From: Tobias Brunner <tobias@strongswan.org>
Date: Fri, 17 Oct 2014 08:16:19 +0000 (+0200)
Subject: pkcs5: Add support for PBES2 encryption schemes other than 3DES
X-Git-Tag: 5.2.2rc1~33
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7bd55485386bc32f0b24fb39bc41d4a43ba3f03c;p=thirdparty%2Fstrongswan.git

pkcs5: Add support for PBES2 encryption schemes other than 3DES

This allows using e.g. AES for PKCS#8 and PKCS#12 files.

Some legacy schemes defined in RFC 2898 are not supported (like RC2).

Fixes #740.
---

diff --git a/src/libstrongswan/crypto/pkcs5.c b/src/libstrongswan/crypto/pkcs5.c
index 3b4df0e8a7..478926f2fa 100644
--- a/src/libstrongswan/crypto/pkcs5.c
+++ b/src/libstrongswan/crypto/pkcs5.c
@@ -108,13 +108,13 @@ struct private_pkcs5_t {
  * Verify padding of decrypted blob.
  * Length of blob is adjusted accordingly.
  */
-static bool verify_padding(chunk_t *blob)
+static bool verify_padding(crypter_t *crypter, chunk_t *blob)
 {
 	u_int8_t padding, count;
 
 	padding = count = blob->ptr[blob->len - 1];
 
-	if (padding > 8)
+	if (padding > crypter->get_block_size(crypter))
 	{
 		return FALSE;
 	}
@@ -153,7 +153,7 @@ static bool decrypt_generic(private_pkcs5_t *this, chunk_t password,
 		return FALSE;
 	}
 	memwipe(keymat.ptr, keymat.len);
-	if (verify_padding(decrypted))
+	if (verify_padding(this->crypter, decrypted))
 	{
 		return TRUE;
 	}
@@ -504,6 +504,7 @@ static bool parse_pbes2_params(private_pkcs5_t *this, chunk_t blob, int level0)
 {
 	asn1_parser_t *parser;
 	chunk_t object, params;
+	size_t keylen;
 	int objectID;
 	bool success = FALSE;
 
@@ -533,20 +534,35 @@ static bool parse_pbes2_params(private_pkcs5_t *this, chunk_t blob, int level0)
 			{
 				int oid = asn1_parse_algorithmIdentifier(object,
 									parser->get_level(parser) + 1, &params);
-				if (oid != OID_3DES_EDE_CBC)
+				this->encr = encryption_algorithm_from_oid(oid, &keylen);
+				if (this->encr == ENCR_UNDEFINED)
 				{	/* unsupported encryption scheme */
 					goto end;
 				}
-				if (this->keylen <= 0)
-				{	/* default key length for DES-EDE3-CBC-Pad */
-					this->keylen = 24;
+				/* prefer encoded key length */
+				this->keylen = this->keylen ?: keylen / 8;
+				if (!this->keylen)
+				{	/* set default key length for known algorithms */
+					switch (this->encr)
+					{
+						case ENCR_DES:
+							this->keylen = 8;
+							break;
+						case ENCR_3DES:
+							this->keylen = 24;
+							break;
+						case ENCR_BLOWFISH:
+							this->keylen = 16;
+							break;
+						default:
+							goto end;
+					}
 				}
 				if (!asn1_parse_simple_object(&params, ASN1_OCTET_STRING,
 									parser->get_level(parser) + 1, "IV"))
 				{
 					goto end;
 				}
-				this->encr = ENCR_3DES;
 				this->data.pbes2.iv = chunk_clone(params);
 				break;
 			}