auth2-skey.c

   1 #include "includes.h"
   2 RCSID("$OpenBSD: auth2-skey.c,v 1.1 2000/10/11 20:14:38 markus Exp $");
   3
   4 #ifdef SKEY
   5 #include "ssh.h"
   6 #include "ssh2.h"
   7 #include "auth.h"
   8 #include "packet.h"
   9 #include "xmalloc.h"
  10 #include "dispatch.h"
  11
  12 void    send_userauth_into_request(Authctxt *authctxt, int echo);
  13 void    input_userauth_info_response(int type, int plen, void *ctxt);
  14
  15 /*
  16  * try skey authentication, always return -1 (= postponed) since we have to
  17  * wait for the s/key response.
  18  */
  19 int
  20 auth2_skey(Authctxt *authctxt)
  21 {
  22         send_userauth_into_request(authctxt, 0);
  23         dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &input_userauth_info_response);
  24         return -1;
  25 }
  26
  27 void
  28 send_userauth_into_request(Authctxt *authctxt, int echo)
  29 {
  30         int retval = -1;
  31         struct skey skey;
  32         char challenge[SKEY_MAX_CHALLENGE];
  33         char *fake;
  34
  35         if (authctxt->user == NULL)
  36                 fatal("send_userauth_into_request: internal error: no user");
  37
  38         /* get skey challenge */
  39         if (authctxt->valid)
  40                 retval = skeychallenge(&skey, authctxt->user, challenge);
  41
  42         if (retval == -1) {
  43                 fake = skey_fake_keyinfo(authctxt->user);
  44                 strlcpy(challenge, fake, sizeof challenge);
  45         }
  46         /* send our info request */
  47         packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
  48         packet_put_cstring("S/Key Authentication");     /* Name */
  49         packet_put_cstring(challenge);                  /* Instruction */
  50         packet_put_cstring("");                         /* Language */
  51         packet_put_int(1);                              /* Number of prompts */
  52         packet_put_cstring(echo ?
  53                  "Response [Echo]: ": "Response: ");    /* Prompt */
  54         packet_put_char(echo);                          /* Echo */
  55         packet_send();
  56         packet_write_wait();
  57         memset(challenge, 'c', sizeof challenge);
  58 }
  59
  60 void
  61 input_userauth_info_response(int type, int plen, void *ctxt)
  62 {
  63         Authctxt *authctxt = ctxt;
  64         int authenticated = 0;
  65         unsigned int nresp, rlen;
  66         char *resp, *method;
  67
  68         if (authctxt == NULL)
  69                 fatal("input_userauth_info_response: no authentication context");
  70
  71         if (authctxt->attempt++ >= AUTH_FAIL_MAX)
  72                 packet_disconnect("too many failed userauth_requests");
  73
  74         nresp = packet_get_int();
  75         if (nresp == 1) {
  76                 /* we only support s/key and assume s/key for nresp == 1 */
  77                 method = "s/key";
  78                 resp = packet_get_string(&rlen);
  79                 packet_done();
  80                 if (strlen(resp) == 0) {
  81                         /*
  82                          * if we received a null response, resend prompt with
  83                          * echo enabled
  84                          */
  85                         authenticated = -1;
  86                         userauth_log(authctxt, authenticated, method);
  87                         send_userauth_into_request(authctxt, 1);
  88                 } else {
  89                         /* verify skey response */
  90                         if (authctxt->valid &&
  91                             skey_haskey(authctxt->pw->pw_name) == 0 &&
  92                             skey_passcheck(authctxt->pw->pw_name, resp) != -1) {
  93                                 authenticated = 1;
  94                         } else {
  95                                 authenticated = 0;
  96                         }
  97                         memset(resp, 'r', rlen);
  98                         /* unregister callback */
  99                         dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
 100                         userauth_log(authctxt, authenticated, method);
 101                         userauth_reply(authctxt, authenticated);
 102                 }
 103                 xfree(resp);
 104         }
 105 }
 106
 107 #endif /* SKEY */