Re: [Re: xmonisdn (isdn4k-utils/Linux) bug report]

[ant () NOTATLA DEMON CO UK (Antonomasia)]

From: Brock Tellier <btellier () USA NET>

> > This was my try to exploit myself. When I make the 'killall -8 xmonisdn' >my
> > xmonisdn dies only with an Floating exception but it doesn't dump a core.

> Good, it shouldn't. If you look at the original post, this person executed
> those commands as root, which, on his system, allowed him to make the suid
> xmonisdn dump core.  xmonisdn won't dump core unless you are running it as
> root.  This isn't a security hole unless it were to dump core in a world
> readable mode.

Or in a directory writable by others, in which case files could get trashed.

With O_NOFOLLOW in the core file open(), as it is in recent kernels, you
now require hard links rather than symbolic links to achieve this.
I've put O_EXCL in some of my kernels for this reason.

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# Antonomasia   ant () notatla demon co uk                      #
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