1 files changed, 101 insertions, 0 deletions
diff --git a/fuzz/fuzz_gcrypt_gcm.cpp b/fuzz/fuzz_gcrypt_gcm.cpp
new file mode 100644
index 000000000..37bb35e3d
--- /dev/null
+++ b/fuzz/fuzz_gcrypt_gcm.cpp
@@ -0,0 +1,101 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+#include "fuzzer/FuzzedDataProvider.h"
+
+#define MBEDTLS_CHECK_RETURN_TYPICAL
+#define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret )  do { } while( 0 )
+#include "../src/lib/third_party/include/gcrypt/aes.h"
+#include "../src/lib/third_party/include/gcrypt/cipher.h"
+#include "../src/lib/third_party/include/gcrypt/gcm.h"
+
+extern int force_no_aesni;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  FuzzedDataProvider fuzzed_data(data, size);
+  mbedtls_aes_context *aes_e_ctx, *aes_d_ctx;
+  mbedtls_gcm_context *gcm_e_ctx, *gcm_d_ctx;
+  int key_lens[] = { 128, 192, 256, 512 /* invalid */ };
+  unsigned char *output, *decrypted;
+  int key_len, rc_e, rc_d;
+  mbedtls_cipher_id_t cipher;
+  unsigned char *tag;
+  int iv_len, tag_len, input_length;
+
+  /* No real memory allocations involved */
+
+  if(fuzzed_data.remaining_bytes() < 1 + 4 + 512 / 8 +
+				     1 + 64 + /* iv */
+				     1 + /* tag_len */
+				     1 + 64 + /* input */
+				     1 /* useless data: to be able to add the check with assert */)
+    return -1;
+
+  gcm_e_ctx = (mbedtls_gcm_context *)malloc(sizeof(mbedtls_gcm_context));
+  gcm_d_ctx = (mbedtls_gcm_context *)malloc(sizeof(mbedtls_gcm_context));
+  aes_e_ctx = (mbedtls_aes_context *)malloc(sizeof(mbedtls_aes_context));
+  aes_d_ctx = (mbedtls_aes_context *)malloc(sizeof(mbedtls_aes_context));
+
+  /* Not sure if it is really necessary... */
+  force_no_aesni = 0;
+  if(fuzzed_data.ConsumeBool())
+    force_no_aesni = 1;
+
+  key_len = fuzzed_data.PickValueInArray(key_lens);
+  std::vector<unsigned char>key = fuzzed_data.ConsumeBytes<u_int8_t>(key_len / 8);
+
+  iv_len = fuzzed_data.ConsumeIntegralInRange(0, 64);
+  std::vector<u_int8_t>iv = fuzzed_data.ConsumeBytes<uint8_t>(iv_len);
+
+  tag_len = fuzzed_data.ConsumeIntegralInRange(0, 17);
+  tag = (unsigned char *)malloc(tag_len);
+
+  input_length = fuzzed_data.ConsumeIntegralInRange(16, 64);
+  std::vector<unsigned char>input = fuzzed_data.ConsumeBytes<u_int8_t>(input_length);
+  output = (unsigned char *)malloc(input_length);
+  decrypted = (unsigned char *)malloc(input_length);
+
+  cipher = static_cast<mbedtls_cipher_id_t>(fuzzed_data.ConsumeIntegralInRange(0, (int)MBEDTLS_CIPHER_ID_CHACHA20));
+
+  assert(fuzzed_data.remaining_bytes() > 0);
+
+  mbedtls_gcm_init(gcm_e_ctx, aes_e_ctx);
+  mbedtls_gcm_init(gcm_d_ctx, aes_d_ctx);
+
+  rc_e = mbedtls_gcm_setkey(gcm_e_ctx, cipher, key.data(), key.size() * 8);
+  rc_d = mbedtls_gcm_setkey(gcm_d_ctx, cipher, key.data(), key.size() * 8);
+
+  if (rc_e == 0 && rc_d == 0) {
+    rc_e = mbedtls_gcm_crypt_and_tag(gcm_e_ctx, MBEDTLS_GCM_ENCRYPT,
+				     input.size(),
+				     iv.data(), iv.size(),
+				     NULL, 0, /* TODO */
+				     input.data(),
+				     output,
+				     tag_len, tag);
+    if(rc_e == 0) {
+      rc_d = mbedtls_gcm_auth_decrypt(gcm_d_ctx,
+				      input.size(),
+				      iv.data(), iv.size(),
+				      NULL, 0, /* TODO */
+				      tag, tag_len,
+				      output,
+				      decrypted);
+      if (rc_d == 0)
+        assert(memcmp(input.data(), decrypted, input.size()) == 0);
+    }
+  }
+
+  mbedtls_gcm_free(gcm_e_ctx);
+  mbedtls_gcm_free(gcm_d_ctx);
+
+  free(tag);
+  free(gcm_e_ctx);
+  free(gcm_d_ctx);
+  free(aes_e_ctx);
+  free(aes_d_ctx);
+  free(output);
+  free(decrypted);
+
+  return 0;
+}