JWS functions are supposed to return 0 upon error or when nothing was
produced. This was done in order to put easily the return value in
trash->data without having to check the return value.
However functions like a2base64url() or snprintf() could return a
negative value, which would be casted in a unsigned int if this happen.
This patch add checks on the JWS functions to ensure that no negative
value can be returned, and change the prototype from int to size_t.
This is also related to issue #3114.
Must be backported to 3.2.
jwk_thumbprint() is a function which is a function which implements
RFC7368 and emits a JWK thumbprint using a EVP_PKEY.
EVP_PKEY_EC_to_pub_jwk() and EVP_PKEY_RSA_to_pub_jwk() were changed in
order to match what is required to emit a thumbprint (ie, no spaces or
lines and the lexicographic order of the fields)
This patch implements the function EVP_PKEY_to_jws_algo() which returns
a jwt_alg compatible with the private key.
This value can then be passed to jws_b64_protected() and
jws_b64_signature() which modified to take an jwt_alg instead of a char.
This test returns a JWS payload signed a specified private key in the
PEM format, and uses the "jose" command tool to check if the signature
is correct against the jwk public key.
The test could be improved later by using the code from jwt.c allowing
to check a signature.
This commits implement JWS signing, this is divided in 3 parts:
- jws_b64_protected() creates a JWS "protected" header, which takes the
algorithm, kid or jwk, nonce and url as input, and fill a destination
buffer with the base64url version of the header
- jws_b64_payload() just encode a payload in base64url
- jws_b64_signature() generates a signature using as input the protected
header and the payload, it supports ES256, ES384 and ES512 for ECDSA
keys, and RS256 for RSA ones. The RSA signature just use the
EVP_DigestSign() API with its result encoded in base64url. For ECDSA
it's a little bit more complicated, and should follow section 3.4 of
RFC7518, R and S should be padded to byte size.
Then the JWS can be output with jws_flattened() which just formats the 3
base64url output in a JSON representation with the 3 fields, protected,
payload and signature.
OpenSSL version greater than 3.0 does not use the same API when
manipulating EVP_PKEY structures, the EC_KEY API is deprecated and it's
not possible anymore to get an EC_GROUP and simply call
EC_GROUP_get_curve_name().
Instead, one must call EVP_PKEY_get_utf8_string_param with the
OSSL_PKEY_PARAM_GROUP_NAME parameter, but this would result in a SECG
curves name, instead of a NIST curves name in previous version.
(ex: secp384r1 vs P-384)
This patch adds 2 functions:
- the first one look for a curves name and converts it to an openssl
NID.
- the second one converts a NID to a NIST curves name
The list only contains: P-256, P-384 and P-521 for now, it could be
extended in the fure with more curves.
Implement a converter which takes an EVP_PKEY and converts it to a
public JWK key. This is the first step of the JWS implementation.
It supports both EC and RSA keys.
Know to work with:
- LibreSSL
- AWS-LC
- OpenSSL > 1.1.1
