/*
   GSS-PROXY

   Copyright (C) 2011 Red Hat, Inc.
   Copyright (C) 2011 Simo Sorce <simo.sorce@redhat.com>

   Permission is hereby granted, free of charge, to any person obtaining a
   copy of this software and associated documentation files (the "Software"),
   to deal in the Software without restriction, including without limitation
   the rights to use, copy, modify, merge, publish, distribute, sublicense,
   and/or sell copies of the Software, and to permit persons to whom the
   Software is furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   DEALINGS IN THE SOFTWARE.
*/

#include "config.h"
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <errno.h>
#include <netinet/in.h>
#include <gssapi/gssapi.h>
#include <gssapi/gssapi_krb5.h>
#include "src/gp_debug.h"
#include "src/gp_log.h"
#include "popt.h"
#include <libintl.h>

#define MAX_RPC_SIZE 1024*1024
#define _(STRING) gettext(STRING)

static int gp_send_buffer(int fd, char *buf, uint32_t len)
{
    uint32_t size;
    size_t wn;
    size_t pos;

    size = htonl(len);

    wn = write(fd, &size, sizeof(uint32_t));
    if (wn != 4) {
        return EIO;
    }

    pos = 0;
    while (len > pos) {
        wn = write(fd, buf + pos, len - pos);
        if (wn == -1) {
            if (errno == EINTR) {
                continue;
            }
            return errno;
        }
        pos += wn;
    }

    return 0;
}

static int gp_recv_buffer(int fd, char *buf, uint32_t *len)
{
    uint32_t size;
    size_t rn;
    size_t pos;

    rn = read(fd, &size, sizeof(uint32_t));
    if (rn != 4) {
        return EIO;
    }

    *len = ntohl(size);

    if (*len > MAX_RPC_SIZE) {
        return EINVAL;
    }

    pos = 0;
    while (*len > pos) {
        rn = read(fd, buf + pos, *len - pos);
        if (rn == -1) {
            if (errno == EINTR) {
                continue;
            }
            return errno;
        }
        if (rn == 0) {
            return EIO;
        }
        pos += rn;
    }

    return 0;
}

#define PROXY_LOCAL_ONLY 0
#define PROXY_LOCAL_FIRST 1
#define PROXY_REMOTE_FIRST 2
#define PROXY_REMOTE_ONLY 3

struct aproc {
    int proxy_type;
    int *cli_pipe;
    int *srv_pipe;
    char *target;
};

void run_client(struct aproc *data)
{
    uint32_t ret_maj;
    uint32_t ret_min;
    char buffer[MAX_RPC_SIZE];
    uint32_t buflen;
    gss_buffer_desc target_buf;
    gss_buffer_desc in_token = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc out_token = GSS_C_EMPTY_BUFFER;
    gss_name_t name = GSS_C_NO_NAME;
    gss_ctx_id_t ctx = GSS_C_NO_CONTEXT;
    gss_cred_id_t cred_handle = GSS_C_NO_CREDENTIAL;
    gss_buffer_desc msg_buf = GSS_C_EMPTY_BUFFER;
    char *message = "SECRET";
    int ret = 0;

    target_buf.value = (void *)data->target;
    target_buf.length = strlen(data->target) + 1;

    ret_maj = gss_import_name(&ret_min, &target_buf,
                              GSS_C_NT_HOSTBASED_SERVICE, &name);
    if (ret_maj) {
        goto done;
    }

    do {
        ret_maj = gss_init_sec_context(&ret_min,
                                       cred_handle,
                                       &ctx,
                                       name,
                                       GSS_C_NO_OID,
                                       GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG,
                                       0,
                                       GSS_C_NO_CHANNEL_BINDINGS,
                                       &in_token,
                                       NULL,
                                       &out_token,
                                       NULL,
                                       NULL);
        if (ret_maj != GSS_S_COMPLETE &&
            ret_maj != GSS_S_CONTINUE_NEEDED) {
            fprintf(stdout,
                    "gss_init_sec_context() failed with: %d\n", ret_maj);
            gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
            goto done;
        }
        if (out_token.length != 0) {
            /* send to server */
            ret = gp_send_buffer(data->srv_pipe[1],
                                 out_token.value, out_token.length);
            if (ret) {
                goto done;
            }

