Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [PATCH 1/4] module: add syscall to load module from fd | Date | Thu, 04 Oct 2012 15:09:04 +0930 |
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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.
Thanks, Rusty.
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