crypto: Support DER encodings

Add encoding interfaces for DER encoding:
1. support decoding of 'bit string', 'octet string', 'object id'
and 'context specific tag' for DER encoder.
2. implemented a simple DER encoder.
3. add more testsuits for DER encoder.

Signed-off-by: lei he <helei.sig11@bytedance.com>
Message-Id: <20221008085030.70212-3-helei.sig11@bytedance.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

1 files changed, 208 insertions, 3 deletions

diff --git a/crypto/der.h b/crypto/der.h
index e3d3aeacdc..0e895bbeec 100644
--- a/crypto/der.h
+++ b/crypto/der.h
@@ -22,6 +22,11 @@
 
 #include "qapi/error.h"
 
+typedef struct QCryptoEncodeContext QCryptoEncodeContext;
+
+/* rsaEncryption: 1.2.840.113549.1.1.1 */
+#define QCRYPTO_OID_rsaEncryption "\x2A\x86\x48\x86\xF7\x0D\x01\x01\x01"
+
 /* Simple decoder used to parse DER encoded rsa keys. */
 
 /**
@@ -47,14 +52,13 @@ typedef int (*QCryptoDERDecodeCb) (void *opaque, const uint8_t *value,
  * will be set to the rest length of data, if cb is not NULL, must
  * return 0 to make decode success, at last, the length of the data
  * part of the decoded INTEGER will be returned. Otherwise, -1 is
- * returned.
+ * returned and the valued of *data and *dlen keep unchanged.
  */
 int qcrypto_der_decode_int(const uint8_t **data,
                            size_t *dlen,
                            QCryptoDERDecodeCb cb,
                            void *opaque,
                            Error **errp);
-
 /**
  * qcrypto_der_decode_seq:
  *
@@ -70,7 +74,7 @@ int qcrypto_der_decode_int(const uint8_t **data,
  * will be set to the rest length of data, if cb is not NULL, must
  * return 0 to make decode success, at last, the length of the data
  * part of the decoded SEQUENCE will be returned. Otherwise, -1 is
- * returned.
+ * returned and the valued of *data and *dlen keep unchanged.
  */
 int qcrypto_der_decode_seq(const uint8_t **data,
                            size_t *dlen,
@@ -78,4 +82,205 @@ int qcrypto_der_decode_seq(const uint8_t **data,
                            void *opaque,
                            Error **errp);
 
