fix: remove -O from nmap; OS detection requires root - #36
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nmap hard-codes geteuid()==0 for -O (OS fingerprinting) regardless of Linux file capabilities. Running as non-root uid 1000 always triggers: 'TCP/IP fingerprinting (for OS scan) requires root privileges. QUITTING!' causing the entire nmap scan to abort, losing all service/version data. -O was documented as best-effort; os_guess will be empty string. All other scan data (ports, services, version banners) is unaffected. Test added: test_does_not_use_os_detection_flag asserts -O absent. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Problem
ARP scan finds hosts correctly, but nmap immediately quits:
This aborts the entire nmap run — no port or service data is collected.
Root Cause
nmap's OS detection (
-O) contains a hard-codedgeteuid() == 0check. File capabilities (setcap cap_net_raw+ep) do not affectgeteuid()— it always returns non-zero for uid 1000. No capability-based workaround exists.Fix
Remove
-Ofrom the nmap command. Persystem_config.md, OS detection was already documented as "best-effort".os_guesswill be an empty string; all port and service/version data is unaffected.Test
test_does_not_use_os_detection_flag— asserts-Ois absent and-sVis present in the built command.