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/ChangeLog b/ChangeLog
index e0b016d..b2bee2b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
mbed TLS ChangeLog (Sorted per branch, date)
+= mbed TLS x.x.x branch released xxx-xx-xx
+
+Bugfix
+ * Fix parsing of PKCS#8 encoded Elliptic Curve keys. Previously Mbed TLS was
+ unable to parse keys with only the optional parameters field of the
+ ECPrivateKey structure. Found by jethrogb, fixed in #1379.
+
= mbed TLS 2.8.0 branch released 2018-03-16
Default behavior changes
