Add wrappers for reinterpret_cast between char* and uint8_t*

Generally speaking reinterpret_cast is sketchy stuff. But the
special case of char*/uint8_t* is both common and safe. By
isolating those, the remaining (likely sketchy) cases are easier
to grep for.

5 files changed, 35 insertions, 15 deletions

diff --git a/src/lib/utils/data_src.cpp b/src/lib/utils/data_src.cpp
index 078d3f2ea..f4645bb85 100644
--- a/src/lib/utils/data_src.cpp
+++ b/src/lib/utils/data_src.cpp
@@ -95,8 +95,8 @@ bool DataSource_Memory::end_of_data() const
 * DataSource_Memory Constructor
 */
 DataSource_Memory::DataSource_Memory(const std::string& in) :
-   m_source(reinterpret_cast<const uint8_t*>(in.data()),
-          reinterpret_cast<const uint8_t*>(in.data()) + in.length()),
+   m_source(cast_char_ptr_to_uint8(in.data()),
+            cast_char_ptr_to_uint8(in.data()) + in.length()),
    m_offset(0)
    {
    }
@@ -106,7 +106,7 @@ DataSource_Memory::DataSource_Memory(const std::string& in) :
 */
 size_t DataSource_Stream::read(uint8_t out[], size_t length)
    {
-   m_source.read(reinterpret_cast<char*>(out), length);
+   m_source.read(cast_uint8_ptr_to_char(out), length);
    if(m_source.bad())
       throw Stream_IO_Error("DataSource_Stream::read: Source failure");
 
@@ -137,7 +137,7 @@ size_t DataSource_Stream::peek(uint8_t out[], size_t length, size_t offset) cons
    if(offset)
       {
       secure_vector<uint8_t> buf(offset);
-      m_source.read(reinterpret_cast<char*>(buf.data()), buf.size());
+      m_source.read(cast_uint8_ptr_to_char(buf.data()), buf.size());
       if(m_source.bad())
          throw Stream_IO_Error("DataSource_Stream::peek: Source failure");
       got = static_cast<size_t>(m_source.gcount());
@@ -145,7 +145,7 @@ size_t DataSource_Stream::peek(uint8_t out[], size_t length, size_t offset) cons
 
    if(got == offset)
       {
-      m_source.read(reinterpret_cast<char*>(out), length);
+      m_source.read(cast_uint8_ptr_to_char(out), length);
       if(m_source.bad())
          throw Stream_IO_Error("DataSource_Stream::peek: Source failure");
       got = static_cast<size_t>(m_source.gcount());
diff --git a/src/lib/utils/http_util/http_util.cpp b/src/lib/utils/http_util/http_util.cpp
index 73efb7adc..035176c17 100644
--- a/src/lib/utils/http_util/http_util.cpp
+++ b/src/lib/utils/http_util/http_util.cpp
@@ -40,7 +40,7 @@ std::string http_transact(const std::string& hostname,
       }
 
    // Blocks until entire message has been written
-   socket->write(reinterpret_cast<const uint8_t*>(message.data()),
+   socket->write(cast_char_ptr_to_uint8(message.data()),
                  message.size());
 
    std::ostringstream oss;
@@ -51,7 +51,7 @@ std::string http_transact(const std::string& hostname,
       if(got == 0) // EOF
          break;
 
-      oss.write(reinterpret_cast<const char*>(buf.data()),
+      oss.write(cast_uint8_ptr_to_char(buf.data()),
                 static_cast<std::streamsize>(got));
       }
 
@@ -75,7 +75,7 @@ std::string url_encode(const std::string& in)
       else if(c == '-' || c == '_' || c == '.' || c == '~')
          out << c;
       else
-         out << '%' << hex_encode(reinterpret_cast<uint8_t*>(&c), 1);
+         out << '%' << hex_encode(cast_char_ptr_to_uint8(&c), 1);
       }
 
    return out.str();
@@ -87,7 +87,7 @@ std::ostream& operator<<(std::ostream& o, const Response& resp)
    for(auto h : resp.headers())
       o << "Header '" << h.first << "' = '" << h.second << "'\n";
    o << "Body " << std::to_string(resp.body().size()) << " bytes:\n";
-   o.write(reinterpret_cast<const char*>(&resp.body()[0]), resp.body().size());
+   o.write(cast_uint8_ptr_to_char(resp.body().data()), resp.body().size());
    return o;
    }
 
