[HICN-52] Fix signature computation and verification in libtransport

Change-Id: I9b30a9c9e95e2cb2f135fe7efd43e633235196d9
Signed-off-by: Mauro Sardara <msardara@cisco.com>

2 files changed, 32 insertions, 22 deletions

diff --git a/libtransport/src/hicn/transport/utils/signer.cc b/libtransport/src/hicn/transport/utils/signer.cc
index 22bdf54d0..d3a322a5e 100644
--- a/libtransport/src/hicn/transport/utils/signer.cc
+++ b/libtransport/src/hicn/transport/utils/signer.cc
@@ -87,12 +87,17 @@ void Signer::sign(Packet &packet) {
     throw errors::MalformedAHPacketException();
   }
 
+  packet.setSignatureSize(sign_len_bytes);
+
   // Copy IP+TCP/ICMP header before zeroing them
   hicn_header_t header_copy;
-  if (format & HFO_INET) {
-    memcpy(&header_copy, hicn_packet, sizeof(hicn_v4_hdr_t));
-  } else if (format & HFO_INET6) {
-    memcpy(&header_copy, hicn_packet, sizeof(hicn_v6_hdr_t));
+  if (format == HF_INET_TCP_AH) {
+    memcpy(&header_copy, hicn_packet, HICN_V4_TCP_HDRLEN);
+  } else if (format == HF_INET6_TCP_AH) {
+    memcpy(&header_copy, hicn_packet, HICN_V6_TCP_HDRLEN);
+  } else {
+    throw errors::RuntimeException(
+        "Signer::sign -- Packet format not expected.");
   }
 
   std::size_t header_len = Packet::getHeaderSizeFromFormat(format);
@@ -104,7 +109,6 @@ void Signer::sign(Packet &packet) {
   auto now = duration_cast<milliseconds>(system_clock::now().time_since_epoch())
                  .count();
   packet.setSignatureTimestamp(now);
-
   packet.setValidationAlgorithm(
       CryptoSuite(parcSigner_GetCryptoSuite(this->signer_)));
 
@@ -117,7 +121,6 @@ void Signer::sign(Packet &packet) {
   utils::CryptoHasher hasher(parcSigner_GetCryptoHasher(signer_));
   hasher.init();
   hasher.updateBytes(hicn_packet, header_len + sign_len_bytes);
-  // hasher.updateBytes(zeros, sign_len_bytes);
 
   for (utils::MemBuf *current = payload_chain; current != header_chain;
        current = current->next()) {
@@ -126,10 +129,10 @@ void Signer::sign(Packet &packet) {
 
   utils::CryptoHash hash = hasher.finalize();
 
-  PARCSignature *signature =
-      parcSigner_SignDigest(this->signer_, hash.hash_, packet.getSignature(),
-                            (uint32_t)sign_len_bytes);
+  PARCSignature *signature = parcSigner_SignDigest(
+      this->signer_, hash.hash_, packet.getSignature(), sign_len_bytes);
   PARCBuffer *buffer = parcSignature_GetSignature(signature);
+
   size_t bytes_len = parcBuffer_Remaining(buffer);
 
   if (bytes_len > sign_len_bytes) {
@@ -138,9 +141,9 @@ void Signer::sign(Packet &packet) {
 
   /* Restore the resetted fields */
   if (format & HFO_INET) {
-    memcpy(hicn_packet, &header_copy, sizeof(hicn_v4_hdr_t));
+    memcpy(hicn_packet, &header_copy, HICN_V4_TCP_HDRLEN);
   } else if (format & HFO_INET6) {
-    memcpy(hicn_packet, &header_copy, sizeof(hicn_v6_hdr_t));
+    memcpy(hicn_packet, &header_copy, HICN_V6_TCP_HDRLEN);
   }
 }
 
diff --git a/libtransport/src/hicn/transport/utils/verifier.cc b/libtransport/src/hicn/transport/utils/verifier.cc
index bc460b821..aec80cff6 100644
--- a/libtransport/src/hicn/transport/utils/verifier.cc
+++ b/libtransport/src/hicn/transport/utils/verifier.cc
@@ -109,10 +109,13 @@ int Verifier::verify(const Packet &packet) {
 
   // Copy IP+TCP/ICMP header before zeroing them
   hicn_header_t header_copy;
-  if (format & HFO_INET) {
-    memcpy(&header_copy, hicn_packet, sizeof(hicn_v4_hdr_t));
-  } else if (format & HFO_INET6) {
-    memcpy(&header_copy, hicn_packet, sizeof(hicn_v6_hdr_t));
+  if (format == HF_INET_TCP_AH) {
+    memcpy(&header_copy, hicn_packet, HICN_V4_TCP_HDRLEN);
+  } else if (format == HF_INET6_TCP_AH) {
+    memcpy(&header_copy, hicn_packet, HICN_V6_TCP_HDRLEN);
+  } else {
+    throw errors::RuntimeException(
+        "Verifier::verify -- Packet format not expected.");
   }
 
   std::size_t header_len = Packet::getHeaderSizeFromFormat(format);
@@ -125,8 +128,13 @@ int Verifier::verify(const Packet &packet) {
   PARCKeyId *key_id = parcKeyId_Create(buffer);
   parcBuffer_Release(&buffer);
 
-  int ah_payload_len = (int)(header_chain->next()->length());
-  uint8_t *signature = header_chain->next()->writableData();
+  int ah_payload_len = packet.getSignatureSize();
+  uint8_t *_signature = packet.getSignature();
+  uint8_t signature[ah_payload_len];
+
+  // TODO Remove signature copy at this point, by not setting to zero
+  // the validation payload.
+  std::memcpy(signature, _signature, ah_payload_len);
 
   // Reset fields that should not appear in the signature
   const_cast<Packet &>(packet).resetForHash();
@@ -135,9 +143,7 @@ int Verifier::verify(const Packet &packet) {
   utils::CryptoHasher hasher(
       parcVerifier_GetCryptoHasher(verifier_, key_id, hashtype));
 
-  hasher.init()
-      .updateBytes(hicn_packet, header_len)
-      .updateBytes(zeros, ah_payload_len);
+  hasher.init().updateBytes(hicn_packet, header_len + ah_payload_len);
 
   for (utils::MemBuf *current = payload_chain; current != header_chain;
        current = current->next()) {
@@ -180,9 +186,9 @@ int Verifier::verify(const Packet &packet) {
 
   /* Restore the resetted fields */
   if (format & HFO_INET) {
-    memcpy(hicn_packet, &header_copy, sizeof(hicn_v4_hdr_t));
+    memcpy(hicn_packet, &header_copy, HICN_V4_TCP_HDRLEN);
   } else if (format & HFO_INET6) {
-    memcpy(hicn_packet, &header_copy, sizeof(hicn_v6_hdr_t));
+    memcpy(hicn_packet, &header_copy, HICN_V6_TCP_HDRLEN);
   }
 
   parcKeyId_Release(&key_id);
@@ -192,4 +198,5 @@ int Verifier::verify(const Packet &packet) {
 
   return valid;
 }
+
 }  // namespace utils