Messages in this thread | | | Date | Mon, 2 Jul 2007 11:38:35 -0700 | From | Andy Isaacson <> | Subject | Re: [patch 0/4] MAP_NOZERO v2 - VM_NOZERO/MAP_NOZERO early summer madness |
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On Sat, Jun 30, 2007 at 12:03:07PM -0700, Davide Libenzi wrote: > I think the focus should be to find a case where under the currently > implemented policy for MAP_NOZERO, MAP_NOZERO represent a loss of security > WRT no MAP_NOZERO. I have not been able to find one yet, although Andy > found a potential one in the setuid+exec/ptrace race (fixed by a patch > that should IMO go in in any case).
BTW, the ptrace variant of this issue is not a problem -- PTRACE_ATTACH running as newuid gets EPERM when trying to attach at /* here */ below.
setuid(newuid); /* here */ exec(...); exit(1);
sys_setuid sets current->mm->dumpable = suid_dumpable, so unless the admin asked for it, there is no risk WRT PTRACE_ATTACH. However, this risk vector does need to be considered when implementing MAP_NOZERO.
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