From: Tianjia Zhang tianjia.zhang@linux.alibaba.com
[ Upstream commit 0815291a8fd66cdcf7db1445d4d99b0d16065829 ]
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: Sasha Levin sashal@kernel.org --- crypto/asymmetric_keys/public_key.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c index 7c9e6be35c30..2f8352e88860 100644 --- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -304,6 +304,10 @@ static int cert_sig_digest_update(const struct public_key_signature *sig,
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) @@ -414,8 +418,7 @@ int public_key_verify_signature(const struct public_key *pkey, 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;