1 files changed, 119 insertions, 0 deletions
diff --git a/src/test/fuzz/fuzz_hsdescv3_inner.c b/src/test/fuzz/fuzz_hsdescv3_inner.c
new file mode 100644
index 0000000000..5aa719f5c3
--- /dev/null
+++ b/src/test/fuzz/fuzz_hsdescv3_inner.c
@@ -0,0 +1,119 @@
+/* Copyright (c) 2017-2021, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#define HS_DESCRIPTOR_PRIVATE
+
+#include "core/or/or.h"
+#include "trunnel/ed25519_cert.h" /* Trunnel interface. */
+#include "lib/crypt_ops/crypto_ed25519.h"
+#include "feature/hs/hs_descriptor.h"
+#include "feature/dirparse/unparseable.h"
+
+#include "test/fuzz/fuzzing.h"
+
+static void
+mock_dump_desc__nodump(const char *desc, const char *type)
+{
+  (void)desc;
+  (void)type;
+}
+
+static int
+mock_rsa_ed25519_crosscert_check(const uint8_t *crosscert,
+                                 const size_t crosscert_len,
+                                 const crypto_pk_t *rsa_id_key,
+                                 const ed25519_public_key_t *master_key,
+                                 const time_t reject_if_expired_before)
+{
+  (void) crosscert;
+  (void) crosscert_len;
+  (void) rsa_id_key;
+  (void) master_key;
+  (void) reject_if_expired_before;
+  return 0;
+}
+
+static size_t
+mock_decrypt_desc_layer(const hs_descriptor_t *desc,
+                        const uint8_t *descriptor_cookie,
+                        bool is_superencrypted_layer,
+                        char **decrypted_out)
+{
+  (void)is_superencrypted_layer;
+  (void)desc;
+  (void)descriptor_cookie;
+  const size_t overhead = HS_DESC_ENCRYPTED_SALT_LEN + DIGEST256_LEN;
+  const uint8_t *encrypted_blob = (is_superencrypted_layer)
+    ? desc->plaintext_data.superencrypted_blob
+    : desc->superencrypted_data.encrypted_blob;
+  size_t encrypted_blob_size = (is_superencrypted_layer)
+    ? desc->plaintext_data.superencrypted_blob_size
+    : desc->superencrypted_data.encrypted_blob_size;
+
+  if (encrypted_blob_size < overhead)
+    return 0;
+  *decrypted_out = tor_memdup_nulterm(
+                   encrypted_blob + HS_DESC_ENCRYPTED_SALT_LEN,
+                   encrypted_blob_size - overhead);
+  size_t result = strlen(*decrypted_out);
+  if (result) {
+    return result;
+  } else {
+    tor_free(*decrypted_out);
+    return 0;
+  }
+}
+
+static const uint8_t *decrypted_data = NULL;
+static size_t decrypted_len = 0;
+static size_t
+mock_desc_decrypt_encrypted(const hs_descriptor_t *desc,
+                        const curve25519_secret_key_t *client_auth_sk,
+                        char **decrypted_out)
+{
+  (void)desc;
+  (void)client_auth_sk;
+  *decrypted_out = (char*)tor_memdup_nulterm(decrypted_data, decrypted_len);
+  return decrypted_len;
+}
+
+int
+fuzz_init(void)
+{
+  disable_signature_checking();
+  MOCK(dump_desc, mock_dump_desc__nodump);
+  MOCK(rsa_ed25519_crosscert_check, mock_rsa_ed25519_crosscert_check);
+  MOCK(decrypt_desc_layer, mock_decrypt_desc_layer);
+  MOCK(desc_decrypt_encrypted, mock_desc_decrypt_encrypted);
+  ed25519_init();
+  return 0;
+}
+
+int
+fuzz_cleanup(void)
+{
+  return 0;
+}
+
+int
+fuzz_main(const uint8_t *data, size_t sz)
+{
+  decrypted_data = data;
+  decrypted_len = sz;
+
+  hs_descriptor_t *desc = tor_malloc_zero(sizeof(hs_descriptor_t));
+  hs_desc_encrypted_data_t *output = tor_malloc_zero(sizeof(*output));
+  curve25519_secret_key_t *client_auth_sk = NULL;
+  hs_desc_decode_status_t status;
+
+  status = desc_decode_encrypted_v3(desc, client_auth_sk, output);
+  if (status == HS_DESC_DECODE_OK) {
+    log_debug(LD_GENERAL, "Decoding okay");
+  } else {
+    log_debug(LD_GENERAL, "Decoding failed");
+  }
+
+  hs_descriptor_free(desc);
+  hs_desc_encrypted_data_free(output);
+  return 0;
+}