Export headers for libverity_tree

Also factor out a function to convert a hex string to the byte array.

Bug: 25170618
Test: unit tests pass
Change-Id: Id9252d58d8de065bce332e806e2302dd18a54a8c

7 files changed, 37 insertions, 17 deletions

diff --git a/verity/Android.bp b/verity/Android.bp
index d1d81fac..526e7f27 100644
--- a/verity/Android.bp
+++ b/verity/Android.bp
@@ -92,6 +92,7 @@ cc_library_static {
         "verity_tree_defaults",
     ],
 
+    export_include_dirs: ["include"],
     srcs: [
         "build_verity_tree.cpp",
         "build_verity_tree_utils.cpp",
diff --git a/verity/build_verity_tree.cpp b/verity/build_verity_tree.cpp
index 27f9255f..9edc81a1 100644
--- a/verity/build_verity_tree.cpp
+++ b/verity/build_verity_tree.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "build_verity_tree.h"
+#include "verity/build_verity_tree.h"
 
 #include <android-base/logging.h>
 #include <android-base/unique_fd.h>
diff --git a/verity/build_verity_tree_main.cpp b/verity/build_verity_tree_main.cpp
index 76164cc5..ca693610 100644
--- a/verity/build_verity_tree_main.cpp
+++ b/verity/build_verity_tree_main.cpp
@@ -29,9 +29,8 @@
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/unique_fd.h>
-#include <openssl/bn.h>
 
-#include "build_verity_tree.h"
+#include "verity/build_verity_tree.h"
 
 static void usage(void) {
   printf(
@@ -75,19 +74,11 @@ int main(int argc, char** argv) {
         salt.clear();
         salt.insert(salt.end(), optarg, &optarg[strlen(optarg)]);
         break;
-      case 'A': {
-        BIGNUM* bn = nullptr;
-        if (!BN_hex2bn(&bn, optarg)) {
-          LOG(ERROR) << "Failed to convert salt from hex";
+      case 'A':
+        if (!HashTreeBuilder::ParseBytesArrayFromString(optarg, &salt)) {
           return 1;
         }
-        size_t salt_size = BN_num_bytes(bn);
-        salt.resize(salt_size);
-        if (BN_bn2bin(bn, salt.data()) != salt_size) {
-          LOG(ERROR) << "Failed to convert salt to bytes";
-          return 1;
-        }
-      } break;
+        break;
       case 'h':
         usage();
         return 1;
diff --git a/verity/build_verity_tree_test.cpp b/verity/build_verity_tree_test.cpp
index 50f6e397..c1cb6a39 100644
--- a/verity/build_verity_tree_test.cpp
+++ b/verity/build_verity_tree_test.cpp
@@ -25,7 +25,7 @@
 #include <openssl/evp.h>
 
 #include "build_verity_tree_utils.h"
-#include "hash_tree_builder.h"
+#include "verity/hash_tree_builder.h"
 
 // The hex string we are using in build_image.py
 // aee087a5be3b982978c923f566a94613496b417f2af592639bc80d141e34dfe7
diff --git a/verity/hash_tree_builder.cpp b/verity/hash_tree_builder.cpp
index 41649900..27909255 100644
--- a/verity/hash_tree_builder.cpp
+++ b/verity/hash_tree_builder.cpp
@@ -14,15 +14,17 @@
  * limitations under the License.
  */
 
-#include "hash_tree_builder.h"
+#include "verity/hash_tree_builder.h"
 
 #include <algorithm>
+#include <memory>
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
+#include <openssl/bn.h>
 
 #include "build_verity_tree_utils.h"
 
@@ -67,6 +69,29 @@ std::string HashTreeBuilder::BytesArrayToString(
   return result;
 }
 
+bool HashTreeBuilder::ParseBytesArrayFromString(
+    const std::string& hex_string, std::vector<unsigned char>* bytes) {
+  if (hex_string.size() % 2 != 0) {
+    LOG(ERROR) << "Hex string size must be even number " << hex_string;
+    return false;
+  }
+
+  BIGNUM* bn = nullptr;
+  if (!BN_hex2bn(&bn, hex_string.c_str())) {
+    LOG(ERROR) << "Failed to parse hex in " << hex_string;
+    return false;
+  }
+  std::unique_ptr<BIGNUM, decltype(&BN_free)> guard(bn, BN_free);
+
+  size_t bytes_size = BN_num_bytes(bn);
+  bytes->resize(bytes_size);
+  if (BN_bn2bin(bn, bytes->data()) != bytes_size) {
+    LOG(ERROR) << "Failed to convert hex to bytes " << hex_string;
+    return false;
+  }
+  return true;
+}
+
 uint64_t HashTreeBuilder::CalculateSize(uint64_t input_size) const {
   uint64_t verity_blocks = 0;
   size_t level_blocks;
diff --git a/verity/build_verity_tree.h b/verity/include/verity/build_verity_tree.h
index 9ca40005..9ca40005 100644
--- a/verity/build_verity_tree.h
+++ b/verity/include/verity/build_verity_tree.h
diff --git a/verity/hash_tree_builder.h b/verity/include/verity/hash_tree_builder.h
index 2a1ee56c..d933b488 100644
--- a/verity/hash_tree_builder.h
+++ b/verity/include/verity/hash_tree_builder.h
@@ -55,7 +55,10 @@ class HashTreeBuilder {
   // Converts |bytes| to string for hexdump.
   static std::string BytesArrayToString(
       const std::vector<unsigned char>& bytes);
-
+  // Inverse of the above function. It parses the input hex string and stores
+  // the result in |bytes|.
+  static bool ParseBytesArrayFromString(const std::string& str,
+                                        std::vector<unsigned char>* bytes);
   // Returns the hash function given the name of the hash algorithm. Returns
   // nullptr if the algorithm is unrecongnized or not supported.
   static const EVP_MD* HashFunction(const std::string& hash_name);