This swaps the implementation of the client TLS state machine to use the
new state machine code instead.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
The new state machine code will split up the reading and writing of
hanshake messages into discrete phases. In order to facilitate that the
existing "get" type functions will be split into two halves: one to get
the message and one to process it. The "send" type functions will also have
all work relating to constructing the message split out into a separate
function just for that. For some functions there will also be separate
pre and post "work" phases to prepare or update state.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
This is the first drop of the new state machine code.
The rewrite has the following objectives:
- Remove duplication of state code between client and server
- Remove duplication of state code between TLS and DTLS
- Simplify transitions and bring the logic together in a single location
so that it is easier to validate
- Remove duplication of code between each of the message handling functions
- Receive a message first and then work out whether that is a valid
transition - not the other way around (the other way causes lots of issues
where we are expecting one type of message next but actually get something
else)
- Separate message flow state from handshake state (in order to better
understand each)
- message flow state = when to flush buffers; handling restarts in the
event of NBIO events; handling the common flow of steps for reading a
message and the common flow of steps for writing a message etc
- handshake state = what handshake message are we working on now
- Control complexity: only the state machine can change state: keep all
the state changes local to a file
This builds on previous state machine related work:
- Surface CCS processing in the state machine
- Version negotiation rewrite
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
The function ssl3_get_message gets a whole message from the underlying bio
and returns it to the state machine code. The new state machine code will
split this into two discrete steps: get the message header and get the
message body. This commit splits the existing function into these two
sub steps to facilitate the state machine implementation.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Note that this commit constifies a user callback parameter and therefore
will break compilation for applications using this callback. But unless
they are abusing write access to the buffer, the fix is trivial.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Move all packet parsing to the beginning of the method. This limits the
SSLv2 compatibility soup to the parsing, and makes the rest of the
processing uniform.
This is also needed for simpler EMS support: EMS servers need to do an
early scan for EMS to make resumption decisions. This'll be easier when
the entire ClientHello is parsed in the beginning.
As a side effect,
1) PACKETize ssl_get_prev_session and tls1_process_ticket; and
2) Delete dead code for SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG.
Reviewed-by: Matt Caswell <matt@openssl.org>
This patch updates the "DEFAULT" cipherstring to be
"ALL:!COMPLEMENTOFDEFAULT:!eNULL". COMPLEMENTOFDEFAULT is now defined
internally by a flag on each ciphersuite indicating whether it should be
excluded from DEFAULT or not. This gives us control at an individual
ciphersuite level as to exactly what is in DEFAULT and what is not.
Finally all DES, RC4 and RC2 ciphersuites are added to COMPLEMENTOFDEFAULT
and hence removed from DEFAULT.
Reviewed-by: Tim Hudson <tjh@openssl.org>
The old implementation of DTLSv1_listen which has now been replaced still
had a few vestiges scattered throughout the code. This commit removes them.
Reviewed-by: Andy Polyakov <appro@openssl.org>
The existing implementation of DTLSv1_listen() is fundamentally flawed. This
function is used in DTLS solutions to listen for new incoming connections
from DTLS clients. A client will send an initial ClientHello. The server
will respond with a HelloVerifyRequest containing a unique cookie. The
client the responds with a second ClientHello - which this time contains the
cookie.
Once the cookie has been verified then DTLSv1_listen() returns to user code,
which is typically expected to continue the handshake with a call to (for
example) SSL_accept().
Whilst listening for incoming ClientHellos, the underlying BIO is usually in
an unconnected state. Therefore ClientHellos can come in from *any* peer.
The arrival of the first ClientHello without the cookie, and the second one
with it, could be interspersed with other intervening messages from
different clients.
The whole purpose of this mechanism is as a defence against DoS attacks. The
idea is to avoid allocating state on the server until the client has
verified that it is capable of receiving messages at the address it claims
to come from. However the existing DTLSv1_listen() implementation completely
fails to do this. It attempts to super-impose itself on the standard state
machine and reuses all of this code. However the standard state machine
expects to operate in a stateful manner with a single client, and this can
cause various problems.
