Clean up extension decoding

TLS_Reader handles the offset checks for us

2 files changed, 11 insertions, 27 deletions

diff --git a/src/lib/tls/tls_extensions.cpp b/src/lib/tls/tls_extensions.cpp
index 917a76b92..ca4e1200f 100644
--- a/src/lib/tls/tls_extensions.cpp
+++ b/src/lib/tls/tls_extensions.cpp
@@ -34,7 +34,7 @@ Extension* make_extension(TLS_Data_Reader& reader, uint16_t code, uint16_t size,
          return new Supported_Groups(reader, size);
 
       case TLSEXT_CERT_STATUS_REQUEST:
-         return new Certificate_Status_Request(reader, size);
+         return new Certificate_Status_Request(reader, size, side);
 
       case TLSEXT_EC_POINT_FORMATS:
          return new Supported_Point_Formats(reader, size);
@@ -538,37 +538,19 @@ std::vector<uint8_t> Certificate_Status_Request::serialize() const
    }
 
 Certificate_Status_Request::Certificate_Status_Request(TLS_Data_Reader& reader,
-                                                       uint16_t extension_size) :
-   m_server_side(false) // This ctor is used by both client and server, so the information is wrong here. 
-                        // However, m_server_side is only evaluated when sending the object, thus the error 
-                        // made will not matter. However, a better modelling would be nice.
+                                                       uint16_t extension_size,
+                                                       Connection_Side side) :
+   m_server_side(side == SERVER)
    {
    if(extension_size > 0)
       {
       const uint8_t type = reader.get_byte();
       if(type == 1)
          {
-           extension_size -= 1;
-           size_t len_resp_id_list = reader.get_uint16_t();  
-           extension_size -= 2;
-           if(len_resp_id_list + 2 > extension_size)
-           {
-             throw Decoding_Error("Bad size of responder id list in Certificate_Status_Request extension");
-           }
-           m_ocsp_names = reader.get_fixed<uint8_t>(len_resp_id_list);
-           extension_size -= len_resp_id_list;
-           size_t len_requ_ext = reader.get_uint16_t();
-           extension_size -= 2;
-           if(len_requ_ext > extension_size)
-           {
-             throw Decoding_Error("Bad size of extensions in Certificate_Status_Request extension");
-           }
-           m_extension_bytes = reader.get_fixed<uint8_t>(len_requ_ext );
-           extension_size -= len_requ_ext;
-           if(extension_size != 0)
-           {
-             throw Decoding_Error("trailing bytes in Certificate_Status_Request extension");
-           }
+         size_t len_resp_id_list = reader.get_uint16_t();
+         m_ocsp_names = reader.get_fixed<uint8_t>(len_resp_id_list);
+         size_t len_requ_ext = reader.get_uint16_t();
+         m_extension_bytes = reader.get_fixed<uint8_t>(len_requ_ext );
          }
       else
          {
diff --git a/src/lib/tls/tls_extensions.h b/src/lib/tls/tls_extensions.h
index 35c3ee554..5920a1576 100644
--- a/src/lib/tls/tls_extensions.h
+++ b/src/lib/tls/tls_extensions.h
@@ -414,7 +414,9 @@ class BOTAN_UNSTABLE_API Certificate_Status_Request final : public Extension
       Certificate_Status_Request(const std::vector<uint8_t>& ocsp_responder_ids,
                                  const std::vector<std::vector<uint8_t>>& ocsp_key_ids);
 
-      Certificate_Status_Request(TLS_Data_Reader& reader, uint16_t extension_size);
+      Certificate_Status_Request(TLS_Data_Reader& reader,
+                                 uint16_t extension_size,
+                                 Connection_Side side);
    private:
       std::vector<uint8_t> m_ocsp_names;
       std::vector<std::vector<uint8_t>> m_ocsp_keys; // is this field really needed