From: Kurt Roeckx <Q@ping.be>
To: Vadim Lebedev <vlebedev@aplio.fr>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Potenitial security hole in the kernel
Date: Tue, 29 May 2001 01:15:22 +0200 [thread overview]
Message-ID: <20010529011522.A3293@ping.be> (raw)
In-Reply-To: <003601c0e7bf$41953080$0101a8c0@LAP> <20010529002900.A3190@ping.be> <009601c0e7c5$bd7021f0$0101a8c0@LAP>
In-Reply-To: <009601c0e7c5$bd7021f0$0101a8c0@LAP>
On Tue, May 29, 2001 at 12:30:03AM +0200, Vadim Lebedev wrote:
> Kurt,
>
> Maybe i'm missing something but it seems that during execution of the signal
> handler, user mode stack contains kernel mode context...
> Hence the security hole
It's rather complicated how things work.
Both the user and kernel stack are changed.
On the user stack we add a frame from the calling function. This
just looks a function call.
On the kernel stack we change the last frame so we "return" to
the signal handler from the kernel.
The signal handler then "returns" to the place where the process
did the system call. You do not return to the kernel.
I hope this helps you understand things better.
Kurt
next prev parent reply other threads:[~2001-05-28 23:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-05-28 21:43 Potenitial security hole in the kernel Vadim Lebedev
2001-05-28 22:21 ` Philip Blundell
2001-05-28 22:26 ` Vadim Lebedev
2001-05-28 22:29 ` Kurt Roeckx
2001-05-28 22:30 ` Vadim Lebedev
2001-05-28 23:15 ` Kurt Roeckx [this message]
2001-05-28 22:44 ` Brett Frankenberger
2001-05-28 23:12 ` Russell King
2001-05-28 23:30 ` Kurt Roeckx
2001-05-28 23:46 ` Kurt Roeckx
2001-05-29 0:32 ` Jamie Lokier
2001-05-29 7:35 ` Chris Wedgwood
2001-05-29 10:14 ` Jamie Lokier
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