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>

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>

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>

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>

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>

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>

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

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

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

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

Previously, state variant was not advanced, which resulted in state
being stuck in the st1 variant (usually "_A").

This broke certificate callback retry logic when accepting connections
that were using SSLv2 ClientHello (hence reusing the message), because
their state never advanced to SSL3_ST_SR_CLNT_HELLO_C variant required
for the retry code path.

Reported by Yichun Zhang (agentzh).

Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>

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

The current documentation contains a bunch of spelling and grammar mistakes. I also
found it hard to understand some paragraphs, so here is my attempt to improve its
readability.

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

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

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

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

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

PR#1767

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

PR#3613

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

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

PR#3612

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

Workaround for NetWare CodeWarrior compiler which doesn't properly lookup
includes when in same directory as the C file which includes it.

PR#3569
Reviewed-by: Stephen Henson <steve@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>

Minor changes made by Matt Caswell

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

Minor changes made by Matt Caswell.

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

Minor changes made by Matt Caswell.

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

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

PR#3608

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

PR#3574

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

When using the -xcert option to test certificate validity print out
if we pass Suite B compliance. We print out "not tested" if we aren't
in Suite B mode.
Reviewed-by: Matt Caswell <matt@openssl.org>

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

In keygen, return KEY_SIZE_TOO_SMALL not INVALID_KEYBITS.

** I also increased the minimum from 256 to 512, which is now
documented in CHANGES file. **

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

Fix CONF_load_modules to CONF_modules_load.
Document that it calls exit.
Advise against using it now.
Add an error print to stderr.

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

the session's version (server).

See also BoringSSL's commit bdf5e72f50e25f0e45e825c156168766d8442dde.

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

ECDH_compute_key is silently ignored and the KDF is run on duff data

Thanks to github user tomykaira for the suggested fix.

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

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

once the ChangeCipherSpec message is received. Previously, the server would
set the flag once at SSL3_ST_SR_CERT_VRFY and again at SSL3_ST_SR_FINISHED.
This would allow a second CCS to arrive and would corrupt the server state.

(Because the first CCS would latch the correct keys and subsequent CCS
messages would have to be encrypted, a MitM attacker cannot exploit this,
though.)

Thanks to Joeri de Ruiter for reporting this issue.

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

The server must send a NewSessionTicket message if it advertised one
in the ServerHello, so make a missing ticket message an alert
in the client.

An equivalent change was independently made in BoringSSL, see commit
6444287806d801b9a45baf1f6f02a0e3a16e144c.

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

The client sends a session ID with the session ticket, and uses
the returned ID to detect resumption, so we do not need to peek
at handshake messages: s->hit tells us explicitly if we're resuming.

An equivalent change was independently made in BoringSSL, see commit
407886f589cf2dbaed82db0a44173036c3bc3317.

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

The same change was independently made in BoringSSL, see commit
9eaeef81fa2d4fd6246dc02b6203fa936a5eaf67

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

This ensures that it's zeroed even if the SSL object is reused
(as in ssltest.c). It also ensures that it applies to DTLS, too.

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

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