[PATCH] public_key: Add a comment to public_key_signature struct definition

[Eric Biggers]

On Fri, Jan 20, 2023 at 02:21:04PM -0500, Paul Moore wrote:
> On Wed, Dec 7, 2022 at 5:55 AM Roberto Sassu
> <roberto.sassu at huaweicloud.com> wrote:
> >
> > From: Roberto Sassu <roberto.sassu at huawei.com>
> >
> > public_key_verify_signature() calls sg_set_buf() to set the signature and
> > digest for the signature verification.
> >
> > As sg_set_buf() requires the buffer to be in physically contiguous memory,
> > see commit ac4e97abce9b8 ("scatterlist: sg_set_buf() argument must be in
> > linear mapping"), mention that in a comment for the signature and digest
> > fields of the public_key_signature structure.
> >
> > 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>
> > ---
> >  include/crypto/public_key.h | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> This seems especially important considering the BUG_ON that could be triggered.
> 
> David, are you going to pick this up?
> 
> Reviewed-by: Paul Moore <paul at paul-moore.com>
> 
> > diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h
> > index 68f7aa2a7e55..6d623e063034 100644
> > --- a/include/crypto/public_key.h
> > +++ b/include/crypto/public_key.h
> > @@ -37,8 +37,8 @@ extern void public_key_free(struct public_key *key);
> >   */
> >  struct public_key_signature {
> >         struct asymmetric_key_id *auth_ids[3];
> > -       u8 *s;                  /* Signature */
> > -       u8 *digest;
> > +       u8 *s;                  /* Signature (in physically contiguous mem) */
> > +       u8 *digest;             /* Digest (in physically contiguous mem) */
> >         u32 s_size;             /* Number of bytes in signature */
> >         u32 digest_size;        /* Number of bytes in digest */
> >         const char *pkey_algo;
> > --
> > 2.25.1

This patch has been superseded by
"KEYS: asymmetric: Copy sig and digest in public_key_verify_signature()"
(https://lore.kernel.org/r/20221227142740.2807136-1-roberto.sassu@huaweicloud.com).

- Eric