ssl.h should be first. Also two lines after includes and the rest of the
file.

Change-Id: Icb7586e00a3e64170082c96cf3f8bfbb2b7e1611
Reviewed-on: https://boringssl-review.googlesource.com/5892
Reviewed-by: Adam Langley <agl@google.com>

Bidirectional shutdown doesn't make sense over DTLS; you can't reuse the
underlying channel after receiving close_notify because the channel is
unordered. This removes one caller of dtls1_read_bytes.

Really close_notify makes no sense in DTLS. It can't even protect
against some kind of truncation because it's all unordered. But continue
to send it in case anything is (unreliably since the channel is lossy)
relying on close_notify to signal some kind of session end. This only
makes SSL_shutdown stop trying to wait for one once we've already
decided to shut down the connection.

BUG=526437

Change-Id: I6afad7cb7209c4aba0b96f9246b04c81d90987a9
Reviewed-on: https://boringssl-review.googlesource.com/5770
Reviewed-by: Adam Langley <agl@google.com>

The old empty record logic discarded the records at a very low-level.
Let the error bubble up to ssl3_read_bytes so the type mismatch logic
may kick in before the empty record is skipped.

Add tests for when the record in question is application data, before
before the handshake and post ChangeCipherSpec.

BUG=521840

Change-Id: I47dff389cda65d6672b9be39d7d89490331063fa
Reviewed-on: https://boringssl-review.googlesource.com/5754
Reviewed-by: Adam Langley <agl@google.com>

This begins decoupling the transport from the SSL state machine. The buffering
logic is hidden behind an opaque API. Fields like ssl->packet and
ssl->packet_length are gone.

ssl3_get_record and dtls1_get_record now call low-level tls_open_record and
dtls_open_record functions that unpack a single record independent of who owns
the buffer. Both may be called in-place. This removes ssl->rstate which was
redundant with the buffer length.

Future work will push the buffer up the stack until it is above the handshake.
Then we can expose SSL_open and SSL_seal APIs which act like *_open_record but
return a slightly larger enum due to other events being possible. Likewise the
handshake state machine will be detached from its buffer. The existing
SSL_read, SSL_write, etc., APIs will be implemented on top of SSL_open, etc.,
combined with ssl_read_buffer_* and ssl_write_buffer_*. (Which is why
ssl_read_buffer_extend still tries to abstract between TLS's and DTLS's fairly
different needs.)

The new buffering logic does not support read-ahead (removed previously) since
it lacks a memmove on ssl_read_buffer_discard for TLS, but this could be added
if desired. The old buffering logic wasn't quite right anyway; it tried to
avoid the memmove in some cases and could get stuck too far into the buffer and
not accept records. (The only time the memmove is optional is in DTLS or if
enough of the record header is available to know that the entire next record
would fit in the buffer.)

The new logic also now actually decrypts the ciphertext in-place again, rather
than almost in-place when there's an explicit nonce/IV. (That accidentally
switched in https://boringssl-review.googlesource.com/#/c/4792/; see
3d59e04bce96474099ba76786a2337e99ae14505.)

BUG=468889

Change-Id: I403c1626253c46897f47c7ae93aeab1064b767b2
Reviewed-on: https://boringssl-review.googlesource.com/5715
Reviewed-by: Adam Langley <agl@google.com>

Take the sequence number as a parameter. Also replace satsub64be with
the boring thing: convert to uint64_t and subtract normally.

BUG=468889

Change-Id: Icab75f872b5e55cf4e9d68b66934ec91afeb198b
Reviewed-on: https://boringssl-review.googlesource.com/5558
Reviewed-by: Adam Langley <agl@google.com>

The split was only needed for buffering records. Likewise, the extra
seq_num field is now unnecessary.

This also fixes a bug where dtls1_process_record will push an error on
the queue if the decrypted record is too large, which dtls1_get_record
will ignore but fail to clear, leaving garbage on the error queue. The
error is now treated as fatal; the reason DTLS silently drops invalid
packets is worrying about ease of DoS, but after SSL_AEAD_CTX_open, the
packet has been authenticated. (Unless it's the null cipher, but that's
during the handshake and the handshake is already DoS-able by breaking
handshake reassembly state.)

