Re: [PATCH] kernel_read result fixes

[Andres Salomon <dilinger@voxel.net>]

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On Fri, 2004-12-24 at 02:24 -0500, Andres Salomon wrote:
> Hi,
> 
> A few potential vulnerabilities were pointed out by Katrina Tsipenyuk in
> <http://seclists.org/lists/linux-kernel/2004/Dec/1878.html>.  I haven't
> seen any discussion or fixes of the issue yet, so here's a patch
> (against 2.6.9).  The fixes are along the same lines as the previous
> binfmt_elf fixes.  There's one additional place (inside fs/binfmt_som.c)
> that a fix could be applied, but since that doesn't compile anyways, I
> didn't see a point in patching it.
> 
> 

Ok, you can ignore this; I believe the original advisory is bogus.
prepare_binprm ensures a 128 byte buffer that kernel_read data is copied
to; in case something smaller is copied in, the rest of the space is
zero'd out.  Thus, <128 reads are fine, and in many cases (as in
binfmt_script w/ tiny scripts less than 128 bytes in total) perfectly
valid.


-- 
Andres Salomon <dilinger@voxel.net>

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