Richard Levitte [Wed, 12 Oct 2016 13:30:43 +0000 (15:30 +0200)]
Add support for C++ in Configurations/unix-Makefile.tmpl
Note that it relies on a trick from Configure, where file names for
object files made from C++ source get '.cc' replaced with '_cc.o' to
recognise them. This is needed so the correct compiler is used when
linking binaries.
Richard Levitte [Wed, 12 Oct 2016 13:30:08 +0000 (15:30 +0200)]
Add support for C++ in Configure
A note: this will form object file names by changing '.cc' to
'_cc.o'. This will permit other configuration code to recognise these
object files were built for C++ rather than C.
David Benjamin [Mon, 10 Oct 2016 16:01:24 +0000 (12:01 -0400)]
Remove trailing whitespace from some files.
The prevailing style seems to not have trailing whitespace, but a few
lines do. This is mostly in the perlasm files, but a few C files got
them after the reformat. This is the result of:
Matt Caswell [Fri, 30 Sep 2016 09:50:57 +0000 (10:50 +0100)]
Remove the special case processing for finished construction
tls_construct_finished() used to have different arguments to all of the
other construction functions. It doesn't anymore, so there is no neeed to
treat it as a special case.
Matt Caswell [Fri, 30 Sep 2016 09:38:32 +0000 (10:38 +0100)]
Harmonise setting the header and closing construction
Ensure all message types work the same way including CCS so that the state
machine doesn't need to know about special cases. Put all the special logic
into ssl_set_handshake_header() and ssl_close_construct_packet().
Matt Caswell [Thu, 29 Sep 2016 21:40:15 +0000 (22:40 +0100)]
Rename ssl_set_handshake_header2()
ssl_set_handshake_header2() was only ever a temporary name while we had
to have ssl_set_handshake_header() for code that hadn't been converted to
WPACKET yet. No code remains that needed that so we can rename it.
Matt Caswell [Thu, 29 Sep 2016 10:43:37 +0000 (11:43 +0100)]
Add the WPACKET_reserve_bytes() function
WPACKET_allocate_bytes() requires you to know the size of the data you
are allocating for, before you create it. Sometimes this isn't the case,
for example we know the maximum size that a signature will be before we
create it, but not the actual size. WPACKET_reserve_bytes() enables us to
reserve bytes in the WPACKET, but not count them as written yet. We then
subsequently need to acall WPACKET_allocate_bytes to actually count them as
written.
Matt Caswell [Thu, 29 Sep 2016 13:26:36 +0000 (14:26 +0100)]
Remove tls12_copy_sigalgs_old()
This was a temporary function needed during the conversion to WPACKET. All
callers have now been converted to the new way of doing this so this
function is no longer required.
Matt Caswell [Wed, 28 Sep 2016 10:15:36 +0000 (11:15 +0100)]
Delete some unneeded code
Some functions were being called from both code that used WPACKETs and code
that did not. Now that more code has been converted to use WPACKETs some of
that duplication can be removed.
Richard Levitte [Wed, 28 Sep 2016 19:28:00 +0000 (21:28 +0200)]
apps/apps.c: initialize and de-initialize engine around key loading
Before loading a key from an engine, it may need to be initialized.
When done loading the key, we must de-initialize the engine.
(if the engine is already initialized somehow, only the reference
counter will be incremented then decremented)
David Woodhouse [Wed, 28 Sep 2016 12:08:45 +0000 (13:08 +0100)]
Call ENGINE_init() before trying to use keys from engine
When I said before that s_client "used to work in 1.0.2" that was only
partly true. It worked for engines which provided a default generic
method for some key type, because it called ENGINE_set_default() and
that ended up being an implicit initialisation and functional refcount.
But an engine which doesn't provide generic methods doesn't get initialised,
and then when you try to use it you get an error:
cannot load client certificate private key file from engine 140688147056384:error:26096075:engine routines:ENGINE_load_private_key:not initialised:crypto/engine/eng_pkey.c:66:
unable to load client certificate private key file
cf. https://github.com/OpenSC/libp11/issues/107 (in which we discover
that engine_pkcs11 *used* to provide generic methods that OpenSSL would
try to use for ephemeral DH keys when negotiating ECDHE cipher suites in
TLS, and that didn't work out very well.)
Reviewed-by: Rich Salz <rsalz@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1639)
Matt Caswell [Fri, 23 Sep 2016 15:58:11 +0000 (16:58 +0100)]
Fix Use After Free for large message sizes
The buffer to receive messages is initialised to 16k. If a message is
received that is larger than that then the buffer is "realloc'd". This can
cause the location of the underlying buffer to change. Anything that is
referring to the old location will be referring to free'd data. In the
recent commit c1ef7c97 (master) and 4b390b6c (1.1.0) the point in the code
where the message buffer is grown was changed. However s->init_msg was not
updated to point at the new location.
Matt Caswell [Wed, 21 Sep 2016 10:20:18 +0000 (11:20 +0100)]
Add warning about a potential pitfall with WPACKET_allocate_bytes()
If the underlying BUF_MEM gets realloc'd then the pointer returned could
become invalid. Therefore we should always ensure that the allocated
memory is filled in prior to any more WPACKET_* calls.
