Messages in this thread | | | Date | Fri, 19 Oct 2012 07:49:24 -0400 | Subject | Re: RFC: sign the modules at install time | From | Josh Boyer <> |
| |
On Thu, Oct 18, 2012 at 9:16 PM, Rusty Russell <rusty@rustcorp.com.au> wrote: > Josh Boyer <jwboyer@gmail.com> writes: >> On Thu, Oct 18, 2012 at 2:46 PM, Linus Torvalds >> <torvalds@linux-foundation.org> wrote: >>> On Wed, Oct 17, 2012 at 10:34 PM, Rusty Russell <rusty@rustcorp.com.au> wrote: >>>> >>>> Hacking the keyid and signer-name to be extracted every time by >>>> sign-file takes my modules_install time from 18.6 seconds to 19.1. We'd >>>> get that back easily by making sign-file a perl script anyway; it calls >>>> out to perl 3 times already. >>> >>> Ok, that tiny slowdown seems worth the cleanup, especially if we'd get >>> it back from somebody re-writing it in perl. >>> >>> Want to sign off on the two patches, or put them in your git tree? >> >> I tested Rusty's version of the 'sign modules at module_install time' >> patch in a Fedora kernel build today. It seems to work well enough, >> even if we wind up signing things twice. A brief cleanup of my patch >> to add a modules_sign target on top of that is below. > > I'm surprised. Only the first signature (create on the unstripped > module) will be used by the kernel; this should fail to verify the > stripped module. A quick and dirty check is: > > grep -abo '~Module' /tmp/mod/lib/modules/3.7.0-rc1+/kernel/sound/pci/snd-intel8x0.ko > 39828:~Module > 40432:~Module > > Perhaps eu-strip actually strips the appended signature?
Yes. The abbreviated flow chart is:
build install (signed at install time now) find-debuginfo.sh (eu-strip) which strips off the signature from above modules_sign to put it back
You are certainly correct in that if I am building outside of RPM and run modules_install followed by modules_sign, it will append a second signature.
A further check could be done in scripts/Makefile.modsign to see if each module is already signed and skip it if so. I can take a look at doing that next week if people think it would be worthwhile.
josh
| |