A handshake message can go up to 2^24 bytes = 16MB which is a little large for
the peer to force us to buffer. Accordingly, we bound the size of a
handshake message.
Rather than have a global limit, the existing logic uses a different limit at
each state in the handshake state machine and, for certificates, allows
configuring the maximum certificate size. This is nice in that we engage larger
limits iff the relevant state is reachable from the handshake. Servers without
client auth get a tighter limit "for free".
However, this doesn't work for DTLS due to out-of-order messages and we use a
simpler scheme for DTLS. This scheme also is tricky on optional messages and
makes the handshake <-> message layer communication complex.
Apart from an ignored 20,000 byte limit on ServerHello, the largest
non-certificate limit is the common 16k limit on ClientHello. So this
complexity wasn't buying us anything. Unify everything on the DTLS scheme
except, so as not to regress bounds on client-auth-less servers, also correctly
check for whether client auth is configured. The value of 16k was chosen based
on this value.
(The 20,000 byte ServerHello limit makes no sense. We can easily bound the
ServerHello because servers may not send extensions we don't implement. But it
gets overshadowed by the certificate anyway.)
Change-Id: I00309b16d809a3c2a1543f99fd29c4163e3add81
Reviewed-on: https://boringssl-review.googlesource.com/7941
Reviewed-by: David Benjamin <davidben@google.com>
Having bbio be tri-state (not allocated, allocated but not active, and
allocated and active) is confusing.
The extra state is only used in the client handshake, where ClientHello is
special-cased to not go through the buffer while everything else is. This dates
to OpenSSL's initial commit and doesn't seem to do much. I do not believe it
can affect renego as the buffer only affects writes; although OpenSSL accepted
interleave on read (though this logic predates it slightly), it never sent
application data while it believed a handshake was active. The handshake would
always be driven to completion first.
My guess is this was to save a copy since the ClientHello is a one-message
flight so it wouldn't need to be buffered? This is probably not worth the extra
variation in the state. (Especially with the DTLS state machine going through
ClientHello twice and pushing the BIO in between the two. Though I suspect that
was a mistake in itself. If the optimization guess is correct, there was no
need to do that.)
Change-Id: I6726f866e16ee7213cab0c3e6abb133981444d47
Reviewed-on: https://boringssl-review.googlesource.com/7873
Reviewed-by: Adam Langley <agl@google.com>
That we're ignoring the return value is clearly wrong when
dtls1_retransmit_message has other code that doesn't ignore it, by way of
dtls1_do_handshake_write.
Change-Id: Ie3f8c0defdf1f5e709d67af4ca6fa4f0d83c76c9
Reviewed-on: https://boringssl-review.googlesource.com/7872
Reviewed-by: Adam Langley <agl@google.com>
The DTLS bbio logic is rather problematic, but this shouldn't make things
worse. In the in-handshake case, the new code merges the per-message
(unchecked) BIO_flush calls into one call at the end but otherwise the BIO is
treated as is. Otherwise any behavior around non-block writes should be
preserved.
In the post-handshake case, we now install the buffer when we didn't
previously. On write error, the buffer will have garbage in it, but it will be
discarded, so that will preserve any existing retry behavior. (Arguably the
existing retry behavior is a bug, but that's another matter.)
Add a test for all this, otherwise it is sure to regress. Testing for
record-packing is a little fuzzy, but we can assert ChangeCipherSpec always
shares a record with something.
BUG=57
Change-Id: I8603f20811d502c71ded2943b0e72a8bdc4e46f2
Reviewed-on: https://boringssl-review.googlesource.com/7871
Reviewed-by: Adam Langley <agl@google.com>
We reset it to SSL_NOTHING at the start of ever SSL_get_error-using operation.
Then we only set it to a non-NOTHING value in the rest of the stack on error
paths.
Currently, ssl->rwstate is set all over the place. Sometimes the pattern is:
ssl->rwstate = SSL_WRITING;
if (BIO_write(...) <= 0) {
goto err;
}
ssl->rwstate = SSL_NOTHING;
Sometimes we only set it to the non-NOTHING value on error.
if (BIO_write(...) <= 0) {
ssl->rwstate = SSL_WRITING;
}
ssl->rwstate = SSL_NOTHING;
Sometimes we just set it to SSL_NOTHING far from any callback in random places.
The third case is arbitrary and clearly should be removed.
But, in the second case, we sometimes forget to undo it afterwards. This is
largely harmless since an error in the error queue overrides rwstate, but we
don't always put something in the error queue (falling back to
SSL_ERROR_SYSCALL for "I'm not sure why it failed. Perhaps it was one of your
callbacks? Check your errno equivalent."), but in that case a stray rwstate
value will cause it to be wrong.
We could fix the cases where we fail to set SSL_NOTHING on success cases, but
this doesn't account for there being multiple SSL_get_error operations. The
consumer may have an SSL_read and an SSL_write running concurrently. Instead,
it seems the best option is to lift the SSL_NOTHING reset to the operations and
set SSL_WRITING and friends as in the second case.
(Someday hopefully we can fix this to just be an enum that is internally
returned. It can convert to something stateful at the API layer.)
Change-Id: I54665ec066a64eb0e48a06e2fcd0d2681a42df7f
Reviewed-on: https://boringssl-review.googlesource.com/7453
Reviewed-by: David Benjamin <davidben@google.com>
A lot of consumers of obj.h only want the NID values. Others didn't need
it at all. This also removes some OBJ_nid2sn and OBJ_nid2ln calls in EVP
error paths which isn't worth pulling a large table in for.
BUG=chromium:499653
Change-Id: Id6dff578f993012e35b740a13b8e4f9c2edc0744
Reviewed-on: https://boringssl-review.googlesource.com/7563
Reviewed-by: David Benjamin <davidben@google.com>
Change-Id: I6267c9bfb66940d0b6fe5368514210a058ebd3cc
Reviewed-on: https://boringssl-review.googlesource.com/7494
Reviewed-by: Emily Stark (Dunn) <estark@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
That we're half and half is really confusing.
Change-Id: I1c2632682e8a3e63d01dada8e0eb3b735ff709ce
Reviewed-on: https://boringssl-review.googlesource.com/6785
Reviewed-by: Adam Langley <agl@google.com>
This fixes a number of bugs with the original logic:
- If handshake messages are fragmented and writes need to be retried, frag_off
gets completely confused.
- The BIO_flush call didn't set rwstate, so it wasn't resumable at that point.
- The msg_callback call gets garbage because the fragment header would get
scribbled over the handshake buffer.
The original logic was also extremely confusing with how it handles init_off.
(init_off gets rewound to make room for the fragment header. Depending on
where you pause, resuming may or may not have already been rewound.)
For simplicity, just allocate a new buffer to assemble the fragment in and
avoid clobbering the old one. I don't think it's worth the complexity to
optimize that. If we want to optimize this sort of thing, not clobbering seems
better anyway because the message may need to be retransmitted. We could avoid
doing a copy when buffering the outgoing message for retransmission later.
We do still need to track how far we are in sending the current message via
init_off, so I haven't opted to disconnect this function from
init_{buf,off,num} yet.
Test the fix to the retry + fragment case by having the splitHandshake option
to the state machine tests, in DTLS, also clamp the MTU to force handshake
fragmentation.
Change-Id: I66f634d6c752ea63649db8ed2f898f9cc2b13908
Reviewed-on: https://boringssl-review.googlesource.com/6421
Reviewed-by: Adam Langley <agl@google.com>
They run through completely different logic as only handshake is fragmented.
This'll make it easier to rewrite the handshake logic in a follow-up.
Change-Id: I9515feafc06bf069b261073873966e72fcbe13cb
Reviewed-on: https://boringssl-review.googlesource.com/6420
Reviewed-by: Adam Langley <agl@google.com>
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>
clang scan-build found a memory leak if the overflow codepath in
dtls1_hm_fragment is hit. Along the way, tidy up that function.
Change-Id: I3c4b88916ee56ab3ab63f93d4a967ceae381d187
Reviewed-on: https://boringssl-review.googlesource.com/5870
Reviewed-by: Adam Langley <agl@google.com>
One tedious thing about using CBB is that you can't safely CBB_cleanup
until CBB_init is successful, which breaks the general 'goto err' style
of cleanup. This makes it possible:
CBB_zero ~ EVP_MD_CTX_init
CBB_init ~ EVP_DigestInit
CBB_cleanup ~ EVP_MD_CTX_cleanup
Change-Id: I085ecc4405715368886dc4de02285a47e7fc4c52
Reviewed-on: https://boringssl-review.googlesource.com/5267
Reviewed-by: Adam Langley <agl@google.com>
See also upstream's 9dcab127e14467733523ff7626da8906e67eedd6. The root problem
is dtls1_read_bytes is wrong, but we can get the right behavior now and add a
regression test for it before cleaning it up.
Change-Id: I4e5c39ab254a872d9f64242c9b77b020bdded6e6
Reviewed-on: https://boringssl-review.googlesource.com/5123
Reviewed-by: Adam Langley <agl@google.com>
The ctrl hooks are left alone since they should just go away.
