- 13 Oct, 2016 1 commit
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Rich Salz authored
Reviewed-by: Tim Hudson <tjh@openssl.org> (Merged from https://github.com/openssl/openssl/pull/1702) (cherry picked from commit 7954dced)
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- 22 Sep, 2016 2 commits
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Matt Caswell authored
Reviewed-by: Richard Levitte <levitte@openssl.org>
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Matt Caswell authored
Reviewed-by: Richard Levitte <levitte@openssl.org>
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- 21 Sep, 2016 8 commits
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Matt Caswell authored
Reviewed-by: Richard Levitte <levitte@openssl.org>
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Dmitry Belyavsky authored
Russian GOST ciphersuites are vulnerable to the KCI attack because they use long-term keys to establish the connection when ssl client authorization is on. This change brings the GOST implementation into line with the latest specs in order to avoid the attack. It should not break backwards compatibility. Reviewed-by: Rich Salz <rsalz@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org> Reviewed-by: Matt Caswell <matt@openssl.org>
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Matt Caswell authored
A malicious client can send an excessively large OCSP Status Request extension. If that client continually requests renegotiation, sending a large OCSP Status Request extension each time, then there will be unbounded memory growth on the server. This will eventually lead to a Denial Of Service attack through memory exhaustion. Servers with a default configuration are vulnerable even if they do not support OCSP. Builds using the "no-ocsp" build time option are not affected. I have also checked other extensions to see if they suffer from a similar problem but I could not find any other issues. CVE-2016-6304 Issue reported by Shi Lei. Reviewed-by: Rich Salz <rsalz@openssl.org>
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Dr. Stephen Henson authored
Reviewed-by: Rich Salz <rsalz@openssl.org>
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Dr. Stephen Henson authored
Grow TLS/DTLS 16 bytes more than strictly necessary as a precaution against OOB reads. In most cases this will have no effect because the message buffer will be large enough already. Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit 006a788c)
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Dr. Stephen Henson authored
Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit bc9563f8)
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Dr. Stephen Henson authored
The overflow check will never be triggered because the the n2l3 result is always less than 2^24. Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit 709ec8b3)
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Dr. Stephen Henson authored
In ssl3_get_client_certificate, ssl3_get_server_certificate and ssl3_get_certificate_request check we have enough room before reading a length. Thanks to Shi Lei (Gear Team, Qihoo 360 Inc.) for reporting these bugs. CVE-2016-6306 Reviewed-by: Richard Levitte <levitte@openssl.org> Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit ff553f83)
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- 26 Aug, 2016 1 commit
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David Woodhouse authored
Commit d8e8590e ("Fix missing return value checks in SCTP") made the DTLS handshake fail, even for non-SCTP connections, if SSL_export_keying_material() fails. Which it does, for DTLS1_BAD_VER. Apply the trivial fix to make it succeed, since there's no real reason why it shouldn't even though we never need it. Reviewed-by: Rich Salz <rsalz@openssl.org> Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit c8a18468)
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- 24 Aug, 2016 2 commits
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Dr. Stephen Henson authored
Thanks to Shi Lei for reporting this issue. CVE-2016-6303 Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit 55d83bf7)
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Rich Salz authored
Reviewed-by: Viktor Dukhovni <viktor@openssl.org> Reviewed-by: Emilia Käsper <emilia@openssl.org> (cherry picked from commit 0fff5065)
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- 23 Aug, 2016 1 commit
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Dr. Stephen Henson authored
If a ticket callback changes the HMAC digest to SHA512 the existing sanity checks are not sufficient and an attacker could perform a DoS attack with a malformed ticket. Add additional checks based on HMAC size. Thanks to Shi Lei for reporting this bug. CVE-2016-6302 Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit baaabfd8)
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- 22 Aug, 2016 3 commits
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Kazuki Yamaguchi authored
Fix an off by one error in the overflow check added by 07bed46f ("Check for errors in BN_bn2dec()"). Reviewed-by: Stephen Henson <steve@openssl.org> Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit 099e2968)
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Matt Caswell authored
