Fix a race condition in process.run_duplicate_streams
#186
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This commit fixes a race condition in a standard stream duplicating loop in `process.run_duplicate_streams`, where the subprocess would write to its standard streams after the last read in the parent process, and then terminate before another iteration would be started, and therefor leaving the last parts of the streams unread. This fix includes a last post-loop read, which can only take place after the process has terminated, and no longer writes to its streams.
This fixes a potential subversion of the timeout parameter in `process.run_duplicate_streams`. That is, if the child process writes to much and too fast to its standard streams, the parent process will take too long (or even indefinitely) to read and then write the contents to its own standard streams, before it e.g. checks whether the process should timeout. This change adds a size parameter to the relevant read functions to prevent above.
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3cec858 fixes another issue in |
lukpueh
added a commit
to in-toto/in-toto
that referenced
this pull request
Oct 1, 2019
The added patches fix two race conditions in in-toto's process module. They will be fixed upstream, but not in in-toto but in securesystemslib, where the process module has been moved to. See secure-systems-lab/securesystemslib#186 Signed-off-by: Lukas Puehringer <[email protected]>
3 tasks
adityasaky
approved these changes
Oct 15, 2019
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Many thanks, @adityasaky! |
3 tasks
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Fixes issue #:
in-toto/in-toto#282
Description of the changes being introduced by the pull request:
This PR fixes a race condition in a standard stream duplicating loop in
process.run_duplicate_streams, where the subprocess would write to its standard streams after the last read in the parent process, and then terminate before another iteration would be started, and therefor leaving the last parts of the streams unread.Also adds a note about buffered outputs in child process to the function's docstring.
Please verify and check that the pull request fulfills the following
requirements: