Messages in this thread | | | Subject | Re: [PATCH 1/4] module: add syscall to load module from fd | From | Mimi Zohar <> | Date | Thu, 04 Oct 2012 08:50:32 -0400 |
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On Thu, 2012-10-04 at 15:09 +0930, Rusty Russell wrote: > Kees Cook <keescook@chromium.org> writes: > > > On Thu, Sep 20, 2012 at 3:14 PM, Kees Cook <keescook@chromium.org> wrote: > >> As part of the effort to create a stronger boundary between root and > >> kernel, Chrome OS wants to be able to enforce that kernel modules are > >> being loaded only from our read-only crypto-hash verified (dm_verity) > >> root filesystem. Since the init_module syscall hands the kernel a module > >> as a memory blob, no reasoning about the origin of the blob can be made. > >> > >> Earlier proposals for appending signatures to kernel modules would not be > >> useful in Chrome OS, since it would involve adding an additional set of > >> keys to our kernel and builds for no good reason: we already trust the > >> contents of our root filesystem. We don't need to verify those kernel > >> modules a second time. Having to do signature checking on module loading > >> would slow us down and be redundant. All we need to know is where a > >> module is coming from so we can say yes/no to loading it. > >> > >> If a file descriptor is used as the source of a kernel module, many more > >> things can be reasoned about. In Chrome OS's case, we could enforce that > >> the module lives on the filesystem we expect it to live on. In the case > >> of IMA (or other LSMs), it would be possible, for example, to examine > >> extended attributes that may contain signatures over the contents of > >> the module. > >> > >> This introduces a new syscall (on x86), similar to init_module, that has > >> only two arguments. The first argument is used as a file descriptor to > >> the module and the second argument is a pointer to the NULL terminated > >> string of module arguments. > > > > Hi Rusty, > > > > Is this likely to land in the 3.7 change window? I'd really like to > > get the syscall number assigned so I can start sending patches to > > glibc, kmod, etc. My tree is here, FWIW: > > No, unfortunately it's a little late and there were issues with ARM > signoffs and syscall numbers... > > > http://git.kernel.org/?p=linux/kernel/git/kees/linux.git;a=shortlog;h=refs/heads/module-fd-syscall > > Messy merge due to the module signing stuff going in :( > > Please rebase on top of my kernel.org modules-next branch, and I'll pull > into my modules-wip branch for 3.8.
Why? Not only have you had these patches sitting for a while, way before you had the kernel module patches, they've been acked/signed off by Kees, Serge, Eric, and myself. All security subtree maintainers. The module patches could have easily been built on top of Kees' small patches. I am really disappointed!
Mimi
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