            gss_release_buffer(&ret_min, &out_token);
        }

        if (!ctx) {
            goto done;
        }

        if (ret_maj == GSS_S_CONTINUE_NEEDED) {
            /* and wait for reply */
            ret = gp_recv_buffer(data->cli_pipe[0], buffer, &buflen);
            if (ret) {
                goto done;
            }

            in_token.value = buffer;
            in_token.length = buflen;
        }

    } while (ret_maj == GSS_S_CONTINUE_NEEDED);

    /* test encryption */
    msg_buf.length = strlen(message) + 1;
    msg_buf.value = (void *)message;
    ret_maj = gss_wrap(&ret_min, ctx, 1, 0, &msg_buf, NULL, &out_token);
    if (ret_maj != GSS_S_COMPLETE) {
        fprintf(stdout, "Failed to wrap message.\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    ret = gp_send_buffer(data->srv_pipe[1], out_token.value, out_token.length);
    if (ret) {
        goto done;
    }

    gss_release_buffer(&ret_min, &out_token);

    fprintf(stdout, "client: Success!\n");

done:
    gss_release_name(&ret_min, &name);
    gss_release_buffer(&ret_min, &out_token);
    close(data->cli_pipe[0]);
    close(data->srv_pipe[1]);
    exit(0);
}

void run_server(struct aproc *data)
{
    char buffer[MAX_RPC_SIZE];
    uint32_t buflen;
    gss_buffer_desc in_token = GSS_C_EMPTY_BUFFER;
    uint32_t ret_maj;
    uint32_t ret_min;
    gss_ctx_id_t context_handle = GSS_C_NO_CONTEXT;
    gss_cred_id_t cred_handle = GSS_C_NO_CREDENTIAL;
    gss_name_t src_name;
    gss_buffer_desc out_token = GSS_C_EMPTY_BUFFER;
    gss_cred_id_t deleg_cred = GSS_C_NO_CREDENTIAL;
    gss_OID_set mech_set = GSS_C_NO_OID_SET;
    gss_OID_set mech_names = GSS_C_NO_OID_SET;
    gss_OID_set mech_types = GSS_C_NO_OID_SET;
    gss_OID_set mech_attrs = GSS_C_NO_OID_SET;
    gss_OID_set known_mech_attrs = GSS_C_NO_OID_SET;
    gss_buffer_desc sasl_mech_name = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc mech_name = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc mech_description = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc name = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc short_desc = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc long_desc = GSS_C_EMPTY_BUFFER;
    gss_OID_set mechs = GSS_C_NO_OID_SET;
    gss_buffer_desc target_buf;
    gss_name_t target_name = GSS_C_NO_NAME;
    gss_name_t canon_name = GSS_C_NO_NAME;
    gss_buffer_desc out_name_buf = GSS_C_EMPTY_BUFFER;
    gss_OID out_name_type = GSS_C_NO_OID;
    int ret;

    target_buf.value = (void *)data->target;
    target_buf.length = strlen(data->target) + 1;

    /* import name family functions tests */
    ret_maj = gss_import_name(&ret_min, &target_buf,
                              GSS_C_NT_HOSTBASED_SERVICE, &target_name);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }
    ret_maj = gss_canonicalize_name(&ret_min, target_name,
                                    gss_mech_krb5, &canon_name);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }
    ret_maj = gss_display_name(&ret_min, canon_name,
                               &out_name_buf, &out_name_type);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }
    fprintf(stdout, "Acquiring for: %s\n", (char *)out_name_buf.value);

