Check for excessively small times in kern_clock_settime().
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Authored by markj on May 3 2019, 4:05 PM.

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cem
imp
kib

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rS347063: Disallow excessively small times of day in clock_settime(2).

Summary

This addresses a panic hit by syzkaller if wall_cmos_clock is set.

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rS FreeBSD src repository - subversion

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markj created this revision.May 3 2019, 4:05 PM

Harbormaster completed remote builds in B24087: Diff 57012.May 3 2019, 4:05 PM

markj added reviewers: cem, imp, kib.May 3 2019, 4:06 PM

If this causes a panic, maybe it shouldn't be conditional on allow_insane_settime? After all, syzkaller may eventually discovered sysctls.

Otherwise, LGTM.

This revision is now accepted and ready to land.May 3 2019, 4:37 PM

In D20151#433908, @cem wrote:

If this causes a panic, maybe it shouldn't be conditional on allow_insane_settime? After all, syzkaller may eventually discovered sysctls.

The commit log message for r312702 hints that allow_insane_settime already prevents a privileged user from panicking the system.

syzkaller would probably discover debug.kdb.panic first. :)

I forget why we left that knob, then. :)

kib accepted this revision.May 3 2019, 6:04 PM

Closed by commit rS347063: Disallow excessively small times of day in clock_settime(2). (authored by markj). · Explain WhyMay 3 2019, 9:27 PM

This revision was automatically updated to reflect the committed changes.

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head/

sys/

kern/

kern_time.c

4 lines

Diff 57019

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Check for excessively small times in kern_clock_settime().ClosedPublicActions