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 #include <algorithm>
29
30 using android::base::StringAppendF;
31
32 namespace android {
33 namespace net {
34
35 namespace {
36
compUidRangeParcel(const UidRangeParcel & lhs,const UidRangeParcel & rhs)37 bool compUidRangeParcel(const UidRangeParcel& lhs, const UidRangeParcel& rhs) {
38 return lhs.start != rhs.start ? (lhs.start < rhs.start) : (lhs.stop < rhs.stop);
39 };
40
41 // Check whether two uid ranges have overlapped uid. For any uid included in both ranges, it is
42 // considered as overlap.
isOverlapped(const UidRangeParcel & r1,const UidRangeParcel & r2)43 bool isOverlapped(const UidRangeParcel& r1, const UidRangeParcel& r2) {
44 return (r1.stop >= r2.start) && (r1.start <= r2.stop);
45 }
46
makeUidRangeParcel(int start,int stop)47 UidRangeParcel makeUidRangeParcel(int start, int stop) {
48 UidRangeParcel res;
49 res.start = start;
50 res.stop = stop;
51
52 return res;
53 }
54
length(const UidRangeParcel & t)55 uint32_t length(const UidRangeParcel& t) {
56 if (t.start == -1 || t.stop == -1) {
57 return 0;
58 }
59 return static_cast<uint32_t>(t.stop - t.start + 1);
60 }
61
62 } // namespace
63
hasUid(uid_t uid) const64 bool UidRanges::hasUid(uid_t uid) const {
65 if (uid > (unsigned) INT32_MAX) {
66 ALOGW("UID larger than 32 bits: %" PRIu64, static_cast<uint64_t>(uid));
67 return false;
68 }
69 const int32_t intUid = static_cast<int32_t>(uid);
70
71 auto iter = std::lower_bound(mRanges.begin(), mRanges.end(), makeUidRangeParcel(intUid, intUid),
72 compUidRangeParcel);
73 return (iter != mRanges.end() && iter->start == intUid) ||
74 (iter != mRanges.begin() && (--iter)->stop >= intUid);
75 }
76
getRanges() const77 const std::vector<UidRangeParcel>& UidRanges::getRanges() const {
78 return mRanges;
79 }
80
parseFrom(int argc,char * argv[])81 bool UidRanges::parseFrom(int argc, char* argv[]) {
82 mRanges.clear();
83 for (int i = 0; i < argc; ++i) {
84 if (!*argv[i]) {
85 // The UID string is empty.
86 return false;
87 }
88 char* endPtr;
89 uid_t uidStart = strtoul(argv[i], &endPtr, 0);
90 uid_t uidEnd;
91 if (!*endPtr) {
92 // Found a single UID. The range contains just the one UID.
93 uidEnd = uidStart;
94 } else if (*endPtr == '-') {
95 if (!*++endPtr) {
96 // Unexpected end of string.
97 return false;
98 }
99 uidEnd = strtoul(endPtr, &endPtr, 0);
100 if (*endPtr) {
101 // Illegal trailing chars.
102 return false;
103 }
104 if (uidEnd < uidStart) {
105 // Invalid order.
106 return false;
107 }
108 } else {
109 // Not a single uid, not a range. Found some other illegal char.
110 return false;
111 }
112 if (uidStart == INVALID_UID || uidEnd == INVALID_UID) {
113 // Invalid UIDs.
114 return false;
115 }
116 mRanges.push_back(makeUidRangeParcel(uidStart, uidEnd));
117 }
118 std::sort(mRanges.begin(), mRanges.end(), compUidRangeParcel);
119 return true;
120 }
121
UidRanges(const std::vector<UidRangeParcel> & ranges)122 UidRanges::UidRanges(const std::vector<UidRangeParcel>& ranges) {
123 mRanges = ranges;
124 std::sort(mRanges.begin(), mRanges.end(), compUidRangeParcel);
125 }
126
add(const UidRanges & other)127 void UidRanges::add(const UidRanges& other) {
128 auto middle = mRanges.insert(mRanges.end(), other.mRanges.begin(), other.mRanges.end());
129 std::inplace_merge(mRanges.begin(), middle, mRanges.end(), compUidRangeParcel);
130 }
131
remove(const UidRanges & other)132 void UidRanges::remove(const UidRanges& other) {
133 auto end = std::set_difference(mRanges.begin(), mRanges.end(), other.mRanges.begin(),
134 other.mRanges.end(), mRanges.begin(), compUidRangeParcel);
135 mRanges.erase(end, mRanges.end());
136 }
137
overlapsSelf() const138 bool UidRanges::overlapsSelf() const {
139 // Compare each element one by one
140 for (size_t i = 0; i < mRanges.size(); i++) {
141 for (size_t j = i + 1; j < mRanges.size(); j++) {
142 if (isOverlapped(mRanges[i], mRanges[j])) {
143 return true;
144 }
145 }
146 }
147 return false;
148 }
149
toString() const150 std::string UidRanges::toString() const {
151 std::string s("uids{ ");
152 for (const auto &range : mRanges) {
153 if (length(range) == 0) {
154 StringAppendF(&s, "<BAD: %u-%u> ", range.start, range.stop);
155 } else if (length(range) == 1) {
156 StringAppendF(&s, "%u ", range.start);
157 } else {
158 StringAppendF(&s, "%u-%u ", range.start, range.stop);
159 }
160 }
161 StringAppendF(&s, "}");
162 return s;
163 }
164
165 } // namespace net
166 } // namespace android
167