Two system properties have been added which control the keep alive behavior of HttpURLConnection in the case where the server does not specify a keep alive time. Two properties are defined for controlling connections to servers and proxies separately. They are:
respectively. More information about them can be found on the Networking Properties page.
The HttpServer can be optionally configured with a maximum connection limit by setting the jdk.httpserver.maxConnections system property. A value of
0 or a negative integer is ignored and considered to represent no connection limit. In the case of a positive integer value, any newly accepted connections will be first checked against the current count of established connections and, if the configured limit has been reached, then the newly accepted connection will be closed immediately.
Previous JDK releases used an incorrect interpretation of the Linux cgroups parameter "cpu.shares". This might cause the JVM to use fewer CPUs than available, leading to an under utilization of CPU resources when the JVM is used inside a container.
Starting from this JDK release, by default, the JVM no longer considers "cpu.shares" when deciding the number of threads to be used by the various thread pools. The
-XX:+UseContainerCpuShares command-line option can be used to revert to the previous behaviour. This option is deprecated and may be removed in a future JDK release.
JARs signed with SHA-1 algorithms are now restricted by default and treated as if they were unsigned. This applies to the algorithms used to digest, sign, and optionally timestamp the JAR. It also applies to the signature and digest algorithms of the certificates in the certificate chain of the code signer and the Timestamp Authority, and any CRLs or OCSP responses that are used to verify if those certificates have been revoked. These restrictions also apply to signed JCE providers.
To reduce the compatibility risk for JARs that have been previously timestamped, there is one exception to this policy:
This exception may be removed in a future JDK release. To determine if your signed JARs are affected by this change, run:
$ jarsigner -verify -verbose -certs`
on the signed JAR, and look for instances of "SHA1" or "SHA-1" and "disabled" and a warning that the JAR will be treated as unsigned in the output.
Signed by "CN="Signer"" Digest algorithm: SHA-1 (disabled) Signature algorithm: SHA1withRSA (disabled), 2048-bit key WARNING: The jar will be treated as unsigned, because it is signed with a weak algorithm that is now disabled by the security property: jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024, DSA keySize < 1024, SHA1 denyAfter 2019-01-01
JARs affected by these new restrictions should be replaced or re-signed with stronger algorithms.
Users can, at their own risk, remove these restrictions by modifying the
java.security configuration file (or override it by using the
java.security.properties system property) and removing "SHA1 usage SignedJAR & denyAfter 2019-01-01" from the
jdk.certpath.disabledAlgorithms security property and "SHA1 denyAfter 2019-01-01" from the
jdk.jar.disabledAlgorithms security property.
The default MAC algorithm used in a PKCS #12 keystore has been updated. The new algorithm is based on SHA-256 and is stronger than the old one based on SHA-1. See the security properties starting with
keystore.pkcs12 in the
java.security file for detailed information.
The new SHA-256 based MAC algorithms were introduced in the 11.0.12 release. Keystores created using this newer, stronger, MAC algorithm cannot be opened in versions of OpenJDK 11 earlier than 11.0.12. A 'java.security.NoSuchAlgorithmException' exception will be thrown in such circumstances.
For compatibility, use the
keystore.pkcs12.legacy system property, which will revert the algorithms to use the older, weaker
algorithms. There is no value defined for this property.
It is now possible to monitor deserialization of objects using JDK Flight Recorder (JFR). When JFR is enabled and the JFR configuration includes deserialization events, JFR will emit an event whenever the running program attempts to deserialize an object. The deserialization event is named
jdk.Deserialization, and it is disabled by default. The deserialization event contains information that is used by the serialization filter mechanism; see the ObjectInputFilter API specification for details.
Additionally, if a filter is enabled, the JFR event indicates whether the filter accepted or rejected deserialization of the object. For further information about how to use the JFR deserialization event, see the article "Monitoring Deserialization to Improve Application Security".
rc4-hmac Kerberos encryption types (etypes) are now deprecated and disabled by default. Users can set
allow_weak_crypto = true in the
krb5.conf configuration file to re-enable them (along with other weak etypes including
des-cbc-md5) at their own risk. To disable a subset of the weak etypes, users can list preferred etypes explicitly in any of the
Updates may require up to 24 hours to propagate to mirrors. If the following command doesn't work, please retry later:
sudo dnf upgrade --refresh --advisory=FEDORA-2022-d989953883
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