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: Matt Caswell <matt@openssl.org>
Matt Caswell [Sat, 10 Sep 2016 20:24:40 +0000 (21:24 +0100)]
Fix a hang with SSL_peek()
If while calling SSL_peek() we read an empty record then we go into an
infinite loop, continually trying to read data from the empty record and
never making any progress. This could be exploited by a malicious peer in
a Denial Of Service attack.
Matt Caswell [Fri, 9 Sep 2016 09:53:39 +0000 (10:53 +0100)]
Fix a mem leak in NPN handling
If a server sent multiple NPN extensions in a single ClientHello then a
mem leak can occur. This will only happen where the client has requested
NPN in the first place. It does not occur during renegotiation. Therefore
the maximum that could be leaked in a single connection with a malicious
server is 64k (the maximum size of the ServerHello extensions section). As
this is client side, only occurs if NPN has been requested and does not
occur during renegotiation this is unlikely to be exploitable.
Matt Caswell [Fri, 9 Sep 2016 09:08:45 +0000 (10:08 +0100)]
Fix OCSP Status Request extension unbounded memory growth
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.
Matt Caswell [Mon, 19 Sep 2016 10:57:07 +0000 (11:57 +0100)]
Excessive allocation of memory in dtls1_preprocess_fragment()
This issue is very similar to CVE-2016-6307 described in the previous
commit. The underlying defect is different but the security analysis and
impacts are the same except that it impacts DTLS.
A DTLS message includes 3 bytes for its length in the header for the
message.
This would allow for messages up to 16Mb in length. Messages of this length
are excessive and OpenSSL includes a check to ensure that a peer is sending
reasonably sized messages in order to avoid too much memory being consumed
to service a connection. A flaw in the logic of version 1.1.0 means that
memory for the message is allocated too early, prior to the excessive
message length check. Due to way memory is allocated in OpenSSL this could
mean an attacker could force up to 21Mb to be allocated to service a
connection. This could lead to a Denial of Service through memory
exhaustion. However, the excessive message length check still takes place,
and this would cause the connection to immediately fail. Assuming that the
application calls SSL_free() on the failed conneciton in a timely manner
then the 21Mb of allocated memory will then be immediately freed again.
Therefore the excessive memory allocation will be transitory in nature.
This then means that there is only a security impact if:
1) The application does not call SSL_free() in a timely manner in the
event that the connection fails
or
2) The application is working in a constrained environment where there
is very little free memory
or
3) The attacker initiates multiple connection attempts such that there
are multiple connections in a state where memory has been allocated for
the connection; SSL_free() has not yet been called; and there is
insufficient memory to service the multiple requests.
Except in the instance of (1) above any Denial Of Service is likely to
be transitory because as soon as the connection fails the memory is
subsequently freed again in the SSL_free() call. However there is an
increased risk during this period of application crashes due to the lack
of memory - which would then mean a more serious Denial of Service.
This issue does not affect TLS users.
Issue was reported by Shi Lei (Gear Team, Qihoo 360 Inc.).
CVE-2016-6308
Reviewed-by: Richard Levitte <levitte@openssl.org>
Matt Caswell [Mon, 19 Sep 2016 10:39:21 +0000 (11:39 +0100)]
Excessive allocation of memory in tls_get_message_header()
A TLS message includes 3 bytes for its length in the header for the message.
This would allow for messages up to 16Mb in length. Messages of this length
are excessive and OpenSSL includes a check to ensure that a peer is sending
reasonably sized messages in order to avoid too much memory being consumed
to service a connection. A flaw in the logic of version 1.1.0 means that
memory for the message is allocated too early, prior to the excessive
message length check. Due to way memory is allocated in OpenSSL this could
mean an attacker could force up to 21Mb to be allocated to service a
connection. This could lead to a Denial of Service through memory
exhaustion. However, the excessive message length check still takes place,
and this would cause the connection to immediately fail. Assuming that the
application calls SSL_free() on the failed conneciton in a timely manner
then the 21Mb of allocated memory will then be immediately freed again.
Therefore the excessive memory allocation will be transitory in nature.
This then means that there is only a security impact if:
1) The application does not call SSL_free() in a timely manner in the
event that the connection fails
or
2) The application is working in a constrained environment where there
is very little free memory
or
3) The attacker initiates multiple connection attempts such that there
are multiple connections in a state where memory has been allocated for
the connection; SSL_free() has not yet been called; and there is
insufficient memory to service the multiple requests.
Except in the instance of (1) above any Denial Of Service is likely to
be transitory because as soon as the connection fails the memory is
subsequently freed again in the SSL_free() call. However there is an
increased risk during this period of application crashes due to the lack
of memory - which would then mean a more serious Denial of Service.
This issue does not affect DTLS users.
Issue was reported by Shi Lei (Gear Team, Qihoo 360 Inc.).
CVE-2016-6307
Reviewed-by: Richard Levitte <levitte@openssl.org>
Matt Caswell [Wed, 21 Sep 2016 13:07:31 +0000 (14:07 +0100)]
Don't allow too many consecutive warning alerts
Certain warning alerts are ignored if they are received. This can mean that
no progress will be made if one peer continually sends those warning alerts.
Implement a count so that we abort the connection if we receive too many.