diff options
Diffstat (limited to 'botan/src/entropy/egd/es_egd.cpp')
-rw-r--r-- | botan/src/entropy/egd/es_egd.cpp | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/botan/src/entropy/egd/es_egd.cpp b/botan/src/entropy/egd/es_egd.cpp new file mode 100644 index 0000000..9e37f8f --- /dev/null +++ b/botan/src/entropy/egd/es_egd.cpp @@ -0,0 +1,156 @@ +/* +* EGD EntropySource +* (C) 1999-2009 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#include <botan/es_egd.h> +#include <botan/parsing.h> +#include <botan/exceptn.h> +#include <cstring> +#include <stdexcept> + +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> + +#include <sys/socket.h> +#include <sys/un.h> + +#ifndef PF_LOCAL + #define PF_LOCAL PF_UNIX +#endif + +namespace Botan { + +EGD_EntropySource::EGD_Socket::EGD_Socket(const std::string& path) : + socket_path(path), m_fd(-1) + { + } + +/** +* Attempt a connection to an EGD/PRNGD socket +*/ +int EGD_EntropySource::EGD_Socket::open_socket(const std::string& path) + { + int fd = ::socket(PF_LOCAL, SOCK_STREAM, 0); + + if(fd >= 0) + { + sockaddr_un addr; + std::memset(&addr, 0, sizeof(addr)); + addr.sun_family = PF_LOCAL; + + if(sizeof(addr.sun_path) < path.length() + 1) + throw std::invalid_argument("EGD socket path is too long"); + + std::strcpy(addr.sun_path, path.c_str()); + + int len = sizeof(addr.sun_family) + std::strlen(addr.sun_path) + 1; + + if(::connect(fd, reinterpret_cast<struct ::sockaddr*>(&addr), len) < 0) + { + ::close(fd); + fd = -1; + } + } + + return fd; + } + +/** +* Attempt to read entropy from EGD +*/ +u32bit EGD_EntropySource::EGD_Socket::read(byte outbuf[], u32bit length) + { + if(length == 0) + return 0; + + if(m_fd < 0) + { + m_fd = open_socket(socket_path); + if(m_fd < 0) + return 0; + } + + try + { + // 1 == EGD command for non-blocking read + byte egd_read_command[2] = { + 1, static_cast<byte>(std::min<u32bit>(length, 255)) }; + + if(::write(m_fd, egd_read_command, 2) != 2) + throw std::runtime_error("Writing entropy read command to EGD failed"); + + byte out_len = 0; + if(::read(m_fd, &out_len, 1) != 1) + throw std::runtime_error("Reading response length from EGD failed"); + + if(out_len > egd_read_command[1]) + throw std::runtime_error("Bogus length field recieved from EGD"); + + ssize_t count = ::read(m_fd, outbuf, out_len); + + if(count != out_len) + throw std::runtime_error("Reading entropy result from EGD failed"); + + return static_cast<u32bit>(count); + } + catch(std::exception) + { + this->close(); + // Will attempt to reopen next poll + } + + return 0; + } + +void EGD_EntropySource::EGD_Socket::close() + { + if(m_fd > 0) + { + ::close(m_fd); + m_fd = -1; + } + } + +/** +* EGD_EntropySource constructor +*/ +EGD_EntropySource::EGD_EntropySource(const std::vector<std::string>& paths) + { + for(size_t i = 0; i != paths.size(); ++i) + sockets.push_back(EGD_Socket(paths[i])); + } + +EGD_EntropySource::~EGD_EntropySource() + { + for(size_t i = 0; i != sockets.size(); ++i) + sockets[i].close(); + sockets.clear(); + } + +/** +* Gather Entropy from EGD +*/ +void EGD_EntropySource::poll(Entropy_Accumulator& accum) + { + u32bit go_get = std::min<u32bit>(accum.desired_remaining_bits() / 8, 32); + + MemoryRegion<byte>& io_buffer = accum.get_io_buffer(go_get); + + for(size_t i = 0; i != sockets.size(); ++i) + { + u32bit got = sockets[i].read(io_buffer.begin(), io_buffer.size()); + + if(got) + { + accum.add(io_buffer.begin(), got, 8); + break; + } + } + } + +} |