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HewlettPackard / netperf

Netperf is a benchmark that can be used to measure the performance of many different types of networking. It provides tests for both unidirectional throughput, and end-to-end latency.
MIT License
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netserver changes permissions on /dev/null by default #26

Open daniellawson opened 6 years ago

daniellawson commented 6 years ago

On non-Windows systems, if you run netserver without the -d parameter, it sets the debug output file 'FileName' to /dev/null

eg, see open_debug_file() in netserver.c:259

Later on in the same function, it then calls chmod(FileName,0644); (netserver.c:281). If the executing user has the right permissions (eg, is root), netserver will change the permissions on /dev/null which may then cause other issues on the machine, as many non-root processes assume they can write to /dev/null

Arguably, no one should be running netserver as root, but there are plenty of people who do.

I'm not entirely sure why the chmod call is needed - I suspect setting a better umask on netserver in general, or at least when opening the debug log file, would be better. The other improvement would be that instead of continuing to write debug logs to /dev/null, to just not write them out at all. But I've only just skimmed the source, I don't think I fully understand the way debug logging is implemented

grundlerchromium commented 6 years ago

Daniel, totally right. I'm one of those people that usually runs netperf as root. :) Have time to submit a patch that uses umask instead of chmod? (That way you get credit for spotting+fixing this)

luisgerhorst commented 9 months ago

For those not wanting to search further, the following should work on most distros:

$ sudo -u nobody netserver