lkml.org 
[lkml]   [2003]   [Jul]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2.5.73] Signal stack fixes #1 introduce PF_SS_ACTIVE
Jörn Engel writes:

> The problem is with a broken signal handler, that moves the stack
> pointer to nirvana. You get a signal, set up the signal stack, move
> the pointer to nirvana, get a signal, set up the signal stack, move
> the pointer to nirvana, get a signal, ...

You can get the same effect by doing kill(0, SIGINT) inside a handler
for SIGINT. All you seem to be saying is "if you behave stupidly then
bad things happen to you". I don't see that this example exposes any
bug or vulnerability in the kernel.

> If I was just going down the signal stack, I would be perfectly happy,
> but instead the kernel believes each signal is the very first on the
> signal stack and sets it up again (and again...) each time.

You had to go to some trouble to get this effect - you had to use an
asm statement to change the stack pointer, which is well and truly
into "undefined behaviour" territory, and so you deserve all you
get. :) It's a very contrived example IMHO.

Paul.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:46    [W:0.032 / U:0.280 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site