tkt. Thus if we want any of its |
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246 | * return values to reach the client, we have to jump out of |
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247 | * the routine. |
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248 | */ |
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249 | |
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250 | if (setjmp(rii.env) == 0) { |
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251 | if (status = krb_get_in_tkt(info.aname, info.inst, info.realm, |
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252 | info.sname, info.sinst, info.lifetime, |
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253 | NULL, decrypt_tkt, (char *)&rii)) { |
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254 | strcpy(errmsg, krb_err_txt[status]); |
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255 | rpc_send_error(errmsg); |
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256 | } |
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257 | else |
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258 | rpc_send_success(); |
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259 | } |
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260 | else |
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261 | rpc_send_error(errbuf); |
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262 | |
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263 | return(RKINIT_SUCCESS); |
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264 | } |
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