kdc/token_validator.c

   1 /*
   2  * Copyright (c) 2019 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "kdc_locl.h"
  35 #include "token_validator_plugin.h"
  36
  37 struct plctx {
  38     const char              *realm;
  39     const char              *token_kind;
  40     krb5_data               *token;
  41     const char * const      *audiences;
  42     size_t                  naudiences;
  43     krb5_boolean            result;
  44     krb5_principal          actual_principal;
  45     krb5_times              token_times;
  46 };
  47
  48 static krb5_error_code KRB5_LIB_CALL
  49 plcallback(krb5_context context, const void *plug, void *plugctx, void *userctx)
  50 {
  51     const krb5plugin_token_validator_ftable *validator = plug;
  52     krb5_error_code ret;
  53     struct plctx *plctx = userctx;
  54
  55     ret = validator->validate(plugctx, context, plctx->realm,
  56                               plctx->token_kind, plctx->token,
  57                               plctx->audiences, plctx->naudiences,
  58                               &plctx->result, &plctx->actual_principal,
  59                               &plctx->token_times);
  60     if (ret) {
  61         krb5_free_principal(context, plctx->actual_principal);
  62         plctx->actual_principal = NULL;
  63     }
  64     return ret;
  65 }
  66
  67 static const char *plugin_deps[] = { "krb5", NULL };
  68
  69 static struct heim_plugin_data token_validator_data = {
  70     "kdc",
  71     KDC_PLUGIN_BEARER,
  72     1,
  73     plugin_deps,
  74     krb5_get_instance
  75 };
  76
  77 /*
  78  * Invoke a plugin to validate a JWT/SAML/OIDC token and partially-evaluate
  79  * access control.
  80  */
  81 KDC_LIB_FUNCTION krb5_error_code KDC_LIB_CALL
  82 kdc_validate_token(krb5_context context,
  83                    const char *realm,
  84                    const char *token_kind,
  85                    krb5_data *token,
  86                    const char * const *audiences,
  87                    size_t naudiences,
  88                    krb5_principal *actual_principal,
  89                    krb5_times *token_times)
  90 {
  91     krb5_error_code ret;
  92     struct plctx ctx;
  93
  94     memset(&ctx, 0, sizeof(ctx));
  95     ctx.realm = realm;
  96     ctx.token_kind = token_kind;
  97     ctx.token = token;
  98     ctx.audiences = audiences;
  99     ctx.naudiences = naudiences;
 100     ctx.result = FALSE;
 101     ctx.actual_principal = NULL;
 102
 103     krb5_clear_error_message(context);
 104     ret = _krb5_plugin_run_f(context, &token_validator_data, 0, &ctx,
 105                              plcallback);
 106     if (ret == 0 && ctx.result && actual_principal) {
 107         *actual_principal = ctx.actual_principal;
 108         ctx.actual_principal = NULL;
 109     }
 110
 111     if (token_times)
 112         *token_times = ctx.token_times;
 113
 114     krb5_free_principal(context, ctx.actual_principal);
 115     if (ret)
 116         krb5_prepend_error_message(context, ret, "bearer token validation "
 117                                    "failed: ");
 118     else if (!ctx.result)
 119         krb5_set_error_message(context, ret = EACCES,
 120                                "bearer token validation failed");
 121     return ret;
 122 }