A second more minor issue is that the return codes from this function are
quite confused, with no distinction made between fatal and non-fatal errors.
Most user code treats all errors as non-fatal, and simply retries the call
to DTLSv1_listen().
This commit completely rewrites the implementation of DTLSv1_listen() and
provides a stand alone implementation that does not rely on the existing
state machine. It also provides more consistent return codes.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Since SSLv3, a CipherSuite is always 2 bytes. The only place where we
need 3-byte ciphers is SSLv2-compatible ClientHello processing.
So, remove the ssl_put_cipher_by_char indirection.
Reviewed-by: Rich Salz <rsalz@openssl.org>
For server use a PSK identity hint value in the CERT structure which
is inherited when SSL_new is called and which allows applications to
set hints on a per-SSL basis. The previous version of
SSL_use_psk_identity_hint tried (wrongly) to use the SSL_SESSION structure.
PR#4039
Reviewed-by: Matt Caswell <matt@openssl.org>
This was obsolete in 2001. This is not the same as Gost94 digest.
Thanks to Dmitry Belyavsky <beldmit@gmail.com> for review and advice.
Reviewed-by: Matt Caswell <matt@openssl.org>
Continuing on from the previous commit this moves the processing of DTLS
CCS messages out of the record layer and into the state machine.
Reviewed-by: Tim Hudson <tjh@openssl.org>
The handling of incoming CCS records is a little strange. Since CCS is not
a handshake message it is handled differently to normal handshake messages.
Unfortunately whilst technically it is not a handhshake message the reality
is that it must be processed in accordance with the state of the handshake.
Currently CCS records are processed entirely within the record layer. In
order to ensure that it is handled in accordance with the handshake state
a flag is used to indicate that it is an acceptable time to receive a CCS.
Previously this flag did not exist (see CVE-2014-0224), but the flag should
only really be considered a workaround for the problem that CCS is not
visible to the state machine.
Outgoing CCS messages are already handled within the state machine.
This patch makes CCS visible to the TLS state machine. A separate commit
will handle DTLS.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Provide more robust (inline) functions to replace n2s, n2l, etc. These
functions do the same thing as the previous macros, but also keep track
of the amount of data remaining and return an error if we try to read more
data than we've got.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Add support for RSAPSK, DHEPSK and ECDHEPSK server side.
Update various checks to ensure certificate and server key exchange messages
are only sent when required.
Update message handling. PSK server key exchange parsing now include an
identity hint prefix for all PSK server key exchange messages. PSK
client key exchange message expects PSK identity and requests key for
all PSK key exchange ciphersuites.
Update flags for RSA, DH and ECDH so they are also used in PSK.
Reviewed-by: Matt Caswell <matt@openssl.org>
This flag was not set anywhere within the codebase (only read). It could
only be set by an app reaching directly into s->s3->flags and setting it
directly. However that method became impossible when libssl was opaquified.
Even in 1.0.2/1.0.1 if an app set the flag directly it is only relevant to
ssl3_connect(), which calls SSL_clear() during initialisation that clears
any flag settings. Therefore it could take effect if the app set the flag
after the handshake has started but before it completed. It seems quite
unlikely that any apps really do this (especially as it is completely
undocumented).
The purpose of the flag is suppress flushing of the write bio on the client
side at the end of the handshake after the client has written the Finished
message whilst resuming a session. This enables the client to send
application data as part of the same flight as the Finished message.
This flag also controls the setting of a second flag SSL3_FLAGS_POP_BUFFER.
There is an interesting comment in the code about this second flag in the
implementation of ssl3_write:
/* This is an experimental flag that sends the
* last handshake message in the same packet as the first
* use data - used to see if it helps the TCP protocol during
* session-id reuse */
It seems the experiment did not work because as far as I can tell nothing
is using this code. The above comment has been in the code since SSLeay.
