Messages in this thread | | | Date | Thu, 21 Jun 2007 20:05:57 +0200 | From | Adrian Bunk <> | Subject | Re: [PATCH] signed binaries support [0/4] |
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On Thu, Jun 21, 2007 at 07:34:45PM +0200, Alexander Wuerstlein wrote: > On 070621 19:26, Adrian Bunk <bunk@stusta.de> wrote: > > On Thu, Jun 21, 2007 at 06:29:17PM +0200, Alexander Wuerstlein wrote: > > > On 070621 18:19, Adrian Bunk <bunk@stusta.de> wrote: > > > > On Thu, Jun 21, 2007 at 05:55:16PM +0200, Johannes Schlumberger wrote: > > > > > > > > > Hi, > > > > > > > > Hi Johannes, > > > > > > > > > We (two students of CS) built a system for signing binaries and verifying them > > > > > before executing. Our main focus was to implement a way to inhibit execution > > > > > of suid-binaries, which are not trustworthy (i.e. not signed). > > > > >... > > > > > > > > doesn't anyone who is able to install a not trustworthy suid-binary > > > > already have the priviliges to do anything he wants to without requiring > > > > an suid bit? > > > > > > Yes, quite correct in most cases. But if you have taken control of a computer > > > on of the more common ways to keep the control for some time is the > > > installation of a suid-binary (e.g. as part of a rootkit). > > > > There are so many ways for manipulating a computer that controlling > > setuid binaries hardly brings a real security gain. > > Even if it does not really improve security too much it can be helpful as a > part of a larger system. For example around here we use a 'sbit-checker' that > basically does a 'find' and 'chmod', which we would be able to replace by this > patch.
Something that sounds as if it would increase security but doesn't really increase security is actually bad since it gives users a false impression of security.
> Also our patch is not solely about suid-binaries, we just implemented > suid-checking because it seemed a simple and obvious thing to do. Our real aim > was to implement binary signatures, which can be used in numerous security > related checks around the kernel. Btw. if you have any good ideas where one > could use them, please tell us :)
Linux systems usually ship and heavily use interpreters like bash, perl or python.
Does writing an ELF loader in perl circumvent everything you want to do?
> Ciao, > Alexander Wuerstlein.
cu Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed
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