]> andersk Git - openssh.git/blobdiff - entropy.c
- djm@cvs.openbsd.org 2010/01/30 02:54:53
[openssh.git] / entropy.c
index 66cf75fbeb9259502f63d8b40abfa1b73b60983e..8b705397ff9a1870b743583b69913808fc92b3b9 100644 (file)
--- a/entropy.c
+++ b/entropy.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000 Damien Miller.  All rights reserved.
+ * Copyright (c) 2001 Damien Miller.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
 
 #include "includes.h"
 
-#include <openssl/rand.h>
-#include <openssl/sha.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+
+#ifdef HAVE_FCNTL_H
+# include <fcntl.h>
+#endif
+#include <stdarg.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
 
-/* SunOS 4.4.4 needs this */
-#ifdef HAVE_FLOATINGPOINT_H
-# include <floatingpoint.h>
-#endif /* HAVE_FLOATINGPOINT_H */
+#include <openssl/rand.h>
+#include <openssl/crypto.h>
+#include <openssl/err.h>
 
 #include "ssh.h"
 #include "misc.h"
 #include "atomicio.h"
 #include "pathnames.h"
 #include "log.h"
+#include "buffer.h"
 
-RCSID("$Id$");
-
-#ifndef offsetof
-# define offsetof(type, member) ((size_t) &((type *)0)->member)
-#endif
-
-/* Number of times to pass through command list gathering entropy */
-#define NUM_ENTROPY_RUNS       1
-
-/* Scale entropy estimates back by this amount on subsequent runs */
-#define SCALE_PER_RUN          10.0
-
-/* Minimum number of commands to be considered valid */
-#define MIN_ENTROPY_SOURCES 16
-
-#define WHITESPACE " \t\n"
+/*
+ * Portable OpenSSH PRNG seeding:
+ * If OpenSSL has not "internally seeded" itself (e.g. pulled data from
+ * /dev/random), then we execute a "ssh-rand-helper" program which
+ * collects entropy and writes it to stdout. The child program must
+ * write at least RANDOM_SEED_SIZE bytes. The child is run with stderr
+ * attached, so error/debugging output should be visible.
+ *
+ * XXX: we should tell the child how many bytes we need.
+ */
 
-#ifndef RUSAGE_SELF
-# define RUSAGE_SELF 0
+#ifndef OPENSSL_PRNG_ONLY
+#define RANDOM_SEED_SIZE 48
+static uid_t original_uid, original_euid;
 #endif
-#ifndef RUSAGE_CHILDREN
-# define RUSAGE_CHILDREN 0
-#endif
-
-#if defined(EGD_SOCKET) || defined(RANDOM_POOL)
-
-#ifdef EGD_SOCKET
-/* Collect entropy from EGD */
-int get_random_bytes(unsigned char *buf, int len)
-{
-       int fd;
-       char msg[2];
-       struct sockaddr_un addr;
-       int addr_len, rval, errors;
-       mysig_t old_sigpipe;
-
-       /* Sanity checks */
-       if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path))
-               fatal("Random pool path is too long");
-       if (len > 255)
-               fatal("Too many bytes to read from EGD");
-
-       memset(&addr, '\0', sizeof(addr));
-       addr.sun_family = AF_UNIX;
-       strlcpy(addr.sun_path, EGD_SOCKET, sizeof(addr.sun_path));
-       addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET);
-
-       old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
-
-       errors = rval = 0;
-reopen:
-       fd = socket(AF_UNIX, SOCK_STREAM, 0);
-       if (fd == -1) {
-               error("Couldn't create AF_UNIX socket: %s", strerror(errno));
-               goto done;
-       }
-
-       if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
-               error("Couldn't connect to EGD socket \"%s\": %s",
-                       addr.sun_path, strerror(errno));
-               goto done;
-       }
-
-       /* Send blocking read request to EGD */
-       msg[0] = 0x02;
-       msg[1] = len;
-
-       if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) {
-               if (errno == EPIPE && errors < 10) {
-                       close(fd);
-                       errors++;
-                       goto reopen;
-               }
-               error("Couldn't write to EGD socket \"%s\": %s",
-                       EGD_SOCKET, strerror(errno));
-               goto done;
-       }
 
