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| public class SshKeyValidator {
/**
*
* Enum Type of key.
*
*/
private enum TypeOfKey {
notDefined, openSSH, SSH2
}
/**
*
* @param inKey
* @return true if the key is valid.
* @throws IllegalSizeException
* @throws IllegalSshFormat
*/
public static boolean validateSshKey(final String inKey) throws IllegalSizeException, IllegalSshFormat {
TypeOfKey typeOfKey = TypeOfKey.notDefined;
try {
validateKeyByteContent(inKey);
BufferedReader reader = new BufferedReader(new StringReader(inKey));
String line = null;
StringBuilder builder = new StringBuilder();
line = reader.readLine();
// Check if it is a SSH2 Public Key
if (line != null && "---- BEGIN SSH2 PUBLIC KEY ----".equals(line)) {
typeOfKey = validateSSH2PublicKey(reader, builder);
} else {
// Check if it is a Open Public Key
typeOfKey = validateOpenPublicKey(typeOfKey, line, builder);
}
// Check if can be decoded from B64 en encoded to Hexa
byte[] keyB64Decoded = Base64.decode(builder.toString());
validateKeyLenght(typeOfKey, keyB64Decoded);
} catch (IOException e) {
throw new IllegalSshFormat("The ssh key is not valid", e);
}
return true;
}
/**
* @param inKey
* @throws IOException
*/
private static void validateKeyByteContent(final String inKey) throws IOException {
InputStream is = new ByteArrayInputStream(inKey.getBytes());
DataInputStream dis = new DataInputStream(is);
dis.readFully(inKey.getBytes());
dis.close();
}
/**
* @param reader
* @param builder
* @param isFooterPresent
* @return
* @throws IOException
* @throws IllegalSshFormat
*/
private static TypeOfKey validateSSH2PublicKey(BufferedReader reader, StringBuilder builder) throws IOException, IllegalSshFormat {
boolean isFooterPresent = false;
TypeOfKey typeOfKey;
String line;
typeOfKey = TypeOfKey.SSH2;
// Check if footer are present and get the B54 key
while ((line = reader.readLine()) != null) {
if (line.startsWith("Comment:")) {
continue;
} else if ("---- END SSH2 PUBLIC KEY ----".equals(line)) {
isFooterPresent = true;
break;
}
if (builder.length() == 0 && !line.startsWith("AAAAB3NzaC1yc2EAAAA")) {
throw new IllegalSshFormat("no valid rsa-ssh key");
}
builder.append(line);
}
if (!isFooterPresent) {
throw new IllegalSshFormat("Invalid Footer");
}
return typeOfKey;
}
/**
* @param typeOfKey
* @param line
* @param builder
* @return
* @throws IllegalSshFormat
*/
private static TypeOfKey validateOpenPublicKey(TypeOfKey typeOfKey, String line, StringBuilder builder) throws IllegalSshFormat {
if (line != null && line.startsWith("ssh-rsa AAAAB3NzaC1yc2EAAAA")) {
typeOfKey = TypeOfKey.openSSH;
line = line.replaceFirst("ssh-rsa ", "");
builder.append(line.substring(0, line.lastIndexOf(" ")));
} else {
throw new IllegalSshFormat("Invalid Header");
}
return typeOfKey;
}
/**
* @param typeOfKey
* @param keyB64Decoded
* @throws IllegalSizeException
*/
private static void validateKeyLenght(TypeOfKey typeOfKey, byte[] keyB64Decoded) throws IllegalSizeException {
// Check lenght of the Key
int keyLenght = (keyB64Decoded.length - 20) * 8;
if (typeOfKey == TypeOfKey.openSSH) {
keyLenght = keyLenght - 8;
}
if (keyLenght < 2048 || keyLenght > 4104) {// 4104 = lenght of ssh 4096
throw new IllegalSizeException("Invalid lenght: should be [2048 >= lenght <= 4096]");
}
}
/**
* IllegalSizeException Thrown when the size of the sshKey is not correct.
*
* @author same
*
* @since 1.2.5
*
*/
public static class IllegalSizeException extends Exception {
/**
*
*/
private static final long serialVersionUID = 1340984138460417925L;
/**
* @param message
* @param cause
*/
public IllegalSizeException(String message, Throwable cause) {
super(message, cause);
}
/**
* @param message
*/
public IllegalSizeException(String message) {
super(message);
}
}
/**
*
* IllegalSshFormat Thrown when the format of the sshKey is not correct..
*
* @author same
*
* @since 1.2.5
*
*/
public static class IllegalSshFormat extends Exception {
/**
*
*/
private static final long serialVersionUID = -1714326896531848932L;
/**
* @param message
* @param cause
*/
public IllegalSshFormat(String message, Throwable cause) {
super(message, cause);
}
/**
* @param message
*/
public IllegalSshFormat(String message) {
super(message);
}
}
} |
[API] Comment valider une clé SSH2 / open SSH
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