Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 25 Sep 2019 10:10:37 -0700 | Subject | Re: [PATCH v1 1/4] lib: introduce copy_struct_from_user() helper |
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On Wed, Sep 25, 2019 at 10:00 AM Aleksa Sarai <cyphar@cyphar.com> wrote: > > +int is_zeroed_user(const void __user *from, size_t size)
I like how you've done this, but it's buggy and only works on 64-bit.
All the "u64" and "8" cases need to be "unsigned long" and "sizeof(unsigned long)".
Part of that requirement is:
> + unsafe_get_user(val, (u64 __user *) from, err_fault);
This part works fine - although 64-bit accesses migth be much more expensive and the win of unrolling might not be sufficient - but:
> + if (align) { > + /* @from is unaligned. */ > + val &= ~aligned_byte_mask(align); > + align = 0; > + }
This part fundamentally only works on 'unsigned long'.
Linus
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