-       if (atomicio(read, fd, buf, len) != len) {
-               if (errno == EPIPE && errors < 10) {
-                       close(fd);
-                       errors++;
-                       goto reopen;
-               }
-               error("Couldn't read from EGD socket \"%s\": %s",
-                       EGD_SOCKET, strerror(errno));
-               goto done;
-       }
-
-       rval = 1;
-done:
-       mysignal(SIGPIPE, old_sigpipe);
-       if (fd != -1)
-               close(fd);
-       return(rval);
-}
-#else /* !EGD_SOCKET */
-#ifdef RANDOM_POOL
-/* Collect entropy from /dev/urandom or pipe */
-int get_random_bytes(unsigned char *buf, int len)
-{
-       int random_pool;
-
-       random_pool = open(RANDOM_POOL, O_RDONLY);
-       if (random_pool == -1) {
-               error("Couldn't open random pool \"%s\": %s",
-                       RANDOM_POOL, strerror(errno));
-               return(0);
-       }
-
-       if (atomicio(read, random_pool, buf, len) != len) {
-               error("Couldn't read from random pool \"%s\": %s",
-                       RANDOM_POOL, strerror(errno));
-               close(random_pool);
-               return(0);
-       }
-
-       close(random_pool);
-
-       return(1);
-}
-#endif /* RANDOM_POOL */
-#endif /* EGD_SOCKET */
-
-/*
- * Seed OpenSSL's random number pool from Kernel random number generator
- * or EGD
- */
 void
 seed_rng(void)
 {
-       char buf[32];
-
-       debug("Seeding random number generator");
-
-       if (!get_random_bytes(buf, sizeof(buf))) {
-               if (!RAND_status())
-                       fatal("Entropy collection failed and entropy exhausted");
-       } else {
-               RAND_add(buf, sizeof(buf), sizeof(buf));
-       }
-
-       memset(buf, '\0', sizeof(buf));
-}
-
-/* No-op */
-void init_rng(void) {}
-
-#else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
-
-/*
- * FIXME: proper entropy estimations. All current values are guesses
- * FIXME: (ATL) do estimates at compile time?
- * FIXME: More entropy sources
- */
-
-/* slow command timeouts (all in milliseconds) */
-/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
-static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
-
-static int prng_seed_saved = 0;
-static int prng_initialised = 0;
-uid_t original_uid;
-
-typedef struct
-{
-       /* Proportion of data that is entropy */
-       double rate;
-       /* Counter goes positive if this command times out */
-       unsigned int badness;
-       /* Increases by factor of two each timeout */
-       unsigned int sticky_badness;
-       /* Path to executable */
-       char *path;
-       /* argv to pass to executable */
-       char *args[5];
-       /* full command string (debug) */
-       char *cmdstring;
-} entropy_source_t;
-
-double stir_from_system(void);
-double stir_from_programs(void);
-double stir_gettimeofday(double entropy_estimate);
-double stir_clock(double entropy_estimate);
-double stir_rusage(int who, double entropy_estimate);
-double hash_output_from_command(entropy_source_t *src, char *hash);
-
-/* this is initialised from a file, by prng_read_commands() */
-entropy_source_t *entropy_sources = NULL;
-
-double
-stir_from_system(void)
-{
-       double total_entropy_estimate;
-       long int i;
-
-       total_entropy_estimate = 0;
-
-       i = getpid();
-       RAND_add(&i, sizeof(i), 0.5);
-       total_entropy_estimate += 0.1;
-
-       i = getppid();
-       RAND_add(&i, sizeof(i), 0.5);
-       total_entropy_estimate += 0.1;
-
-       i = getuid();
-       RAND_add(&i, sizeof(i), 0.0);
-       i = getgid();
-       RAND_add(&i, sizeof(i), 0.0);
-
-       total_entropy_estimate += stir_gettimeofday(1.0);
-       total_entropy_estimate += stir_clock(0.5);
-       total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
-
-       return(total_entropy_estimate);
-}
-
-double
-stir_from_programs(void)
-{
-       int i;
-       int c;
-       double entropy_estimate;
-       double total_entropy_estimate;
-       char hash[SHA_DIGEST_LENGTH];
-
-       total_entropy_estimate = 0;
-       for(i = 0; i < NUM_ENTROPY_RUNS; i++) {
-               c = 0;
-               while (entropy_sources[c].path != NULL) {
-
-                       if (!entropy_sources[c].badness) {
-                               /* Hash output from command */
-                               entropy_estimate = hash_output_from_command(&entropy_sources[c], hash);
-
-                               /* Scale back entropy estimate according to command's rate */
-                               entropy_estimate *= entropy_sources[c].rate;
-
-                               /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */
-                               if (entropy_estimate > SHA_DIGEST_LENGTH)
-                                       entropy_estimate = SHA_DIGEST_LENGTH;
-
-                               /* Scale back estimates for subsequent passes through list */
-                               entropy_estimate /= SCALE_PER_RUN * (i + 1.0);
-
-                               /* Stir it in */
-                               RAND_add(hash, sizeof(hash), entropy_estimate);
-
-                               debug3("Got %0.2f bytes of entropy from '%s'", entropy_estimate,
-                                       entropy_sources[c].cmdstring);
-
-                               total_entropy_estimate += entropy_estimate;
-
-                       /* Execution times should be a little unpredictable */
-                               total_entropy_estimate += stir_gettimeofday(0.05);
-                               total_entropy_estimate += stir_clock(0.05);
-                               total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1);
-                               total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1);
-                       } else {
-                               debug2("Command '%s' disabled (badness %d)",
-                                       entropy_sources[c].cmdstring, entropy_sources[c].badness);
-
-                               if (entropy_sources[c].badness > 0)
-                                       entropy_sources[c].badness--;
-                       }
-
-                       c++;
-               }
-       }
-
-       return(total_entropy_estimate);
-}
-
-double
-stir_gettimeofday(double entropy_estimate)
-{
-       struct timeval tv;
-
-       if (gettimeofday(&tv, NULL) == -1)
-               fatal("Couldn't gettimeofday: %s", strerror(errno));
-
-       RAND_add(&tv, sizeof(tv), entropy_estimate);
-
-       return(entropy_estimate);
-}
-
-double
-stir_clock(double entropy_estimate)
-{
-#ifdef HAVE_CLOCK
-       clock_t c;
-
-       c = clock();
-       RAND_add(&c, sizeof(c), entropy_estimate);
-
-       return(entropy_estimate);
-#else /* _HAVE_CLOCK */
-       return(0);
-#endif /* _HAVE_CLOCK */
-}
-
-double
-stir_rusage(int who, double entropy_estimate)
-{
-#ifdef HAVE_GETRUSAGE
-       struct rusage ru;
-
-       if (getrusage(who, &ru) == -1)
-               return(0);
-
-       RAND_add(&ru, sizeof(ru), entropy_estimate);
-
-       return(entropy_estimate);
-#else /* _HAVE_GETRUSAGE */
-       return(0);
-#endif /* _HAVE_GETRUSAGE */
-}
-
-
-static
-int
-_get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) {
-       int secdiff, usecdiff;
-
-       secdiff = t2->tv_sec - t1->tv_sec;
-       usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
-       return (int)(usecdiff / 1000);
-}
-
-double
-hash_output_from_command(entropy_source_t *src, char *hash)
-{
-       static int devnull = -1;
+#ifndef OPENSSL_PRNG_ONLY
+       int devnull;
        int p[2];
-       fd_set rdset;
-       int cmd_eof = 0, error_abort = 0;
-       struct timeval tv_start, tv_current;
-       int msec_elapsed = 0;
        pid_t pid;
-       int status;
-       char buf[16384];
-       int bytes_read;
-       int total_bytes_read;
-       SHA_CTX sha;
-
-       debug3("Reading output from \'%s\'", src->cmdstring);
+       int ret;
+       unsigned char buf[RANDOM_SEED_SIZE];
+       mysig_t old_sigchld;
 