    /* indicate mechs family functions tests */
    ret_maj = gss_indicate_mechs(&ret_min, &mech_set);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    ret_maj = gss_inquire_names_for_mech(&ret_min,
                                         &mech_set->elements[0],
                                         &mech_names);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(&mech_set->elements[0], ret_maj, ret_min);
        goto done;
    }
    ret_maj = gss_inquire_attrs_for_mech(&ret_min,
                                         &mech_set->elements[0],
                                         &mech_attrs,
                                         &known_mech_attrs);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(&mech_set->elements[0], ret_maj, ret_min);
        goto done;
    }
    ret_maj = gss_inquire_saslname_for_mech(&ret_min,
                                            &mech_set->elements[0],
                                            &sasl_mech_name,
                                            &mech_name,
                                            &mech_description);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(&mech_set->elements[0], ret_maj, ret_min);
        goto done;
    }
    ret_maj = gss_display_mech_attr(&ret_min,
                                    &mech_attrs->elements[0],
                                    &name, &short_desc, &long_desc);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }
    ret_maj = gss_indicate_mechs_by_attrs(&ret_min,
                                          GSS_C_NO_OID_SET,
                                          GSS_C_NO_OID_SET,
                                          GSS_C_NO_OID_SET,
                                          &mechs);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }
    ret_maj = gss_inquire_mechs_for_name(&ret_min, target_name, &mech_types);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    ret_maj = gss_acquire_cred(&ret_min,
                               GSS_C_NO_NAME,
                               GSS_C_INDEFINITE,
                               mech_set,
                               GSS_C_ACCEPT,
                               &cred_handle,
                               NULL,
                               NULL);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    ret = gp_recv_buffer(data->srv_pipe[0], buffer, &buflen);
    if (ret) {
        fprintf(stdout, "Failed to get data from client!\n");
        goto done;
    }

    in_token.value = buffer;
    in_token.length = buflen;

    ret_maj = gss_accept_sec_context(&ret_min,
                                     &context_handle,
                                     cred_handle,
                                     &in_token,
                                     GSS_C_NO_CHANNEL_BINDINGS,
                                     &src_name,
                                     NULL,
                                     &out_token,
                                     NULL,
                                     NULL,
                                     &deleg_cred);
    if (ret_maj) {
        fprintf(stdout, "gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    if (out_token.length) {
        ret = gp_send_buffer(data->cli_pipe[1],
                             out_token.value, out_token.length);
        if (ret) {
            fprintf(stdout, "Failed to send data to client!\n");
            goto done;
        }
    }

    gss_release_buffer(&ret_min, &out_token);

    ret = gp_recv_buffer(data->srv_pipe[0], buffer, &buflen);
    if (ret) {
        fprintf(stdout, "Failed to get data from client!\n");
        goto done;
    }
    in_token.value = buffer;
    in_token.length = buflen;

    ret_maj = gss_unwrap(&ret_min, context_handle,
                         &in_token, &out_token, NULL, NULL);
    if (ret_maj != GSS_S_COMPLETE) {
        fprintf(stdout, "Failed to unwrap message.\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    fprintf(stdout, "Server, RECV: %s\n", (char *)out_token.value);

    gss_release_buffer(&ret_min, &out_token);

done:
    gss_release_name(&ret_min, &src_name);
    gss_release_buffer(&ret_min, &out_token);
    gss_release_cred(&ret_min, &deleg_cred);
    gss_delete_sec_context(&ret_min, &context_handle, GSS_C_NO_BUFFER);
    gss_release_oid_set(&ret_min, &mech_set);
    gss_release_oid_set(&ret_min, &mech_names);
    gss_release_oid_set(&ret_min, &mech_types);
    gss_release_oid_set(&ret_min, &mech_attrs);
    gss_release_oid_set(&ret_min, &known_mech_attrs);
    gss_release_buffer(&ret_min, &sasl_mech_name);
    gss_release_buffer(&ret_min, &mech_name);
    gss_release_buffer(&ret_min, &mech_description);
    gss_release_buffer(&ret_min, &name);
    gss_release_buffer(&ret_min, &short_desc);
    gss_release_buffer(&ret_min, &long_desc);
    gss_release_oid_set(&ret_min, &mechs);
    gss_release_name(&ret_min, &target_name);
    gss_release_name(&ret_min, &canon_name);
    gss_release_buffer(&ret_min, &out_name_buf);
    gss_release_oid(&ret_min, &out_name_type);
    close(data->srv_pipe[0]);
    close(data->cli_pipe[1]);
    exit(0);
}