Follow on from CVE-2016-2179 The investigation and analysis of CVE-2016-2179 highlighted a related flaw. This commit fixes a security "near miss" in the buffered message handling code. Ultimately this is not currently believed to be exploitable due to the reasons outlined below, and therefore there is no CVE for this on its own. The issue this commit fixes is a MITM attack where the attacker can inject a Finished message into the handshake. In the description below it is assumed that the attacker injects the Finished message for the server to receive it. The attack could work equally well the other way around (i.e where the client receives the injected Finished message). The MITM requires the following capabilities: - The ability to manipulate the MTU that the client selects such that it is small enough for the client to fragment Finished messages. - The ability to selectively drop and modify records sent from the client - The ability to inject its own records and send them to the server The MITM forces the client to select a small MTU such that the client will fragment the Finished message. Ideally for the attacker the first fragment will contain all but the last byte of the Finished message, with the second fragment containing the final byte. During the handshake and prior to the client sending the CCS the MITM injects a plaintext Finished message fragment to the server containing all but the final byte of the Finished message. The message sequence number should be the one expected to be used for the real Finished message. OpenSSL will recognise that the received fragment is for the future and will buffer it for later use. After the client sends the CCS it then sends its own Finished message in two fragments. The MITM causes the first of these fragments to be dropped. The OpenSSL server will then receive the second of the fragments and reassemble the complete Finished message consisting of the MITM fragment and the final byte from the real client. The advantage to the attacker in injecting a Finished message is that this provides the capability to modify other handshake messages (e.g. the ClientHello) undetected. A difficulty for the attacker is knowing in advance what impact any of those changes might have on the final byte of the handshake hash that is going to be sent in the "real" Finished message. In the worst case for the attacker this means that only 1 in 256 of such injection attempts will succeed. It may be possible in some situations for the attacker to improve this such that all attempts succeed. For example if the handshake includes client authentication then the final message flight sent by the client will include a Certificate. Certificates are ASN.1 objects where the signed portion is DER encoded. The non-signed portion could be BER encoded and so the attacker could re-encode the certificate such that the hash for the whole handshake comes to a different value. The certificate re-encoding would not be detectable because only the non-signed portion is changed. As this is the final flight of messages sent from the client the attacker knows what the complete hanshake hash value will be that the client will send - and therefore knows what the final byte will be. Through a process of trial and error the attacker can re-encode the certificate until the modified handhshake also has a hash with the same final byte. This means that when the Finished message is verified by the server it will be correct in all cases. In practice the MITM would need to be able to perform the same attack against both the client and the server. If the attack is only performed against the server (say) then the server will not detect the modified handshake, but the client will and will abort the connection. Fortunately, although OpenSSL is vulnerable to Finished message injection, it is not vulnerable if *both* client and server are OpenSSL. The reason is that OpenSSL has a hard "floor" for a minimum MTU size that it will never go below. This minimum means that a Finished message will never be sent in a fragmented form and therefore the MITM does not have one of its pre-requisites. Therefore this could only be exploited if using OpenSSL and some other DTLS peer that had its own and separate Finished message injection flaw. The fix is to ensure buffered messages are cleared on epoch change. Reviewed-by: Richard Levitte <levitte@openssl.org>
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Matt Caswell authored
DTLS can handle out of order record delivery. Additionally since handshake messages can be bigger than will fit into a single packet, the messages can be fragmented across multiple records (as with normal TLS). That means that the messages can arrive mixed up, and we have to reassemble them. We keep a queue of buffered messages that are "from the future", i.e. messages we're not ready to deal with yet but have arrived early. The messages held there may not be full yet - they could be one or more fragments that are still in the process of being reassembled. The code assumes that we will eventually complete the reassembly and when that occurs the complete message is removed from the queue at the point that we need to use it. However, DTLS is also tolerant of packet loss. To get around that DTLS messages can be retransmitted. If we receive a full (non-fragmented) message from the peer after previously having received a fragment of that message, then we ignore the message in the queue and just use the non-fragmented version. At that point the queued message will never get removed. Additionally the peer could send "future" messages that we never get to in order to complete the handshake. Each message has a sequence number (starting from 0). We will accept a message fragment for the current message sequence number, or for any