/* rndegd.c - interface to the EGD * Copyright (C) 1999, 2000, 2002, 2003 Free Software Foundation, Inc. * * This file is part of Libgcrypt. * * Libgcrypt is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * Libgcrypt is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA */ #include #include #include #include #include #include #include #include #include #include #include #include "types.h" #include "g10lib.h" #include "cipher.h" #include "rand-internal.h" #ifndef offsetof #define offsetof(type, member) ((size_t) &((type *)0)->member) #endif static int egd_socket = -1; /* Allocated name of the socket if supplied at runtime. */ static char *user_socket_name; /* Allocate a new filename from FIRST_PART and SECOND_PART and to tilde expansion for first_part. SECOND_PART might be NULL. */ static char * my_make_filename (const char *first_part, const char *second_part) { size_t n; char *name, *home, *p; n = strlen(first_part)+1; if (second_part) n += strlen (second_part) + 1; home = NULL; if( *first_part == '~' && first_part[1] == '/' && (home = getenv("HOME")) && *home ) n += strlen(home); name = gcry_xmalloc(n); p = (home ? stpcpy (stpcpy (name, home), first_part+1 ) : stpcpy (name, first_part) ); if (second_part) strcpy (stpcpy(p,"/"), second_part); return name; } static int do_write( int fd, void *buf, size_t nbytes ) { size_t nleft = nbytes; int nwritten; while( nleft > 0 ) { nwritten = write( fd, buf, nleft); if( nwritten < 0 ) { if( errno == EINTR ) continue; return -1; } nleft -= nwritten; buf = (char*)buf + nwritten; } return 0; } static int do_read( int fd, void *buf, size_t nbytes ) { int n, nread = 0; do { do { n = read(fd, (char*)buf + nread, nbytes ); } while( n == -1 && errno == EINTR ); if( n == -1) return nread? nread:-1; if( n == 0) return -1; nread += n; nbytes -= n; } while( nread < nbytes ); return nread; } /* Note that his fucntion is not thread-safe. */ gpg_error_t _gcry_rndegd_set_socket_name (const char *name) { char *newname; struct sockaddr_un addr; newname = my_make_filename (name, NULL); if (strlen (newname)+1 >= sizeof addr.sun_path) { gcry_free (newname); return gpg_error_from_syserror (); } gcry_free (user_socket_name); user_socket_name = newname; return 0; } /* Connect to the EGD and return the file descriptor. Return -1 on error. With NOFAIL set to true, silently fail and return the error, otherwise print an error message and die. */ int _gcry_rndegd_connect_socket (int nofail) { int fd; const char *bname = NULL; char *name; struct sockaddr_un addr; int addr_len; if (egd_socket != -1) { close (egd_socket); egd_socket = -1; } #ifdef EGD_SOCKET_NAME bname = EGD_SOCKET_NAME; #endif if (user_socket_name) { name = gcry_strdup (user_socket_name); if (!name) { if (!nofail) log_fatal ("error allocating memory in rndegd: %s\n", strerror(errno) ); return -1; } } else if ( !bname || !*bname ) name = my_make_filename ("~/.gnupg", "entropy"); else name = my_make_filename (bname, NULL); if (strlen(name)+1 >= sizeof addr.sun_path) log_fatal ("EGD socketname is too long\n"); memset( &addr, 0, sizeof addr ); addr.sun_family = AF_UNIX; strcpy( addr.sun_path, name ); addr_len = (offsetof( struct sockaddr_un, sun_path ) + strlen( addr.sun_path )); fd = socket(AF_UNIX, SOCK_STREAM, 0); if (fd == -1 && !nofail) log_fatal("can't create unix domain socket: %s\n", strerror(errno) ); else if (connect (fd, (struct sockaddr*)&addr, addr_len) == -1) { if (!nofail) log_fatal("can't connect to EGD socket `%s': %s\n", name, strerror(errno) ); close (fd); fd = -1; } gcry_free(name); if (fd != -1) egd_socket = fd; return fd; } /**************** * Note: We always use the highest level. * To boost the performance we may want to add some * additional code for level 1 * * Using a level of 0 should never block and better add nothing * to the pool. So this is just a dummy for EGD. */ int _gcry_rndegd_gather_random (void (*add)(const void*, size_t, enum random_origins), enum random_origins origin, size_t length, int level ) { int fd = egd_socket; int n; byte buffer[256+2]; int nbytes; int do_restart = 0; if( !length ) return 0; if( !level ) return 0; restart: if (fd == -1 || do_restart) fd = _gcry_rndegd_connect_socket (0); do_restart = 0; nbytes = length < 255? length : 255; /* First time we do it with a non blocking request */ buffer[0] = 1; /* non blocking */ buffer[1] = nbytes; if( do_write( fd, buffer, 2 ) == -1 ) log_fatal("can't write to the EGD: %s\n", strerror(errno) ); n = do_read( fd, buffer, 1 ); if( n == -1 ) { log_error("read error on EGD: %s\n", strerror(errno)); do_restart = 1; goto restart; } n = buffer[0]; if( n ) { n = do_read( fd, buffer, n ); if( n == -1 ) { log_error("read error on EGD: %s\n", strerror(errno)); do_restart = 1; goto restart; } (*add)( buffer, n, origin ); length -= n; } if( length ) { log_info ( _("Please wait, entropy is being gathered. Do some work if it would\n" "keep you from getting bored, because it will improve the quality\n" "of the entropy.\n") ); } while( length ) { nbytes = length < 255? length : 255; buffer[0] = 2; /* blocking */ buffer[1] = nbytes; if( do_write( fd, buffer, 2 ) == -1 ) log_fatal("can't write to the EGD: %s\n", strerror(errno) ); n = do_read( fd, buffer, nbytes ); if( n == -1 ) { log_error("read error on EGD: %s\n", strerror(errno)); do_restart = 1; goto restart; } (*add)( buffer, n, origin ); length -= n; } memset(buffer, 0, sizeof(buffer) ); return 0; /* success */ }