Simplifying the cipher story will happen in the next CL.
BUG=468889
Change-Id: I979971c90f59c55cd5d17554f1253158b114f18b
Reviewed-on: https://boringssl-review.googlesource.com/4957
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>
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>
Also size them based on the limits in the quantities they control (after
checking bounds at the API boundary).
BUG=404754
Change-Id: Id56ba45465a473a1a793244904310ef747f29b63
Reviewed-on: https://boringssl-review.googlesource.com/4559
Reviewed-by: Adam Langley <agl@google.com>
This is consistent with C's free function and upstream's convention.
Change-Id: I83f6e2f5824e28f69a9916e580dc2d8cb3b94234
Reviewed-on: https://boringssl-review.googlesource.com/4512
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>
These are redundant with the lower level ones in s3_pkt.c just before BIO_read.
Only the operation which actually failed an operation on the BIO should set
the wait state.
Not all failure paths in ssl3_read_bytes and dtls1_read_bytes set SSL_READING,
but those that don't leave the BIO in a retry state, so SSL_READING doesn't
matter.
Change-Id: I2ae064ecc8b2946cc8ae8f724be09dfe49e077b5
Reviewed-on: https://boringssl-review.googlesource.com/4230
Reviewed-by: Adam Langley <agl@google.com>
signed/unsigned comparison. Just add a cast for now as in s3_both.c. Later
we'll properly size_t it alongside other tightening of this interface.
Change-Id: Idc8441d65e8ca65e39ab7172a8ec87d9ad710ed6
Reviewed-on: https://boringssl-review.googlesource.com/3860
Reviewed-by: Adam Langley <agl@google.com>
Turn them into static functions that take in an hm_fragment. It's not
immediately obvious that the frag_off/frag_len bounds checks and the msg_len
consistency check are critical to avoiding an out-of-bounds write. Better to
have dtls1_hm_fragment_mark also check internally.
Also rework the bitmask logic to be clearer and avoid a table.
Change-Id: Ica54e98f66295efb323e033cb6c67ab21e7d6cbc
Reviewed-on: https://boringssl-review.googlesource.com/3765
Reviewed-by: Adam Langley <agl@google.com>
Notably, drop all special cases around receiving a message in order and
receiving a full message. It makes things more complicated and was the source
of bugs (the MixCompleteMessageWithFragments tests added in this CL did not
pass before). Instead, every message goes through an hm_fragment, and
dtls1_get_message always checks buffered_messages to see if the next is
complete.
The downside is that we pay one more copy of the message data in the common
case. This is only during connection setup, so I think it's worth the
simplicity. (If we want to optimize later, we could either tighten
ssl3_get_message's interface to allow the handshake data being in the
hm_fragment's backing store rather than s->init_buf or swap out s->init_buf
with the hm_fragment's backing store when a mesasge completes.
This CL does not address ssl_read_bytes being an inappropriate API for DTLS.
Future work will revise the handshake/transport boundary to align better with
DTLS's needs. Also other problems that I've left as TODOs.
Change-Id: Ib4570d45634b5181ecf192894d735e8699b1c86b
Reviewed-on: https://boringssl-review.googlesource.com/3764
Reviewed-by: Adam Langley <agl@google.com>
We don't support DTLS renego. Removing this separately from the rewrite to call
out intentionally dropping this logic.
Change-Id: Ie4428eea0d2dbbb8b4b8b6474df4821de62558cc
Reviewed-on: https://boringssl-review.googlesource.com/3761
Reviewed-by: Adam Langley <agl@google.com>
That might be a reasonable check to make, maybe.
DTLS handshake message reading has a ton of other bugs and needs a complete
rewrite. But let's fix this and get a test in now.
Change-Id: I4981fc302feb9125908bb6161ed1a18288c39e2b
Reviewed-on: https://boringssl-review.googlesource.com/3600
Reviewed-by: Adam Langley <agl@google.com>
We can pass the fragment pointer to dtls1_retransmit_message rather than
having it look it up again.
Change-Id: If6957428418a44e7ceac91a93f7c6032d331d9d8
Reviewed-on: https://boringssl-review.googlesource.com/3510
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
It may fail because the BIO_write to the memory BIO can allocate.
Unfortunately, this bubbles up pretty far up now that we've moved the handshake
hash to ssl3_set_handshake_header.
Change-Id: I58884347a4456bb974ac4783078131522167e29d
Reviewed-on: https://boringssl-review.googlesource.com/3483
Reviewed-by: Adam Langley <agl@google.com>
SSL_AEAD_CTX ownership is currently too confusing. Instead, rely on the lack of
renego, so the previous epoch always uses the NULL cipher. (Were we to support
DTLS renego, we could keep track of s->d1->last_aead_write_ctx like
s->d1->last_write_sequence, but it isn't worth it.)
