On Sun, Feb 20, 2022 at 06:21:36PM -0800, Eric Biggers wrote:
> On Mon, Feb 21, 2022 at 02:46:26AM +0100, Jarkko Sakkinen wrote:
> > On Mon, Jan 31, 2022 at 04:34:14PM -0800, Eric Biggers wrote:
> > > From: Eric Biggers <ebiggers@xxxxxxxxxx>
> > >
> > > It is insecure to allow arbitrary hash algorithms and signature
> > > encodings to be used with arbitrary signature algorithms. Notably,
> > > ECDSA, ECRDSA, and SM2 all sign/verify raw hash values and don't
> > > disambiguate between different hash algorithms like RSA PKCS#1 v1.5
> > > padding does. Therefore, they need to be restricted to certain sets of
> > > hash algorithms (ideally just one, but in practice small sets are used).
> > > Additionally, the encoding is an integral part of modern signature
> > > algorithms, and is not supposed to vary.
> > >
> > > Therefore, tighten the checks of hash_algo and encoding done by
> > > software_key_determine_akcipher().
> > >
> > > Also rearrange the parameters to software_key_determine_akcipher() to
> > > put the public_key first, as this is the most important parameter and it
> > > often determines everything else.
> > >
> > > Fixes: 299f561a6693 ("x509: Add support for parsing x509 certs with ECDSA keys")
> > > Fixes: 215525639631 ("X.509: support OSCCA SM2-with-SM3 certificate verification")
> > > Fixes: 0d7a78643f69 ("crypto: ecrdsa - add EC-RDSA (GOST 34.10) algorithm")
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> > > ---
> > > crypto/asymmetric_keys/public_key.c | 111 +++++++++++++++++++---------
> > > 1 file changed, 76 insertions(+), 35 deletions(-)
> > >
> > > diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
> > > index aba7113d86c76..a603ee8afdb8d 100644
> > > --- a/crypto/asymmetric_keys/public_key.c
> > > +++ b/crypto/asymmetric_keys/public_key.c
> > > @@ -60,39 +60,83 @@ static void public_key_destroy(void *payload0, void *payload3)
> > > }
> > >
> > > /*
> > > - * Determine the crypto algorithm name.
> > > + * Given a public_key, and an encoding and hash_algo to be used for signing
> > > + * and/or verification with that key, determine the name of the corresponding
> > > + * akcipher algorithm. Also check that encoding and hash_algo are allowed.
> > > */
> > > -static
> > > -int software_key_determine_akcipher(const char *encoding,
> > > - const char *hash_algo,
> > > - const struct public_key *pkey,
> > > - char alg_name[CRYPTO_MAX_ALG_NAME])
> > > +static int
> > > +software_key_determine_akcipher(const struct public_key *pkey,
> > > + const char *encoding, const char *hash_algo,
> > > + char alg_name[CRYPTO_MAX_ALG_NAME])
> >
> > Why is changing parameter order necessary?
> >
>
> It's mentioned in the commit message. It's obviously not necessary but this way
> makes much more sense IMO.
Ah, so it is.
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
BR, Jarkko
