/* #pragma ident        "@(#)g_accept_sec_context.c     1.19    04/02/23 SMI" */

/*
 * Copyright 1996 by Sun Microsystems, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of Sun Microsystems not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission. Sun Microsystems makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * SUN MICROSYSTEMS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL SUN MICROSYSTEMS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/*
 *  glue routine for gss_accept_sec_context
 */

#include "mglueP.h"
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <string.h>
#include <errno.h>
#include <time.h>

#ifndef LEAN_CLIENT
static OM_uint32
val_acc_sec_ctx_args(
    OM_uint32 *minor_status,
    gss_ctx_id_t *context_handle,
    gss_cred_id_t verifier_cred_handle,
    gss_buffer_t input_token_buffer,
    gss_channel_bindings_t input_chan_bindings,
    gss_name_t *src_name,
    gss_OID *mech_type,
    gss_buffer_t output_token,
    OM_uint32 *ret_flags,
    OM_uint32 *time_rec,
    gss_cred_id_t *d_cred)
{

    /* Initialize outputs. */

    if (minor_status != NULL)
        *minor_status = 0;

    if (src_name != NULL)
        *src_name = GSS_C_NO_NAME;

    if (mech_type != NULL)
        *mech_type = GSS_C_NO_OID;

    if (output_token != GSS_C_NO_BUFFER) {
        output_token->length = 0;
        output_token->value = NULL;
    }

    if (ret_flags != NULL)
        *ret_flags = 0;

    if (time_rec != NULL)
        *time_rec = 0;

    if (d_cred != NULL)
        *d_cred = GSS_C_NO_CREDENTIAL;

    /* Validate arguments. */

    if (minor_status == NULL)
        return (GSS_S_CALL_INACCESSIBLE_WRITE);

    if (context_handle == NULL)
        return (GSS_S_CALL_INACCESSIBLE_WRITE);

    if (input_token_buffer == GSS_C_NO_BUFFER)
        return (GSS_S_CALL_INACCESSIBLE_READ);

    if (output_token == GSS_C_NO_BUFFER)
        return (GSS_S_CALL_INACCESSIBLE_WRITE);

    return (GSS_S_COMPLETE);
}

/* Return true if mech should be accepted with no acceptor credential. */
static int
allow_mech_by_default(gss_OID mech)
{
    OM_uint32 status, minor;
    gss_OID_set attrs;
    int reject = 0, p;

    /* Whether we accept an interposer mech depends on whether we accept the
     * mech it interposes. */
    mech = gssint_get_public_oid(mech);
    if (mech == GSS_C_NO_OID)
        return 0;

    status = gss_inquire_attrs_for_mech(&minor, mech, &attrs, NULL);
    if (status)
        return 0;

    /* If the mechanism doesn't support RFC 5587, don't exclude it. */
    if (attrs == GSS_C_NO_OID_SET)
        return 1;

    /* Check for each attribute which would cause us to exclude this mech from
     * the default credential. */
    if (generic_gss_test_oid_set_member(&minor, GSS_C_MA_DEPRECATED,
                                        attrs, &p) != GSS_S_COMPLETE || p)
        reject = 1;
    else if (generic_gss_test_oid_set_member(&minor, GSS_C_MA_NOT_DFLT_MECH,
                                             attrs, &p) != GSS_S_COMPLETE || p)
        reject = 1;

    (void) gss_release_oid_set(&minor, &attrs);
    return !reject;
}

OM_uint32 KRB5_CALLCONV
gss_accept_sec_context(OM_uint32 *minor_status, gss_ctx_id_t *context_handle,
                       gss_cred_id_t verifier_cred_handle,
                       gss_buffer_t input_token_buffer,
                       gss_channel_bindings_t input_chan_bindings,
                       gss_name_t *src_name, gss_OID *mech_type,
                       gss_buffer_t output_token, OM_uint32 *ret_flags,
                       OM_uint32 *time_rec, gss_cred_id_t *d_cred)
{
    OM_uint32           status, temp_status, temp_minor_status;
    OM_uint32           temp_ret_flags = 0;
    gss_union_ctx_id_t  union_ctx_id = NULL;
    gss_cred_id_t       input_cred_handle = GSS_C_NO_CREDENTIAL;
    gss_cred_id_t       tmp_d_cred = GSS_C_NO_CREDENTIAL;
    gss_name_t          internal_name = GSS_C_NO_NAME;
    gss_name_t          tmp_src_name = GSS_C_NO_NAME;
    gss_OID_desc        token_mech_type_desc;
    gss_OID             token_mech_type = &token_mech_type_desc;
    gss_OID             actual_mech = GSS_C_NO_OID;
    gss_OID             selected_mech = GSS_C_NO_OID;
    gss_OID             public_mech;
    gss_mechanism       mech = NULL;
    gss_union_cred_t    uc;
    int                 i;

