roughtime: decode integer values properly also on big endian arch (fix #2137)

Signed-off-by: Nuno Goncalves <[email protected]>

1 files changed, 30 insertions, 2 deletions

diff --git a/src/lib/misc/roughtime/roughtime.cpp b/src/lib/misc/roughtime/roughtime.cpp
index c9767546a..94a9a6b82 100644
--- a/src/lib/misc/roughtime/roughtime.cpp
+++ b/src/lib/misc/roughtime/roughtime.cpp
@@ -21,6 +21,34 @@ namespace Botan {
 
 namespace {
 
+template< bool B, class T = void >
+using enable_if_t = typename std::enable_if<B,T>::type;
+
+template<class T>
+struct is_array : std::false_type {};
+
+template<class T, std::size_t N>
+struct is_array<std::array<T,N>>:std::true_type{};
+
+template<typename T>
+T from_little_endian(const uint8_t* t, size_t N = sizeof(T))
+   {
+   static_assert(sizeof(T)<=sizeof(int64_t),"");
+   return (N == 0) ? T(0) : (T(static_cast<int64_t>(t[N-1]) << ((N-1)*8)) + from_little_endian<T>(t,N-1));
+   }
+
+template<typename T, enable_if_t<is_array<T>::value>* = nullptr>
+T copy(const uint8_t* t)
+   {
+   return typecast_copy<T>(t); //arrays are endianess indepedent, so we do a memcpy
+   }
+
+template<typename T, enable_if_t<!is_array<T>::value>* = nullptr>
+T copy(const uint8_t* t)
+   {
+   return from_little_endian<T>(t); //other types are arithmetic, so we account that roughtime serializes as little endian
+   }
+
 template<typename T>
 std::map<std::string, std::vector<uint8_t>> unpack_roughtime_packet(T bytes)
    {
@@ -35,7 +63,7 @@ std::map<std::string, std::vector<uint8_t>> unpack_roughtime_packet(T bytes)
    std::map<std::string, std::vector<uint8_t>> tags;
    for(uint32_t i=0; i<num_tags; ++i)
       {
-      const uint32_t end = ((i+1) == num_tags) ? bytes.size() : start_content + typecast_copy<uint32_t>(buf + 4 + i*4);
+      const uint32_t end = ((i+1) == num_tags) ? bytes.size() : start_content + from_little_endian<uint32_t>(buf + 4 + i*4);
       if(end > bytes.size())
          { throw Roughtime::Roughtime_Error("Tag end index out of bounds"); }
       if(end < start)
@@ -58,7 +86,7 @@ T get(const std::map<std::string, std::vector<uint8_t>>& map, const std::string&
       { throw Roughtime::Roughtime_Error("Tag " + label + " not found"); }
    if(tag->second.size() != sizeof(T))
       { throw Roughtime::Roughtime_Error("Tag " + label + " has unexpected size"); }
-   return typecast_copy<T>(tag->second.data());
+   return copy<T>(tag->second.data());
    }
 
 const std::vector<uint8_t>& get_v(const std::map<std::string, std::vector<uint8_t>>& map, const std::string& label)