Let `ssh_stream_free()` take a NULL stream, as free functions should,
and remove the check from the connection setup.
The connection setup would not need the check anyhow, as we always have
a stream by the time we reach this code.
The public key field is optional and as such can take NULL. Account for
that and do not call strlen() on NULL values. Also assert() for non-NULL
values of username & private key.
This can be used by tools to show mesages about failing to communicate
with the server. The error message in this case will often contain the
server's error message, as far as it managed to send anything.
When we fail to read from stdout, it's typically because the URL was
wrong and the server process has sent some output over its stderr
output.
Read that output and set the error message to whatever we read from it.
Having an ssh stream would require extra work for stream capabilities we
don't need anywhere else (oob auth and command execution) so for now
let's move away from the gitno connection to use socket_stream.
We can introduce an ssh stream interface if and as we need it.
Instead of spreading the data in function arguments, some of which
aren't used for ssh and having a struct only for ssh, use a struct for
both, using a common parent to pass to the callback.
We should let the user decide whether to cancel the connection or not
regardless of whether our checks have decided that the certificate is
fine. We provide our own assessment to the callback to let the user fall
back to our checks if they so desire.
If the certificate validation fails (or always in the case of ssh),
let the user decide whether to allow the connection.
The data structure passed to the user is the native certificate
information from the underlying implementation, namely OpenSSL or
WinHTTP.
When the call to the agent fails, we must retrieve the error message
just after the function call, as other calls may overwrite it.
As the agent authentication is the only one which has a teardown and
there does not seem to be a way to get the error message from a stored
error number, this tries to introduce some small changes to store the
error from the agent.
Clearing the error at the beginning of the loop lets us know whether the
agent has already set the libgit2 error message and we should skip it,
or if we should set it.
git allows you to set which paths to use for the git server programs
when connecting over ssh; and we want to provide something similar.
We do this by providing a factory function which can be set as the
remote's transport callback which will set the given paths upon
creation.
When the stream writing function was written, it assume that
libssh2_channel_write() would always write all of the data to the
wire. This is only true for the first 32k of data, which it tries to
fit into one ssh packet.
Since it can perform short writes, call it in a loop like we do for
send(), advancing the buffer offset.
In order to know which authentication methods are supported/allowed by
the ssh server, we need to send a NONE auth request, which needs a
username associated with it.
Most ssh server implementations do not allow switching the username
between authentication attempts, which means we cannot use a dummy
username and then switch. There are two ways around this.
The first is to use a different connection, which an earlier commit
implements, but this increases how long it takes to get set up, and
without knowing the right username, we cannot guarantee that the
list we get in response is the right one.
The second is what's implemented here: if there is no username specified
in the url, ask for it first. We can then ask for the list of auth
methods and use the user's credentials in the same connection.
Before calling the credentials callback, ask the sever which
authentication methods it supports and report that to the user, instead
of simply reporting everything that the transport supports.
In case of an error, we do fall back to listing all of them.
Allow the credentials callback to return GIT_PASSTHROUGH to make the
transports code behave as though none was set.
This should make it easier for bindings to behave closer to the C code
when there is no credentials callback set at their level.
The ssh-specific credentials allow the username to be missing. The idea
being that the ssh transport will then use the username provided in the
url, if it's available. There are two main issues with this.
The credential callback already knows what username was provided by the
url and needs to figure out whether it wants to ask the user for it or
it can reuse it, so passing NULL as the username means the credential
callback is suspicious.
The username provided in the url is not in fact used by the
transport. The only time it even considers it is for the user/pass
credential, which asserts the existence of a username in its
constructor. For the ssh-specific ones, it passes in the username stored
in the credential, which is NULL. The libssh2 macro we use runs strlen()
against this value (which is no different from what we would be doing
ourselves), so we then crash.
As the documentation doesn't suggest to leave out the username, assert
the need for a username in the code, which removes this buggy behavior
and removes implicit state.
git_cred_has_username() becomes a blacklist of credential types that do
not have a username. The only one at the moment is the 'default' one,
which is meant to call up some Microsoft magic.
- added MSVC cmake definitions to disable warnings
- general.c is rewritten so it is ansi-c compatible and compiles ok on microsoft windows
- some MSVC reported warning fixes
The names from libssh2 are somewhat obtuse for us. We can simplify the
usual key/passphrase credential's name, as well as make clearer what the
custom signature function is.
Key-based authentication also needs an username, so include it in each
one.
Also stop assuming a default username of "git" in the ssh transport
which has no business making such a decision.
The SSH error checking and reporting could still be further
improved by using the libssh2 native methods to get error info,
but at least this ensures that all error codes are checked and
translated into libgit2 error messages.