    status = val_acc_sec_ctx_args(minor_status,
                                  context_handle,
                                  verifier_cred_handle,
                                  input_token_buffer,
                                  input_chan_bindings,
                                  src_name,
                                  mech_type,
                                  output_token,
                                  ret_flags,
                                  time_rec,
                                  d_cred);
    if (status != GSS_S_COMPLETE)
        return (status);

    /*
     * if context_handle is GSS_C_NO_CONTEXT, allocate a union context
     * descriptor to hold the mech type information as well as the
     * underlying mechanism context handle. Otherwise, cast the
     * value of *context_handle to the union context variable.
     */

    if(*context_handle == GSS_C_NO_CONTEXT) {

        if (input_token_buffer == GSS_C_NO_BUFFER)
            return (GSS_S_CALL_INACCESSIBLE_READ);

        /* Get the token mech type */
        status = gssint_get_mech_type(token_mech_type, input_token_buffer);
        if (status)
            return status;

        /*
         * An interposer calling back into the mechglue can't pass in a special
         * mech, so we have to recognize it using verifier_cred_handle.  Use
         * the mechanism for which we have matching creds, if available.
         */
        if (verifier_cred_handle != GSS_C_NO_CREDENTIAL) {
            uc = (gss_union_cred_t)verifier_cred_handle;
            for (i = 0; i < uc->count; i++) {
                public_mech = gssint_get_public_oid(&uc->mechs_array[i]);
                if (public_mech && g_OID_equal(token_mech_type, public_mech)) {
                    selected_mech = &uc->mechs_array[i];
                    break;
                }
            }
        }

        if (selected_mech == GSS_C_NO_OID) {
            status = gssint_select_mech_type(minor_status, token_mech_type,
                                             &selected_mech);
            if (status)
                return status;
        }

    } else {
        union_ctx_id = (gss_union_ctx_id_t)*context_handle;
        selected_mech = union_ctx_id->mech_type;
        if (union_ctx_id->internal_ctx_id == GSS_C_NO_CONTEXT)
            return (GSS_S_NO_CONTEXT);
    }

    /* Now create a new context if we didn't get one. */
    if (*context_handle == GSS_C_NO_CONTEXT) {
        status = gssint_create_union_context(minor_status, selected_mech,
                                             &union_ctx_id);
        if (status != GSS_S_COMPLETE)
            return (status);
    }

    /*
     * get the appropriate cred handle from the union cred struct.
     */
    if (verifier_cred_handle != GSS_C_NO_CREDENTIAL) {
        input_cred_handle =
            gssint_get_mechanism_cred((gss_union_cred_t)verifier_cred_handle,
                                      selected_mech);
        if (input_cred_handle == GSS_C_NO_CREDENTIAL) {
            /* verifier credential specified but no acceptor credential found */
            status = GSS_S_NO_CRED;
            goto error_out;
        }
    } else if (!allow_mech_by_default(selected_mech)) {
        status = GSS_S_NO_CRED;
        goto error_out;
    }

    /*
     * now select the approprate underlying mechanism routine and
     * call it.
     */

    mech = gssint_get_mechanism(selected_mech);
    if (mech && mech->gss_accept_sec_context) {

            status = mech->gss_accept_sec_context(minor_status,
                                                  &union_ctx_id->internal_ctx_id,
                                                  input_cred_handle,
                                                  input_token_buffer,
                                                  input_chan_bindings,
                                                  src_name ? &internal_name : NULL,
                                                  &actual_mech,
                                                  output_token,
                                                  &temp_ret_flags,
                                                  time_rec,
                                        d_cred ? &tmp_d_cred : NULL);

            /* If there's more work to do, keep going... */
            if (status == GSS_S_CONTINUE_NEEDED) {
                *context_handle = (gss_ctx_id_t)union_ctx_id;
                return GSS_S_CONTINUE_NEEDED;
            }

