Fix parsing of PKCS#8 encoded Elliptic Curve keys.
The relevant ASN.1 definitions for a PKCS#8 encoded Elliptic Curve key are:
PrivateKeyInfo ::= SEQUENCE {
version Version,
privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
privateKey PrivateKey,
attributes [0] IMPLICIT Attributes OPTIONAL
}
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL
}
ECParameters ::= CHOICE {
namedCurve OBJECT IDENTIFIER
-- implicitCurve NULL
-- specifiedCurve SpecifiedECDomain
}
ECPrivateKey ::= SEQUENCE {
version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
privateKey OCTET STRING,
parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
publicKey [1] BIT STRING OPTIONAL
}
Because of the two optional fields, there are 4 possible variants that need to
be parsed: no optional fields, only parameters, only public key, and both
optional fields. Previously mbedTLS was unable to parse keys with "only
parameters". Also, only "only public key" was tested. There was a test for "no
optional fields", but it was labelled incorrectly as SEC.1 and not run because
of a great renaming mixup.
diff --git a/library/pkparse.c b/library/pkparse.c
index 9022db2..5ad5edf 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -861,7 +861,10 @@
mbedtls_ecp_keypair_free( eck );
return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );
}
+ }
+ if( p != end )
+ {
/*
* Is 'publickey' present? If not, or if we can't read it (eg because it
* is compressed), create it from the private key.