The function is still rather a mess. Later changes will clean this up.

BUG=468889

Change-Id: I96a54afe0755d43c34456f76e77fc4ee52ad01e3
Reviewed-on: https://boringssl-review.googlesource.com/5557
Reviewed-by: Adam Langley <agl@google.com>

Much of this was done automatically with
  find . -name '*.c' | xargs sed -E -i '' -e 's/(OPENSSL_PUT_ERROR\([a-zA-Z_0-9]+, )[a-zA-Z_0-9]+, ([a-zA-Z_0-9]+\);)/\1\2/'
  find . -name '*.c' | xargs sed -E -i '' -e 's/(OPENSSL_PUT_ERROR\([a-zA-Z_0-9]+, )[a-zA-Z_0-9]+,  ([a-zA-Z_0-9]+\);)/\1\2/'

BUG=468039

Change-Id: I4c75fd95dff85ab1d4a546b05e6aed1aeeb499d8
Reviewed-on: https://boringssl-review.googlesource.com/5276
Reviewed-by: Adam Langley <agl@google.com>

This still needs significant work, especially the close_notify half, but
clarify the interface and get *_read_bytes out of SSL_PROTOCOL_METHOD.
read_bytes is an implementation detail of those two and get_message
rather than both an implementation detail of get_message for handshake
and a (wholly inappropriate) exposed interface for the other two.

BUG=468889

Change-Id: I7dd23869e0b7c3532ceb2e9dd31ca25ea31128e7
Reviewed-on: https://boringssl-review.googlesource.com/4956
Reviewed-by: Adam Langley <agl@google.com>

The SSL_PROTOCOL_METHOD table needs work, but this makes it clearer
exactly what the shared interface between the upper later and TLS/DTLS
is.

BUG=468889

Change-Id: I38931c484aa4ab3f77964d708d38bfd349fac293
Reviewed-on: https://boringssl-review.googlesource.com/4955
Reviewed-by: Adam Langley <agl@google.com>

Now that WebRTC honors packet boundaries (https://crbug.com/447431), we
can start enforcing them correctly. Configuring read-ahead now does
nothing. Instead DTLS will always set "read-ahead" and also correctly
enforce packet boundaries when reading records. Add tests to ensure that
badly fragmented packets are ignored. Because such packets don't fail
the handshake, the tests work by injecting an alert in the front of the
handshake stream and ensuring the DTLS implementation ignores them.

ssl3_read_n can be be considerably unraveled now, but leave that for
future cleanup. For now, make it correct.

BUG=468889

Change-Id: I800cfabe06615af31c2ccece436ca52aed9fe899
Reviewed-on: https://boringssl-review.googlesource.com/4820
Reviewed-by: Adam Langley <agl@google.com>

MSVC hates unsigned unary minus.

Change-Id: I777f792f19868bfc4572c383a723b10ea091c0ca
Reviewed-on: https://boringssl-review.googlesource.com/4840
Reviewed-by: Adam Langley <agl@google.com>

This is considerably less scary than swapping out connection state. It also
fixes a minor bug where, if dtls1_do_write had an alert to dispatch and we
happened to retry during a rexmit, it would use the wrong epoch.

BUG=468889

Change-Id: I754b0d46bfd02f797f4c3f7cfde28d3e5f30c52b
Reviewed-on: https://boringssl-review.googlesource.com/4793
Reviewed-by: Adam Langley <agl@google.com>

tls1_enc is now SSL_AEAD_CTX_{open,seal}. This starts tidying up a bit
of the record-layer logic. This removes rr->input, as encrypting and
decrypting records no longer refers to various globals. It also removes
wrec altogether. SSL3_RECORD is now only used to maintain state about
the current incoming record. Outgoing records go straight to the write
buffer.

