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: make /dev/cpu/<n>/cpuid world readable

PATCH Applied Andre Przywara 2 participants 2 messages Apr 23, 2009

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PATCH 1/1 : make /dev/cpu/<n>/cpuid world readable

Hi,

as I don't see any security implications, to be actually useful /dev/cpu/<n>/cpuid should be world readable. The cpuid instruction can be called from userspace anyway, so there is nothing to hide. The device does not support any write operation, so 0444 should suffice. Please apply so that distributions can follow.

Regards,
Andre.

rules/rules.d/50-udev-default.rules +1 -1
index 240cb3b..72e5b55 100644
@@ -95,7 +95,7 @@ SUBSYSTEM="aoe", KERNEL="err", MODE="0440"
 KERNEL="tun",                 NAME="net/%k", MODE="0666"
 
 # CPU
-KERNEL="cpu[0-9]*",           NAME="cpu/%n/cpuid"
+KERNEL="cpu[0-9]*",           NAME="cpu/%n/cpuid", MODE="0444"
 KERNEL="msr[0-9]*",           NAME="cpu/%n/msr"
 KERNEL="microcode",           NAME="cpu/microcode", MODE="0600"
 

--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 488-3567-12
----to satisfy European Law for business letters:
Advanced Micro Devices GmbH
Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen
Geschaeftsfuehrer: Jochen Polster; Thomas M. McCoy; Giuliano Meroni
Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632

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Quoted 3 lines · Andre Przywara

as I don't see any security implications, to be actually useful /dev/cpu/<n>/cpuid should be world readable. The cpuid instruction can be called from userspace anyway, so there is nothing to hide.

Applied.

Thanks,
Kay