Added support for downgrading the SASL authentication mechanism when the
decoding of CRAM-MD5, DIGEST-MD5 and NTLM messages fails. This enhances
the previously added support for graceful cancellation by allowing the
client to retry a lesser SASL mechanism such as LOGIN or PLAIN, or even
APOP / clear text (in the case of POP3 and IMAP) when supported by the
server.
In preparation for the upcoming SASL downgrade feature renamed the
imap__perform_authenticate(), pop3__perform_authenticate() and
smtp__perform_authenticate() functions.
Otherwise a NOOP operation would be performed which a) only returns a
single line response and not a multiline response where -I needs to be
used, and b) provides an inconsistent user experience compared to that
of the POP3 and IMAP protocols.
Incorrectly processed multiline server greeting responses as "wanted"
continue responses in smtp_endofresp(), from commit f16c0de4e9,
which in turn broke the SMTP server detection in the test suite,
because the EHLO command would not be sent.
Added a loop to smtp_statemach_act() in which Curl_pp_readresp() is
called until the cache is drained. Without this multiple responses
received in a single packet could result in a hang or delay.
Similar to the processing of untagged CAPABILITY responses in IMAP moved
the processing of multiline EHLO responses to smtp_state_ehlo_resp() and
introduced an internal response code of one to differentiate a multiline
continuation from the end of command. This also allows for the separate
processing of multiline responses from commands such as VRFY and EXPN.
Should a client application fail to decode an authentication message
received from a server, or not support any of the parameters given by
the server in the message, then the authentication phrase should be
cancelled gracefully by the client rather than simply terminating the
connection.
The authentication phrase should be cancelled by simply sending a '*'
to the server, in response to erroneous data being received, as per
RFC-3501, RFC-4954 and RFC-5034.
This patch adds the necessary state machine constants and appropriate
response handlers in order to add this functionality for the CRAM-MD5,
DIGEST-MD5 and NTLM authentication mechanisms.
This workaround had been previously been implemented for IMAP and POP3
but not SMTP. Some of the recent test case additions implemented this
behaviour to emulate a bad server and the SMTP code didn't cope with it.
Moved the standard SASL mechanism strings into curl_sasl.h rather than
hard coding the same values over and over again in the protocols that
use SASL authentication.
For more information about the mechanism strings see:
http://www.iana.org/assignments/sasl-mechanisms
XOAUTH2 would be selected in preference to LOGIN and PLAIN if the IMAP
or SMTP server advertised support for it even though a user's password
was supplied but bearer token wasn't.
Modified the selection logic so that XOAUTH2 will only be selected if
the server supports it and A) The curl user/libcurl programmer has
specifically asked for XOAUTH via the ;AUTH=XOAUTH login option or 2)
The bearer token is specified. Obviously if XOAUTH is asked for via
the login option but no token is specified the user will receive a
authentication failure which makes more sense than no known
authentication mechanisms supported!
Added the ability to use an XOAUTH2 bearer token [RFC6750] with SMTP for
authentication using RFC6749 "OAuth 2.0 Authorization Framework".
The bearer token is expected to be valid for the user specified in
conn->user. If CURLOPT_XOAUTH2_BEARER is defined and the connection has
an advertised auth mechanism of "XOAUTH2", the user and access token are
formatted as a base64 encoded string and sent to the server as
"AUTH XOAUTH2 <bearer token>".
All protocol handler structs are now opaque (void *) in the
SessionHandle struct and moved in the request-specific sub-struct
'SingleRequest'. The intension is to keep the protocol specific
knowledge in their own dedicated source files [protocol].c etc.
There's some "leakage" where this policy is violated, to be addressed at
a later point in time.
1 - always allocate the struct in protocol->setup_connection. Some
protocol handlers had to get this function added.
2 - always free at the end of a request. This is also an attempt to keep
less memory in the handle after it is completed.
If the mail sent during the transfer contains a terminating <CRLF> then
we should not send the first <CRLF> of the EOB as specified in RFC-5321.
Additionally don't send the <CRLF> if there is "no mail data" as the
DATA command already includes it.
The curl command line utility would display the the completed progress
bar with a percentage of zero as the progress routines didn't know the
size of the transfer.
Removed the hard returns from imap and pop3 by using the same style for
sending the authentication string as smtp. Moved the "Other mechanisms
not supported" check in smtp to match that of imap and pop3 to provide
consistency between the three email protocols.
Updated the default behaviour of sending the client's initial response in the AUTH
command to not send it and added support for CURLOPT_SASL_IR to allow the user to
specify including the response.
Related Bug: http://curl.haxx.se/mail/lib-2012-03/0114.html
Reported-by: Gokhan Sengun
Moved the blocking state machine to the disconnect functions so that the
logout / quit functions are only responsible for sending the actual
command needed to logout or quit.
Additionally removed the hard return on failure.
Some state changes would be performed after a failure test that
performed a hard return, whilst others would be performed within a test
for success. Updated the code, for consistency, so all instances are
performed within a success test.
Removed this pointer to a downloaded bytes counter because it was set in
smtp_init() to point to the same variable the transfer functions keep
the count in (k->bytecount), effectively making the code in transfer.c
"*k->bytecountp = k->bytecount" a no-op.
Removed user and passwd from the SMTP struct as these cannot be set on
a per-request basis and are leftover from legacy FTP code.
Changed some comments still using FTP terminology.
... since they're not used by the easy interface really, I wanted to
remove the association. Also, I unified the pingpong statemachine driver
into a single function with a 'wait' argument: Curl_pp_statemach.
Reworked the pp->endofresp() function so that the conndata, line and
line length are passed down to it just as with Curl_client_write()
rather than each implementation of the function having to query
these values.
Additionally changed the int return type to bool as this is more
representative of the function's usage.
Corrected the order of the upgrade_tls() functions and moved the handler
upgrade and getsock() functions out from the middle of the state related
functions.
Added honoring of the tls_supported flag when starting a TLS upgrade
rather than unconditionally attempting it. If the use_ssl flag is set
to CURLUSESSL_TRY and the server doesn't support TLS upgrades then the
connection will continue to authenticate. If this flag is set to
CURLUSESSL_ALL then the connection will complete with a failure as it
did previously.
Follow up fix to commit 62bd217464 to cater for servers that don't
respond with a 250 in their EHLO responses. Additionally updated the
SMTP tests to respond with a 250 response code as per RFC5321.
Fixed a small issue where smtp_endofresp() would look for capabilities
in the description part of a failure response. In theory a server
shouldn't respond with SIZE or AUTH in an EHLO command's failure
response but if it did then capabilities would be unnecessarily set
before eventually failing.
Changed the SMTP_AUTH_PASSWD state constant to SMTP_AUTH_LOGIN_PASSWD to
better describe the state as the second part of an AUTH LOGIN command,
as well as for consistency with the imap and pop3 modules.