sequence up to 10 into the future. However if the Finished message has a sequence number of 2, anything greater than that in the queue is just left there. So, in those two ways we can end up with "orphaned" data in the queue that will never get removed - except when the connection is closed. At that point all the queues are flushed. An attacker could seek to exploit this by filling up the queues with lots of large messages that are never going to be used in order to attempt a DoS by memory exhaustion. I will assume that we are only concerned with servers here. It does not seem reasonable to be concerned about a memory exhaustion attack on a client. They are unlikely to process enough connections for this to be an issue. A "long" handshake with many messages might be 5 messages long (in the incoming direction), e.g. ClientHello, Certificate, ClientKeyExchange, CertificateVerify, Finished. So this would be message sequence numbers 0 to 4. Additionally we can buffer up to 10 messages in the future. Therefore the maximum number of messages that an attacker could send that could get orphaned would typically be 15. The maximum size that a DTLS message is allowed to be is defined by max_cert_list, which by default is 100k. Therefore the maximum amount of "orphaned" memory per connection is 1500k. Message sequence numbers get reset after the Finished message, so renegotiation will not extend the maximum number of messages that can be orphaned per connection. As noted above, the queues do get cleared when the connection is closed. Therefore in order to mount an effective attack, an attacker would have to open many simultaneous connections. Issue reported by Quan Luo. CVE-2016-2179 Reviewed-by: Richard Levitte <levitte@openssl.org>
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- 20 Aug, 2016 1 commit
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Kurt Roeckx authored
Reviewed-by: Rich Salz <rsalz@openssl.org> MR: #3176 (cherry picked from commit a73be798)
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- 19 Aug, 2016 4 commits
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Rich Salz authored
Reviewed-by: Richard Levitte <levitte@openssl.org> (cherry picked from commit 2a9afa40)
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Matt Caswell authored
A function error code needed updating due to merge issues. Reviewed-by: Richard Levitte <levitte@openssl.org>
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Matt Caswell authored
The DTLS implementation provides some protection against replay attacks in accordance with RFC6347 section 4.1.2.6. A sliding "window" of valid record sequence numbers is maintained with the "right" hand edge of the window set to the highest sequence number we have received so far. Records that arrive that are off the "left" hand edge of the window are rejected. Records within the window are checked against a list of records received so far. If we already received it then we also reject the new record. If we have not already received the record, or the sequence number is off the right hand edge of the window then we verify the MAC of the record. If MAC verification fails then we discard the record. Otherwise we mark the record as received. If the sequence number was off the right hand edge of the window, then we slide the window along so that the right hand edge is in line with the newly received sequence number. Records may arrive for future epochs, i.e. a record from after a CCS being sent, can arrive before the CCS does if the packets get re-ordered. As we have not yet received the CCS we are not yet in a position to decrypt or validate the MAC of those records. OpenSSL places those records on an unprocessed records queue. It additionally updates the window immediately, even though we have not yet verified the MAC. This will only occur if currently in a handshake/renegotiation. This could be exploited by an attacker by sending a record for the next epoch (which does not have to decrypt or have a valid MAC), with a very large sequence number. This means the right hand edge of the window is moved very far to the right, and all subsequent legitimate packets are dropped causing a denial of service. A similar effect can be achieved during the initial handshake. In this case there is no MAC key negotiated yet. Therefore an attacker can send a message for the current epoch with a very large sequence number. The code will process the record as normal. If the hanshake message sequence number (as opposed to the record sequence number that we have been talking about so far) is in the future then the injected message is bufferred to be handled later, but the window is still updated. Therefore all subsequent legitimate handshake records are dropped. This aspect is not considered a security issue because there are many ways for an attacker to disrupt the initial handshake and prevent it from completing successfully (e.g. injection of a handshake message will cause the Finished MAC to fail and the handshake to be aborted). This issue comes about as a result of trying to do replay protection, but having no integrity mechanism in place yet. Does it even make sense to have replay protection in epoch 0? That issue isn't addressed here though. This addressed an OCAP Audit issue. CVE-2016-2181 Reviewed-by: Richard Levitte <levitte@openssl.org>
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Matt Caswell authored
