Messages in this thread | | | Subject | Re: [PATCH] stronger ELF sanity checks v2 | From | (Eric W. Biederman) | Date | 13 Jan 2004 03:39:11 -0700 |
| |
Aaron Lehmann <aaronl@vitelus.com> writes:
> On Tue, Jan 13, 2004 at 02:55:07AM +0100, Jesper Juhl wrote: > > Here's the second version of my patch to add better sanity checks for > > binfmt_elf > > I assume this breaks Brian Raiter's tiny ELF executables[1].
Hmm. I would expect most of the to continue to work because they are valid. The only problem I see is when he starts scrunching things together by changing the value of fields that have a specified meaning.
> Even > though these binaries are evil hacks that don't comply to standards > and serve no serious purpose, I'm not sure what the purpose of the > sanity checks is. Are there any risks associated with running > non-compliant ELF executables?
Sanity checks are always good for future compatibility so someone does not come to rely on your bugs. This is less of a problem in linux than in some systems but still. This is the primary reason cpus have undefined opcode exceptions for example.
> (Now that I mention it, the > proof-of-concept exploit for the brk() hole comes to mind, but I don't > know offhand if that did anything against the spec.) I don't mean to > question the usefulness of your work, especially as I don't know much > about ELF, but I'm personally curious about why you think additional > sanity checks are worth a slight increase in code complexity.
That was my impression as well. Increasing the complexity of the if statements when goto's are already in use seems silly.
Eric - 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/
| |