| Message ID | 149141171185.29162.10595534113980773776.stgit@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Apr 5, 2017 at 10:01 AM, David Howells <dhowells@redhat.com> wrote: > When the kernel is running in secure boot mode, we lock down the kernel to > prevent userspace from modifying the running kernel image. Whilst this > includes prohibiting access to things like /dev/mem, it must also prevent > access by means of configuring driver modules in such a way as to cause a > device to access or modify the kernel image. > > To this end, annotate module_param* statements that refer to hardware > configuration and indicate for future reference what type of parameter they > specify. The parameter parser in the core sees this information and can > skip such parameters with an error message if the kernel is locked down. > The module initialisation then runs as normal, but just sees whatever the > default values for those parameters is. > > Note that we do still need to do the module initialisation because some > drivers have viable defaults set in case parameters aren't specified and > some drivers support automatic configuration (e.g. PNP or PCI) in addition > to manually coded parameters. > > This patch annotates drivers in fs/pstore/. > > Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk> > Signed-off-by: David Howells <dhowells@redhat.com> > cc: Anton Vorontsov <anton@enomsg.org> > cc: Colin Cross <ccross@android.com> > cc: Kees Cook <keescook@chromium.org> > cc: Tony Luck <tony.luck@intel.com> Acked-by: Kees Cook <keescook@chromium.org> -Kees > --- > > fs/pstore/ram.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c > index 11f918d34b1e..cce1d38417ca 100644 > --- a/fs/pstore/ram.c > +++ b/fs/pstore/ram.c > @@ -58,7 +58,7 @@ module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400); > MODULE_PARM_DESC(pmsg_size, "size of user space message log"); > > static unsigned long long mem_address; > -module_param(mem_address, ullong, 0400); > +module_param_hw(mem_address, ullong, other, 0400); > MODULE_PARM_DESC(mem_address, > "start of reserved RAM used to store oops/panic logs"); > >
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 11f918d34b1e..cce1d38417ca 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -58,7 +58,7 @@ module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400); MODULE_PARM_DESC(pmsg_size, "size of user space message log"); static unsigned long long mem_address; -module_param(mem_address, ullong, 0400); +module_param_hw(mem_address, ullong, other, 0400); MODULE_PARM_DESC(mem_address, "start of reserved RAM used to store oops/panic logs");
When the kernel is running in secure boot mode, we lock down the kernel to prevent userspace from modifying the running kernel image. Whilst this includes prohibiting access to things like /dev/mem, it must also prevent access by means of configuring driver modules in such a way as to cause a device to access or modify the kernel image. To this end, annotate module_param* statements that refer to hardware configuration and indicate for future reference what type of parameter they specify. The parameter parser in the core sees this information and can skip such parameters with an error message if the kernel is locked down. The module initialisation then runs as normal, but just sees whatever the default values for those parameters is. Note that we do still need to do the module initialisation because some drivers have viable defaults set in case parameters aren't specified and some drivers support automatic configuration (e.g. PNP or PCI) in addition to manually coded parameters. This patch annotates drivers in fs/pstore/. Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> cc: Anton Vorontsov <anton@enomsg.org> cc: Colin Cross <ccross@android.com> cc: Kees Cook <keescook@chromium.org> cc: Tony Luck <tony.luck@intel.com> --- fs/pstore/ram.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html