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| author | Denis Kenzior <denkenz@gmail.com> | 2022-08-26 09:51:19 -0500 |
|---|---|---|
| committer | Jarkko Sakkinen <jarkko@kernel.org> | 2023-02-13 10:11:20 +0200 |
| commit | 10de7b54293995368c52d9aa153f3e7a359f04a1 (patch) | |
| tree | b93a672b3acc4afe73d3990378efe17a46ebe543 /crypto/asymmetric_keys/public_key.c | |
| parent | c95e8f6fd157b45ef0685c221931561e943e82da (diff) | |
| download | lwn-10de7b54293995368c52d9aa153f3e7a359f04a1.tar.gz lwn-10de7b54293995368c52d9aa153f3e7a359f04a1.zip | |
KEYS: asymmetric: Fix ECDSA use via keyctl uapi
When support for ECDSA keys was added, constraints for data & signature
sizes were never updated. This makes it impossible to use such keys via
keyctl API from userspace.
Update constraint on max_data_size to 64 bytes in order to support
SHA512-based signatures. Also update the signature length constraints
per ECDSA signature encoding described in RFC 5480.
Fixes: 299f561a6693 ("x509: Add support for parsing x509 certs with ECDSA keys")
Signed-off-by: Denis Kenzior <denkenz@gmail.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'crypto/asymmetric_keys/public_key.c')
| -rw-r--r-- | crypto/asymmetric_keys/public_key.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c index 2f8352e88860..eca5671ad3f2 100644 --- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -186,8 +186,28 @@ 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 (strncmp(pkey->pkey_algo, "ecdsa", 5) == 0) { + /* + * ECDSA key sizes are much smaller than RSA, and thus could + * operate on (hashed) inputs that are larger than key size. + * For example SHA384-hashed input used with secp256r1 + * based keys. Set max_data_size to be at least as large as + * the largest supported hash size (SHA512) + */ + info->max_data_size = 64; + + /* + * Verify takes ECDSA-Sig (described in RFC 5480) as input, + * which is actually 2 'key_size'-bit integers encoded in + * ASN.1. Account for the ASN.1 encoding overhead here. + */ + info->max_sig_size = 2 * (len + 3) + 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 | |