Commit Graph

12 Commits

Author SHA1 Message Date
David Benjamin
3120950b1e Size TLS read buffers based on the size requested.
Like the write half, rather than allocating the maximum size needed and
relying on the malloc implementation to pool this sanely, allocate the
size the TLS record-layer code believes it needs.

As currently arranged, this will cause us to alternate from a small
allocation (for the record header) and then an allocation sized to the
record itself. Windows is reportedly bad at pooling large allocations,
so, *if the server sends us smaller records*, this will avoid hitting
the problem cases.

If the server sends us size 16k records, the maximum allowed by ther
protocol, we simply must buffer up to that amount and will continue to
allocate similar sizes as before (although slightly smaller; this CL
also fixes small double-counting we did on the allocation sizes).

Separately, we'll gather some metrics in Chromium to see what common
record sizes are to determine if this optimization is sufficient. This
is intended as an easy optimization we can do now, in advance of ongoing
work to fix the extra layer of buffering between Chromium and BoringSSL
with an in-place decrypt API.

Bug: chromium:524258
Change-Id: I233df29df1212154c49fee4285ccc37be12f81dc
Reviewed-on: https://boringssl-review.googlesource.com/17329
Reviewed-by: Adam Langley <agl@google.com>
2017-06-23 23:08:35 +00:00
David Benjamin
0f5d7d3f04 Just allocate what's needed for SSL write buffers.
When we refactored all the buffering logic, we retained upstream
OpenSSL's allocation patterns. In particular, we always allocated fixed
size write buffer, even though, unlike when reading, we trivially know a
tighter bound (namely however much we happen to be writing right now).

Since the cutoff for when Windows' malloc starts having a hard time is
just below the TLS maximum record size, do the more natural thing of
allocating what we need to hold outgoing ciphertext.

(This only does anything to the write half. Read half is a bit more
involved.)

BUG=chromium:524258

Change-Id: I0165f9ce822b9cc413f3c77e269e6154160537a7
Reviewed-on: https://boringssl-review.googlesource.com/14405
Reviewed-by: Steven Valdez <svaldez@chromium.org>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2017-03-27 16:37:53 +00:00
David Benjamin
17cf2cb1d2 Work around language and compiler bug in memcpy, etc.
Most C standard library functions are undefined if passed NULL, even
when the corresponding length is zero. This gives them (and, in turn,
all functions which call them) surprising behavior on empty arrays.
Some compilers will miscompile code due to this rule. See also
https://www.imperialviolet.org/2016/06/26/nonnull.html

Add OPENSSL_memcpy, etc., wrappers which avoid this problem.

BUG=23

Change-Id: I95f42b23e92945af0e681264fffaf578e7f8465e
Reviewed-on: https://boringssl-review.googlesource.com/12928
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
2016-12-21 20:34:47 +00:00
David Benjamin
ce079fda12 Add SSL_is_dtls.
OpenSSL 1.1.0 added a function to tell if an SSL* is DTLS or not. This
is probably a good idea, especially since SSL_version returns
non-normalized versions.

BUG=91

Change-Id: I25c6cf08b2ebabf0c610c74691de103399f729bc
Reviewed-on: https://boringssl-review.googlesource.com/9077
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2016-08-02 20:43:58 +00:00
David Benjamin
1a01e1fc88 Remove in-place TLS record assembly for now.
Decrypting is very easy to do in-place, but encrypting in-place is a hassle.
The rules actually were wrong due to record-splitting. The aliasing prefix and
the alignment prefix actually differ by 1. Take it out for now in preparation
for tightening the aliasing rules.

If we decide to do in-place encrypt later, probably it'd be more useful to
return header + in-place ciphertext + trailer. (That, in turn, needs a
scatter/gather thing on the AEAD thanks to TLS 1.3's padding and record type
construction.) We may also wish to rethink how record-splitting works here.

Change-Id: I0187d39c541e76ef933b7c2c193323164fd8a156
Reviewed-on: https://boringssl-review.googlesource.com/8230
Reviewed-by: Adam Langley <agl@google.com>
2016-06-09 19:47:44 +00:00
David Benjamin
728f354a2b Push alert handling down into the record functions.
Alert handling is more-or-less identical across all contexts. Push it down from
read_bytes into the low-level record functions. This also deduplicates the code
shared between TLS and DTLS.

Now the only type mismatch managed by read_bytes is if we get handshake data in
read_app_data.

Change-Id: Ia8331897b304566e66d901899cfbf31d2870194e
Reviewed-on: https://boringssl-review.googlesource.com/8124
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
2016-06-08 18:35:58 +00:00
David Benjamin
0d275bdb32 Don't call ERR_clear_system_error in so many places.
We've got it in entry points. That should be sufficient. (Do we even need it
there?)

Change-Id: I39b245a08fcde7b57e61b0bfc595c6ff4ce2a07a
Reviewed-on: https://boringssl-review.googlesource.com/8127
Reviewed-by: David Benjamin <davidben@google.com>
2016-06-07 15:53:44 +00:00
David Benjamin
4c5ddb8047 Set rwstate consistently.
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>
2016-04-18 20:30:32 +00:00
David Benjamin
03f000577f Remove SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER.
This dates to SSLeay 0.8.0 (or earlier). The use counter sees virtually
no hits.

Change-Id: Iff4c8899d5cb0ba4afca113c66d15f1d980ffe41
Reviewed-on: https://boringssl-review.googlesource.com/6558
Reviewed-by: Adam Langley <agl@google.com>
2015-12-15 19:14:00 +00:00
David Benjamin
13e81fc971 Fix DTLS asynchronous write handling.
Although the DTLS transport layer logic drops failed writes on the floor, it is
actually set up to work correctly. If an SSL_write fails at the transport,
dropping the buffer is fine. Arguably it works better than in TLS because we
don't have the weird "half-committed to data" behavior. Likewise, the handshake
keeps track of how far its gotten and resumes the message at the right point.

This broke when the buffering logic was rewritten because I didn't understand
what the DTLS code was doing. The one thing that doesn't work as one might
expect is non-fatal write errors during rexmit are not recoverable. The next
timeout must fire before we try again.

This code is quite badly sprinkled in here, so add tests to guard it against
future turbulence. Because of the rexmit issues, the tests need some hacks
around calls which may trigger them. It also changes the Go DTLS implementation
from being completely strict about sequence numbers to only requiring they be
monotonic.

The tests also revealed another bug. This one seems to be upstream's fault, not
mine. The logic to reset the handshake hash on the second ClientHello (in the
HelloVerifyRequest case) was a little overenthusiastic and breaks if the
ClientHello took multiple tries to send.

Change-Id: I9b38b93fff7ae62faf8e36c4beaf848850b3f4b9
Reviewed-on: https://boringssl-review.googlesource.com/6417
Reviewed-by: Adam Langley <agl@google.com>
2015-11-02 23:16:22 +00:00
David Benjamin
2c99d289fd Fix buffer size computation.
The maximum buffer size computation wasn't quite done right in
ssl_buffer.c, so we were failing with BUFFER_TOO_SMALL for sufficiently
large records. Fix this and, as penance, add 103 tests.

(Test that we can receive maximum-size records in all cipher suites.
Also test SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER while I'm here.)

BUG=526998

Change-Id: I714c16dda2ed13f49d8e6cd1b48adc5a8491f43c
Reviewed-on: https://boringssl-review.googlesource.com/5785
Reviewed-by: Adam Langley <agl@google.com>
2015-09-01 20:18:21 +00:00
David Benjamin
b8d28cf532 Factor out the buffering and low-level record code.
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>
2015-08-28 22:01:02 +00:00