Add KDF for DH.

Add X9.42 DH KDF. Move sharedinfo generation code to CMS library as the
same structure is used by DH and ECDH.

Move ASN1_OBJECT typedef to ossl_typ.h so it can be picked up by dh headers
without the need to use ASN1.

2 files changed, 46 insertions, 0 deletions

diff --git a/crypto/cms/cms.h b/crypto/cms/cms.h
index f644cbfbc4..8b1d29f0c1 100644
--- a/crypto/cms/cms.h
+++ b/crypto/cms/cms.h
@@ -364,6 +364,9 @@ EVP_CIPHER_CTX *CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo *ri);
 int CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri,
 					CMS_RecipientEncryptedKey *rek);
 
+int CMS_SharedInfo_encode(unsigned char **pder, X509_ALGOR *kekalg, 
+			ASN1_OCTET_STRING *ukm, int keylen);
+
 /* BEGIN ERROR CODES */
 /* The following lines are auto generated by the script mkerr.pl. Any changes
  * made after this point may be overwritten when the script is next run.
diff --git a/crypto/cms/cms_asn1.c b/crypto/cms/cms_asn1.c
index 7d79db221a..83ae2cc0f3 100644
--- a/crypto/cms/cms_asn1.c
+++ b/crypto/cms/cms_asn1.c
@@ -423,3 +423,46 @@ ASN1_SEQUENCE(CMS_Receipt) = {
   ASN1_SIMPLE(CMS_Receipt, originatorSignatureValue, ASN1_OCTET_STRING)
 } ASN1_SEQUENCE_END(CMS_Receipt)
 
+/* Utilities to encode the CMS_SharedInfo structure used during key
+ * derivation.
+ */
+
+typedef struct {
+	X509_ALGOR *keyInfo;
+	ASN1_OCTET_STRING *entityUInfo;
+	ASN1_OCTET_STRING *suppPubInfo;
+} CMS_SharedInfo;
+
+ASN1_SEQUENCE(CMS_SharedInfo) = {
+  ASN1_SIMPLE(CMS_SharedInfo, keyInfo, X509_ALGOR),
+  ASN1_EXP_OPT(CMS_SharedInfo, entityUInfo, ASN1_OCTET_STRING, 0),
+  ASN1_EXP_OPT(CMS_SharedInfo, suppPubInfo, ASN1_OCTET_STRING, 2),
+} ASN1_SEQUENCE_END(CMS_SharedInfo)
+
+int CMS_SharedInfo_encode(unsigned char **pder, X509_ALGOR *kekalg, 
+			ASN1_OCTET_STRING *ukm, int keylen)
+	{
+	union {
+		CMS_SharedInfo *pecsi;
+		ASN1_VALUE *a;
+	} intsi = {NULL};
+
+	ASN1_OCTET_STRING oklen;
+	unsigned char kl[4];
+	CMS_SharedInfo ecsi;
+
+	keylen <<= 3;
+	kl[0] = (keylen >> 24) & 0xff;
+	kl[1] = (keylen >> 16) & 0xff;
+	kl[2] = (keylen >> 8) & 0xff;
+	kl[3] = keylen & 0xff;
+	oklen.length = 4;
+	oklen.data = kl;
+	oklen.type = V_ASN1_OCTET_STRING;
+	oklen.flags = 0;
+	ecsi.keyInfo = kekalg;
+	ecsi.entityUInfo = ukm;
+	ecsi.suppPubInfo = &oklen;
+	intsi.pecsi = &ecsi;
+	return ASN1_item_i2d(intsi.a, pder, ASN1_ITEM_rptr(CMS_SharedInfo));
+	}