This also removes the outgoing alignment memcpy and simply calls
SSL_AEAD_CTX_seal with the parameters as appropriate. From bssl speed
tests, this seems to be faster on non-ARM and a bit of a wash on ARM.

Later it may be worth recasting these open/seal functions to write into
a CBB (tweaked so it can be malloc-averse), but for now they take an
out/out_len/max_out trio like their EVP_AEAD counterparts.

BUG=468889

Change-Id: Ie9266a818cc053f695d35ef611fd74c5d4def6c3
Reviewed-on: https://boringssl-review.googlesource.com/4792
Reviewed-by: Adam Langley <agl@google.com>

Nothing should call ssl3_setup_read_buffer or ssl3_setup_write_buffer unless it
intends to write into the buffer. This way buffer management can later be an
implementation detail of the record layer.

Change-Id: Idb0effba00e77c6169764843793f40ec37868b61
Reviewed-on: https://boringssl-review.googlesource.com/4687
Reviewed-by: Adam Langley <agl@google.com>

It's completely redundant with the extend bit. If extend is 0, we're reading a
new record, and rbuf.len is passed. Then it needs to get clamped by ssl3_read_n
post alignment anyway. If extend is 1, we're reading the rest of the current
record and max is always n. (For TLS, we actually could just read more, but not
for DTLS. Basically no one sets it on the TLS side of things, so instead, after
WebRTC's broken DTLS handling is fixed, read_ahead can go away altogether and
DTLS/TLS record layers can be separated.)

This removes ssl3_read_n's callers' dependency on ssl3_setup_read_buffer
setting up rbuf.len.

Change-Id: Iaf11535d01017507a52a33b19240f42984d6cf52
Reviewed-on: https://boringssl-review.googlesource.com/4686
Reviewed-by: Adam Langley <agl@google.com>

They date to https://rt.openssl.org/Ticket/Display.html?id=2533, but no
particularly good justification was given for them. It seems it was just a
bandaid because d1_pkt.c forgot to initialize the buffer. I went through
codesearch for all accesses to SSL3_BUFFER::buf and SSL::packet. They seem
appropriately guarded but for this one.

Change-Id: Ife4e7afdb7a7c137d6be4791542eb5de6dd5b1b6
Reviewed-on: https://boringssl-review.googlesource.com/4685
Reviewed-by: Adam Langley <agl@google.com>

BUG=404754

Change-Id: I5f11485fbafa07cddcf2612e2f616f90bf7c722d
Reviewed-on: https://boringssl-review.googlesource.com/4554
Reviewed-by: Adam Langley <agl@google.com>

The rest of ssl/ still includes things everywhere, but this at least fixes the
includes that were implicit from ssl/internal.h.

Change-Id: I7ed22590aca0fe78af84fd99a3e557f4b05f6782
Reviewed-on: https://boringssl-review.googlesource.com/4281
Reviewed-by: Adam Langley <agl@google.com>

Match the other internal headers.

Change-Id: Iff7e2dd06a1a7bf993053d0464cc15638ace3aaa
Reviewed-on: https://boringssl-review.googlesource.com/4280
Reviewed-by: Adam Langley <agl@google.com>

Change-Id: I250d3cf5b8124f205d67268958a01cb02a6d05ac
Reviewed-on: https://boringssl-review.googlesource.com/4240
Reviewed-by: Adam Langley <agl@google.com>

This conceivably has a use, but NSS doesn't do this buffer either and it still
suffers from the same problems as the other uses of record_pqueue. This removes
the last use of record_pqueue. It also opens the door to removing pqueue
altogether as it isn't the right data structure for either of the remaining
uses either. (It's not clear it was right for record_pqueue either, but I don't
feel like digging into this code.)

