SFTP packets come as [32 bit length][payload] and the code didn't
previously handle that the initial 32 bit field was read only partially
when it was read.
While setting up the session, ssh tries to determine the type of
encryption method it can use for the session. This requires looking at
the keys offered by the remote host and comparing these with the methods
supported by libssh2 (rsa & dss). To do this there is an iteration over
the array containing the methods supported by libssh2.
If there is no agreement on the type of encryption we come to the 3rd
entry of the hostkeyp array. Here hostkeyp is valid but *hostkep is
NULL. Thus when we dereference that in (*hostkeyp)->name there is a
crash
There were some chances that they would cause -1 to get returned by
public functions and as we're hunting down all such occurances and since
the underlying functions do return valuable information the code now
passes back proper return codes better.
The man page clearly says it returns 1 for "already authenticated" but
the code said non-zero. I changed the code to use 1 now, as that is also
non-zero but it gets the benefit that it now matches the documentation.
Using 1 instead of non-zero is better for two reasons:
1. We have the opportunity to introduce other return codes in the future for
things like error and what not.
2. We don't expose the internal bitmask variable value.
First I wanted to free the memory in session_free() but then
I had still memory leaks because in my test case the function
userauth_keyboard_interactive() is called twice. It is called
twice perhaps because the server has this authentication
methods available: publickey,gssapi-with-mic,keyboard-interactive
The keyboard-interactive method is successful.
I found an undocumented public function and we can't have it like
that. The description here is incomplete, but should serve as a template
to allow filling in...
The sftp_write function shouldn't assume that the buffer pointer will be
the same in subsequent calls, even if it assumes that the data already
passed in before haven't changed.
The sftp structs are now moved to sftp.h (which I forgot to add before)
sftp_write was rewritten to split up outgoing data into multiple packets
and deal with the acks in a more asynchronous manner. This is meant to
help overcome latency and round-trip problems with the SFTP protocol.
Neither _libssh2_channel_write nor sftp_write now have the 32500 size
limit anymore and instead the channel writing function now has its own
logic to send data in multiple calls until everything is sent.
The new function takes two data areas, combines them and sends them as a
single SSH packet. This allows several functions to allocate and copy
less data.
I also found and fixed a mixed up use of the compression function
arguments that I introduced in my rewrite in a recent commit.
We now allow libssh2_session_flag() to enable compression with a new
flag and I added documentation for the previous LIBSSH2_FLAG_SIGPIPE
flag which I wasn't really aware of!
As a zero return code from channel_read() is not an error we must make
sure that the SCP functions deal with that properly. channel_read()
always returns 0 if the channel is EOFed already so we check for EOF
after 0-reads to be able to return error properly.
In the transport functions we avoid a strcmp() now and just check a
boolean instead.
The compress/decompress function's return code is now acknowledged and
used as actual return code in case of failures.
The function libssh2_session_startup() is now considered deprecated due
to the portability issue with the socket argument.
libssh2_session_handshake() is the name of the replacement.
