Various build fixes, mostly uncovered by clang's unused-const-variable
and unused-function errors.

Reviewed-by: Kurt Roeckx <kurt@openssl.org>

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

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

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

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

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

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

From BoringSSL
- Send an alert when the client key exchange isn't correctly formatted.
- Reject overly short RSA ciphertexts to avoid a (benign) out-of-bounds memory access.

Reviewed-by: Kurt Roeckx <kurt@openssl.org>
(cherry picked from commit 4aecfd4d)

master branch has a specific regression test for a bug in x86_64-mont5 code,
see commit cdfe0fdd

.

This code is now in 1.0.2/1.0.1, so also backport the test.

Reviewed-by: Richard Levitte <levitte@openssl.org>

Invalid zero-padding in the divisor could cause a division by 0.

Reviewed-by: Richard Levitte <levitte@openssl.org>

(cherry picked from commit 66f96fe2

)

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

ssl_locl.h

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

The client_version needs to be preserved for the RSA key exchange.

This change also means that renegotiation will, like TLS, repeat the old
client_version rather than advertise only the final version. (Either way,
version change on renego is not allowed.) This is necessary in TLS to work
around an SChannel bug, but it's not strictly necessary in DTLS.

(From BoringSSL)

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit ec1af3c4)

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit db812f2d)

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit af6e2d51)

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 55e53026)

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 1904d211)

The temporary variable causes unused variable warnings in opt mode with clang,
because the subsequent assert is compiled out.

Reviewed-by: Rich Salz <rsalz@openssl.org>

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@openssl.org>

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@openssl.org>

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 41bf2501)

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 76e65090)

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 376e2ca3)

Odd-length lists should be rejected everywhere upon parsing. Nevertheless,
be extra careful and add guards against off-by-one reads.

Also, drive-by replace inexplicable double-negation with an explicit comparison.

Reviewed-by: Matt Caswell <matt@openssl.org>

Reviewed-by: Dr Stephen Henson <steve@openssl.org>

The Supported Elliptic Curves extension contains a vector of NamedCurves
of 2 bytes each, so the total length must be even. Accepting odd-length
lists was observed to lead to a non-exploitable one-byte out-of-bounds
read in the latest development branches (1.0.2 and master). Released
versions of OpenSSL are not affected.

Thanks to Felix Groebert of the Google Security Team for reporting this issue.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 33d5ba86)

RT3596
Reviewed-by: Matt Caswell <matt@openssl.org>

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

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 4bb8eb9c)

than the mtu we are already using

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 047f2159)

and UDP header) when setting an mtu. This constant is not always correct (e.g.
if using IPv6). Use the new DTLS_CTRL functions instead.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 464ce920)

we will support then dtls1_do_write can go into an infinite loop. This commit
fixes that.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit d3d9eef3)

at least the minimum or it will fail.
There were some instances in dtls1_query_mtu where the final mtu can end up
being less than the minimum, i.e. where the user has set an mtu manually. This
shouldn't be allowed. Also remove dtls1_guess_mtu that, despite having
logic for guessing an mtu, was actually only ever used to work out the minimum
mtu to use.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 1620a2e4)

and instead use the value provided by the underlying BIO. Also provide some
new DTLS_CTRLs so that the library user can set the mtu without needing to
know this constant. These new DTLS_CTRLs provide the capability to set the
link level mtu to be used (i.e. including this IP/UDP overhead). The previous
DTLS_CTRLs required the library user to subtract this overhead first.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 59669b6a)

Conflicts:
	ssl/d1_both.c

used with no explanation. Some of this was introduced as part of RT#1929. The
value 28 is the length of the IP header (20 bytes) plus the UDP header (8
bytes). However use of this constant is incorrect because there may be
instances where a different value is needed, e.g. an IPv4 header is 20 bytes
but an IPv6 header is 40. Similarly you may not be using UDP (e.g. SCTP).
This commit introduces a new BIO_CTRL that provides the value to be used for
this mtu "overhead". It will be used by subsequent commits.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 0d3ae34d)

mtu that we have received is not less than the minimum. If its less it uses the
minimum instead. The second call to query the mtu does not do that, but
instead uses whatever comes back. We have seen an instance in RT#3592 where we
have got an unreasonably small mtu come back. This commit makes both query
checks consistent.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 6abb0d1f)

automatically updated, and we should use the one provided instead.
Unfortunately there are a couple of locations where this is not respected.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 00123577)

RT#3592 provides an instance where the OPENSSL_assert that this commit
replaces can be hit. I was able to recreate this issue by forcing the
underlying BIO to misbehave and come back with very small mtu values. This
happens the second time around the while loop after we have detected that the
MTU has been exceeded following the call to dtls1_write_bytes.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit cf75017b)

If SSLv2 and SSLv3 are both disabled we still support SSL/TLS.

Reviewed-by: Richard Levitte <levitte@openssl.org>

Reviewed-by: Matt Caswell <matt@openssl.org>