Changes between 1.0.2m and 1.0.2n [xx XXX xxxx]
- *)
+ *) Read/write after SSL object in error state
+
+ OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state"
+ mechanism. The intent was that if a fatal error occurred during a handshake
+ then OpenSSL would move into the error state and would immediately fail if
+ you attempted to continue the handshake. This works as designed for the
+ explicit handshake functions (SSL_do_handshake(), SSL_accept() and
+ SSL_connect()), however due to a bug it does not work correctly if
+ SSL_read() or SSL_write() is called directly. In that scenario, if the
+ handshake fails then a fatal error will be returned in the initial function
+ call. If SSL_read()/SSL_write() is subsequently called by the application
+ for the same SSL object then it will succeed and the data is passed without
+ being decrypted/encrypted directly from the SSL/TLS record layer.
+
+ In order to exploit this issue an application bug would have to be present
+ that resulted in a call to SSL_read()/SSL_write() being issued after having
+ already received a fatal error.
+
+ This issue was reported to OpenSSL by David Benjamin (Google).
+ (CVE-2017-3737)
+ [Matt Caswell]
+
+ *) rsaz_1024_mul_avx2 overflow bug on x86_64
+
+ There is an overflow bug in the AVX2 Montgomery multiplication procedure
+ used in exponentiation with 1024-bit moduli. No EC algorithms are affected.
+ Analysis suggests that attacks against RSA and DSA as a result of this
+ defect would be very difficult to perform and are not believed likely.
+ Attacks against DH1024 are considered just feasible, because most of the
+ work necessary to deduce information about a private key may be performed
+ offline. The amount of resources required for such an attack would be
+ significant. However, for an attack on TLS to be meaningful, the server
+ would have to share the DH1024 private key among multiple clients, which is
+ no longer an option since CVE-2016-0701.
+
+ This only affects processors that support the AVX2 but not ADX extensions
+ like Intel Haswell (4th generation).
+
+ This issue was reported to OpenSSL by David Benjamin (Google). The issue
+ was originally found via the OSS-Fuzz project.
+ (CVE-2017-3738)
+ [Andy Polyakov]
Changes between 1.0.2l and 1.0.2m [2 Nov 2017]