1 /*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "grant_store.h"
18
19 #include <algorithm>
20 #include <sstream>
21
22 namespace keystore {
23
24 static constexpr uint64_t kInvalidGrantNo = std::numeric_limits<uint64_t>::max();
25 static const char* kKeystoreGrantInfix = "_KEYSTOREGRANT_";
26 static constexpr size_t kKeystoreGrantInfixLength = 15;
27
Grant(const std::string & alias,const std::string & owner_dir_name,const uid_t owner_uid,const uint64_t grant_no)28 Grant::Grant(const std::string& alias, const std::string& owner_dir_name, const uid_t owner_uid,
29 const uint64_t grant_no)
30 : alias_(alias), owner_dir_name_(owner_dir_name), owner_uid_(owner_uid),
31 grant_no_(grant_no) {}
32
parseGrantAlias(const std::string & grantAlias)33 static std::pair<uint64_t, std::string> parseGrantAlias(const std::string& grantAlias) {
34 auto pos = grantAlias.rfind(kKeystoreGrantInfix);
35 if (pos == std::string::npos) return {kInvalidGrantNo, ""};
36 std::stringstream s(grantAlias.substr(pos + kKeystoreGrantInfixLength));
37 std::string wrapped_alias = grantAlias.substr(0, pos);
38 uint64_t grant_no = kInvalidGrantNo;
39 s >> grant_no;
40 if (s.fail() || grant_no == kInvalidGrantNo) return {kInvalidGrantNo, ""};
41 return {grant_no, wrapped_alias};
42 }
43
put(const uid_t uid,const std::string & alias,const std::string & owner_dir_name,const uid_t owner_uid)44 std::string GrantStore::put(const uid_t uid, const std::string& alias,
45 const std::string& owner_dir_name, const uid_t owner_uid) {
46 std::stringstream s;
47 s << alias << kKeystoreGrantInfix;
48 auto& uid_grant_list = grants_[uid];
49
50 bool success = false;
51 auto iterator = std::find_if(uid_grant_list.begin(), uid_grant_list.end(),
52 [&](auto& entry) {
53 return success = entry.alias_ == alias && entry.owner_dir_name_ == owner_dir_name
54 && entry.owner_uid_ == owner_uid;
55 });
56 while (!success) {
57 std::tie(iterator, success) = uid_grant_list.emplace(alias, owner_dir_name, owner_uid,
58 std::rand());
59 }
60 s << iterator->grant_no_;
61 return s.str();
62 }
63
get(const uid_t uid,const std::string & alias) const64 const Grant* GrantStore::get(const uid_t uid, const std::string& alias) const {
65 uint64_t grant_no;
66 std::string wrappedAlias;
67 std::tie(grant_no, wrappedAlias) = parseGrantAlias(alias);
68 if (grant_no == kInvalidGrantNo) return nullptr;
69 auto uid_set_iter = grants_.find(uid);
70 if (uid_set_iter == grants_.end()) return nullptr;
71 auto& uid_grant_list = uid_set_iter->second;
72 auto grant = uid_grant_list.find(grant_no);
73 if (grant == uid_grant_list.end()) return nullptr;
74 if (grant->alias_ != wrappedAlias) return nullptr;
75 return &(*grant);
76 }
77
removeByFileAlias(const uid_t granteeUid,const uid_t granterUid,const std::string & alias)78 bool GrantStore::removeByFileAlias(const uid_t granteeUid, const uid_t granterUid,
79 const std::string& alias) {
80 auto& uid_grant_list = grants_[granteeUid];
81 for (auto i = uid_grant_list.begin(); i != uid_grant_list.end(); ++i) {
82 if (i->alias_ == alias && i->owner_uid_ == granterUid) {
83 uid_grant_list.erase(i);
84 return true;
85 }
86 }
87 return false;
88 }
89
removeAllGrantsToKey(const uid_t granterUid,const std::string & alias)90 void GrantStore::removeAllGrantsToKey(const uid_t granterUid, const std::string& alias) {
91 for (auto& uid_grant_list : grants_) {
92 for (auto i = uid_grant_list.second.begin(); i != uid_grant_list.second.end(); ++i) {
93 if (i->alias_ == alias && i->owner_uid_ == granterUid) {
94 uid_grant_list.second.erase(i);
95 break;
96 }
97 }
98 }
99 }
100
removeAllGrantsToUid(const uid_t granteeUid)101 void GrantStore::removeAllGrantsToUid(const uid_t granteeUid) {
102 grants_.erase(granteeUid);
103 }
104
105 } // namespace keystore
106