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?
BR, Jarkko