Change-Id: If8a43e7332b3cd11a78a516f3e8ebf828052316f
Reviewed-on: https://boringssl-review.googlesource.com/4239
Reviewed-by: Adam Langley <agl@google.com>

It was only ever enabled for handshake and alert messages. The comments cite
renego as a use case though even then I'm not clear on why. The only use I see
is if, say, the Finished message and ClientKeyExchange came in out-of-order.
DTLS is unreliable so leaning on retransmit seems fine, and usually flights
will be packed into one packet where possible. NSS doesn't have any such
buffer and doesn't seem to have problems.

The buffering mechanism is also rather dubious. It stows away the entire packet
and read buffer---all 16K of it---and there may have been other records in that
packet.

Change-Id: Ic3b7bf817be380dc73102eec62c690ed093e6667
Reviewed-on: https://boringssl-review.googlesource.com/4238
Reviewed-by: Adam Langley <agl@google.com>

Also check for overflow, although it really shouldn't happen.

Change-Id: I34dfe8eaf635aeaa8bef2656fda3cd0bad7e1268
Reviewed-on: https://boringssl-review.googlesource.com/4235
Reviewed-by: Adam Langley <agl@google.com>

It's still rather a mess, but this is at least somewhat clearer. The old one
had a lot of remnants of compression, etc.

Change-Id: Iffcb4dd4e8c4ab14f60abf917d22b7af960c93ba
Reviewed-on: https://boringssl-review.googlesource.com/4233
Reviewed-by: Adam Langley <agl@google.com>

Thanks to Sean Burford.

Change-Id: I4efa352f3e830c4c3761660508a1a8aa927eedf1
Reviewed-on: https://boringssl-review.googlesource.com/3841
Reviewed-by: Adam Langley <agl@google.com>

This mostly[*] doesn't matter for TLS since the message would have been
rejected anyway, but, in DTLS, if the peer rejects our Finished, it will send
an encrypted alert. This will then cause it to hang, which isn't very helpful.

I've made the change on both TLS and DTLS so the two protocols don't diverge on
this point. It is true that we're accepting nominally encrypted and
authenticated alerts before Finished, but, prior to ChangeCipherSpec, the
alerts are sent in the clear anyway so an attacker could already inject alerts.
A consumer could only be sensitive to it being post-CCS if it was watching
msg_callback. The only non-debug consumer of msg_callback I've found anywhere
is some hostapd code to detect Heartbeat.

See https://code.google.com/p/webrtc/issues/detail?id=4403 for an instance
where the equivalent behavior in OpenSSL masks an alert.

[*] This does change behavior slightly if the peer sends a warning alert
between CCS and Finished. I believe this is benign as warning alerts are
usually ignored apart from info_callback and msg_callback. The one exception is
a close_notify which is a slightly new state (accepting close_notify during a
handshake seems questionable...), but they're processed pre-CCS too.

Change-Id: Idd0d49b9f9aa9d35374a9f5e2f815cdb931f5254
Reviewed-on: https://boringssl-review.googlesource.com/3883
Reviewed-by: Adam Langley <agl@google.com>

It doesn't do anything.

Change-Id: I0bba4e22a0b2053aae491d0ad695c892803cafca
Reviewed-on: https://boringssl-review.googlesource.com/3767
Reviewed-by: Adam Langley <agl@google.com>

If the peer fragments Finished into multiple pieces, there is no need to
retransmit multiple times.

Change-Id: Ibf708ad079e1633afd420ff1c9be88a80020cba9
Reviewed-on: https://boringssl-review.googlesource.com/3762
Reviewed-by: Adam Langley <agl@google.com>

Align the DTLS and TLS implementations more. s3_pkt.c's version still has
remnants of fragmentable alerts and only one side marks some variables as
const. Also use warning/fatal constants rather than the numbers with comments.

Change-Id: Ie62d3af1747b6fe4336496c047dfccc9d71fde3f
Reviewed-on: https://boringssl-review.googlesource.com/3562
Reviewed-by: Adam Langley <agl@google.com>

The new V2ClientHello sniff asserts, for safety, that nothing else has
initialized the record layer before it runs. However, OpenSSL allows you to
avoid explicitly calling SSL_connect/SSL_accept and instead let
SSL_read/SSL_write implicitly handshake for you. This check happens at a fairly
low-level in the ssl3_read_bytes function, at which point the record layer has
already been initialized.

