Re: CVE request: kernel: setup_arg_pages: diagnose excessive argument size

[Josh Bressers <bressers () redhat com>]

Please use CVE-2010-3858

Thanks.

-- 
    JB


----- "Eugene Teo" <eugene () redhat com> wrote:

> "The CONFIG_STACK_GROWSDOWN variant of setup_arg_pages() does not
> check 
> the size of the argument/environment area on the stack. When it is 
> unworkably large, shift_arg_pages() hits its BUG_ON. This is
> exploitable 
> with a very large RLIMIT_STACK limit, to create a crash pretty
> easily.
>
> Check that the initial stack is not too large to make it possible to
> map 
> in any executable.  We're not checking that the actual executable (or
>
> intepreter, for binfmt_elf) will fit.  So those mappings might clobber
>
> part of the initial stack mapping.  But that is just userland lossage
>
> that userland made happen, not a kernel problem."
>
> Upstream commit:
> http://git.kernel.org/linus/1b528181b2ffa14721fb28ad1bd539fe1732c583
>
> References:
> http://grsecurity.net/~spender/64bit_dos.c
> https://bugzilla.redhat.com/show_bug.cgi?id=645222
>
> Eugene
> -- 
> main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i);
> }