--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: noise.c,v 1.1 1997/08/07 09:45:26 mdw Exp $
+ *
+ * Collection of environmental noise
+ *
+ * (c) 1997 EBI
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of `become'
+ *
+ * `Become' is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * `Become' 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with `become'; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: noise.c,v $
+ * Revision 1.1 1997/08/07 09:45:26 mdw
+ * New source file added to acquire environmental noise and add it to the
+ * randomness pool (see `rand.c').
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+/* --- ANSI headers --- */
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+/* --- Unix headers --- */
+
+#include <sys/types.h>
+#include <sys/time.h>
+
+#include "config.h"
+#if defined(HAVE_GETRUSAGE)
+# include <sys/resource.h>
+#elif defined(HAVE_VTIMES)
+# include <sys/vtimes.h>
+#endif
+
+#include <sys/wait.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+
+/* --- Local headers --- */
+
+#include "noise.h"
+#include "rand.h"
+#include "utils.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @noise__shell@ --- *
+ *
+ * Arguments: @const char *cmd@ = pointer to a shell command
+ *
+ * Returns: ---
+ *
+ * Use: Adds the output of the shell command to the randomness pool.
+ * Some care is taken to do the Right Thing when running setuid.
+ */
+
+static void noise__shell(const char *cmd)
+{
+ int pfd[2];
+ pid_t pid;
+
+ /* --- Create a pipe for talking to the child --- */
+
+ if (pipe(pfd))
+ return;
+
+ /* --- Create the child process --- */
+
+ pid = fork();
+ if (pid < 0)
+ return;
+
+ if (pid == 0) {
+ int fd;
+ char *argv[] = { "/bin/sh", "-c", 0, 0 };
+ char *env[] = {
+ "PATH=/bin:/usr/bin:/usr/ucb:/usr/etc:/sbin:/usr/sbin",
+ 0
+ };
+
+ /* --- Become whoever I'm being run as --- */
+
+ setuid(getuid());
+
+ /* --- Close the old standard streams --- */
+
+ close(0);
+ close(1);
+ close(2);
+
+ /* --- Set up stdin and stderr to be empty, and stdout as our pipe --- */
+
+ if (((fd = open("/dev/null", O_RDONLY)) != 0 &&
+ (fd = dup2(fd, 0)) != 0) ||
+ ((fd = dup2(pfd[1], 1)) != 1) ||
+ ((fd = open("/dev/null", O_WRONLY)) != 2 &&
+ (fd = dup2(fd, 2)) != 2))
+ goto child_fail;
+
+ /* --- Close the original pipe file descriptors --- */
+
+ close(pfd[0]);
+ close(pfd[1]);
+ burn(pfd);
+
+ /* --- Now run the child process --- */
+
+ argv[2] = (char *)cmd; /* POSIX screwed up the prototype */
+ execve("/bin/sh", argv, env);
+
+ /* --- Something went horribly wrong --- */
+
+ child_fail:
+ _exit(127);
+ }
+
+ /* --- Now read from the child until it's all done --- */
+
+ {
+ char buf[1024];
+ ssize_t sz;
+
+ close(pfd[1]);
+ for (;;) {
+ sz = read(pfd[0], buf, sizeof(buf));
+ if (sz == 0 || (sz < 0 && sz != EINTR))
+ break;
+ rand_add(buf, sz);
+ }
+ close(pfd[0]);
+ rand_add(pfd, sizeof(pfd));
+ burn(buf); burn(pfd);
+ }
+
+ /* --- The child should be dead now, so wait for it --- */
+
+ {
+ int st;
+
+ wait(&st);
+ rand_add(&st, sizeof(st));
+ rand_add(&pid, sizeof(pid));
+ }
+}
+
+/* --- @noise_acquire@ --- *
+ *
+ * Arguments: ---
+ *
+ * Returns: ---
+ *
+ * Use: Attempts to acquire an amount of random noise from the
+ * environment. A lot of it's not actually much good, but
+ * it's better than nothing. There's probably a bit or two's
+ * worth in each item which gets added.
+ */
+
+void noise_acquire(void)
+{
+ /* --- Try a real random number source --- *
+ *
+ * Some operating systems (notably Linux) provide a `/dev/random' which
+ * contains distilled random numbers from the outside world.
+ */
+
+ {
+ int fd;
+ int f;
+ unsigned char buff[64];
+ ssize_t sz;
+
+ if ((fd = open("/dev/random", O_RDONLY) >= 0) &&
+ (f = fcntl(fd, F_GETFL, 0)) >= 0 &&
+ fcntl(fd, F_SETFL, f | O_NONBLOCK) >= 0 &&
+ (sz = read(fd, buff, sizeof(buff))) > 0) {
+ rand_add(buff, sz);
+ burn(buff);
+ }
+ if (fd >= 0)
+ close(fd);
+ }
+
+ /* --- Squeeze some entropy from the current time --- */
+
+ {
+ struct timeval tv;
+ clock_t c;
+
+ gettimeofday(&tv, 0);
+ c = clock();
+ rand_add(&tv, sizeof(tv));
+ rand_add(&c, sizeof(c));
+ burn(tv); burn(c);
+ }
+
+ /* --- Try some commands which ask the outside world some questions --- */
+
+ noise__shell("ps auxww");
+ noise__shell("ps -ef");
+ noise__shell("df");
+ /* @noise__shell("netstat -a");@ -- takes too long */
+
+ /* --- Get our resource usage to see if that's at all interesting --- */
+
+#if defined(HAVE_GETRUSAGE)
+ {
+ struct rusage ru;
+ getrusage(RUSAGE_SELF, &ru);
+ rand_add(&ru, sizeof(ru));
+ getrusage(RUSAGE_CHILDREN, &ru);
+ rand_add(&ru, sizeof(ru));
+ burn(ru);
+ }
+#elif defined(HAVE_VTIMES)
+ {
+ struct vtimes vt, vtc;
+ vtimes(&vt, &vtc);
+ rand_add(&vt, sizeof(vt));
+ rand_add(&vtc, sizeof(vtc));
+ burn(vt); burn(vtc);
+ }
+#endif
+
+ /* --- Squeeze some more entropy from the current time --- */
+
+ {
+ struct timeval tv;
+ clock_t c;
+
+ gettimeofday(&tv, 0);
+ c = clock();
+ rand_add(&tv, sizeof(tv));
+ rand_add(&c, sizeof(c));
+ burn(tv); burn(c);
+ }
+
+ /* --- Done -- churn the random pool --- */
+
+ rand_churn();
+}
+
+/*----- That's all, folks -------------------------------------------------*/
--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: noise.h,v 1.1 1997/08/07 09:45:26 mdw Exp $
+ *
+ * Collection of environmental noise
+ *
+ * (c) 1997 EBI
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of `become'
+ *
+ * `Become' is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * `Become' 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with `become'; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: noise.h,v $
+ * Revision 1.1 1997/08/07 09:45:26 mdw
+ * New source file added to acquire environmental noise and add it to the
+ * randomness pool (see `rand.c').
+ *
+ */
+
+#ifndef NOISE_H
+#define NOISE_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @noise_acquire@ --- *
+ *
+ * Arguments: ---
+ *
+ * Returns: ---
+ *
+ * Use: Attempts to acquire an amount of random noise from the
+ * environment. A lot of it's not actually much good, but
+ * it's better than nothing. There's probably a bit or two's
+ * worth in each item which gets added.
+ */
+
+extern void noise_acquire(void);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif
+
~mdw / become / commitdiff