Add some tests to ensure this mode works.

(Later we'll lift the handshake check to a higher-level which is probably
simpler.)

Change-Id: Ibeb7fb78e5eb75af5411ba15799248d94f12820b
Reviewed-on: https://boringssl-review.googlesource.com/3334
Reviewed-by: Adam Langley <agl@google.com>

The check on the DTLS side was broken anyway. On the TLS side, the spec does
say to ignore them, but there should be no need for this in future-proofing and
NSS doesn't appear to be lenient here. See also
https://boringssl-review.googlesource.com/#/c/3233/

Change-Id: I0846222936c5e08acdcfd9d6f854a99df767e468
Reviewed-on: https://boringssl-review.googlesource.com/3290
Reviewed-by: Adam Langley <agl@google.com>

Nothing recognized through those codepaths is fragmentable in DTLS. Also remove
an unnecessary epoch check. It's not possible to process a record from the
wrong epoch.

Change-Id: I9d0f592860bb096563e2bdcd2c8e50a0d2b65f59
Reviewed-on: https://boringssl-review.googlesource.com/3232
Reviewed-by: Adam Langley <agl@google.com>

We have no use for DTLS renego and it's even more complex than TLS renego.

Change-Id: I8680ab361cc8761dd7fc8dfb1bfe1ff4abc6612f
Reviewed-on: https://boringssl-review.googlesource.com/3218
Reviewed-by: Adam Langley <agl@google.com>

This regressed in e95d20dcb8. EVP_AEAD will push
errors on the error queue (unlike the EVP_CIPHER codepath which checked
everything internally to ssl/ and didn't bother pushing anything). This meant
that a dropped packet would leave junk in the error queue.

Later, when SSL_read returns <= 0 (EOF or EWOULDBLOCK), the non-empty error
queue check in SSL_get_error kicks in and SSL_read looks to have failed.

BUG=https://code.google.com/p/webrtc/issues/detail?id=4214

Change-Id: I1e5e41c77a3e5b71e9eb0c72294abf0da677f840
Reviewed-on: https://boringssl-review.googlesource.com/2982
Reviewed-by: Adam Langley <agl@google.com>

The distinction between publicly and non-publicly invalid is barely acted upon
and slightly silly now that the CBC padding check has been folded into
EVP_AEAD.

Change-Id: Idce4b9b8d29d624e3c95243a147265d071612127
Reviewed-on: https://boringssl-review.googlesource.com/2980
Reviewed-by: Adam Langley <agl@google.com>

Everything is an AEAD now.

Change-Id: Ib47638e128843fc8299c3dbf9bd60c01eb5afa16
Reviewed-on: https://boringssl-review.googlesource.com/2700
Reviewed-by: Adam Langley <agl@google.com>

This CL removes the last of the EVP_CIPHER codepath in ssl/. The dead code is
intentionally not pruned for ease of review, except in DTLS-only code where
adding new logic to support both, only to remove half, would be cumbersome.

Fixes made:
- dtls1_retransmit_state is taught to retain aead_write_ctx rather than
  enc_write_ctx.
- d1_pkt.c reserves space for the variable-length nonce when echoed into the
  packet.
- dtls1_do_write sizes the MTU based on EVP_AEAD max overhead.
- tls1_change_cipher_state_cipher should not free AEAD write contexts in DTLS.
  This matches the (rather confused) ownership for the EVP_CIPHER contexts.
  I've added a TODO to resolve this craziness.

A follow-up CL will remove all the resultant dead code.

