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List:       oss-security
Subject:    Re: [oss-security] CVE request: kernel: setup_arg_pages: diagnose
From:       Josh Bressers <bressers () redhat ! com>
Date:       2010-10-22 14:33:39
Message-ID: 282104569.1470581287758019044.JavaMail.root () zmail01 ! collab ! prod ! int ! phx2 ! redhat ! com
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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);
> }
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