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IMAP: detect infinite loop on the client side

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git-svn-id: http://svn.code.sf.net/p/davmail/code/trunk@1665 3d1905a2-6b24-0410-a738-b14d5a86fcbd
This commit is contained in:
mguessan 2011-04-13 10:45:51 +00:00
parent 31214b1be2
commit e81f0c3f91
1 changed files with 34 additions and 0 deletions
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34
src/java/davmail/imap/ImapConnection.java
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@ -92,6 +92,9 @@ public class ImapConnection extends AbstractConnection {
tokens = new IMAPTokenizer(line);
if (tokens.hasMoreTokens()) {
commandId = tokens.nextToken();
checkInfiniteLoop(line);
if (tokens.hasMoreTokens()) {
String command = tokens.nextToken();
@ -209,6 +212,7 @@ public class ImapConnection extends AbstractConnection {
}
} else if ("select".equalsIgnoreCase(command) || "examine".equalsIgnoreCase(command)) {
if (tokens.hasMoreTokens()) {
@SuppressWarnings({"NonConstantStringShouldBeStringBuffer"})
String folderName = BASE64MailboxDecoder.decode(tokens.nextToken());
if (baseMailboxPath != null && !folderName.startsWith("/")) {
folderName = baseMailboxPath + folderName;
@ -613,6 +617,36 @@ public class ImapConnection extends AbstractConnection {
DavGatewayTray.resetIcon();
}
protected String lastCommand;
protected int lastCommandCount;
/**
* Detect infinite loop on the client side.
* @param line IMAP command line
* @throws IOException on infinite loop
*/
protected void checkInfiniteLoop(String line) throws IOException {
int spaceIndex = line.indexOf(' ');
if (spaceIndex < 0) {
// invalid command line, reset
lastCommand = null;
lastCommandCount = 0;
} else {
String command = line.substring(spaceIndex);
if (command.equals(lastCommand)) {
lastCommandCount++;
if (lastCommandCount > 100 && !"NOOP".equalsIgnoreCase(lastCommand)) {
// more than a hundred times the same command => this is a client infinite loop, close connection
throw new IOException("Infinite loop on command "+command+" detected");
}
} else {
// new command, reset
lastCommand = command;
lastCommandCount = 0;
}
}
}
/**
* Detect shared mailbox access.
* see http://msexchangeteam.com/archive/2004/03/31/105275.aspx