Change-Id: I644557f4db53bbfb182950823ab96d5e4c908866
Reviewed-on: https://boringssl-review.googlesource.com/2699
Reviewed-by: Adam Langley <agl@google.com>

A memory leak can occur in dtls1_buffer_record if either of the calls to
ssl3_setup_buffers or pqueue_insert fail. The former will fail if there
is a malloc failure, whilst the latter will fail if attempting to add a
duplicate record to the queue. This should never happen because
duplicate records should be detected and dropped before any attempt to
add them to the queue. Unfortunately records that arrive that are for
the next epoch are not being recorded correctly, and therefore replays
are not being detected. Additionally, these "should not happen" failures
that can occur in dtls1_buffer_record are not being treated as fatal and
therefore an attacker could exploit this by sending repeated replay
records for the next epoch, eventually causing a DoS through memory
exhaustion.

Thanks to Chris Mueller for reporting this issue and providing initial
analysis and a patch. Further analysis and the final patch was performed
by Matt Caswell from the OpenSSL development team.

CVE-2015-0206

(Imported from upstream's 7c6a3cf237).

Change-Id: I765fe61c75bc295bcc4ab356b8a5ce88c8964764
Reviewed-on: https://boringssl-review.googlesource.com/2782
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

This change has no semantic effect (I hope!). It's just a reformatting
of a few files in ssl/. This is just a start – the other files in ssl/
should follow in the coming days.

Change-Id: I5eb3f4b18d0d46349d0f94d3fe5ab2003db5364e

DTLS_method() can now negotiate versions without switching methods.

Change-Id: I0655b3221b6e7e4b3ed4acc45f1f41c594447021
Reviewed-on: https://boringssl-review.googlesource.com/2582
Reviewed-by: Adam Langley <agl@google.com>

SSL3_ENC_METHOD will remain version-specific while SSL_METHOD will become
protocol-specific. This finally removes all the version-specific portions of
SSL_METHOD but the version tag itself.

(SSL3_ENC_METHOD's version-specific bits themselves can probably be handled by
tracking a canonicalized protocol version. It would simplify version
comparisons anyway. The one catch is SSLv3 has a very different table. But
that's a cleanup for future. Then again, perhaps a version-specific method
table swap somewhere will be useful later for TLS 1.3.)

Much of this commit was generated with sed invocation:
    s/method->ssl3_enc/enc_method/g

Change-Id: I2b192507876aadd4f9310240687e562e56e6c0b1
Reviewed-on: https://boringssl-review.googlesource.com/2581
Reviewed-by: Adam Langley <agl@google.com>

PR#1767

(Imported from upstream's fe78f08d15)

Not sure this is reachable (upstream's PR references custom engines), but
better be tidy. Note this is slightly different from upstream's: EVP_Cipher is
documented to return -1 on failure, not 0.

Change-Id: I836f12b73c6912a8ae8cbd37cfd3d33466acbc9e
Reviewed-on: https://boringssl-review.googlesource.com/2478
Reviewed-by: Adam Langley <agl@google.com>

first_packet is a temporary connection-global flag set for the duration of some
call and then queried from other code. This kind of logic is too difficult to
reason through. It also incorrectly treats renegotiate ClientHellos as
pre-version-negotiation records. This eliminates the need to query
enc_write_ctx (which wasn't EVP_AEAD-aware anyway).

Instead, take a leaf from Go TLS's book and add a have_version bit. This is
placed on s->s3 as it is connection state; s->s3 automatically gets reset on
SSL_clear while s doesn't.

This new flag will also be used to determine whether to do the V2ClientHello
sniff when the version-locked methods merge into SSLv23_method. It will also
replace needing to condition s->method against a dummy DTLS_ANY_VERSION value
to determine whether DTLS version negotiation has happened yet.

Change-Id: I5c8bc6258b182ba4ab175a48a84eab6d3a001333
Reviewed-on: https://boringssl-review.googlesource.com/2442
Reviewed-by: Adam Langley <agl@google.com>

It's unused. Also per the previous commit message, it historically had a bug
anyway.

Change-Id: I5868641e7938ddebbc0ffd72d218c81cd17c7739
Reviewed-on: https://boringssl-review.googlesource.com/2437
Reviewed-by: Adam Langley <agl@google.com>

This fixes bugs that kept the tests from working:

- Resolve DTLS version and cookie before the session.