+/**
+ * qcrypto_der_decode_oid:
+ *
+ * Decode OID from DER-encoded data, similar with der_decode_int.
+ *
+ * @data: pointer to address of input data
+ * @dlen: pointer to length of input data
+ * @cb: callback invoked when decode succeed, if cb equals NULL, no
+ * callback will be invoked
+ * @opaque: parameter passed to cb
+ *
+ * Returns: On success, *data points to rest data, and *dlen
+ * will be set to the rest length of data, if cb is not NULL, must
+ * return 0 to make decode success, at last, the length of the data
+ * part of the decoded OID will be returned. Otherwise, -1 is
+ * returned and the valued of *data and *dlen keep unchanged.
+ */
+int qcrypto_der_decode_oid(const uint8_t **data,
+                           size_t *dlen,
+                           QCryptoDERDecodeCb cb,
+                           void *opaque,
+                           Error **errp);
+
+/**
+ * qcrypto_der_decode_octet_str:
+ *
+ * Decode OCTET STRING from DER-encoded data, similar with der_decode_int.
+ *
+ * @data: pointer to address of input data
+ * @dlen: pointer to length of input data
+ * @cb: callback invoked when decode succeed, if cb equals NULL, no
+ * callback will be invoked
+ * @opaque: parameter passed to cb
+ *
+ * Returns: On success, *data points to rest data, and *dlen
+ * will be set to the rest length of data, if cb is not NULL, must
+ * return 0 to make decode success, at last, the length of the data
+ * part of the decoded OCTET STRING will be returned. Otherwise, -1 is
+ * returned and the valued of *data and *dlen keep unchanged.
+ */
+int qcrypto_der_decode_octet_str(const uint8_t **data,
+                                 size_t *dlen,
+                                 QCryptoDERDecodeCb cb,
+                                 void *opaque,
+                                 Error **errp);
+
+/**
+ * qcrypto_der_decode_bit_str:
+ *
+ * Decode BIT STRING from DER-encoded data, similar with der_decode_int.
+ *
+ * @data: pointer to address of input data
+ * @dlen: pointer to length of input data
+ * @cb: callback invoked when decode succeed, if cb equals NULL, no
+ * callback will be invoked
+ * @opaque: parameter passed to cb
+ *
+ * Returns: On success, *data points to rest data, and *dlen
+ * will be set to the rest length of data, if cb is not NULL, must
+ * return 0 to make decode success, at last, the length of the data
+ * part of the decoded BIT STRING will be returned. Otherwise, -1 is
+ * returned and the valued of *data and *dlen keep unchanged.
+ */
+int qcrypto_der_decode_bit_str(const uint8_t **data,
+                               size_t *dlen,
+                               QCryptoDERDecodeCb cb,
+                               void *opaque,
+                               Error **errp);
+
+
+/**
+ * qcrypto_der_decode_ctx_tag:
+ *
+ * Decode context specific tag
+ *
+ * @data: pointer to address of input data
+ * @dlen: pointer to length of input data
+ * @tag: expected value of context specific tag
+ * @cb: callback invoked when decode succeed, if cb equals NULL, no
+ * callback will be invoked
+ * @opaque: parameter passed to cb
+ *
+ * Returns: On success, *data points to rest data, and *dlen
+ * will be set to the rest length of data, if cb is not NULL, must
+ * return 0 to make decode success, at last, the length of the data
+ * part of the decoded BIT STRING will be returned. Otherwise, -1 is
+ * returned and the valued of *data and *dlen keep unchanged.
+ */
+int qcrypto_der_decode_ctx_tag(const uint8_t **data,
+                               size_t *dlen, int tag_id,
+                               QCryptoDERDecodeCb cb,
+                               void *opaque,
+                               Error **errp);
+
+/**
+ * qcrypto_der_encode_ctx_new:
+ *
+ * Allocate a context used for der encoding.
+ */
+QCryptoEncodeContext *qcrypto_der_encode_ctx_new(void);
+
+/**
+ * qcrypto_der_encode_seq_begin:
+ * @ctx: the encode context.
+ *
+ * Start encoding a SEQUENCE for ctx.
+ *
+ */
+void qcrypto_der_encode_seq_begin(QCryptoEncodeContext *ctx);
+
+/**
+ * qcrypto_der_encode_seq_begin:
+ * @ctx: the encode context.
+ *
+ * Finish uencoding a SEQUENCE for ctx.
+ *
+ */
+void qcrypto_der_encode_seq_end(QCryptoEncodeContext *ctx);
+
+
+/**
+ * qcrypto_der_encode_oid:
+ * @ctx: the encode context.
+ * @src: the source data of oid, note it should be already encoded, this
+ * function only add tag and length part for it.
+ *
+ * Encode an oid into ctx.
+ */
+void qcrypto_der_encode_oid(QCryptoEncodeContext *ctx,
+                            const uint8_t *src, size_t src_len);
+
+/**
+ * qcrypto_der_encode_int:
+ * @ctx: the encode context.
+ * @src: the source data of integer, note it should be already encoded, this
+ * function only add tag and length part for it.
+ *
+ * Encode an integer into ctx.
+ */
+void qcrypto_der_encode_int(QCryptoEncodeContext *ctx,
+                            const uint8_t *src, size_t src_len);
+
+/**
+ * qcrypto_der_encode_null:
+ * @ctx: the encode context.
+ *
+ * Encode a null into ctx.
+ */
+void qcrypto_der_encode_null(QCryptoEncodeContext *ctx);
+
+/**
+ * qcrypto_der_encode_octet_str:
+ * @ctx: the encode context.
+ * @src: the source data of the octet string.
+ *
+ * Encode a octet string into ctx.
+ */
+void qcrypto_der_encode_octet_str(QCryptoEncodeContext *ctx,
+                                  const uint8_t *src, size_t src_len);
+
+/**
+ * qcrypto_der_encode_octet_str_begin:
+ * @ctx: the encode context.
+ *
+ * Start encoding a octet string, All fields between
+ * qcrypto_der_encode_octet_str_begin and qcrypto_der_encode_octet_str_end
+ * are encoded as an octet string. This is useful when we need to encode a
+ * encoded SEQUNCE as OCTET STRING.
+ */
+void qcrypto_der_encode_octet_str_begin(QCryptoEncodeContext *ctx);
+
+/**
+ * qcrypto_der_encode_octet_str_end:
+ * @ctx: the encode context.
+ *
+ * Finish encoding a octet string, All fields between
+ * qcrypto_der_encode_octet_str_begin and qcrypto_der_encode_octet_str_end
+ * are encoded as an octet string. This is useful when we need to encode a
+ * encoded SEQUNCE as OCTET STRING.
+ */
+void qcrypto_der_encode_octet_str_end(QCryptoEncodeContext *ctx);
+
+/**
+ * qcrypto_der_encode_ctx_buffer_len:
+ * @ctx: the encode context.
+ *
+ * Compute the expected buffer size to save all encoded things.
+ */
+size_t qcrypto_der_encode_ctx_buffer_len(QCryptoEncodeContext *ctx);
+
+/**
+ * qcrypto_der_encode_ctx_flush_and_free:
+ * @ctx: the encode context.
+ * @dst: the distination to save the encoded data, the length of dst should
+ * not less than qcrypto_der_encode_cxt_buffer_len
+ *
+ * Flush all encoded data into dst, then free ctx.
+ */
+void qcrypto_der_encode_ctx_flush_and_free(QCryptoEncodeContext *ctx,
+                                           uint8_t *dst);
+
 #endif  /* QCRYPTO_ASN1_DECODER_H */