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

[Roberto Sassu]

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 at huawei.com>
> > 
> > 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 at vger.kernel.org # 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 at kernel.org>
> > Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
> > ---
> >  crypto/asymmetric_keys/public_key.c | 38 ++++++++++++++++-------------
> >  1 file changed, 21 insertions(+), 17 deletions(-)
> 
> Reviewed-by: Eric Biggers <ebiggers at google.com>

Hi David

could you please take this patch in your repo, if it is ok?

Thanks

Roberto