From: Tianjia Zhang tianjia.zhang@linux.alibaba.com
commit 0815291a8fd66cdcf7db1445d4d99b0d16065829 upstream.
The signature verification of SM2 needs to add the Za value and recalculate sig->digest, which requires the detection of the pkey_algo in public_key_verify_signature(). As Eric Biggers said, the pkey_algo field in sig is attacker-controlled and should be use pkey->pkey_algo instead of sig->pkey_algo, and secondly, if sig->pkey_algo is NULL, it will also cause signature verification failure.
The software_key_determine_akcipher() already forces the algorithms are matched, so the SM3 algorithm is enforced in the SM2 signature, although this has been checked, we still avoid using any algorithm information in the signature as input.
Fixes: 215525639631 ("X.509: support OSCCA SM2-with-SM3 certificate verification") Reported-by: Eric Biggers ebiggers@google.com Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Tianjia Zhang tianjia.zhang@linux.alibaba.com Reviewed-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- crypto/asymmetric_keys/public_key.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -260,6 +260,10 @@ static int cert_sig_digest_update(const
BUG_ON(!sig->data);
+ /* SM2 signatures always use the SM3 hash algorithm */ + if (!sig->hash_algo || strcmp(sig->hash_algo, "sm3") != 0) + return -EINVAL; + ret = sm2_compute_z_digest(tfm_pkey, SM2_DEFAULT_USERID, SM2_DEFAULT_USERID_LEN, dgst); if (ret) @@ -356,8 +360,7 @@ int public_key_verify_signature(const st if (ret) goto error_free_key;
- if (sig->pkey_algo && strcmp(sig->pkey_algo, "sm2") == 0 && - sig->data_size) { + if (strcmp(pkey->pkey_algo, "sm2") == 0 && sig->data_size) { ret = cert_sig_digest_update(sig, tfm); if (ret) goto error_free_key;