int main(int argc, const char *argv[])
{
    int opt;
    poptContext pc;
    int opt_version = 0;
    char *opt_target = NULL;
    int srv_pipe[2];
    int cli_pipe[2];
    struct aproc client, server;
    pid_t cli, srv, w;
    int closewait;
    int options;
    int status;
    int ret;

    struct poptOption long_options[] = {
        POPT_AUTOHELP
        {"target", 't', POPT_ARG_STRING, &opt_target, 0, \
         _("Specify the target name used for the tests"), NULL}, \
        {"version", '\0', POPT_ARG_NONE, &opt_version, 0, \
         _("Print version number and exit"), NULL }, \
        POPT_TABLEEND
    };

    pc = poptGetContext(argv[0], argc, argv, long_options, 0);
    while((opt = poptGetNextOpt(pc)) != -1) {
        switch(opt) {
        default:
            fprintf(stderr, "\nInvalid option %s: %s\n\n",
                    poptBadOption(pc, 0), poptStrerror(opt));
            poptPrintUsage(pc, stderr, 0);
            return 1;
        }
    }

    if (opt_version) {
        puts(VERSION""DISTRO_VERSION""PRERELEASE_VERSION);
        return 0;
    }

    if (opt_target == NULL) {
        fprintf(stderr, "Missing target!\n");
        poptPrintUsage(pc, stderr, 0);
        return 1;
    }

    ret = pipe(srv_pipe);
    if (ret) {
        return -1;
    }
    ret = pipe(cli_pipe);
    if (ret) {
        return -1;
    }

    srv = -1;
    cli = -1;

    server.proxy_type = PROXY_LOCAL_ONLY;
    server.srv_pipe = srv_pipe;
    server.cli_pipe = cli_pipe;
    server.target = opt_target;

    srv = fork();
    switch (srv) {
    case -1:
        ret = -1;
        goto done;
    case 0:
        run_server(&server);
        exit(0);
    default:
        close(srv_pipe[0]);
        close(cli_pipe[1]);
        break;
    }

    client.proxy_type = PROXY_LOCAL_ONLY;
    client.srv_pipe = srv_pipe;
    client.cli_pipe = cli_pipe;
    client.target = opt_target;

    cli = fork();
    switch (cli) {
    case -1:
        ret = -1;
        goto done;
    case 0:
        run_client(&client);
        exit(0);
    default:
        close(srv_pipe[1]);
        close(cli_pipe[0]);
        break;
    }

    closewait = -1;
    while (cli != -1 || srv != -1) {
        if (closewait < 0) {
            options = 0;
        } else {
            options = WNOHANG;
        }
        w = waitpid(-1, &status, options);
        closewait = 0;
        if (w == cli) {
            cli = -1;
        } else if (w == srv) {
            srv = -1;
        } else {
            /* ? */
            ret = -1;
            goto done;
        }
        /* wait 0.1s for max ten times for the other process to terminate,
         * then just exit */
        if (closewait > 10) {
            ret = -1;
            goto done;
        } else {
            usleep(100000);
            closewait++;
        }
    }
    ret = 0;

done:
    if (cli > 0) {
        kill(cli, SIGKILL);
    }
    if (srv > 0) {
        kill(srv, SIGKILL);
    }
    return ret;
}