1 files changed, 82 insertions, 0 deletions
diff --git a/rpc_pkcs1.c b/rpc_pkcs1.c
new file mode 100644
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+++ b/rpc_pkcs1.c
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+/*
+ * rpc_pkcs1.c
+ * -----------
+ * PKCS #1 (RSA) support code layered on top of RPC hash API.
+ *
+ * Copyright (c) 2016, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ *   be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <assert.h>
+
+#include "hal.h"
+#include "hal_internal.h"
+
+/*
+ * Construct a PKCS #1 DigestInfo object.  This requires some (very
+ * basic) ASN.1 encoding, which we perform inline.
+ */
+
+hal_error_t hal_rpc_pkcs1_construct_digestinfo(const hal_hash_handle_t handle,
+					       uint8_t *digest_info, size_t *digest_info_len,
+					       const size_t digest_info_max)
+{
+  assert(digest_info != NULL && digest_info_len != NULL);
+
+  hal_digest_algorithm_t alg;
+  size_t len, alg_len;
+  hal_error_t err;
+
+  if ((err = hal_rpc_hash_get_algorithm(handle, &alg))                     != HAL_OK ||
+      (err = hal_rpc_hash_get_digest_length(alg, &len))                    != HAL_OK ||
+      (err = hal_rpc_hash_get_digest_algorithm_id(alg, NULL, &alg_len, 0)) != HAL_OK)
+    return err;
+
+  *digest_info_len = len + alg_len + 4;
+
+  if (*digest_info_len >= digest_info_max)
+    return HAL_ERROR_RESULT_TOO_LONG;
+
+  assert(*digest_info_len < 130);
+
+  uint8_t *d = digest_info;
+
+  *d++ = 0x30;                /* SEQUENCE */
+  *d++ = (uint8_t) (*digest_info_len - 2);
+
+  if ((err = hal_rpc_hash_get_digest_algorithm_id(alg, d, NULL, alg_len)) != HAL_OK)
+    return err;
+  d += alg_len;
+
+  *d++ = 0x04;                /* OCTET STRING */
+  *d++ = (uint8_t) len;
+
+  assert(digest_info + *digest_info_len == d + len);
+
+  return hal_rpc_hash_finalize(handle, d, len);
+}