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Ignore invalid entries in /etc/resolv.conf when parsing (#9697)

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Motivation:

We should just ignore (and so skip) invalid entries in /etc/resolver.conf.

Modifications:

- Skip invalid entries
- Add unit test

Result:

Fix https://github.com/netty/netty/issues/9684
This commit is contained in:
Norman Maurer 2019-10-22 05:26:25 -07:00 committed by GitHub
parent e745ef0645
commit c7441f68f3
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 55 additions and 38 deletions
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80
resolver-dns/src/main/java/io/netty/resolver/dns/UnixResolverDnsServerAddressStreamProvider.java
View File

@ -167,48 +167,52 @@ public final class UnixResolverDnsServerAddressStreamProvider implements DnsServ
String line;
while ((line = br.readLine()) != null) {
line = line.trim();
char c;
if (line.isEmpty() || (c = line.charAt(0)) == '#' || c == ';') {
continue;
}
if (line.startsWith(NAMESERVER_ROW_LABEL)) {
int i = indexOfNonWhiteSpace(line, NAMESERVER_ROW_LABEL.length());
if (i < 0) {
throw new IllegalArgumentException("error parsing label " + NAMESERVER_ROW_LABEL +
" in file " + etcResolverFile + ". value: " + line);
try {
char c;
if (line.isEmpty() || (c = line.charAt(0)) == '#' || c == ';') {
continue;
}
String maybeIP = line.substring(i);
// There may be a port appended onto the IP address so we attempt to extract it.
if (!NetUtil.isValidIpV4Address(maybeIP) && !NetUtil.isValidIpV6Address(maybeIP)) {
i = maybeIP.lastIndexOf('.');
if (i + 1 >= maybeIP.length()) {
if (line.startsWith(NAMESERVER_ROW_LABEL)) {
int i = indexOfNonWhiteSpace(line, NAMESERVER_ROW_LABEL.length());
if (i < 0) {
throw new IllegalArgumentException("error parsing label " + NAMESERVER_ROW_LABEL +
" in file " + etcResolverFile + ". invalid IP value: " + line);
" in file " + etcResolverFile + ". value: " + line);
}
port = Integer.parseInt(maybeIP.substring(i + 1));
maybeIP = maybeIP.substring(0, i);
String maybeIP = line.substring(i);
// There may be a port appended onto the IP address so we attempt to extract it.
if (!NetUtil.isValidIpV4Address(maybeIP) && !NetUtil.isValidIpV6Address(maybeIP)) {
i = maybeIP.lastIndexOf('.');
if (i + 1 >= maybeIP.length()) {
throw new IllegalArgumentException("error parsing label " + NAMESERVER_ROW_LABEL +
" in file " + etcResolverFile + ". invalid IP value: " + line);
}
port = Integer.parseInt(maybeIP.substring(i + 1));
maybeIP = maybeIP.substring(0, i);
}
addresses.add(SocketUtils.socketAddress(maybeIP, port));
} else if (line.startsWith(DOMAIN_ROW_LABEL)) {
int i = indexOfNonWhiteSpace(line, DOMAIN_ROW_LABEL.length());
if (i < 0) {
throw new IllegalArgumentException("error parsing label " + DOMAIN_ROW_LABEL +
" in file " + etcResolverFile + " value: " + line);
}
domainName = line.substring(i);
if (!addresses.isEmpty()) {
putIfAbsent(domainToNameServerStreamMap, domainName, addresses);
}
addresses = new ArrayList<InetSocketAddress>(2);
} else if (line.startsWith(PORT_ROW_LABEL)) {
int i = indexOfNonWhiteSpace(line, PORT_ROW_LABEL.length());
if (i < 0) {
throw new IllegalArgumentException("error parsing label " + PORT_ROW_LABEL +
" in file " + etcResolverFile + " value: " + line);
}
port = Integer.parseInt(line.substring(i));
} else if (line.startsWith(SORTLIST_ROW_LABEL)) {
logger.info("row type {} not supported. Ignoring line: {}", SORTLIST_ROW_LABEL, line);
}
addresses.add(SocketUtils.socketAddress(maybeIP, port));
} else if (line.startsWith(DOMAIN_ROW_LABEL)) {
int i = indexOfNonWhiteSpace(line, DOMAIN_ROW_LABEL.length());
if (i < 0) {
throw new IllegalArgumentException("error parsing label " + DOMAIN_ROW_LABEL +
" in file " + etcResolverFile + " value: " + line);
}
domainName = line.substring(i);
if (!addresses.isEmpty()) {
putIfAbsent(domainToNameServerStreamMap, domainName, addresses);
}
addresses = new ArrayList<InetSocketAddress>(2);
} else if (line.startsWith(PORT_ROW_LABEL)) {
int i = indexOfNonWhiteSpace(line, PORT_ROW_LABEL.length());
if (i < 0) {
throw new IllegalArgumentException("error parsing label " + PORT_ROW_LABEL +
" in file " + etcResolverFile + " value: " + line);
}
port = Integer.parseInt(line.substring(i));
} else if (line.startsWith(SORTLIST_ROW_LABEL)) {
logger.info("row type {} not supported. ignoring line: {}", SORTLIST_ROW_LABEL, line);
} catch (IllegalArgumentException e) {
logger.warn("Could not parse entry. Ignoring line: {}", line, e);
}
}
if (!addresses.isEmpty()) {

13
resolver-dns/src/test/java/io/netty/resolver/dns/UnixResolverDnsServerAddressStreamProviderTest.java
View File

@ -164,6 +164,19 @@ public class UnixResolverDnsServerAddressStreamProviderTest {
assertEquals(Collections.singletonList("squarecorp.local"), domains);
}
@Test
public void ignoreInvalidEntries() throws Exception {
File f = buildFile("domain netty.local\n" +
"nameserver nil\n" +
"nameserver 127.0.0.3\n");
UnixResolverDnsServerAddressStreamProvider p =
new UnixResolverDnsServerAddressStreamProvider(f, null);
DnsServerAddressStream stream = p.nameServerAddressStream("somehost");
assertEquals(1, stream.size());
assertHostNameEquals("127.0.0.3", stream.next());
}
private File buildFile(String contents) throws IOException {
File f = folder.newFile();
OutputStream out = new FileOutputStream(f);