source: trunk/third/openssh/auth2-pam.c @ 18763

#include "includes.h"
RCSID("$Id: auth2-pam.c,v 1.3 2003-02-06 03:45:45 zacheiss Exp $");

#ifdef USE_PAM
#include <security/pam_appl.h>

#include "ssh.h"
#include "ssh2.h"
#include "auth.h"
#include "auth-pam.h"
#include "packet.h"
#include "xmalloc.h"
#include "dispatch.h"
#include "log.h"

static int do_pam_conversation_kbd_int(int num_msg, 
    const struct pam_message **msg, struct pam_response **resp, 
    void *appdata_ptr);
void input_userauth_info_response_pam(int type, u_int32_t seqnr, void *ctxt);

struct {
        int finished, num_received, num_expected;
        int *prompts;
        struct pam_response *responses;
} context_pam2 = {0, 0, 0, NULL};

static struct pam_conv conv2 = {
        do_pam_conversation_kbd_int,
        NULL,
};

int
auth2_pam(Authctxt *authctxt)
{
        int retval = -1;

        if (authctxt->user == NULL)
                fatal("auth2_pam: internal error: no user");

        conv2.appdata_ptr = authctxt;
        do_pam_set_conv(&conv2);

        dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
            &input_userauth_info_response_pam);
        retval = (do_pam_authenticate(0) == PAM_SUCCESS);
        dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);

        return retval;
}

static int
do_pam_conversation_kbd_int(int num_msg, const struct pam_message **msg,
    struct pam_response **resp, void *appdata_ptr)
{
        int i, j, done;
        char *text;

        context_pam2.finished = 0;
        context_pam2.num_received = 0;
        context_pam2.num_expected = 0;
        context_pam2.prompts = xmalloc(sizeof(int) * num_msg);
        context_pam2.responses = xmalloc(sizeof(struct pam_response) * num_msg);
        memset(context_pam2.responses, 0, sizeof(struct pam_response) * num_msg);

        text = NULL;
        for (i = 0, context_pam2.num_expected = 0; i < num_msg; i++) {
                int style = PAM_MSG_MEMBER(msg, i, msg_style);
                switch (style) {
                case PAM_PROMPT_ECHO_ON:
                case PAM_PROMPT_ECHO_OFF:
                        context_pam2.num_expected++;
                        break;
                case PAM_TEXT_INFO:
                case PAM_ERROR_MSG:
                default:
                        /* Capture all these messages to be sent at once */
                        message_cat(&text, PAM_MSG_MEMBER(msg, i, msg));
                        break;
                }
        }

        if (context_pam2.num_expected == 0)
                return PAM_SUCCESS;

        packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
        packet_put_cstring(""); /* Name */
        packet_put_cstring(""); /* Instructions */
        packet_put_cstring(""); /* Language */
        packet_put_int(context_pam2.num_expected);
        
        for (i = 0, j = 0; i < num_msg; i++) {
                int style = PAM_MSG_MEMBER(msg, i, msg_style);
                
                /* Skip messages which don't need a reply */
                if (style != PAM_PROMPT_ECHO_ON && style != PAM_PROMPT_ECHO_OFF)
                        continue;
                
                context_pam2.prompts[j++] = i;
                if (text) {
                        message_cat(&text, PAM_MSG_MEMBER(msg, i, msg));
                        packet_put_cstring(text);
                        text = NULL;
                } else
                        packet_put_cstring(PAM_MSG_MEMBER(msg, i, msg));
                packet_put_char(style == PAM_PROMPT_ECHO_ON);
        }
        packet_send();
        packet_write_wait();

        /*
         * Grabbing control of execution and spinning until we get what
         * we want is probably rude, but it seems to work properly, and
         * the client *should* be in lock-step with us, so the loop should
         * only be traversed once.
         */
        while(context_pam2.finished == 0) {
                done = 1;
                dispatch_run(DISPATCH_BLOCK, &done, appdata_ptr);
                if (context_pam2.finished == 0)
                        debug("extra packet during conversation");
        }

        if (context_pam2.num_received == context_pam2.num_expected) {
                *resp = context_pam2.responses;
                return PAM_SUCCESS;
        } else
                return PAM_CONV_ERR;
}

void
input_userauth_info_response_pam(int type, u_int32_t seqnr, void *ctxt)
{
        Authctxt *authctxt = ctxt;
        unsigned int nresp = 0, rlen = 0, i = 0;
        char *resp;

        if (authctxt == NULL)
                fatal("input_userauth_info_response_pam: no authentication context");

        nresp = packet_get_int();       /* Number of responses. */
        debug("got %d responses", nresp);

        if (nresp != context_pam2.num_expected)
                fatal("%s: Received incorrect number of responses "
                    "(expected %d, received %u)", __func__, 
                    context_pam2.num_expected, nresp);

        if (nresp > 100)
                fatal("%s: too many replies", __func__);

        for (i = 0; i < nresp; i++) {
                int j = context_pam2.prompts[i];

                resp = packet_get_string(&rlen);
                context_pam2.responses[j].resp_retcode = PAM_SUCCESS;
                context_pam2.responses[j].resp = xstrdup(resp);
                xfree(resp);
                context_pam2.num_received++;
        }

        context_pam2.finished = 1;

        packet_check_eom();
}
#endif