On Tue, 2016-04-26 at 20:07 +0930, Rusty Russell wrote:
> Ben Hutchings <b...@decadent.org.uk> writes:
> >
> > Signing a module should only make it trusted by the specific kernel it
> > was built for, not anything else. Loading a signed module meant for a
> > kernel with a different ABI could have interesting effects.
> > Therefore, treat all signatures as invalid when a module is
> > force-loaded.
> >
> > Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
> > Cc: sta...@vger.kernel.org
> > ---
> > kernel/module.c | 13 +++++++++----
> > 1 file changed, 9 insertions(+), 4 deletions(-)
> >
> > diff --git a/kernel/module.c b/kernel/module.c
> > index 66426f743c29..649b1827ed15 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -2599,13 +2599,18 @@ static inline void kmemleak_load_module(const
> > struct module *mod,
> > #endif
> >
> > #ifdef CONFIG_MODULE_SIG
> > -static int module_sig_check(struct load_info *info)
> > +static int module_sig_check(struct load_info *info, int flags)
> > {
> > int err = -ENOKEY;
> > const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
> > const void *mod = info->hdr;
> >
> > - if (info->len > markerlen &&
> > + /*
> > + * Require flags == 0, as a module with version information
> > + * removed is no longer the module that was signed
> > + */
> > + if (flags == 0 &&
> This check is a bit lazy. We could have other flags in future,
> so this should really be !(flags &
> (MODULE_INIT_IGNORE_MODVERSIONS|MODULE_INIT_IGNORE_VERMAGIC) right?
Yes we could, but I'd prefer this to fail-safe in case no-one thinks
about whether it should be updated then.
Ben.
--
Ben Hutchings
The generation of random numbers is too important to be left to chance.
- Robert Coveyou
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