Re: [PATCH v5 2/2] KEYS: asymmetric: Copy sig and digest in public_key_verify_signature()

[Jarkko Sakkinen]

On Thu, Feb 09, 2023 at 05:46:32PM -0500, Paul Moore wrote:
> On Thu, Feb 9, 2023 at 1:53 PM Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> > On Thu, Feb 09, 2023 at 11:49:19AM +0100, Roberto Sassu wrote:
> > > On Fri, 2023-01-27 at 09:27 +0100, Roberto Sassu wrote:
> > > > On Thu, 2022-12-29 at 14:39 -0800, Eric Biggers wrote:
> > > > > On Tue, Dec 27, 2022 at 03:27:40PM +0100, Roberto Sassu wrote:
> > > > > > From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> > > > > >
> > > > > > Commit ac4e97abce9b8 ("scatterlist: sg_set_buf() argument must be in linear
> > > > > > mapping") checks that both the signature and the digest reside in the
> > > > > > linear mapping area.
> > > > > >
> > > > > > However, more recently commit ba14a194a434c ("fork: Add generic vmalloced
> > > > > > stack support") made it possible to move the stack in the vmalloc area,
> > > > > > which is not contiguous, and thus not suitable for sg_set_buf() which needs
> > > > > > adjacent pages.
> > > > > >
> > > > > > Always make a copy of the signature and digest in the same buffer used to
> > > > > > store the key and its parameters, and pass them to sg_init_one(). Prefer it
> > > > > > to conditionally doing the copy if necessary, to keep the code simple. The
> > > > > > buffer allocated with kmalloc() is in the linear mapping area.
> > > > > >
> > > > > > Cc: stable@xxxxxxxxxxxxxxx # 4.9.x
> > > > > > Fixes: ba14a194a434 ("fork: Add generic vmalloced stack support")
> > > > > > Link: https://lore.kernel.org/linux-integrity/Y4pIpxbjBdajymBJ@sol.localdomain/
> > > > > > Suggested-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> > > > > > Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> > > > > > ---
> > > > > >  crypto/asymmetric_keys/public_key.c | 38 ++++++++++++++++-------------
> > > > > >  1 file changed, 21 insertions(+), 17 deletions(-)
> > > > >
> > > > > Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> > > >
> > > > Hi David
> > > >
> > > > could you please take this patch in your repo, if it is ok?
> > >
> > > Kindly ask your support here. Has this patch been queued somewhere?
> > > Wasn't able to find it, also it is not in linux-next.
> > >
> >
> > The maintainer of asymmetric_keys (David Howells) is ignoring this patch, so
> > you'll need to find someone else to apply it.  Herbert Xu, the maintainer of the
> > crypto subsystem, might be willing to apply it.  Or maybe Jarkko Sakkinen, who
> > is a co-maintainer of the keyrings subsystem (but not asymmetric_keys, for some
> > reason; should that change?).
> 
> It is problematic that David isn't replying to this.  I have no idea
> if it will work, but I just reached out to him to see if I can draw
> his attention back to this ...

See my response to Eric.

BR, Jarkko