            /* if the call failed, return with failure */
            if (status != GSS_S_COMPLETE) {
                map_error(minor_status, mech);
                goto error_out;
            }

            /*
             * if src_name is non-NULL,
             * convert internal_name into a union name equivalent
             * First call the mechanism specific display_name()
             * then call gss_import_name() to create
             * the union name struct cast to src_name
             */
            if (src_name != NULL) {
                if (internal_name != GSS_C_NO_NAME) {
                    /* consumes internal_name regardless of success */
                    temp_status = gssint_convert_name_to_union_name(
                            &temp_minor_status, mech,
                            internal_name, &tmp_src_name);
                    if (temp_status != GSS_S_COMPLETE) {
                        status = temp_status;
                        *minor_status = temp_minor_status;
                        map_error(minor_status, mech);
                        if (output_token->length)
                            (void) gss_release_buffer(&temp_minor_status,
                                                      output_token);
                        goto error_out;
                    }
                    *src_name = tmp_src_name;
                } else
                    *src_name = GSS_C_NO_NAME;
            }

#define g_OID_prefix_equal(o1, o2) \
        (((o1)->length >= (o2)->length) && \
        (memcmp((o1)->elements, (o2)->elements, (o2)->length) == 0))

            /* Ensure we're returning correct creds format */
            if ((temp_ret_flags & GSS_C_DELEG_FLAG) &&
                tmp_d_cred != GSS_C_NO_CREDENTIAL) {
                public_mech = gssint_get_public_oid(selected_mech);
                if (actual_mech != GSS_C_NO_OID &&
                    public_mech != GSS_C_NO_OID &&
                    !g_OID_prefix_equal(actual_mech, public_mech)) {
                    *d_cred = tmp_d_cred; /* unwrapped pseudo-mech */
                } else {
                    gss_union_cred_t d_u_cred = NULL;

                    d_u_cred = malloc(sizeof (gss_union_cred_desc));
                    if (d_u_cred == NULL) {
                        status = GSS_S_FAILURE;
                        goto error_out;
                    }
                    (void) memset(d_u_cred, 0, sizeof (gss_union_cred_desc));

                    d_u_cred->count = 1;

                    status = generic_gss_copy_oid(&temp_minor_status,
                                                  selected_mech,
                                                  &d_u_cred->mechs_array);

                    if (status != GSS_S_COMPLETE) {
                        free(d_u_cred);
                        goto error_out;
                    }

                    d_u_cred->cred_array = malloc(sizeof(gss_cred_id_t));
                    if (d_u_cred->cred_array != NULL) {
                        d_u_cred->cred_array[0] = tmp_d_cred;
                    } else {
                        free(d_u_cred);
                        status = GSS_S_FAILURE;
                        goto error_out;
                    }

                    d_u_cred->loopback = d_u_cred;
                    *d_cred = (gss_cred_id_t)d_u_cred;
                }
            }

            if (mech_type != NULL)
                *mech_type = gssint_get_public_oid(actual_mech);
            if (ret_flags != NULL)
                *ret_flags = temp_ret_flags;
            *context_handle = (gss_ctx_id_t)union_ctx_id;
            return GSS_S_COMPLETE;
    } else {

        status = GSS_S_BAD_MECH;
    }

error_out:
        /*
         * RFC 2744 5.1 requires that we not create a context on a failed first
         * call to accept, and recommends that on a failed subsequent call we
         * make the caller responsible for calling gss_delete_sec_context.
         * Even if the mech deleted its context, keep the union context around
         * for the caller to delete.
         */
    if (union_ctx_id && *context_handle == GSS_C_NO_CONTEXT) {
        if (union_ctx_id->mech_type) {
            if (union_ctx_id->mech_type->elements)
                free(union_ctx_id->mech_type->elements);
            free(union_ctx_id->mech_type);
        }
        if (union_ctx_id->internal_ctx_id && mech &&
            mech->gss_delete_sec_context) {
            mech->gss_delete_sec_context(&temp_minor_status,
                                         &union_ctx_id->internal_ctx_id,
                                         GSS_C_NO_BUFFER);
        }
        free(union_ctx_id);
    }

    if (src_name)
        *src_name = GSS_C_NO_NAME;

    if (tmp_src_name != GSS_C_NO_NAME)
        (void) gss_release_buffer(&temp_minor_status,
                                  (gss_buffer_t)tmp_src_name);

    return (status);
}
#endif /* LEAN_CLIENT */