oss-sec mailing list archives

Re: Vixie/ISC Cron group crontab to root escalation


From: Fiedler Roman <Roman.Fiedler () ait ac at>
Date: Tue, 13 Jun 2017 16:42:06 +0000

Von: Florian Weimer [mailto:fweimer () redhat com]

On 06/13/2017 02:32 PM, Fiedler Roman wrote:
Well, partially: what O_PATH can do, you could also do before O_PATH
using
repeated single-level open(NO_FOLLOW)/fstat-checks. So you had to do
all the
verification by yourself.

That's not completely accurate because open/close on device nodes can
have side effects (the classic example is a rewinding tape device).
O_PATH gives you an opportunity to perform these policy checks before
the side effect happens.

So true, I know about this case. But my initial messages was not intended to 
compare subtle differences O_PATH with other OS file access functionality 
already available but - prove me wrong - to argue for extending open 
functionality in general using features O_PATH to my knowledge cannot provide. 
But all that content was removed in the first reply to the message.

LG Roman

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