On Thu, Dec 30, 2021 at 01:15:10AM +0000, Al Viro wrote:
> On Wed, Dec 29, 2021 at 12:29:59PM -0800, Stefan Roesch wrote:
> > + if (ctx->size) {
> > + if (ctx->size > XATTR_SIZE_MAX)
> > return -E2BIG;
> > - kvalue = kvmalloc(size, GFP_KERNEL);
> > - if (!kvalue)
> > +
> > + ctx->kvalue = kvmalloc(ctx->size, GFP_KERNEL);
> > + if (!ctx->kvalue)
> > return -ENOMEM;
> > - if (copy_from_user(kvalue, value, size)) {
> > - error = -EFAULT;
> > - goto out;
> > +
> > + if (copy_from_user(ctx->kvalue, ctx->value, ctx->size)) {
> > + kvfree(ctx->kvalue);
> > + return -EFAULT;
>
> BTW, what's wrong with using vmemdup_user() here?
Nothing? It's simply timing paired with that specific code not needing
to be touched:
- in 2005 that code was kmalloc(GFP_KERNEL) + copy_from_user()
- in 2009 it was changed to memdup_user(GFP_USER)
- in 2012 it was changed to kvmalloc(GFP_KERNEL) + copy_from_user()
In 2018 you added vmemdup_user() and noone has updated that codepath. :)
