Messages in this thread | | | Subject | Re: [PATCH 1/5] string.h: add array-wrappers for (v)memdup_user() | From | Philipp Stanner <> | Date | Thu, 31 Aug 2023 14:22:08 +0200 |
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On Wed, 2023-08-30 at 17:11 +0300, Andy Shevchenko wrote: > On Wed, Aug 30, 2023 at 4:46 PM Philipp Stanner <pstanner@redhat.com> > wrote: > > > > Currently, user array duplications are sometimes done without an > > overflow check. Sometimes the checks are done manually; sometimes > > the > > array size is calculated with array_size() and sometimes by > > calculating > > n * size directly in code. > > > > Introduce wrappers for arrays for memdup_user() and vmemdup_user() > > to > > provide a standardized and safe way for duplicating user arrays. > > > > This is both for new code as well as replacing usage of > > (v)memdup_user() > > in existing code that uses, e.g., n * size to calculate array > > sizes. > > ... > > > --- a/include/linux/string.h > > +++ b/include/linux/string.h > > I'm wondering if this has no side-effects as string.h/string.c IIRC > is > used also for early stages where some of the APIs are not available. >
I forgot to address this point in my previous reply.
Who's going to decide whether this is a problem or not?
My personal guess is that this is unlikely to be a problem because
A. either (v)memdup_user() is available, in which case (v)memdup_array_user() will always work – B. or (v)memdup_user() is not available, which would cause the code that currently uses (v)memdup_user() for copying arrays to fail anyways.
P.
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