1 /*
2 * Copyright (C) 2014 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 "UidRanges.h"
18
19 #include "NetdConstants.h"
20
21 #include <inttypes.h>
22 #include <limits.h>
23 #include <stdlib.h>
24
25 #include <android-base/stringprintf.h>
26 #include <log/log.h>
27
28 using android::base::StringAppendF;
29
30 namespace android {
31 namespace net {
32
33 namespace {
34
compUidRangeParcel(const UidRangeParcel & lhs,const UidRangeParcel & rhs)35 bool compUidRangeParcel(const UidRangeParcel& lhs, const UidRangeParcel& rhs) {
36 return lhs.start != rhs.start ? (lhs.start < rhs.start) : (lhs.stop < rhs.stop);
37 };
38
39 // Check whether two uid ranges have overlapped uid. For any uid included in both ranges, it is
40 // considered as overlap.
isOverlapped(const UidRangeParcel & r1,const UidRangeParcel & r2)41 bool isOverlapped(const UidRangeParcel& r1, const UidRangeParcel& r2) {
42 return (r1.stop >= r2.start) && (r1.start <= r2.stop);
43 }
44
makeUidRangeParcel(int start,int stop)45 UidRangeParcel makeUidRangeParcel(int start, int stop) {
46 UidRangeParcel res;
47 res.start = start;
48 res.stop = stop;
49
50 return res;
51 }
52
length(const UidRangeParcel & t)53 uint32_t length(const UidRangeParcel& t) {
54 if (t.start == -1 || t.stop == -1) {
55 return 0;
56 }
57 return static_cast<uint32_t>(t.stop - t.start + 1);
58 }
59
60 } // namespace
61
hasUid(uid_t uid) const62 bool UidRanges::hasUid(uid_t uid) const {
63 if (uid > (unsigned) INT32_MAX) {
64 ALOGW("UID larger than 32 bits: %" PRIu64, static_cast<uint64_t>(uid));
65 return false;
66 }
67 const int32_t intUid = static_cast<int32_t>(uid);
68
69 auto iter = std::lower_bound(mRanges.begin(), mRanges.end(), makeUidRangeParcel(intUid, intUid),
70 compUidRangeParcel);
71 return (iter != mRanges.end() && iter->start == intUid) ||
72 (iter != mRanges.begin() && (--iter)->stop >= intUid);
73 }
74
getRanges() const75 const std::vector<UidRangeParcel>& UidRanges::getRanges() const {
76 return mRanges;
77 }
78
parseFrom(int argc,char * argv[])79 bool UidRanges::parseFrom(int argc, char* argv[]) {
80 mRanges.clear();
81 for (int i = 0; i < argc; ++i) {
82 if (!*argv[i]) {
83 // The UID string is empty.
84 return false;
85 }
86 char* endPtr;
87 uid_t uidStart = strtoul(argv[i], &endPtr, 0);
88 uid_t uidEnd;
89 if (!*endPtr) {
90 // Found a single UID. The range contains just the one UID.
91 uidEnd = uidStart;
92 } else if (*endPtr == '-') {
93 if (!*++endPtr) {
94 // Unexpected end of string.
95 return false;
96 }
97 uidEnd = strtoul(endPtr, &endPtr, 0);
98 if (*endPtr) {
99 // Illegal trailing chars.
100 return false;
101 }
102 if (uidEnd < uidStart) {
103 // Invalid order.
104 return false;
105 }
106 } else {
107 // Not a single uid, not a range. Found some other illegal char.
108 return false;
109 }
110 if (uidStart == INVALID_UID || uidEnd == INVALID_UID) {
111 // Invalid UIDs.
112 return false;
113 }
114 mRanges.push_back(makeUidRangeParcel(uidStart, uidEnd));
115 }
116 std::sort(mRanges.begin(), mRanges.end(), compUidRangeParcel);
117 return true;
118 }
119
UidRanges(const std::vector<UidRangeParcel> & ranges)120 UidRanges::UidRanges(const std::vector<UidRangeParcel>& ranges) {
121 mRanges = ranges;
122 std::sort(mRanges.begin(), mRanges.end(), compUidRangeParcel);
123 }
124
add(const UidRanges & other)125 void UidRanges::add(const UidRanges& other) {
126 auto middle = mRanges.insert(mRanges.end(), other.mRanges.begin(), other.mRanges.end());
127 std::inplace_merge(mRanges.begin(), middle, mRanges.end(), compUidRangeParcel);
128 }
129
remove(const UidRanges & other)130 void UidRanges::remove(const UidRanges& other) {
131 auto end = std::set_difference(mRanges.begin(), mRanges.end(), other.mRanges.begin(),
132 other.mRanges.end(), mRanges.begin(), compUidRangeParcel);
133 mRanges.erase(end, mRanges.end());
134 }
135
overlapsSelf() const136 bool UidRanges::overlapsSelf() const {
137 // Compare each element one by one
138 for (size_t i = 0; i < mRanges.size(); i++) {
139 for (size_t j = i + 1; j < mRanges.size(); j++) {
140 if (isOverlapped(mRanges[i], mRanges[j])) {
141 return true;
142 }
143 }
144 }
145 return false;
146 }
147
toString() const148 std::string UidRanges::toString() const {
149 std::string s("uids{ ");
150 for (const auto &range : mRanges) {
151 if (length(range) == 0) {
152 StringAppendF(&s, "<BAD: %u-%u> ", range.start, range.stop);
153 } else if (length(range) == 1) {
154 StringAppendF(&s, "%u ", range.start);
155 } else {
156 StringAppendF(&s, "%u-%u ", range.start, range.stop);
157 }
158 }
159 StringAppendF(&s, "}");
160 return s;
161 }
162
163 } // namespace net
164 } // namespace android
165