RFR: 8300491: SymbolLookup::libraryLookup accepts strings with terminators [v2]

[Maurizio Cimadamore]

> There is a difference in behavior between `System::loadLibrary` and `SymbolLookup::libraryLookup(String)`. While the former catches library names containing NULL chars (because, internally it uses Path/File logic, which reject those), `SymbolLookup` does not. As a result, it is possible to load libraries such as `libGL.so\0foobar`, because the string is passed directly to `dlopen`.
> 
> A similar issue arises when we consider `SymbolLookup::find`, as the name is again sent unmodified to `dlopen`. In reality, some filtering *does* happen in that case, as the native code calls `GetStringUTFChars`:
> 
> https://docs.oracle.com/en/java/javase/20/docs/specs/jni/functions.html#getstringutfchars
> 
> Which encodes the NULL chars in a different form:
> 
> https://docs.oracle.com/en/java/javase/20/docs/specs/jni/types.html#modified-utf-8-strings
> 
> So, in practice, even if the input is not validated, a call to `find` with one or more NULL chars is unlikely to succeed.
> 
> In this patch I have added several checks to make sure that:
> * the name of library passed to `libraryLookup(String)` does not contain `\0` and, if so, throw `IllegalArgumentException` (which is already covered by current spec;
> * the name of a symbol passed to `SymbolLookup::find` does not contain `\0` and, if so, return empty optional. This required changes on all the lookups we implement.

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  Add test for system lookup

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/14126/files
  - new: https://git.openjdk.org/jdk/pull/14126/files/706e9585..52077b57

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14126&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14126&range=00-01

  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14126.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14126/head:pull/14126

PR: https://git.openjdk.org/jdk/pull/14126