This commit removes support for SSL3_FLAGS_DELAY_CLIENT_FINISHED, as well
as the associated SSL3_FLAGS_POP_BUFFER.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Rewrite ssl3_digest_cached_records handling. Only digest cached records
if digest array is NULL: this means it is safe to call
ssl3_digest_cached_records multiple times (subsequent calls are no op).
Remove flag TLS1_FLAGS_KEEP_HANDSHAKE instead only update handshake buffer
if digest array is NULL.
Add additional "keep" parameter to ssl3_digest_cached_records to indicate
if the handshake buffer should be retained after digesting cached records
(needed for TLS 1.2 client authentication).
Reviewed-by: Matt Caswell <matt@openssl.org>
As numerous comments indicate the certificate and key array is not an
appopriate structure to store the peers certificate: so remove it and
just the s->session->peer instead.
Reviewed-by: Richard Levitte <levitte@openssl.org>
If a NewSessionTicket is received by a multi-threaded client when
attempting to reuse a previous ticket then a race condition can occur
potentially leading to a double free of the ticket data.
CVE-2015-1791
This also fixes RT#3808 where a session ID is changed for a session already
in the client session cache. Since the session ID is the key to the cache
this breaks the cache access.
Parts of this patch were inspired by this Akamai change:
c0bf69a791
Reviewed-by: Rich Salz <rsalz@openssl.org>
Given the pervasive nature of TLS extensions it is inadvisable to run
OpenSSL without support for them. It also means that maintaining
the OPENSSL_NO_TLSEXT option within the code is very invasive (and probably
not well tested). Therefore it is being removed.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Move per-connection state out of the CERT structure: which should just be
for shared configuration data (e.g. certificates to use).
In particular move temporary premaster secret, raw ciphers, peer signature
algorithms and shared signature algorithms.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Following the version negotiation rewrite all of the previous code that was
dedicated to version negotiation can now be deleted - all six source files
of it!!
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
This commit changes the way that we do server side protocol version
negotiation. Previously we had a whole set of code that had an "up front"
state machine dedicated to the negotiating the protocol version. This adds
significant complexity to the state machine. Historically the justification
for doing this was the support of SSLv2 which works quite differently to
SSLv3+. However, we have now removed support for SSLv2 so there is little
reason to maintain this complexity.
The one slight difficulty is that, although we no longer support SSLv2, we
do still support an SSLv3+ ClientHello in an SSLv2 backward compatible
ClientHello format. This is generally only used by legacy clients. This
commit adds support within the SSLv3 code for these legacy format
ClientHellos.
Server side version negotiation now works in much the same was as DTLS,
i.e. we introduce the concept of TLS_ANY_VERSION. If s->version is set to
that then when a ClientHello is received it will work out the most
appropriate version to respond with. Also, SSLv23_method and
SSLv23_server_method have been replaced with TLS_method and
TLS_server_method respectively. The old SSLv23* names still exist as
macros pointing at the new name, although they are deprecated.
Subsequent commits will look at client side version negotiation, as well of
removal of the old s23* code.
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
Remove RFC2712 Kerberos support from libssl. This code and the associated
standard is no longer considered fit-for-purpose.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Since COMP_METHOD is now defined in comp_lcl.h, it is no
longer possible to create new TLS compression methods without
using the OpenSSL source. Only ZLIB is supported by default.
Also, since the types are opaque, #ifdef guards to use "char *"
instead of the real type aren't necessary.
The changes are actually minor. Adding missing copyright to some
files makes the diff misleadingly big.
Reviewed-by: Matt Caswell <matt@openssl.org>
The return value is checked for 0. This is currently safe but we should
really check for <= 0 since -1 is frequently used for error conditions.
Thanks to Kevin Wojtysiak (Int3 Solutions) and Paramjot Oberoi (Int3
Solutions) for reporting this issue.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Also push some usage of last_write_sequence out of dtls1_retransmit_message
and into the record layer.
Reviewed-by: Richard Levitte <levitte@openssl.org>