Buffered messages also tracked an old s->session, but this is unnecessary. The
s->session NULL check in tls1_enc dates to the OpenSSL initial commit and is
redundant with the aead NULL check.
Change-Id: I9a510468d95934c65bca4979094551c7536980ae
Reviewed-on: https://boringssl-review.googlesource.com/3234
Reviewed-by: Adam Langley <agl@google.com>
This is only applicable for renego and is wrong anyway. The handshake_read_seq
check doesn't account for message reordering. The correct check is if we
haven't yet processed the peer's CCS in the current handshake.
(The other Finished special-case needs to stay, however.)
Change-Id: Ic42897aab7140285ce2f3be24d52b81851b912b5
Reviewed-on: https://boringssl-review.googlesource.com/3231
Reviewed-by: Adam Langley <agl@google.com>
The existing comments are not very helpful. This code is also quite buggy.
Document two of them as TODOs.
Change-Id: Idfaf93d9c3b8b1ee92f2fb0d292ef513b5f6d824
Reviewed-on: https://boringssl-review.googlesource.com/2830
Reviewed-by: Adam Langley <agl@google.com>
BIO_ctrls do not have terribly well-defined return values on error. (Though the
existing ones seem to all return 0, not -1, on nonexistant operation.)
Change-Id: I08497f023ce3257c253aa71517a98b2fe73c3f74
Reviewed-on: https://boringssl-review.googlesource.com/2829
Reviewed-by: Adam Langley <agl@google.com>
g_probably_mtu and dtls1_guess_mtu is a bunch of logic for guessing the right
MTU, but it only ever returns the maximum (the input is always zero). Trim that
down to only what it actually does.
Change-Id: If3afe3f68ccb36cbf9c4525372564d16a4bbb73f
Reviewed-on: https://boringssl-review.googlesource.com/2828
Reviewed-by: Adam Langley <agl@google.com>
The retry doesn't actually work when we're sending a non-initial fragment; the
s->init_off != 0 block will get re-run each iteration through and continually
prepend headers. It can also infinite loop if the BIO reports
BIO_CTRL_DGRAM_MTU_EXCEEDED but either fails to report an MTU or reports an MTU
that always rounds up to the minimum. See upstream's
d3d9eef31661633f5b003a9e115c1822f79d1870.
WebRTC doesn't participate in any of the MTU logic and inherits the default
MTU, so just remove it for now.
Change-Id: Ib2ed2ba016b7c229811741fb7369c015ba0b551f
Reviewed-on: https://boringssl-review.googlesource.com/2827
Reviewed-by: Adam Langley <agl@google.com>
That setting means that the MTU is provided externally via SSL_set_mtu.
(Imported from upstream's 001235778a6e9c645dc0507cad6092d99c9af8f5)
Change-Id: I4e5743a9dee734ddd0235f080aefe98a7365aaf6
Reviewed-on: https://boringssl-review.googlesource.com/2826
Reviewed-by: Adam Langley <agl@google.com>
Based in part on upstream's cf75017bfd60333ff65edf9840001cd2c49870a3. This
situation really shouldn't be able to happen, but between no static asserts
that the minimum MTU is always large enough and a bug in reseting the MTU later
(to be fixed be a follow-up import from upstream), check these and return a
useful error code.
Change-Id: Ie853e5d35a6a7bc9c0032e74ae71529d490f4fe2
Reviewed-on: https://boringssl-review.googlesource.com/2825
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>
This avoids needing a should_add_to_finished_hash boolean on do_write. The
logic in do_write was a little awkward because do_write would be called
multiple times if the write took several iterations. This also gets complex if
DTLS retransmits are involved. (At a glance, it's not obvious the
BIO_CTRL_DGRAM_MTU_EXCEEDED case actually works.)
Doing it as the handshake message is being prepared avoids this concern. It
also gives a natural point for the extended master secret logic which needs to
do work after the finished hash has been sampled.
As a bonus, we can remove s->d1->retransmitting which was only used to deal
with this issue.
Change-Id: Ifedf23ee4a6c5e08f960d296a6eb1f337a16dc7a
Reviewed-on: https://boringssl-review.googlesource.com/2604
Reviewed-by: Adam Langley <agl@google.com>
The frag_off/frag_len parameters are always zero, and the return value is never
used.
Change-Id: If7487b23c55f2a996e411b25b76a8e1651f25d8b
Reviewed-on: https://boringssl-review.googlesource.com/2601
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
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>
