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      1 // Copyright 2015 The Weave Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef LIBUWEAVE_SRC_MACAROON_H_
      6 #define LIBUWEAVE_SRC_MACAROON_H_
      7 
      8 #include <stdbool.h>
      9 #include <stddef.h>
     10 #include <stdint.h>
     11 
     12 #include "src/macaroon_caveat.h"
     13 #include "src/macaroon_context.h"
     14 
     15 #define UW_MACAROON_MAC_LEN 16
     16 
     17 // Note: If we are looking to make memory savings on MCUs,
     18 // at the cost of a little extra processing, we can make
     19 // the macaroon encoding the actual in-memory representation.
     20 // This can save much copying of macaroon data if need be.
     21 typedef struct {
     22   uint8_t mac_tag[UW_MACAROON_MAC_LEN];
     23   size_t num_caveats;
     24   const UwMacaroonCaveat* const* caveats;
     25 } UwMacaroon;
     26 
     27 // For the delegatee list in the validation result object
     28 typedef enum {
     29   kUwMacaroonDelegateeTypeNone = 0,
     30   kUwMacaroonDelegateeTypeUser = 1,
     31   kUwMacaroonDelegateeTypeApp = 2,
     32   kUwMacaroonDelegateeTypeService = 3,
     33 } UwMacaroonDelegateeType;
     34 
     35 typedef struct {
     36   const uint8_t* id;
     37   size_t id_len;
     38   UwMacaroonDelegateeType type;
     39   uint32_t timestamp;
     40 } UwMacaroonDelegateeInfo;
     41 
     42 #define MAX_NUM_DELEGATEES 10
     43 
     44 typedef struct {
     45   UwMacaroonCaveatScopeType granted_scope;
     46   uint32_t expiration_time;
     47   bool weave_app_restricted;
     48   const uint8_t* lan_session_id;
     49   size_t lan_session_id_len;
     50   UwMacaroonDelegateeInfo delegatees[MAX_NUM_DELEGATEES];
     51   size_t num_delegatees;
     52 } UwMacaroonValidationResult;
     53 
     54 bool uw_macaroon_create_from_root_key_(UwMacaroon* new_macaroon,
     55                                        const uint8_t* root_key,
     56                                        size_t root_key_len,
     57                                        const UwMacaroonContext* context,
     58                                        const UwMacaroonCaveat* const caveats[],
     59                                        size_t num_caveats);
     60 
     61 /** Creates a new macaroon with a new caveat. */
     62 bool uw_macaroon_extend_(const UwMacaroon* old_macaroon,
     63                          UwMacaroon* new_macaroon,
     64                          const UwMacaroonContext* context,
     65                          const UwMacaroonCaveat* additional_caveat,
     66                          uint8_t* buffer,
     67                          size_t buffer_size);
     68 
     69 /**
     70  * Verify and validate the Macaroon, and put relevant information into the
     71  * result object. Note that the resulting granted_scope will be the closest
     72  * valid scope type (to the narrower side) defined in macaroon_caveat.h.
     73  */
     74 bool uw_macaroon_validate_(
     75     const UwMacaroon* macaroon,
     76     const uint8_t* root_key,
     77     size_t root_key_len,
     78     const UwMacaroonContext* context,
     79     UwMacaroonValidationResult* result);
     80 
     81 /** Encode a Macaroon to a byte string. */
     82 bool uw_macaroon_serialize_(const UwMacaroon* macaroon,
     83                             uint8_t* out,
     84                             size_t out_len,
     85                             size_t* resulting_str_len);
     86 
     87 /**
     88  * Decodes a byte string to a Macaroon.
     89  *
     90  * One note is that the function doesn't copy string values to new buffers, so
     91  * the caller must maintain the input string around to make caveats with string
     92  * values to be usable.
     93  */
     94 bool uw_macaroon_deserialize_(const uint8_t* in,
     95                               size_t in_len,
     96                               uint8_t* buffer,
     97                               size_t buffer_size,
     98                               UwMacaroon* new_macaroon);
     99 
    100 #endif  // LIBUWEAVE_SRC_MACAROON_H_
    101