@@ -136,7 +136,7 @@ Response http_sync(http_exch_fn http_transact,
    if(!content_type.empty())
       outbuf << "Content-Type: " << content_type << "\r\n";
    outbuf << "Connection: close\r\n\r\n";
-   outbuf.write(reinterpret_cast<const char*>(body.data()), body.size());
+   outbuf.write(cast_uint8_ptr_to_char(body.data()), body.size());
 
    std::istringstream io(http_transact(hostname, outbuf.str()));
 
@@ -184,7 +184,7 @@ Response http_sync(http_exch_fn http_transact,
    std::vector<uint8_t> buf(4096);
    while(io.good())
       {
-      io.read(reinterpret_cast<char*>(buf.data()), buf.size());
+      io.read(cast_uint8_ptr_to_char(buf.data()), buf.size());
       resp_body.insert(resp_body.end(), buf.data(), &buf[io.gcount()]);
       }
 
diff --git a/src/lib/utils/locking_allocator/locking_allocator.cpp b/src/lib/utils/locking_allocator/locking_allocator.cpp
index f36fa9130..c7ca1662f 100644
--- a/src/lib/utils/locking_allocator/locking_allocator.cpp
+++ b/src/lib/utils/locking_allocator/locking_allocator.cpp
@@ -64,7 +64,7 @@ void* mlock_allocator::allocate(size_t num_elems, size_t elem_size)
          m_freelist.erase(i);
          clear_mem(m_pool + offset, n);
 
-         BOTAN_ASSERT((reinterpret_cast<size_t>(m_pool) + offset) % alignment == 0,
+         BOTAN_ASSERT((reinterpret_cast<uintptr_t>(m_pool) + offset) % alignment == 0,
                       "Returning correctly aligned pointer");
 
          return m_pool + offset;
@@ -107,7 +107,7 @@ void* mlock_allocator::allocate(size_t num_elems, size_t elem_size)
 
       clear_mem(m_pool + offset + alignment_padding, n);
 
-      BOTAN_ASSERT((reinterpret_cast<size_t>(m_pool) + offset + alignment_padding) % alignment == 0,
+      BOTAN_ASSERT((reinterpret_cast<uintptr_t>(m_pool) + offset + alignment_padding) % alignment == 0,
                    "Returning correctly aligned pointer");
 
       return m_pool + offset + alignment_padding;
diff --git a/src/lib/utils/mem_ops.h b/src/lib/utils/mem_ops.h
index 3274bfaf6..ed4d6cb27 100644
--- a/src/lib/utils/mem_ops.h
+++ b/src/lib/utils/mem_ops.h
@@ -117,6 +117,26 @@ inline void set_mem(T* ptr, size_t n, uint8_t val)
       }
    }
 
+inline const uint8_t* cast_char_ptr_to_uint8(const char* s)
+   {
+   return reinterpret_cast<const uint8_t*>(s);
+   }
+
+inline const char* cast_uint8_ptr_to_char(const uint8_t* b)
+   {
+   return reinterpret_cast<const char*>(b);
+   }
+
+inline uint8_t* cast_char_ptr_to_uint8(char* s)
+   {
+   return reinterpret_cast<uint8_t*>(s);
+   }
+
+inline char* cast_uint8_ptr_to_char(uint8_t* b)
+   {
+   return reinterpret_cast<char*>(b);
+   }
+
 /**
 * Memory comparison, input insensitive
 * @param p1 a pointer to an array
diff --git a/src/lib/utils/os_utils.cpp b/src/lib/utils/os_utils.cpp
index 3f7d3cfde..d516e7600 100644
--- a/src/lib/utils/os_utils.cpp
+++ b/src/lib/utils/os_utils.cpp
@@ -163,7 +163,7 @@ class Winsock_Socket final : public OS::Socket
             {
             const size_t left = len - sent_so_far;
             int sent = ::send(m_socket,
-                              reinterpret_cast<const char*>(buf + sent_so_far),
+                              cast_uint8_ptr_to_char(buf + sent_so_far),
                               static_cast<int>(left),
                               0);
 
@@ -178,7 +178,7 @@ class Winsock_Socket final : public OS::Socket
       size_t read(uint8_t buf[], size_t len) override
          {
          int got = ::recv(m_socket,
-                          reinterpret_cast<char*>(buf),
+                          cast_uint8_ptr_to_char(buf),
                           static_cast<int>(len), 0);
 
          if(got == SOCKET_ERROR)