crypto/openssh/auth2-pam.c

   1 #include "includes.h"
   2 RCSID("$Id: auth2-pam.c,v 1.14 2002/06/28 16:48:12 mouring Exp $");
   3 RCSID("$FreeBSD: src/crypto/openssh/auth2-pam.c,v 1.4.2.2 2003/02/03 17:31:06 des Exp $");
   4
   5 #ifdef USE_PAM
   6 #include <security/pam_appl.h>
   7
   8 #include "ssh.h"
   9 #include "ssh2.h"
  10 #include "auth.h"
  11 #include "auth-pam.h"
  12 #include "packet.h"
  13 #include "xmalloc.h"
  14 #include "dispatch.h"
  15 #include "log.h"
  16
  17 static int do_pam_conversation_kbd_int(int num_msg,
  18     const struct pam_message **msg, struct pam_response **resp,
  19     void *appdata_ptr);
  20 void input_userauth_info_response_pam(int type, u_int32_t seqnr, void *ctxt);
  21
  22 struct {
  23         int finished, num_received, num_expected;
  24         int *prompts;
  25         struct pam_response *responses;
  26 } context_pam2 = {0, 0, 0, NULL};
  27
  28 static struct pam_conv conv2 = {
  29         do_pam_conversation_kbd_int,
  30         NULL,
  31 };
  32
  33 int
  34 auth2_pam(Authctxt *authctxt)
  35 {
  36         int retval = -1;
  37
  38         if (authctxt->user == NULL)
  39                 fatal("auth2_pam: internal error: no user");
  40
  41         conv2.appdata_ptr = authctxt;
  42         do_pam_set_conv(&conv2);
  43
  44         dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
  45             &input_userauth_info_response_pam);
  46         retval = (do_pam_authenticate(0) == PAM_SUCCESS);
  47         dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
  48
  49         return retval;
  50 }
  51
  52 static int
  53 do_pam_conversation_kbd_int(int num_msg, const struct pam_message **msg,
  54     struct pam_response **resp, void *appdata_ptr)
  55 {
  56         int i, j, done;
  57         char *text;
  58
  59         context_pam2.finished = 0;
  60         context_pam2.num_received = 0;
  61         context_pam2.num_expected = 0;
  62         context_pam2.prompts = xmalloc(sizeof(int) * num_msg);
  63         context_pam2.responses = xmalloc(sizeof(struct pam_response) * num_msg);
  64         memset(context_pam2.responses, 0, sizeof(struct pam_response) * num_msg);
  65
  66         text = NULL;
  67         for (i = 0, context_pam2.num_expected = 0; i < num_msg; i++) {
  68                 int style = PAM_MSG_MEMBER(msg, i, msg_style);
  69                 switch (style) {
  70                 case PAM_PROMPT_ECHO_ON:
  71                 case PAM_PROMPT_ECHO_OFF:
  72                         context_pam2.num_expected++;
  73                         break;
  74                 case PAM_TEXT_INFO:
  75                 case PAM_ERROR_MSG:
  76                 default:
  77                         /* Capture all these messages to be sent at once */
  78                         message_cat(&text, PAM_MSG_MEMBER(msg, i, msg));
  79                         break;
  80                 }
  81         }
  82
  83         if (context_pam2.num_expected == 0)
  84                 return PAM_SUCCESS;
  85
  86         packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
  87         packet_put_cstring(""); /* Name */
  88         packet_put_cstring(""); /* Instructions */
  89         packet_put_cstring(""); /* Language */
  90         packet_put_int(context_pam2.num_expected);
  91
  92         for (i = 0, j = 0; i < num_msg; i++) {
  93                 int style = PAM_MSG_MEMBER(msg, i, msg_style);
  94
  95                 /* Skip messages which don't need a reply */
  96                 if (style != PAM_PROMPT_ECHO_ON && style != PAM_PROMPT_ECHO_OFF)
  97                         continue;
  98
  99                 context_pam2.prompts[j++] = i;
 100                 if (text) {
 101                         message_cat(&text, PAM_MSG_MEMBER(msg, i, msg));
 102                         packet_put_cstring(text);
 103                         text = NULL;
 104                 } else
 105                         packet_put_cstring(PAM_MSG_MEMBER(msg, i, msg));
 106                 packet_put_char(style == PAM_PROMPT_ECHO_ON);
 107         }
 108         packet_send();
 109         packet_write_wait();
 110
 111         /*
 112          * Grabbing control of execution and spinning until we get what
 113          * we want is probably rude, but it seems to work properly, and
 114          * the client *should* be in lock-step with us, so the loop should
 115          * only be traversed once.
 116          */
 117         while(context_pam2.finished == 0) {
 118                 done = 1;
 119                 dispatch_run(DISPATCH_BLOCK, &done, appdata_ptr);
 120                 if (context_pam2.finished == 0)
 121                         debug("extra packet during conversation");
 122         }
 123
 124         if (context_pam2.num_received == context_pam2.num_expected) {
 125                 *resp = context_pam2.responses;
 126                 return PAM_SUCCESS;
 127         } else
 128                 return PAM_CONV_ERR;
 129 }
 130
 131 void
 132 input_userauth_info_response_pam(int type, u_int32_t seqnr, void *ctxt)
 133 {
 134         Authctxt *authctxt = ctxt;
 135         unsigned int nresp = 0, rlen = 0, i = 0;
 136         char *resp;
 137
 138         if (authctxt == NULL)
 139                 fatal("input_userauth_info_response_pam: no authentication context");
 140
 141         nresp = packet_get_int();       /* Number of responses. */
 142         debug("got %d responses", nresp);
 143
 144
 145         if (nresp != context_pam2.num_expected)
 146                 fatal("%s: Received incorrect number of responses "
 147                     "(expected %d, received %u)", __func__,
 148                     context_pam2.num_expected, nresp);
 149
 150         if (nresp > 100)
 151                 fatal("%s: too many replies", __func__);
 152
 153         for (i = 0; i < nresp; i++) {
 154                 int j = context_pam2.prompts[i];
 155
 156                 resp = packet_get_string(&rlen);
 157                 context_pam2.responses[j].resp_retcode = PAM_SUCCESS;
 158                 context_pam2.responses[j].resp = xstrdup(resp);
 159                 xfree(resp);
 160                 context_pam2.num_received++;
 161         }
 162
 163         context_pam2.finished = 1;
 164
 165         packet_check_eom();
 166 }
 167 #endif