[jboss-jira] [JBoss JIRA] (WFCORE-464) ProcessController's BufferedReader.readLine() usage allows unbounded memory usage

[James Livingston (JIRA)]

James Livingston created WFCORE-464:
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             Summary: ProcessController's BufferedReader.readLine() usage allows unbounded memory usage
                 Key: WFCORE-464
                 URL: https://issues.jboss.org/browse/WFCORE-464
             Project: WildFly Core
          Issue Type: Bug
          Components: Domain Management
    Affects Versions: 1.0.0.Alpha14
            Reporter: James Livingston
            Assignee: Brian Stansberry


org.jboss.as.process.ManagedProcess$ReadTask.run() uses readLine() to read a line of output from the manage process' standard output/error streams, which cause the whole line to be loaded into memory.

Badly written applications may dump excessive amounts of data out in a single line, which would cause the process controller to temporarily use a large amount of memory to process it, potentially leading to an OutOfMemoryError. Practically speaking, with the default -Xmx512m it would require around 128 million characters in a single line to trigger, which is obviously very high.


Were an OOME to occur, it would almost certainly cause the stream to be closed, and "IOException: Broken pipe" exceptions to occur in the child process, which for WildFly would be caught an ignored by JBoss Logging. A hostile managed process exploiting this would be almost impossible.


A reasonable solution would probably be to limit size of the buffer read, causing it to split lines over a certain size (a few megabytes?). That would not likely cause any practical problems.



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