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>

Unlike the Scoped* types, bssl::UniquePtr is available to C++ users, and
offered for a large variety of types.  The 'extern "C++"' trick is used
to make the C++ bits digestible to C callers that wrap header files in
'extern "C"'.

Change-Id: Ifbca4c2997d6628e33028c7d7620c72aff0f862e
Reviewed-on: https://boringssl-review.googlesource.com/10521
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>

This reverts commit 09feb0f3d9.

(In order to make WebRTC happy this also needs to be reverted.)

We currently have the situation where the |tool| and |bssl_shim| code
includes scoped_types.h from crypto/test and ssl/test. That's weird and
shouldn't happen. Also, our C++ consumers might quite like to have
access to the scoped types.

Thus this change moves some of the template code to base.h and puts it
all in a |bssl| namespace to prepare for scattering these types into
their respective headers. In order that all the existing test code be
able to access these types, it's all moved into the same namespace.

Change-Id: I3207e29474dc5fcc344ace43119df26dae04eabb
Reviewed-on: https://boringssl-review.googlesource.com/8730
Reviewed-by: David Benjamin <davidben@google.com>

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>

It's currently a mix of GoogleCPlusPlusStyle and unix_hacker_style. Since it's
now been thoroughly C++-ified, let's go with the former. This also matches the
tool, our other bit of C++ code.

Change-Id: Ie90a166006aae3b8f41628dbb35fcd64e99205df
Reviewed-on: https://boringssl-review.googlesource.com/3348
Reviewed-by: Adam Langley <agl@google.com>

bssl_shim rather needs it. It doesn't even free the SSL* properly most of the
time. Now that it does, this opens the door to running malloc tests under
a leak checker (because it's just not slow enough right now).

Change-Id: I37d2004de27180c41b42a6d9e5aea02caf9b8b32
Reviewed-on: https://boringssl-review.googlesource.com/3340
Reviewed-by: Adam Langley <agl@google.com>

Including string.h in base.h causes any file that includes a BoringSSL
header to include string.h. Generally this wouldn't be a problem,
although string.h might slow down the compile if it wasn't otherwise
needed. However, it also causes problems for ipsec-tools in Android
because OpenSSL didn't have this behaviour.

This change removes string.h from base.h and, instead, adds it to each
.c file that requires it.

Change-Id: I5968e50b0e230fd3adf9b72dd2836e6f52d6fb37
Reviewed-on: https://boringssl-review.googlesource.com/3200
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

write_quota should only be decremented by 1 in datagram mode, otherwise we'll
underflow and always allow writes through. This does not cause any existing
tests to fail.

(It will be useful once the bug in dtls1_do_write is fixed.)

Change-Id: I42aa001d7264790a3726269890635f679497fb1c
Reviewed-on: https://boringssl-review.googlesource.com/2831
Reviewed-by: Adam Langley <agl@google.com>

Change-Id: I7407261bdb2d788c879f2e67e617a615d9ff8f8b
Reviewed-on: https://boringssl-review.googlesource.com/1505
Reviewed-by: Adam Langley <agl@google.com>

Add a framework for testing the asynchronous codepath. Move some handshake
state machine coverage tests to cover a range of record-layer and
handshake-layer asynchronicity.

This adds tests for the previous two async bugs fixed.

Change-Id: I422ef33ba3eeb0ad04766871ed8bc59b677b169e
Reviewed-on: https://boringssl-review.googlesource.com/1410
Reviewed-by: Adam Langley <agl@google.com>