| Message ID | 20220826145119.9375-1-denkenz@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] KEYS: asymmetric: Fix ECDSA use via keyctl uapi | expand |
On 8/26/22 10:51, Denis Kenzior wrote: > 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> > --- > > Version History: > > v2: Update patch description according to Jarkko's comments. No > functional code changes. > > crypto/asymmetric_keys/public_key.c | 24 ++++++++++++++++++++++-- > 1 file 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 |
Hi What's the hold-up with this patch? I would really appreciate if someone could take a look at it and move it along to finally enable iwd to connect to networks using ECDSA certificates (my eduroam network for example). Michael ------- Original Message ------- On Friday, August 26th, 2022 at 16:51, Denis Kenzior <denkenz@gmail.com> wrote: > > > 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 > > --- > > Version History: > > v2: Update patch description according to Jarkko's comments. No > functional code changes. > > crypto/asymmetric_keys/public_key.c | 24 ++++++++++++++++++++++-- > 1 file 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 | > > -- > 2.35.1
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 |
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> --- Version History: v2: Update patch description according to Jarkko's comments. No functional code changes. crypto/asymmetric_keys/public_key.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)