Messages in this thread | | | Date | Wed, 20 May 1998 14:35:32 +0200 (MET DST) | From | Rik van Riel <> | Subject | Re: PATCH: signals security |
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On Wed, 20 May 1998, Pavel Machek wrote:
> > > + * 1998-05-19 Security fix: don't allow SIGKILL & friends just because > > > + * you have same real uid. Pavel Machek > > > > Catastrophe. I can no longer kill processes I created that happened to be > > setuid. Please _THINK_ what you are trying to achieve, and understand why > > Ok - what I'm trying to achieve is that user will no longer be able to > kill suid X server with SIGKILL. Please take a look at code: you still
Let me summarize: - you want to disallow SIGKILL to processes which do raw I/O - so you check for the suid() bit.
This is obviously _not_ correct, since: - raw I/O will be a capability CAP_RAW_IO - root may have some raw-I/O programs that are _not_ suid, since root is the only one who is allowed to use the program
You are probably better off using some of the code in my Out-Of-Memory killer. It checks: - whether the x86 I/O bitmap has been set up - whether the process has raw I/O capability (CAP_RAW_IO)
Now we probably want to modify the ioperm() and iopl() syscalls to set CAP_RAW_IO, so we can do an easy arch independant check. (the capability itself is in the allowed bitmap and it should only be set in the current bitmap when it's actually used)
Rik. +-------------------------------------------+--------------------------+ | Linux: - LinuxHQ MM-patches page | Scouting webmaster | | - kswapd ask-him & complain-to guy | Vries cubscout leader | | http://www.phys.uu.nl/~riel/ | <H.H.vanRiel@phys.uu.nl> | +-------------------------------------------+--------------------------+
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