Re: Further shmctl() SHM_LOCK strangeness

[Rik van Riel]

On Wed, 24 Nov 2004, Hugh Dickins wrote:

> > regardles of the segment's ownership or permissions,
> > providing the size of the segment falls within the
> > process's RLIMIT_MEMLOCK limit.

> Offhand I find it hard to grasp whether it's harmless or bad,
> but inclined to think bad - if there happen to be lots of small
> enough shared memory segments on the system, a series of processes
> run by one unprivileged user can lock down lots of memory?

Mlocking and munlocking of shm segments is accounted
against the user_struct, not against the process.

This should stop any malicious exploits.

--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan
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