Changeset: ac56897d3452 for monetdb-java
URL: https://dev.monetdb.org/hg/monetdb-java/rev/ac56897d3452
Modified Files:
src/main/java/org/monetdb/mcl/net/MapiSocket.java
Branch: monetdbs
Log Message:
comments
diffs (90 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
@@ -387,19 +387,17 @@ public final class MapiSocket {
if (validated.getTls())
return SecureSocket.wrap(validated, sock);
else {
- // Send an even number of NUL bytes.
- // We expect the server to speak the MAPI protocol and
in MAPI,
- // NUL NUL is a no-op.
- // However, if we're accidentally connecting to a
TLS-protected
- // server, that server expects a TLS 'Client Hello'
message and
- // the NULs will hopefully force an error.
- // The error is useful because otherwise we end up in a
deadlock:
- // - the MAPI client is waiting for the server to send
a MAPI challenge,
- // - the TLS server is waiting fot the client to send a
Client Hello.
- // Unfortunately, the number of NULs needed to force an
error
- // varies between implementations. Some TLS servers
abort after
- // the first NUL, others need lots of them.
- // For now we standardize on 8.
+ // Send an even number of NUL bytes to avoid a deadlock
if
+ // we're accidentally connecting to a TLS-protected
server.
+ // The cause of the deadlock is that we speak MAPI and
we wait
+ // for the server to send a MAPI challenge.
+ // However, if the server is trying to set up TLS, it
will be
+ // waiting for us to send a TLS 'Client Hello' packet.
+ // Hence, deadlock.
+ // NUL NUL is a no-op in MAPI and will hopefully force
an error
+ // in the TLS server. This does not always work, some
+ // TLS implementations abort on the first NUL, some
need more NULs
+ // than we are prepared to send here. 8 seems to be a
good number.
sock.getOutputStream().write(NUL_BYTES);
}
return sock;
@@ -531,7 +529,6 @@ public final class MapiSocket {
// 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,
@@ -544,7 +541,9 @@ public final class MapiSocket {
// .. and here's the salt
intermediate.append(salt);
+ responseBuffer.append('{');
MessageDigest responseDigest = pickBestAlgorithm(algoSet,
responseBuffer);
+ // the call above has appended the HASHNAME, now add '}'
responseBuffer.append('}');
// pickBestAlgorithm has appended HASHNAME, buffer now contains
'{' HASHNAME '}'
hexhash(responseBuffer, responseDigest,
intermediate.toString());
@@ -557,7 +556,7 @@ public final class MapiSocket {
* 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
+ * @param appendMapiName if not null, append MAPI name of chose
algorithm to this buffer
* @return instance of the chosen digester
* @throws MCLException if none of the options is supported
*/
@@ -584,7 +583,7 @@ public final class MapiSocket {
}
/**
- * Hash the text into the digest and append the hexadecimal form of the
+ * Hash the text into the MessageDigest and append the hexadecimal form
of the
* resulting digest to buffer.
*
* @param buffer where the hex digits are appended
@@ -1516,13 +1515,14 @@ public final class MapiSocket {
/**
* Callback used during the initial MAPI handshake.
- *
+ *
* Newer MonetDB versions allow setting some options during the
handshake.
* The options are language-specific and each has a 'level'. The server
- * advertises up to which level options are supported for a given
language
- * and for each language/option combination, {@link #addOptions} will
be invoked.
- * It should call {@link #contribute} for each option it wants to set.
- *
+ * advertises up to which level options are supported for a given
language.
+ * For each language/option combination, {@link #addOptions} will be
invoked
+ * during the handshake. This method should call {@link #contribute}
for each
+ * option it wants to set.
+ *
* At the time of writing, only the 'sql' language supports options,
* they are listed in enum mapi_handshake_options_levels in mapi.h.
*/
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