Date: Tue, 13 Mar 2012 07:48:00 -0700 From: Juli Mallett <juli@clockworksquid.com> To: Andrew Duane <aduane@juniper.net> Cc: "freebsd-mips@FreeBSD.org" <freebsd-mips@freebsd.org> Subject: Re: Enforcing soft-float. Message-ID: <CACVs6=8f649CBnqss4TTyZj26aNzoSE7zZWx2GQrskM_jinQNg@mail.gmail.com> In-Reply-To: <AC6674AB7BC78549BB231821ABF7A9AEB82D17C1E4@EMBX01-WF.jnpr.net> References: <CACVs6=9oPR0O0M9VorxY6L7xgRn3JBQqwrJ4M4_j9ZELER7Pmg@mail.gmail.com> <AC6674AB7BC78549BB231821ABF7A9AEB82D17C1E4@EMBX01-WF.jnpr.net>
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On Tue, Mar 13, 2012 at 06:35, Andrew Duane <aduane@juniper.net> wrote: > If it can't be done safely/correctly, it can't be done. I would think > killing the program would be appropriate. > > Getting a wrong answer is catastrophic. My greatest concern is that any user program can use floating point instructions to panic the kernel by getting it to truncate its own pointers. Heck, an even slightly well-crafted program could probably predict likely values of the kernel stack pointer and set up many malicious userspace stacks that could match the truncated address, and get its own code running in kernel mode.
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