1 files changed, 122 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/entropy/dev_random/dev_random.cpp b/comm/third_party/botan/src/lib/entropy/dev_random/dev_random.cpp
new file mode 100644
index 0000000000..44fcbace3f
--- /dev/null
+++ b/comm/third_party/botan/src/lib/entropy/dev_random/dev_random.cpp
@@ -0,0 +1,122 @@
+/*
+* Reader of /dev/random and company
+* (C) 1999-2009,2013 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/dev_random.h>
+#include <botan/exceptn.h>
+
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+
+namespace Botan {
+
+/**
+Device_EntropySource constructor
+Open a file descriptor to each (available) device in fsnames
+*/
+Device_EntropySource::Device_EntropySource(const std::vector<std::string>& fsnames)
+   {
+#ifndef O_NONBLOCK
+  #define O_NONBLOCK 0
+#endif
+
+#ifndef O_NOCTTY
+  #define O_NOCTTY 0
+#endif
+
+   const int flags = O_RDONLY | O_NONBLOCK | O_NOCTTY;
+
+   m_max_fd = 0;
+
+   for(auto fsname : fsnames)
+      {
+      int fd = ::open(fsname.c_str(), flags);
+
+      if(fd < 0)
+         {
+         /*
+         ENOENT or EACCES is normal as some of the named devices may not exist
+         on this system. But any other errno value probably indicates
+         either a bug in the application or file descriptor exhaustion.
+         */
+         if(errno != ENOENT && errno != EACCES)
+            throw System_Error("Opening OS RNG device failed", errno);
+         }
+      else
+         {
+         if(fd > FD_SETSIZE)
+            {
+            ::close(fd);
+            throw Invalid_State("Open of OS RNG succeeded but returned fd is too large for fd_set");
+            }
+
+         m_dev_fds.push_back(fd);
+         m_max_fd = std::max(m_max_fd, fd);
+         }
+      }
+   }
+
+/**
+Device_EntropySource destructor: close all open devices
+*/
+Device_EntropySource::~Device_EntropySource()
+   {
+   for(int fd : m_dev_fds)
+      {
+      // ignoring return value here, can't throw in destructor anyway
+      ::close(fd);
+      }
+   }
+
+/**
+* Gather entropy from a RNG device
+*/
+size_t Device_EntropySource::poll(RandomNumberGenerator& rng)
+   {
+   size_t bits = 0;
+
+   if(m_dev_fds.size() > 0)
+      {
+      fd_set read_set;
+      FD_ZERO(&read_set);
+
+      for(int dev_fd : m_dev_fds)
+         {
+         FD_SET(dev_fd, &read_set);
+         }
+
+      secure_vector<uint8_t> io_buf(BOTAN_SYSTEM_RNG_POLL_REQUEST);
+
+      struct ::timeval timeout;
+      timeout.tv_sec = (BOTAN_SYSTEM_RNG_POLL_TIMEOUT_MS / 1000);
+      timeout.tv_usec = (BOTAN_SYSTEM_RNG_POLL_TIMEOUT_MS % 1000) * 1000;
+
+      if(::select(m_max_fd + 1, &read_set, nullptr, nullptr, &timeout) > 0)
+         {
+         for(int dev_fd : m_dev_fds)
+            {
+            if(FD_ISSET(dev_fd, &read_set))
+               {
+               const ssize_t got = ::read(dev_fd, io_buf.data(), io_buf.size());
+
+               if(got > 0)
+                  {
+                  rng.add_entropy(io_buf.data(), static_cast<size_t>(got));
+                  bits += got * 8;
+                  }
+               }
+            }
+         }
+      }
+
+   return bits;
+   }
+
+}