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