On Mon, 13 May 2024 11:38:40 GMT, Maurizio Cimadamore
wrote:
>> This PR implements [JEP 472](https://openjdk.org/jeps/472), by restricting
>> the use of JNI in the following ways:
>>
>> * `System::load` and `System::loadLibrary` are now restricted methods
>> * `Runtime::load` and `Runtime::loadLibrary` are now restricted methods
>> * binding a JNI `native` method declaration to a native implementation is
>> now considered a restricted operation
>>
>> This PR slightly changes the way in which the JDK deals with restricted
>> methods, even for FFM API calls. In Java 22, the single
>> `--enable-native-access` was used both to specify a set of modules for which
>> native access should be allowed *and* to specify whether illegal native
>> access (that is, native access occurring from a module not specified by
>> `--enable-native-access`) should be treated as an error or a warning. More
>> specifically, an error is only issued if the `--enable-native-access flag`
>> is used at least once.
>>
>> Here, a new flag is introduced, namely
>> `illegal-native-access=allow/warn/deny`, which is used to specify what
>> should happen when access to a restricted method and/or functionality is
>> found outside the set of modules specified with `--enable-native-access`.
>> The default policy is `warn`, but users can select `allow` to suppress the
>> warnings, or `deny` to cause `IllegalCallerException` to be thrown. This
>> aligns the treatment of restricted methods with other mechanisms, such as
>> `--illegal-access` and the more recent `--sun-misc-unsafe-memory-access`.
>>
>> Some changes were required in the package-info javadoc for
>> `java.lang.foreign`, to reflect the changes in the command line flags
>> described above.
>
> Maurizio Cimadamore has updated the pull request incrementally with one
> additional commit since the last revision:
>
> Avoid call to VM::isModuleSystemInited
> Use initial error stream
src/java.base/share/classes/jdk/internal/reflect/Reflection.java line 124:
> 122: if (module != null) {
> 123: // not in init phase
> 124: Holder.JLA.ensureNativeAccess(module, owner, methodName,
> currentClass);
In an earlier iteration I had a call to `VM::isModuleSystemInited`, but I
discovered that caused a performance regression, since that method involves a
volatile access. Perhaps we should rethink that part of the init code to use
stable fields, but it's probably better done separately.
-
PR Review Comment: https://git.openjdk.org/jdk/pull/19213#discussion_r1598328283
