Changeset: 3a477cf520f6 for monetdb-java
URL: https://dev.monetdb.org/hg/monetdb-java/rev/3a477cf520f6
Modified Files:
src/main/java/org/monetdb/mcl/net/MapiSocket.java
Branch: monetdbs
Log Message:
Debug and clarify pasword hashing code
diffs (129 lines):
diff --git a/src/main/java/org/monetdb/mcl/net/MapiSocket.java
b/src/main/java/org/monetdb/mcl/net/MapiSocket.java
--- a/src/main/java/org/monetdb/mcl/net/MapiSocket.java
+++ b/src/main/java/org/monetdb/mcl/net/MapiSocket.java
@@ -460,7 +460,7 @@ public final class MapiSocket {
String parts[] = challengeLine.split(":");
if (parts.length < 3)
throw new MCLException("Invalid challenge: expect at
least 3 fields");
- String challengePart = parts[0];
+ String saltPart = parts[0];
String serverTypePart = parts[1];
String versionPart = parts[2];
int version;
@@ -484,8 +484,6 @@ public final class MapiSocket {
} else {
userResponse = target.getUser();
}
- String passwordResponse = hashPassword(challengePart, password,
passwordHashPart, validated.getHash(), serverHashesPart);
-
String optionsResponse = handleOptions(callback, optionsPart);
// Response looks like this:
@@ -495,7 +493,8 @@ public final class MapiSocket {
StringBuilder response = new StringBuilder(80);
response.append("BIG:");
response.append(userResponse).append(":");
- response.append(passwordResponse).append(":");
+ hashPassword(response, saltPart, password, passwordHashPart,
validated.getHash(), serverHashesPart);
+ response.append(":");
response.append(validated.getLanguage()).append(":");
response.append(validated.getDatabase()).append(":");
response.append("FILETRANS:");
@@ -505,32 +504,53 @@ public final class MapiSocket {
}
// challengePart, passwordHashPart, supportedHashesPart,
target.getPassword()
- private String hashPassword(String challenge, String password, String
passwordAlgo, String configuredHashes, String serverSupportedAlgos) throws
MCLException {
- int maxHashLength = 512;
-
- StringBuilder output = new StringBuilder(10 + maxHashLength /
4);
- MessageDigest passwordDigest =
pickBestAlgorithm(Collections.singleton(passwordAlgo), output);
-
+ private String hashPassword(String salt, String password, String
passwordAlgo, String configuredHashes, String serverSupportedAlgos) throws
MCLException {
+ // First determine which hash algorithms we can choose from for
the challenge response.
+ // This defaults to whatever the server offers but may be
restricted by the user.
Set<String> algoSet = new
HashSet<>(Arrays.asList(serverSupportedAlgos.split(",")));
if (!configuredHashes.isEmpty()) {
- Set<String> keep = new
HashSet<>(Arrays.asList(configuredHashes.toUpperCase().split("[, ]")));
- algoSet.retainAll(keep);
+ String[] allowedList =
configuredHashes.toUpperCase().split("[, ]");
+ Set<String> allowedSet = new
HashSet<>(Arrays.asList(allowedList));
+ algoSet.retainAll(allowedSet);
if (algoSet.isEmpty()) {
- throw new MCLException("None of the hash
algorithms <" + configuredHashes + "> are supported, server only supports <" +
serverSupportedAlgos + ">");
+ throw new MCLException("None of the hash
algorithms in <" + configuredHashes + "> are supported, server only supports <"
+ serverSupportedAlgos + ">");
}
}
- MessageDigest challengeDigest = pickBestAlgorithm(algoSet,
null);
+
+ int maxHashDigits = 512 / 4;
+
+ // We'll collect the result in the responseBuffer.
+ // It will start with '{' HASHNAME '}' followed by hexdigits
+ responseBuffer.append('{');
+
+ // This is where we accumulate what will eventually be hashed
into the hexdigits above.
+ // It consists of the hexadecimal pre-hash of the password,
+ // followed by the salt from the server
+ StringBuilder intermediate = new StringBuilder(maxHashDigits +
salt.length());
- // First we use the password algo to hash the password.
- // Then we use the challenge algo to hash the combination of
the resulting hash digits and the challenge.
- StringBuilder intermediate = new StringBuilder(maxHashLength /
4 + challenge.length());
+ MessageDigest passwordDigest =
pickBestAlgorithm(Collections.singleton(passwordAlgo), null);
+ // Here's the password..
hexhash(intermediate, passwordDigest, password);
- intermediate.append(challenge);
- hexhash(output, challengeDigest, intermediate.toString());
- return output.toString();
+ // .. and here's the salt
+ intermediate.append(salt);
+
+ MessageDigest responseDigest = pickBestAlgorithm(algoSet,
responseBuffer);
+ responseBuffer.append('}');
+ // pickBestAlgorithm has appended HASHNAME, buffer now contains
'{' HASHNAME '}'
+ hexhash(responseBuffer, responseDigest,
intermediate.toString());
+ // response buffer now contains '{' HASHNAME '}'
HEX_DIGITS_OF_INTERMEDIATE_BUFFER
+
+ return responseBuffer.toString();
}
- private MessageDigest pickBestAlgorithm(Set<String> algos,
StringBuilder appendPrefixHere) throws MCLException {
+ /**
+ * Pick the most preferred digest algorithm and return a MessageDigest
instance for that.
+ * @param algos the MAPI names of permitted algorithms
+ * @param appendMapiName if not null, append MAPI name of chose
algorithm here
+ * @return instance of the chosen digester
+ * @throws MCLException if none of the options is supported
+ */
+ private MessageDigest pickBestAlgorithm(Set<String> algos,
StringBuilder appendMapiName) throws MCLException {
for (String[] choice: KNOWN_ALGORITHMS) {
String mapiName = choice[0];
String algoName = choice[1];
@@ -543,10 +563,8 @@ public final class MapiSocket {
continue;
}
// we found a match
- if (appendPrefixHere != null) {
- appendPrefixHere.append('{');
- appendPrefixHere.append(mapiName);
- appendPrefixHere.append('}');
+ if (appendMapiName != null) {
+ appendMapiName.append(mapiName);
}
return digest;
}
@@ -554,6 +572,13 @@ public final class MapiSocket {
throw new MCLException("No supported hash algorithm: " +
algoNames);
}
+ /**
+ * Hash the text into the digest and append the hexadecimal form of the
+ * resulting digest to buffer.
+ * @param buffer where the hex digits are appended
+ * @param digest where the hex digits come from after the text has been
digested
+ * @param text text to digest
+ */
private void hexhash(StringBuilder buffer, MessageDigest digest, String
text) {
byte[] bytes = text.getBytes(StandardCharsets.UTF_8);
digest.update(bytes);
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