Re: [PATCH 00/11] Convert moduleparams to seq_buf

Kees Cook <[email protected]> Mon, 1 Jun 2026 12:59:49 -0700
Newsgroups gmane.comp.freedesktop.xorg.drivers.intel,gmane.comp.emulators.kvm.devel,gmane.linux.kernel.modules,gmane.linux.kernel.mm,gmane.comp.security.apparmor,gmane.linux.kernel.lsm,gmane.linux.uml.devel,gmane.linux.acpi.devel,gmane.linux.kernel.openipmi,gmane.comp.emulators.qemu,gmane.comp.video.dri.devel,gmane.linux.drivers.rdma,gmane.linux.drivers.video-input-infrastructure,gmane.linux.kernel.pci,gmane.linux.scsi,gmane.linux.power-management.general,gmane.linux.ports.ppc64.devel,gmane.linux.serial,gmane.linux.usb.general,gmane.linux.kernel,gmane.linux.kernel.cross-arch,gmane.linux.network,gmane.linux.file-systems
Message-ID <202606011259.CE6E74CE@keescook> 
On Tue, May 26, 2026 at 08:53:06AM +0200, Petr Pavlu wrote:
> On 5/21/26 3:33 PM, Kees Cook wrote:
> > Hi,
> > 
> > I tried to trim the CC list here, but it's still pretty huge...
> > 
> > We've had a long-standing issue with "write to a string pointer" callbacks
> > that don't bounds check the destination (and for which the bounds is
> > also not part of the callback prototype, even if it is "known" to be
> > PAGE_SIZE, which sysfs_emit() depends on). Both moduleparams and sysfs
> > use this pattern. As a first step, and to test the migration method,
> > migrate moduleparams first.
> > 
> > There are 2 "mechanical" treewide patches that are handled by Coccinelle:
> > - treewide: Convert struct kernel_param_ops initializers to DEFINE_KERNEL_PARAM_OPS
> > - treewide: Convert custom kernel_param_ops .get callbacks to seq_buf via cocci
> > 
> > The last treewide patch is manual, and may need to be broken up into
> > per-subsystem patches, though I'd prefer to avoid this, as it would
> > extend the migration from 1 relase to at least 2 releases. (1 to
> > release the migration infrastructure, then 1 release to collect all the
> > subsystem changes, and possibly 1 more release to remove the migration
> > infrastructure.)
> > 
> > Thoughts, questions?
> 
> This looks reasonable to me. I added a few minor comments on the patches
> but they already look solid.

Thanks for the review! I'll get a v2 prepared with your notes addressed. :)

-Kees

-- 
Kees Cook