RFR: 8337408: Use GetTempPath2 API instead of GetTempPath [v2]

[Kevin Walls]

On Thu, 15 Aug 2024 20:28:28 GMT, Dhamoder Nalla <dhanalla at openjdk.org> wrote:

>> Use the GetTempPath2 APIs instead of the GetTempPath APIs in native code across the OpenJDK repository to retrieve the temporary directory path, as GetTempPath2 provides enhanced security. While GetTempPath may still function without errors, using GetTempPath2 reduces the risk of potential exploits for users.
>> 
>> 
>> The code to dynamically load GetTempPath2 is duplicated due to the following reasons.  I would appreciate any suggestions to remove the duplication where possible:
>> 
>> 1. The changes span across four different folders—java.base, jdk.package, jdk.attach, and hotspot—with no shared code between them.
>> 2. Some parts of the code use version A, while others use version W (ANSI vs. Unicode).
>> 3. Some parts of the code are written in C others in C++.
>
> Dhamoder Nalla has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix missing code

Hi,

>From the linked doc:
"When calling this function from a process running as SYSTEM it will return the path C:\Windows\SystemTemp, which is inaccessible to non-SYSTEM processes. For non-SYSTEM processes, GetTempPath2 will behave the same as GetTempPath."

If SYSTEM and regular user processes have a different temp path, and we change temp as it's known to the attach api, they will have a different hsperfdata_username locations.

Then does the attach api only find processes that are of the same category (SYSTEM vs non-SYSTEM)?  e.g. "jps" for a user does not show SYSTEM processes?

SYSTEM is not the "Administrator" user, so it's not going to be a very common problem, but if a Java process run as a SYSTEM then it could be an issue (is that possible?).

And if Java can't be run as a SYSTEM task, then the doc states GetTempPath2 will behave the same as GetTempPath.

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PR Review: https://git.openjdk.org/jdk/pull/20600#pullrequestreview-2250236104