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 684400ce19)
the session's version (server).
See also BoringSSL's commit bdf5e72f50e25f0e45e825c156168766d8442dde.
Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
(cherry picked from commit 9e189b9dc1)
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>
(cherry picked from commit e94a6c0ede)
Conflicts:
CHANGES
ssl/s3_srvr.c
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>
(cherry picked from commit de2c7504eb)
Conflicts:
CHANGES
Tighten client-side session ticket handling during renegotiation:
ensure that the client only accepts a session ticket if the server sends
the extension anew in the ServerHello. Previously, a TLS client would
reuse the old extension state and thus accept a session ticket if one was
announced in the initial ServerHello.
Reviewed-by: Bodo Moeller <bodo@openssl.org>
(cherry picked from commit d663df2399)
Conflicts:
CHANGES
Reencode DigestInto in DER and check against the original: this
will reject any improperly encoded DigestInfo structures.
Note: this is a precautionary measure, there is no known attack
which can exploit this.
Thanks to Brian Smith for reporting this issue.
Reviewed-by: Tim Hudson <tjh@openssl.org>
A missing bounds check in the handling of the TLS heartbeat extension
can be used to reveal up to 64k of memory to a connected client or
server.
Thanks for Neel Mehta of Google Security for discovering this bug and to
Adam Langley <agl@chromium.org> and Bodo Moeller <bmoeller@acm.org> for
preparing the fix (CVE-2014-0160)
Fix for the attack described in the paper "Recovering OpenSSL
ECDSA Nonces Using the FLUSH+RELOAD Cache Side-channel Attack"
by Yuval Yarom and Naomi Benger. Details can be obtained from:
http://eprint.iacr.org/2014/140
Thanks to Yuval Yarom and Naomi Benger for discovering this
flaw and to Yuval Yarom for supplying a fix.
(cherry picked from commit 2198be3483)
Conflicts:
CHANGES
For DTLS we might need to retransmit messages from the previous session
so keep a copy of write context in DTLS retransmission buffers instead
of replacing it after sending CCS. CVE-2013-6450.
Reported by: Phil Pennock <openssl-dev@spodhuis.org>
Make renegotiation work for TLS 1.2, 1.1 by not using a lower record
version client hello workaround if renegotiating.
BUF_mem_grow and BUF_mem_grow_clean. Refuse attempts to shrink buffer
in CRYPTO_realloc_clean.
Thanks to Tavis Ormandy, Google Security Team, for discovering this
issue and to Adam Langley <agl@chromium.org> for fixing it. (CVE-2012-2110)
If OPENSSL_MAX_TLS1_2_CIPHER_LENGTH is set then limit the size of client
ciphersuites to this value. A value of 50 should be sufficient.
Document workarounds in CHANGES.
signatures and MDC2 using EVP or RSA_sign. This has become more apparent
when the dgst utility in OpenSSL 1.0.0 and later switched to using the
EVP_DigestSign functions which call RSA_sign.
This means that the signature format OpenSSL 1.0.0 and later used with
dgst -sign and MDC2 is incompatible with previous versions.
Add detection in RSA_verify so either format works.
Note: MDC2 is disabled by default in OpenSSL and very rarely used in practice.
Thanks to Antonio Martin, Enterprise Secure Access Research and
Development, Cisco Systems, Inc. for discovering this bug and
preparing a fix. (CVE-2012-0050)
