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>
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>
If OPENSSL_sk_insert() calls OPENSSL_realloc() and it fails, it was leaking
the originally allocated memory.
Reviewed-by: Rich Salz <rsalz@openssl.org>
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.
Issue reported by Shi Lei.
Reviewed-by: Rich Salz <rsalz@openssl.org>
There are cases when argc is more trustable than proper argv termination.
Since we trust argc in all other test programs, we might as well treat it
the same way in this program.
Reviewed-by: Matt Caswell <matt@openssl.org>
We should check the last BN_CTX_get() call to ensure that it isn't NULL
before we try and use any of the allocated BIGNUMs.
Issue reported by Shi Lei.
Reviewed-by: Richard Levitte <levitte@openssl.org>
Note: server-cmod doesn't seem to do things right... from loading
cmod.cnf, it tries to load libssl_conf.so.
Reviewed-by: Rich Salz <rsalz@openssl.org>
All the other functions that take an argument for the number of bytes
use convenience macros for this purpose. We should do the same with
WPACKET_put_bytes().
Reviewed-by: Rich Salz <rsalz@openssl.org>
CMS_NOOLDMIMETYPE and PKCS7_NOOLDMIMETYPE are unused in pkcs7/cms code.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1585)
We were casting num_alloc to size_t in lots of places, or just using it in
a context where size_t makes more sense - so convert it. This simplifies
the code a bit.
Also tweak the style in stack.c a bit following on from the previous
commit
Reviewed-by: Rich Salz <rsalz@openssl.org>
no-rsa is no longer an option since 7ec8de1
Fix a typo about poly1305
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1582)
In an earlier attempt to simplify the processing of disabled options,
'no-err' and 'no-async' stopped working properly. 'err' and 'async'
are directories under 'crypto/', but they are special insofar that
they can't be simply skipped, like all the algorithm directories can,
so they need special treatment among the disablable things.
Reviewed-by: Tim Hudson <tjh@openssl.org>
APP_INFO is currently a field of MEM struct.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1583)
Makes the logic a little bit clearer.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1571)
This reverts commit 77a6be4dfc.
There were some unexpected side effects to this commit, e.g. in SSLv3 a
warning alert gets sent "no_certificate" if a client does not send a
Certificate during Client Auth. With the above commit this causes the
connection to abort, which is incorrect. There may be some other edge cases
like this so we need to have a rethink on this.
Reviewed-by: Tim Hudson <tjh@openssl.org>
