/*
   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 <errno.h>
#include <netinet/in.h>
#include <pthread.h>
#include <gssapi/gssapi.h>
#include <gssapi/gssapi_krb5.h>
#include "src/gp_proxy.h"
#include "src/gp_rpc_process.h"
#include "src/gp_conv.h"
#include "src/gp_debug.h"
#include "src/client/gssapi_gpm.h"
#include "popt.h"

#define DEBUG(...) do { \
    char msg[4096]; \
    snprintf(msg, 4096, __VA_ARGS__); \
    fprintf(stderr, "%s:%d: %s", __FUNCTION__, __LINE__, msg); \
    fflush(stderr); \
} while(0);


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;
}

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;
}

int gp_send_accept_sec_context(int fd,
                               gssx_arg_accept_sec_context *arg,
                               gssx_res_accept_sec_context *res)
{
    XDR xdr_call_ctx;
    XDR xdr_reply_ctx;
    gp_rpc_msg msg;
    char buffer[MAX_RPC_SIZE];
    uint32_t length;
    bool xdrok;
    int ret;

    memset(&msg, 0, sizeof(gp_rpc_msg));

    xdrmem_create(&xdr_call_ctx, buffer, MAX_RPC_SIZE, XDR_ENCODE);
    xdrmem_create(&xdr_reply_ctx, buffer, MAX_RPC_SIZE, XDR_DECODE);

    msg.xid = 1;
    msg.header.type = GP_RPC_CALL;
    msg.header.gp_rpc_msg_union_u.chdr.rpcvers = 2;
    msg.header.gp_rpc_msg_union_u.chdr.prog = GSSPROXY;
    msg.header.gp_rpc_msg_union_u.chdr.vers = GSSPROXYVERS;
    msg.header.gp_rpc_msg_union_u.chdr.proc = GSSX_ACCEPT_SEC_CONTEXT;
    msg.header.gp_rpc_msg_union_u.chdr.cred.flavor = GP_RPC_AUTH_NONE;
    msg.header.gp_rpc_msg_union_u.chdr.cred.body.body_len = 0;
    msg.header.gp_rpc_msg_union_u.chdr.cred.body.body_val = NULL;
    msg.header.gp_rpc_msg_union_u.chdr.verf.flavor = GP_RPC_AUTH_NONE;
    msg.header.gp_rpc_msg_union_u.chdr.verf.body.body_len = 0;
    msg.header.gp_rpc_msg_union_u.chdr.verf.body.body_val = NULL;

    /* encode header */
    xdrok = xdr_gp_rpc_msg(&xdr_call_ctx, &msg);
    if (!xdrok) {
        return EFAULT;
    }

    /* encode data */
    xdrok = xdr_gssx_arg_accept_sec_context(&xdr_call_ctx, arg);
    if (!xdrok) {
        return EFAULT;
    }

    /* send to proxy */
    ret = gp_send_buffer(fd, buffer, xdr_getpos(&xdr_call_ctx));
    if (ret) {
        return EIO;
    }

    /* receive answer */
    ret = gp_recv_buffer(fd, buffer, &length);
    if (ret) {
        return EIO;
    }

    /* decode header */
    xdrok = xdr_gp_rpc_msg(&xdr_reply_ctx, &msg);
    if (!xdrok) {
        return EFAULT;
    }

    if (msg.xid != 1 ||
        msg.header.type != GP_RPC_REPLY ||
        msg.header.gp_rpc_msg_union_u.rhdr.status != GP_RPC_MSG_ACCEPTED ||
        msg.header.gp_rpc_msg_union_u.rhdr.gp_rpc_reply_header_u.accepted.reply_data.status != GP_RPC_SUCCESS) {
        return EINVAL;
    }

    /* decode answer */
    xdrok = xdr_gssx_res_accept_sec_context(&xdr_reply_ctx, res);
    if (!xdrok) {
        return EFAULT;
    }

    xdr_free((xdrproc_t)xdr_gp_rpc_msg, (char *)&msg);
    xdr_destroy(&xdr_call_ctx);
    xdr_destroy(&xdr_reply_ctx);
    return 0;
}

struct athread {
    pthread_t tid;
    int *cli_pipe;
    int *srv_pipe;
    char *target;
};

#define CLI_MSG "I am the buffer"

void *client_thread(void *pvt)
{
    struct athread *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;
    struct gssx_name *name = NULL;
    struct gssx_ctx *ctx = NULL;
    struct gssx_cred *cred_handle = NULL;
    int ret = 0;
    gss_buffer_desc msg_buf = GSS_C_EMPTY_BUFFER;
    int conf_state;
    uint32_t max_size;

    data = (struct athread *)pvt;

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

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

    do {
        ret_maj = gpm_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) {
            DEBUG("gss_init_sec_context() failed with: %d\n", ret_maj);
            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);

    memcpy(buffer, CLI_MSG, sizeof(CLI_MSG));
    msg_buf.value = (void *)buffer;
    msg_buf.length = sizeof(CLI_MSG);

    ret_maj = gpm_get_mic(&ret_min, ctx,
                          GSS_C_QOP_DEFAULT,
                          &msg_buf, &out_token);
    if (ret_maj) {
        DEBUG("gpm_get_mic failed: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    /* send msg to server */
    ret = gp_send_buffer(data->srv_pipe[1],
                         msg_buf.value, msg_buf.length);
    if (ret) {
        goto done;
    }

