By using non-DER or invalid encodings outside the signed portion of a
certificate the fingerprint can be changed without breaking the signature.
Although no details of the signed portion of the certificate can be changed
this can cause problems with some applications: e.g. those using the
certificate fingerprint for blacklists.

1. Reject signatures with non zero unused bits.

If the BIT STRING containing the signature has non zero unused bits reject
the signature. All current signature algorithms require zero unused bits.

2. Check certificate algorithm consistency.

Check the AlgorithmIdentifier inside TBS matches the one in the
certificate signature. NB: this will result in signature failure
errors for some broken certificates.

3. Check DSA/ECDSA signatures use DER.

Reencode DSA/ECDSA signatures and compare with the original received
signature. Return an error if there is a mismatch.

This will reject various cases including garbage after signature
(thanks to Antti Karjalainen and Tuomo Untinen from the Codenomicon CROSS
program for discovering this case) and use of BER or invalid ASN.1 INTEGERs
(negative or with leading zeroes).

CVE-2014-8275
Reviewed-by: Emilia Käsper <emilia@openssl.org>

(cherry picked from commit 684400ce)

Conflicts:
	CHANGES
	crypto/dsa/dsa_asn1.c

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 4c52816d)

Conflicts:
	crypto/asn1/x_algor.c
	crypto/x509/x509.h

According to X6.90 null, object identifier, boolean, integer and enumerated
types can only have primitive encodings: return an error if any of
these are received with a constructed encoding.
Reviewed-by: Emilia Käsper <emilia@openssl.org>

(cherry picked from commit f5e4b6b5)

Conflicts:
	crypto/asn1/asn1_err.c

is run with --strict-warnings.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 488f16e3)

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

Causes more problems than it fixes: even though error codes
are not part of the stable API, several users rely on the
specific error code, and the change breaks them. Conversely,
we don't have any concrete use-cases for constant-time behaviour here.

This reverts commit b55ff319

.

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)

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 7f9edfd2)

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

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

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 9beb948c)

Based on commit 66f96fe2

 by Steve Henson

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit ce5ddefc)

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
(cherry picked from commit d04a1e0b)

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
(cherry picked from commit bb1ddd3d)

malloc failure.

Reviewed-by: Kurt Roeckx <kurt@openssl.org>
(cherry picked from commit c6a84ff3)

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: Tim Hudson <tjh@openssl.org>

Conflicts:
	ssl/d1_lib.c

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
	ssl/ssl.h
	ssl/ssl_lib.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)

Conflicts:
	crypto/bio/bio.h
	crypto/bio/bss_dgram.c

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)

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>
(cherry picked from commit 8123d158)

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>
(cherry picked from commit 03b637a7)

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 2db95e09)

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 5fc8bb6a)

PR#1767

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 244d0955)

PR#3613

Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit fc3968a2)

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

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
(cherry picked from commit 5e31a40f)

Conflicts:
	apps/ocsp.c

(cherry picked from commit e1645826)

PR#3612

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
(cherry picked from commit de87dd46)
(cherry picked from commit 4d3df37b)

PR#3608

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 8a35dbb6)