The following entry points have been made async aware:
SSL_accept
SSL_read
SSL_write

Also added is a new mode - SSL_MODE_ASYNC. Calling the above functions with
the async mode enabled will initiate a new async job. If an async pause is
encountered whilst executing the job (such as for example if using SHA1/RSA
with the Dummy Async engine), then the above functions return with
SSL_WANT_ASYNC. Calling the functions again (with exactly the same args
as per non-blocking IO), will resume the job where it left off.
Reviewed-by: NRich Salz <rsalz@openssl.org>

There are lots of calls to EVP functions from within libssl There were
various places where we should probably check the return value but don't.
This adds these checks.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

This disables some ciphersuites which aren't supported in SSL v3:
specifically PSK ciphersuites which use SHA256 or SHA384 for the MAC.

Thanks to the Open Crypto Audit Project for identifying this issue.
Reviewed-by: NMatt Caswell <matt@openssl.org>

The new function SSL_use_certificate_chain_file was always crashing in
the internal function use_certificate_chain_file because it would pass a
NULL value for SSL_CTX *, but use_certificate_chain_file would
unconditionally try to dereference it.
Reviewed-by: NStephen Henson <steve@openssl.org>

Reviewed-by: NAndy Polyakov <appro@openssl.org>

Reviewed-by: NAndy Polyakov <appro@openssl.org>

There were a few remaining references to SSLv2 support which are no longer
relevant now that it has been removed.
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The function dtls1_link_min_mtu() was only used within d1_lib.c so make
it static.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The SSL variable |in_handshake| seems misplaced. It would be better to have
it in the STATEM structure.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Add an OSSL_ prefix onto STATEM
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The |no_cert_verify| should be in the state machine structure not in SSL
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The next_state variable is no longer needed in the new state machine.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Move some function definitions around within the state machine to make sure
they are in the correct files. Also create a statem_locl.h header for stuff
entirely local to the state machine code and move various definitions into
it.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Pull out the state machine into a separate sub directory. Also moved some
functions which were nothing to do with the state machine but were in state
machine files. Pulled all the SSL_METHOD definitions into one place...most
of those files had very little left in them any more.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

ssl_get_message is no longer used so it should be removed from
ssl_method_st
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Previously each message specific process function would create its own
PACKET structure. Rather than duplicate all of this code lots of times we
should create it in the state machine itself.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The SSL structure contained a "state" variable that kept track of the state
machine in the old code. The new state machine does not use this so it can
be removed.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

The SSL structure contained a "type" variable that was set to either
SSL_ST_ACCEPT or SSL_ST_CONNECT depending on whether we are the server or
the client. This duplicates the capability of the "server" variable and was
actually rarely used.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Clean up and remove lots of code that is now no longer needed due to the
move to the new state machine.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Implement all of the necessary changes to make DTLS on the server work
with the new state machine code.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Split the TLS server ssl3_get_* and ssl3_send_* functions into two ready
for the migration to the new state machine code.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Remove all the functions and dead code that is now no longer required as
a result of the DTLS client move into the new state machine code.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Move all DTLS client side processing into the new state machine code. A
subsequent commit will clean up the old dead code.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Create a dtls_get_message function similar to the old dtls1_get_message but
in the format required for the new state machine code. The old function will
eventually be deleted in later commits.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

This swaps the implementation of the client TLS state machine to use the
new state machine code instead.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard 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: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard 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: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard 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: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard 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: NAndy 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: NMatt 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: NTim 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: NAndy 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: NAndy 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: NRich 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: NMatt Caswell <matt@openssl.org>

Process ServerHello messages using the PACKET API
Reviewed-by: NTim Hudson <tjh@openssl.org>

Reviewed-by: NTim Hudson <tjh@openssl.org>

Reviewed-by: NTim Hudson <tjh@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: NMatt 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: NTim Hudson <tjh@openssl.org>