- In DTLS_ANY_VERSION, ServerHello should be read with first_packet = 1. This
  is a regression from f2fedefdca. We'll want to
  do the same for TLS, but first let's change this to a boolean has_version in a
  follow-up.

Things not yet fixed:

- DTLS code is not EVP_AEAD-aware. Those ciphers are disabled for now.

- On the client, DTLS_ANY_VERSION creates SSL_SESSIONs with the wrong
  ssl_version. The tests pass because we no longer enforce the match as of
  e37216f560. (In fact, we've gone from the server
  ignoring ssl_version and client enforcing to the client mostly ignoring
  ssl_version and the server enforcing.)

- ssl3_send_client_hello's ssl_version check checks for equality against
  s->version rather than >.

Change-Id: I5a0dde221b2009413df9b9443882b9bf3b29519c
Reviewed-on: https://boringssl-review.googlesource.com/2403
Reviewed-by: Adam Langley <agl@google.com>

It was a bug anyway.

Change-Id: I59d680ce3615a4b24e72a9b6fa16939d83cc15ac
Reviewed-on: https://boringssl-review.googlesource.com/2234
Reviewed-by: Adam Langley <agl@google.com>

Parameters like these should not change between 32-bit and 64-bit. 64 is also
the value recommended in RFC 6347, section 4.1.2.6. Document those fields while
I'm here.

Change-Id: I8481ee0765ff3d261a96a2e1a53b6ad6695b2d42
Reviewed-on: https://boringssl-review.googlesource.com/2222
Reviewed-by: Adam Langley <agl@google.com>

This was added in http://rt.openssl.org/Ticket/Display.html?id=2033 to support
a mode where a DTLS socket would statelessly perform the ClientHello /
HelloVerifyRequest portion of the handshake, to be handed off to a socket
specific to this peer address.

This is not used by WebRTC or other current consumers. If we need to support
something like this, it would be cleaner to do the listen portion (cookieless
ClientHello + HelloVerifyRequest) externally and then spin up an SSL instance
on receipt of a cookied ClientHello. This would require a slightly more complex
BIO to replay the second ClientHello but would avoid peppering the DTLS
handshake state with a special short-circuiting mode.

Change-Id: I7a413932edfb62f8b9368912a9a0621d4155f1aa
Reviewed-on: https://boringssl-review.googlesource.com/2220
Reviewed-by: Adam Langley <agl@google.com>

Without SSL_MODE_AUTO_RETRY, even blocking mode will return
SSL_ERROR_WANT_{READ|WRITE} in the event of a renegotiation.

The comments in the code speak only of "nasty problems" unless this is
done. The original commit that added SSL_MODE_AUTO_RETRY
(54f10e6adc) gives a little more detail:

    The [...] behaviour is needed by applications such as s_client and
    s_server that use select() to determine when to use SSL_read.

Without the -nbio flag, s_client will use select() to find when the
socket is readable and then call SSL_read with a blocking socket.
However, this will still block in the event of an incomplete record, so
the delay is already unbounded. This it's very unclear what the point of
this behaviour ever was.

Perhaps if the read and write paths were different sockets where the
read socket was non-blocking but the write socket was blocking. But that
seems like an implausible situation to worry too much about.

Change-Id: I9d9f2526afc2e0fd0e5440e9a047f419a2d61afa
Reviewed-on: https://boringssl-review.googlesource.com/2140
Reviewed-by: Adam Langley <agl@google.com>

This code isn't compiled in. It seems there was some half-baked logic for a
7-byte alert that includes more information about handshake messages
retransmit.

No such alert exists, and the code had a FIXME anyway. If it gets resurrected
in DTLS 1.3 or some extension, we can deal with it then.

Change-Id: I8784ea8ee44bb8da4b0fe5d5d507997526557432
Reviewed-on: https://boringssl-review.googlesource.com/2121
Reviewed-by: Adam Langley <agl@google.com>