While this is code not currently in use, it is part of the generic linked
list code and since I found the error I thought I'd better fix it since we
might bring in this function into the code one day.
In case of failure we must make sure that the data we return
doesn't point to a memory area already freed. Reported anonymously
in the bug report #2910103.
Commit 683aa0f6b5 made send_existing() send
more than just the second part of a packet when the kernel did not accept
the full packet, but the function still overlooked the SSH protocol
overhead in each packet, often 48 bytes.
If only the last few bytes of a packet remained, then the packet would
erroneously be considered completely sent, and the next call to write
more data in the session would return a -39 error.
DSA signatures consist of two 160-bit integers called r and s. In ssh-dss
signature blobs r and s are stored directly after each other in binary
representation, making up a 320-bit (40 byte) string. (See RFC4253 p14.)
The crypto wrappers in libssh2 would either pack r and s incorrectly, or
fail, when at least one integer was small enough to be stored in 19 bytes
or less.
The patch ensures that r and s are always stored as two 160 bit numbers.
When libssh2_transport_write() is called to continue sending a
partially sent packet the write direction flag must not be cleared
until the previous packet has been completely sent, or the app would
hang if the packet still isn't sent completely, since select() gets
called by the internal blocking emulation layer in libssh2 but would
then not be watching the socket for writability.
Clear the flag only once processing of previous packet data is
complete and a new packet is about to be prepared.
The forward accepting was not done right before, and the
packet_queue_listener function didn't assign a necessary
variable. All fixed by Juzna. I (Daniel) modified the
forward_accept() change somewhat.
First, win32/msvcproj.{head,foot} are now committed with CRLF line endings,
and .gitattributes specifies that these should not be changed on checkout or
commit. These are win32 files so it makes sense to store them with native
line endings.
Second, the rules for generating libssh2.dsp and libssh2.vcproj are changed
so that the full file contents passes through awk, which strips all CR and
then prints each line with one CRLF line ending. Stripping CR is important
to avoid CRCRLF in case the input already comes with CRLF.
The channel layer sends packets using the transport layer, possibly
calling _libssh2_transport_write() many times for each packet.
The transport layer uses the send_existing() helper to send out any
remaining parts of previous packets before a new packet is started.
The bug made send_existing() consider the entire packet sent as soon as it
successfully sent the second part of a packet, even if the packet was not
completely done yet.
Neil Gierman's patch adds a gettimeofday() function for win32
for the libssh2_trace() functionality. The code originates from
cygwin and was put in the public domain by the author
Danny Smith <dannysmith@users.sourceforge.net>
If the channel is already at EOF or even closed at the end of the
libssh2_channel_read_ex() function and there's no data to return,
we need to signal that back. We may have gotten that info while
draining the incoming transport layer until EAGAIN so we must not
be fooled by that return code.
