santad: Add signal auth to tamper resistence. #1360
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pmarkowsky
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Source/santad/EventProviders/SNTEndpointSecurityTamperResistance.mm
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Root users can currently kill the com.google.santa.daemon process. It will be immediately restarted by sysextd but this opens a very brief window where protection is lost. Hooking AUTH_SIGNAL and blocking all signals to the santad process except those sent by launchd lets us block this without breaking upgrades, reboots, etc. This leaves `launchctl kill` and friends as an avenue, so we're also hooking for exec and blocking executions of launchctl that reference com.google.santa.daemon except in known safe cases.
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mlw
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mlw
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Source/santad/EventProviders/SNTEndpointSecurityTamperResistance.mm
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Root users can currently kill the
com.google.santa.daemonprocess. It will be immediately restarted by sysextd but this opens a very brief window where protection is lost. HookingES_EVENT_TYPE_AUTH_SIGNALand blocking all signals to the santad process prevents this and it doesn't interfere with upgrades.