Messages in this thread | | | Subject | Re: [PATCH] exec: Only allow a threaded init to exec from the thread_group_leader | From | (Eric W. Biederman) | Date | Sun, 29 Jan 2006 14:32:19 -0700 |
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Pavel Machek <pavel@ucw.cz> writes:
> On Ne 29-01-06 02:48:31, Andrew Morton wrote: >> ebiederm@xmission.com (Eric W. Biederman) wrote: >> > >> > If process id namespaces become a reality init stops being >> > terribly special, and becomes something you may have several >> > of running at any one time. If one of those inits is compromised >> > by a hostile user I having the whole system go down so we can >> > avoid executing a cheap test sounds terribly wrong. That is >> > why I really care. >> >> Wouldn't it be better to do nothing until/unless there's some code in the >> kernel or init which actually needs the change?
Well I think deliberate kernel bugs should at least be accompanied by a big fat warning in the code, and an explanation of what is happening and why.
> It is common to do init=/bin/bash, and I guess people are doing it > with all kinds of wonderful apps....
So it is just a matter of time before someone actually hits this.
I went back through and tested and the actual symptoms are weird. The thread calling exec just hangs forever, waiting for pid == 1 to exit. Anyway I found a simple fix so it is probably better to fix it than to paper over the problem anyway.
Patch follows in a minute.
Eric
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