Commit Graph

1 Commits

Author SHA1 Message Date
Alexander Scheel cd213f5fca
Restrict ECDSA/NIST P-Curve hash function sizes for cert signing (#12872)
* Restrict ECDSA signatures with NIST P-Curve hashes

When using an ECDSA signature with a NIST P-Curve, we should follow
recommendations from BIS (Section 4.2) and Mozilla's root store policy
(section 5.1.2) to ensure that arbitrary selection of signature_bits
does not exceed what the curve is capable of signing.

Related: #11245

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Switch to certutil.ValidateKeyTypeSignatureLength(...)

Replaces previous calls to certutil.ValidateKeyTypeLength(...) and
certutil.ValidateSignatureLength(...) with a single call, allowing for
curve<->hash validation.

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Switch to autodetection of signature_bits

This enables detection of whether the caller manually specified a value
for signature_bits or not; when not manually specified, we can provision
a value that complies with new NIST P-Curve policy.

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Select hash function length automatically

Due to our change in behavior (to default to -1 as the value to
signature_bits to allow for automatic hash selection), switch
ValidateKeyTypeSignatureLength(...) to accept a pointer to hashBits and
provision it with valid default values.

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Prevent invalid Curve size lookups

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Switch from -1 to 0 as default SignatureBits

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>

* Add changelog entry

Signed-off-by: Alexander Scheel <alex.scheel@hashicorp.com>
2021-11-12 12:18:38 -05:00