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2014-05-17Change the client connection timeout to 30 sec.Yawning Angel
This is more common than 15 seconds (It's what Firefox uses for the request timeout).
2014-05-17Update the spec with feedback from arma (No functional changes).Yawning Angel
2014-05-16Update README (No functional changes).Yawning Angel
2014-05-16Add a protocol specification.Yawning Angel
This fixes #4.
2014-05-16Treat the PrngSeed frame as part of the handshake.Yawning Angel
Clients will now always add 87 bytes of padding to the clientRequest, and Servers will always send the PRNG seed frame unpadded, and bundled with the serverResponse. Why 87 bytes? The amount of data that the server sends is 87. This fixes #5.
2014-05-16Validate that the padding length is greater than the minimum.Yawning Angel
2014-05-16Change the length field obfscation.Yawning Angel
Instead of including the previous secretbox in the input when calculating the SipHash-2-4 digest used to generate the obfuscation mask, use only the nonce. This is significantly faster, and if someone breaks obfs4 by exploiting the low amount of input entropy between each invocation (a counter incrementing by 1), I hope they publish the attack on the PRF. This breaks wire protocol compatibility.
2014-05-16Change the handshake wire format.Yawning Angel
* HMAC-SHA256 -> HMAC-SHA256-128. * Mark/MAC are now both caluclated using Public Key | NodeID. This breaks wire protocol compatibility.
2014-05-15Send the DRBG seed as a packetTypePrngSeed post server handshake.Yawning Angel
This fixes #3, and brings the code to be on par with the delopyed versions of ScrambleSuit in terms of features.
2014-05-15Load the drbg-seed from the ServerTransportOptions args.Yawning Angel
This also adds the drgb-seed option to the `-gen` obfs4proxy output.
2014-05-15Change hashDrbg to take a drbgSeed for initialization.Yawning Angel
This paves the way for having servers use the same seed for all incoming connections, across multiple startup/shutdown cycles. As opposed to the current situation where each Obfs4Listener will randomly generate it's seed at creation time. Additionally, use 256 bit seeds (128 bit SipHash-2-4 key + 16 bytes of initial material).
2014-05-15Make the output from "-gen" be more useful.Yawning Angel
2014-05-15Use os.MkdirAll() for creating the pt state directory.Yawning Angel
2014-05-15Fix up how Read() errors were processed where appropriate.Yawning Angel
2014-05-14Changed the taglne to "The obfourscator", per dcf's suggestion.Yawning Angel
2014-05-14Remove a newline to make godoc work (No functional changes).Yawning Angel
2014-05-14Change the framing Encoder/Decoder to take the destination slice.Yawning Angel
In theory this is easier on the garbage collector. Probably could reuse more of the intermediary buffers by stashing them in the connection state, but that makes the code kind of messy. This should be an improvement.
2014-05-14Fix comment (No functional changes).Yawning Angel
2014-05-14Update README (No functional changes).Yawning Angel
2014-05-14Kill Obfs4Conn.isOk with fire, and replace it with a state var.Yawning Angel
2014-05-14First pass at cleaning up the write code.Yawning Angel
2014-05-14Implement the io.WriterTo interface.Yawning Angel
2014-05-14First pass at cleaning up the read code.Yawning Angel
2014-05-14Minor stylistic fixes, no functional changes.Yawning Angel
2014-05-13Add vim modelines to some files (No functional changes).Yawning Angel
2014-05-13Fix up import.Yawning Angel
2014-05-13Fix copyLoop to break out the other goroutine on graceful exit.Yawning Angel
This should fix sockets getting stuck in CLOSE_WAIT.
2014-05-13Fix e-mail address in the copyright notice.Yawning Angel
2014-05-13Add preliminary support for packet length obfuscation.Yawning Angel
The same algorithm as ScrambleSuit is used, except: * SipHash-2-4 in OFB mode is used to create the distribution. * The system CSPRNG is used when sampling the distribution. This fixes most of #3, all that remains is generating and sending a persistent distribution on the server side to the client.
2014-05-12Fix logging again.Yawning Angel
On second thought instead of using log.Panicf(), panic() and do the logging with recover(). This somewhat centralizes logging in obfs4proxy, which will be easier to change when I invariably decide to do logging differently in the future.
2014-05-12Log and propagate errors between the 2 goroutines in copyLoop.Yawning Angel
This fixes #1.
2014-05-12Fix a comment (No functional changes).Yawning Angel
2014-05-12Preliminary support padding, log on panic.Yawning Angel
This adds preliminary support for data padding by adding another layer of encapsulation inside each AEAD frame containing a type and length. For now, data is still sent unpadded, but the infrastructure for supporting it is mostly there. Additionally, use log.Panic[f]() instead of panic through out the code so that some panics are logged.
2014-05-12Remove support for Write deadlines since it wasn't working.Yawning Angel
Write timeouts are obnoxious to handle as the frame encoder state already is updated to cover the entire payload for the Write() call that timed out. In theory it is possible to buffer the pending data, but that causes Write() to voilate the semantics of the interface.
2014-05-12Set a timeout on outgoing handshakes as well.Yawning Angel
2014-05-12Reject clients that do not authenticate quickly enough.Yawning Angel
The current timeout value before the server fails the handshake is 15 s. This may need to be increased for clients over slow links.
2014-05-12Close connections that fail to authenticate after a while.Yawning Angel
Like ScrambleSuit, a random interval between 1x and 5x of additional data from the peer is read and immediately discarded before closing. Additionally, obfs4 will close off invalid connections anywhere between 0 and 60 seconds after it determines that the incoming connection will never complete the handshake successfully.
2014-05-12Clean up the logging a bit.Yawning Angel
2014-05-12Run go fmt on obfs4proxy.go (No functional changes).Yawning Angel
2014-05-12Move to a unified client/server binary, and fix bugs.Yawning Angel
* The old and the busted: obfs4-[client,server]. * The new hotness: obfs4client. * Add obfs4.ServerHandshake() that servers need to call after a successful return from Accept(). This allows implementations to move the handshake into a goroutine or whatever.
2014-05-11Change documentation/comments to reflect reality (No functional changes).Yawning Angel
2014-05-09Remove a comment that I forgot to delete, no functional changes.Yawning Angel
2014-05-09Initial import.Yawning Angel