1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
// Copyright (C) 2008 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.sshd;
import static com.google.common.base.Preconditions.checkState;
import static java.nio.charset.StandardCharsets.ISO_8859_1;
import static java.nio.charset.StandardCharsets.UTF_8;
import com.google.common.flogger.FluentLogger;
import com.google.gerrit.common.FileUtil;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.PeerDaemonUser;
import com.google.gerrit.server.account.AccountSshKey;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.config.SitePaths;
import com.google.inject.Inject;
import java.io.BufferedReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.security.KeyPair;
import java.security.PublicKey;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Locale;
import java.util.Set;
import org.apache.commons.codec.binary.Base64;
import org.apache.sshd.common.SshException;
import org.apache.sshd.common.keyprovider.KeyPairProvider;
import org.apache.sshd.common.util.buffer.ByteArrayBuffer;
import org.apache.sshd.server.auth.pubkey.PublickeyAuthenticator;
import org.apache.sshd.server.session.ServerSession;
import org.eclipse.jgit.lib.Config;
/** Authenticates by public key through {@link AccountSshKey} entities. */
class DatabasePubKeyAuth implements PublickeyAuthenticator {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
private final SshKeyCacheImpl sshKeyCache;
private final SshLog sshLog;
private final IdentifiedUser.GenericFactory userFactory;
private final PeerDaemonUser.Factory peerFactory;
private final Config config;
private final SshScope sshScope;
private final Set<PublicKey> myHostKeys;
private volatile PeerKeyCache peerKeyCache;
@Inject
DatabasePubKeyAuth(
SshKeyCacheImpl skc,
SshLog l,
IdentifiedUser.GenericFactory uf,
PeerDaemonUser.Factory pf,
SitePaths site,
KeyPairProvider hostKeyProvider,
@GerritServerConfig Config cfg,
SshScope s) {
sshKeyCache = skc;
sshLog = l;
userFactory = uf;
peerFactory = pf;
config = cfg;
sshScope = s;
myHostKeys = myHostKeys(hostKeyProvider);
peerKeyCache = new PeerKeyCache(site.peer_keys);
}
private static Set<PublicKey> myHostKeys(KeyPairProvider p) {
final Set<PublicKey> keys = new HashSet<>(6);
addPublicKey(keys, p, KeyPairProvider.SSH_ED25519);
addPublicKey(keys, p, KeyPairProvider.ECDSA_SHA2_NISTP256);
addPublicKey(keys, p, KeyPairProvider.ECDSA_SHA2_NISTP384);
addPublicKey(keys, p, KeyPairProvider.ECDSA_SHA2_NISTP521);
addPublicKey(keys, p, KeyPairProvider.SSH_RSA);
addPublicKey(keys, p, KeyPairProvider.SSH_DSS);
return keys;
}
private static void addPublicKey(
final Collection<PublicKey> out, KeyPairProvider p, String type) {
final KeyPair pair = p.loadKey(type);
if (pair != null && pair.getPublic() != null) {
out.add(pair.getPublic());
}
}
@Override
public boolean authenticate(String username, PublicKey suppliedKey, ServerSession session) {
SshSession sd = session.getAttribute(SshSession.KEY);
checkState(sd.getUser() == null);
if (PeerDaemonUser.USER_NAME.equals(username)) {
if (myHostKeys.contains(suppliedKey) || getPeerKeys().contains(suppliedKey)) {
PeerDaemonUser user = peerFactory.create(sd.getRemoteAddress());
return SshUtil.success(username, session, sshScope, sshLog, sd, user);
}
sd.authenticationError(username, "no-matching-key");
return false;
}
if (config.getBoolean("auth", "userNameToLowerCase", false)) {
username = username.toLowerCase(Locale.US);
}
Iterable<SshKeyCacheEntry> keyList = sshKeyCache.get(username);
SshKeyCacheEntry key = find(keyList, suppliedKey);
if (key == null) {
String err;
if (keyList == SshKeyCacheImpl.NO_SUCH_USER) {
err = "user-not-found";
} else if (keyList == SshKeyCacheImpl.NO_KEYS) {
err = "key-list-empty";
} else {
err = "no-matching-key";
}
sd.authenticationError(username, err);
return false;
}
// Double check that all of the keys are for the same user account.
// This should have been true when the cache factory method loaded
// the list into memory, but we want to be extra paranoid about our
// security check to ensure there aren't two users sharing the same
// user name on the server.
//
for (SshKeyCacheEntry otherKey : keyList) {
if (!key.getAccount().equals(otherKey.getAccount())) {
sd.authenticationError(username, "keys-cross-accounts");
return false;
}
}
IdentifiedUser cu = SshUtil.createUser(sd, userFactory, key.getAccount());
if (!cu.getAccount().isActive()) {
sd.authenticationError(username, "inactive-account");
return false;
}
return SshUtil.success(username, session, sshScope, sshLog, sd, cu);
}
private Set<PublicKey> getPeerKeys() {
PeerKeyCache p = peerKeyCache;
if (!p.isCurrent()) {
p = p.reload();
peerKeyCache = p;
}
return p.keys;
}
private SshKeyCacheEntry find(Iterable<SshKeyCacheEntry> keyList, PublicKey suppliedKey) {
for (SshKeyCacheEntry k : keyList) {
if (k.match(suppliedKey)) {
return k;
}
}
return null;
}
private static class PeerKeyCache {
private final Path path;
private final long modified;
final Set<PublicKey> keys;
PeerKeyCache(Path path) {
this.path = path;
this.modified = FileUtil.lastModified(path);
this.keys = read(path);
}
private static Set<PublicKey> read(Path path) {
try (BufferedReader br = Files.newBufferedReader(path, UTF_8)) {
final Set<PublicKey> keys = new HashSet<>();
String line;
while ((line = br.readLine()) != null) {
line = line.trim();
if (line.startsWith("#") || line.isEmpty()) {
continue;
}
try {
byte[] bin = Base64.decodeBase64(line.getBytes(ISO_8859_1));
keys.add(new ByteArrayBuffer(bin).getRawPublicKey());
} catch (RuntimeException | SshException e) {
logBadKey(path, line, e);
}
}
return Collections.unmodifiableSet(keys);
} catch (NoSuchFileException noFile) {
return Collections.emptySet();
} catch (IOException err) {
logger.atSevere().withCause(err).log("Cannot read %s", path);
return Collections.emptySet();
}
}
private static void logBadKey(Path path, String line, Exception e) {
logger.atWarning().withCause(e).log("Invalid key in %s:\n %s", path, line);
}
boolean isCurrent() {
return modified == FileUtil.lastModified(path);
}
PeerKeyCache reload() {
return new PeerKeyCache(path);
}
}
}
|
