On 2/2/22 17:38, Vitaly Chikunov wrote:
On Thu, Feb 03, 2022 at 12:24:37AM +0300, Vitaly Chikunov wrote:
Stefan,
On Wed, Feb 02, 2022 at 07:55:43AM -0500, Stefan Berger wrote:
On 2/2/22 01:59, Vitaly Chikunov wrote:
Rarely used `keyctl pkey_verify' can verify raw signatures, but was
failing, because ECDSA/EC-RDSA signature sizes are twice key sizes which
does not pass in/out sizes check in keyctl_pkey_params_get_2.
This in turn because these values cannot be distinguished by a single
`max_size' callback return value.
Also, `keyctl pkey_query` displays incorrect `max_sig_size' about these
algorithms.
Signed-off-by: Vitaly Chikunov <vt@xxxxxxxxxxxx>
How do you use pkey_query?
$ keyctl padd asymmetric testkey %keyring:test < cert.der
385037223
It should be (for RSA key):
keyctl pkey_query 385037223 0 enc=pkcs1 hash=sha256
`0` is placeholder for a password.
For example, I generated keys with your eckey-testing/generate.sh, and
pkey_query after this patch is applied:
# keyctl padd asymmetric "" @u < ecdsa-ca/ca.crt.der
66509339
# keyctl pkey_query 66509339 0 enc=x962 hash=sha256
key_size=256
max_data_size=64
max_sig_size=64
max_enc_size=32
max_dec_size=32
I just thought, we can also set these to 0 if encrypt/decrypt is not
enabled. Currently, there is no way to detect that encrypt is not
possible, except by extending that if (strcmp...), but if we going to
have it, why not correct other info too?
Sounds good.
This here works for signature verification for ECDSA now. [max_data_size
= len * 2 was not enough]
diff --git a/crypto/asymmetric_keys/public_key.c
b/crypto/asymmetric_keys/public_key.c
index 4fefb219bfdc..9e47a825b418 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -143,8 +143,26 @@ static int software_key_query(const struct
kernel_pkey_params *params,
len = crypto_akcipher_maxsize(tfm);
info->key_size = len * 8;
- info->max_data_size = len;
- info->max_sig_size = len;
+ if (strcmp(alg_name, "ecrdsa") == 0) {
+ /*
+ * For these algos sig size is twice key size.
+ * keyctl uses max_sig_size as minimum input size, and
+ * max_data_size as minimum output size for a signature.
+ */
+ info->max_data_size = len * 2;
+ info->max_sig_size = len * 2;
+ } else if (strncmp(alg_name, "ecdsa-", 6) == 0) {
+ /*
+ * ECDSA encodes the signature in ASN.1 sequence (2 bytes)
+ * with 2 bytes identifying each integer and 1 byte prefixed
+ * to each integer to make it a positive number.
+ */
+ info->max_sig_size = 2 + (2 + 1 + len) * 2;
+ info->max_data_size = 2 + (2 + 1 + len) * 2;
+ } else {
+ info->max_data_size = len;
+ info->max_sig_size = len;
+ }
info->max_enc_size = len;
info->max_dec_size = len;
info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