During a DTLS handshake we may get records destined for the next epoch arrive before we have processed the CCS. In that case we can't decrypt or verify the record yet, so we buffer it for later use. When we do receive the CCS we work through the queue of unprocessed records and process them. Unfortunately the act of processing wipes out any existing packet data that we were still working through. This includes any records from the new epoch that were in the same packet as the CCS. We should only process the buffered records if we've not got any data left. Reviewed-by: Richard Levitte <levitte@openssl.org>
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- 16 Aug, 2016 1 commit
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Richard Levitte authored
(cherry picked from commit a1be17a7 ) Conflicts: crypto/pem/pem_err.c Reviewed-by: Rich Salz <rsalz@openssl.org> Reviewed-by: Stephen Henson <steve@openssl.org>
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- 15 Aug, 2016 3 commits
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Dr. Stephen Henson authored
Apply a limit to the maximum blob length which can be read in do_d2i_bio() to avoid excessive allocation. Thanks to Shi Lei for reporting this. Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit 66bcba14)
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Dr. Stephen Henson authored
If an oversize BIGNUM is presented to BN_bn2dec() it can cause BN_div_word() to fail and not reduce the value of 't' resulting in OOB writes to the bn_data buffer and eventually crashing. Fix by checking return value of BN_div_word() and checking writes don't overflow buffer. Thanks to Shi Lei for reporting this bug. CVE-2016-2182 Reviewed-by: Tim Hudson <tjh@openssl.org> (cherry picked from commit 07bed46f) Conflicts: crypto/bn/bn_print.c
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Dr. Stephen Henson authored
Check for error return in BN_div_word(). Reviewed-by: Tim Hudson <tjh@openssl.org> (cherry picked from commit 8b9afbc0)
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- 05 Aug, 2016 2 commits
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Dr. Stephen Henson authored
Thanks to Hanno Böck for reporting this bug. Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit 39a43280) Conflicts: crypto/pkcs12/p12_utl.c
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Dr. Stephen Henson authored
Fix error path leaks in a2i_ASN1_STRING(), a2i_ASN1_INTEGER() and a2i_ASN1_ENUMERATED(). Thanks to Shi Lei for reporting these issues. Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit e1be1dce)
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- 04 Aug, 2016 3 commits
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Kurt Roeckx authored
GH: #1322 Reviewed-by: Rich Salz <rsalz@openssl.org> Reviewed-by: Stephen Henson <steve@openssl.org> (cherry picked from commit 32baafb2)
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Dr. Stephen Henson authored
Thanks to Shi Lei for reporting this bug. Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit 81f69e5b)
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Dr. Stephen Henson authored
Thanks to Shi Lei for reporting this issue. Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit af601b83)
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- 03 Aug, 2016 1 commit
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Dr. Stephen Henson authored
Use correct length in old ASN.1 indefinite length sequence decoder (only used by SSL_SESSION). This bug was discovered by Hanno Böck using libfuzzer. Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit 436dead2)
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- 02 Aug, 2016 3 commits
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Dr. Stephen Henson authored
Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit 134ab513)
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Dr. Stephen Henson authored
Reviewed-by: Richard Levitte <levitte@openssl.org> (cherry picked from commit e9f17097)
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Dr. Stephen Henson authored
Reviewed-by: Richard Levitte <levitte@openssl.org> (cherry picked from commit 56f9953c)
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- 22 Jul, 2016 1 commit
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Dr. Stephen Henson authored
TS_OBJ_print_bio() misuses OBJ_txt2obj: it should print the result as a null terminated buffer. The length value returned is the total length the complete text reprsentation would need not the amount of data written. CVE-2016-2180 Thanks to Shi Lei for reporting this bug. Reviewed-by: Matt Caswell <matt@openssl.org> (cherry picked from commit 0ed26acc)
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- 30 Jun, 2016 1 commit
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Matt Caswell authored
Ensure things really do get cleared when we intend them to. Addresses an OCAP Audit issue. Reviewed-by: Andy Polyakov <appro@openssl.org> (cherry picked from commit cb5ebf96)
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- 29 Jun, 2016 2 commits
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Richard Levitte authored
Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit 6ad8c482)
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Richard Levitte authored
While travelling up the certificate chain, the internal proxy_path_length must be updated with the pCPathLengthConstraint value, or verification will not work properly. This corresponds to RFC 3820, 4.1.4 (a). Reviewed-by: Rich Salz <rsalz@openssl.org> (cherry picked from commit 30aeb312)
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