    /* send signature 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);

    in_token.value = CLI_MSG;
    in_token.length = strlen(in_token.value) + 1;

    ret_maj = gpm_wrap(&ret_min,
                       ctx,
                       1, /* conf_req_flag */
                       GSS_C_QOP_DEFAULT, /* qop_req */
                       &in_token,
                       &conf_state,
                       &out_token);
    if (ret_maj) {
        DEBUG("gpm_wrap failed: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

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

    ret_maj = gpm_wrap_size_limit(&ret_min,
                                  ctx,
                                  1, /* conf_req */
                                  GSS_C_QOP_DEFAULT, /* qop_req */
                                  4096, /* size_req */
                                  &max_size);
    if (ret_maj) {
        DEBUG("gpm_wrap_size_limit failed: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    DEBUG("client: Success!\n");

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

void *server_thread(void *pvt)
{
    struct athread *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;
    struct gssx_ctx *context_handle = NULL;
    struct gssx_cred *cred_handle = NULL;
    struct gssx_name *src_name = NULL;
    gss_buffer_desc out_token = GSS_C_EMPTY_BUFFER;
    struct gssx_cred *deleg_cred = NULL;
    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;
    struct gssx_name *target_name = NULL;
    struct gssx_name *canon_name = NULL;
    gss_buffer_desc out_name_buf = GSS_C_EMPTY_BUFFER;
    gss_OID out_name_type = GSS_C_NO_OID;
    gss_buffer_desc msg_token = GSS_C_EMPTY_BUFFER;
    int ret;
    gss_buffer_desc input_message_buffer = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc output_message_buffer = GSS_C_EMPTY_BUFFER;
    gss_qop_t qop_state;
    int conf_state;

    data = (struct athread *)pvt;

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

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

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

    ret_maj = gpm_inquire_names_for_mech(&ret_min,
                                         &mech_set->elements[0],
                                         &mech_names);
    if (ret_maj) {
        DEBUG("gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(&mech_set->elements[0], ret_maj, ret_min);
        goto done;
    }
    ret_maj = gpm_inquire_attrs_for_mech(&ret_min,
                                         &mech_set->elements[0],
                                         &mech_attrs,
                                         &known_mech_attrs);
    if (ret_maj) {
        DEBUG("gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(&mech_set->elements[0], ret_maj, ret_min);
        goto done;
    }
    ret_maj = gpm_inquire_saslname_for_mech(&ret_min,
                                            &mech_set->elements[0],
                                            &sasl_mech_name,
                                            &mech_name,
                                            &mech_description);
    if (ret_maj) {
        DEBUG("gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(&mech_set->elements[0], ret_maj, ret_min);
        goto done;
    }
    ret_maj = gpm_display_mech_attr(&ret_min,
                                    &mech_attrs->elements[0],
                                    &name, &short_desc, &long_desc);
    if (ret_maj) {
        DEBUG("gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }
    ret_maj = gpm_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) {
        DEBUG("gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }
    ret_maj = gpm_inquire_mechs_for_name(&ret_min, target_name, &mech_types);
    if (ret_maj) {
        DEBUG("gssproxy returned an error: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    ret_maj = gpm_acquire_cred(&ret_min,
                               NULL,
                               GSS_C_INDEFINITE,
                               mech_set,
                               GSS_C_ACCEPT,
                               &cred_handle,
                               NULL,
                               NULL);
    if (ret_maj) {
        DEBUG("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) {
        DEBUG("Failed to get data from client!\n");
        goto done;
    }

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

    ret_maj = gpm_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) {
        DEBUG("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) {
            DEBUG("Failed to send data to client!\n");
            goto done;
        }
    }

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

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

    ret_maj = gpm_verify_mic(&ret_min, context_handle,
                             &in_token, &msg_token, NULL);
    if (ret_maj) {
        DEBUG("gpm_verify_mic failed: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    DEBUG("Received valid msg from client: [%s]\n", buffer);

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

    input_message_buffer.value = buffer;
    input_message_buffer.length = buflen;

    ret_maj = gpm_unwrap(&ret_min,
                         context_handle,
                         &input_message_buffer,
                         &output_message_buffer,
                         &conf_state,
                         &qop_state);
    if (ret_maj) {
        DEBUG("gpm_unwrap failed: %d\n", ret_maj);
        gp_log_failure(GSS_C_NO_OID, ret_maj, ret_min);
        goto done;
    }

    DEBUG("Received valid msg from client: [%s]\n",
        (char *)output_message_buffer.value);

done:
    gpm_release_name(&ret_min, &src_name);
    gpm_release_buffer(&ret_min, &out_token);
    gpm_release_buffer(&ret_min, &output_message_buffer);
    gpm_release_cred(&ret_min, &deleg_cred);
    gpm_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);
    gpm_release_name(&ret_min, &target_name);
    gpm_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]);
    pthread_exit(NULL);
}

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];
    pthread_attr_t attr;
    struct athread server;
    struct athread client;
    void *retval;
    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;
    }

    /* make thread joinable (portability) */
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);

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

    ret = pthread_create(&server.tid, &attr, server_thread, &server);
    if (ret) {
        return -1;
    }

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

    ret = pthread_create(&client.tid, &attr, client_thread, &client);
    if (ret) {
        return -1;
    }

    pthread_join(server.tid, &retval);
    pthread_join(client.tid, &retval);

    return 0;
}