-       if (devnull == -1) {
-               devnull = open("/dev/null", O_RDWR);
-               if (devnull == -1)
-                       fatal("Couldn't open /dev/null: %s", strerror(errno));
+       if (RAND_status() == 1) {
+               debug3("RNG is ready, skipping seeding");
+               return;
        }
 
-       if (pipe(p) == -1)
-               fatal("Couldn't open pipe: %s", strerror(errno));
-
-       (void)gettimeofday(&tv_start, NULL); /* record start time */
+       debug3("Seeding PRNG from %s", SSH_RAND_HELPER);
 
-       switch (pid = fork()) {
-               case -1: /* Error */
-                       close(p[0]);
-                       close(p[1]);
-                       fatal("Couldn't fork: %s", strerror(errno));
-                       /* NOTREACHED */
-               case 0: /* Child */
-                       dup2(devnull, STDIN_FILENO);
-                       dup2(p[1], STDOUT_FILENO);
-                       dup2(p[1], STDERR_FILENO);
-                       close(p[0]);
-                       close(p[1]);
-                       close(devnull);
+       if ((devnull = open("/dev/null", O_RDWR)) == -1)
+               fatal("Couldn't open /dev/null: %s", strerror(errno));
+       if (pipe(p) == -1)
+               fatal("pipe: %s", strerror(errno));
+
+       old_sigchld = signal(SIGCHLD, SIG_DFL);
+       if ((pid = fork()) == -1)
+               fatal("Couldn't fork: %s", strerror(errno));
+       if (pid == 0) {
+               dup2(devnull, STDIN_FILENO);
+               dup2(p[1], STDOUT_FILENO);
+               /* Keep stderr open for errors */
+               close(p[0]);
+               close(p[1]);
+               close(devnull);
+
+               if (original_uid != original_euid &&
+                   ( seteuid(getuid()) == -1 ||
+                     setuid(original_uid) == -1) ) {
+                       fprintf(stderr, "(rand child) setuid(%li): %s\n",
+                           (long int)original_uid, strerror(errno));
+                       _exit(1);
+               }
 
-                       setuid(original_uid);
-                       execv(src->path, (char**)(src->args));
-                       debug("(child) Couldn't exec '%s': %s", src->cmdstring,
-                             strerror(errno));
-                       _exit(-1);
-               default: /* Parent */
-                       break;
+               execl(SSH_RAND_HELPER, "ssh-rand-helper", NULL);
+               fprintf(stderr, "(rand child) Couldn't exec '%s': %s\n",
+                   SSH_RAND_HELPER, strerror(errno));
+               _exit(1);
        }
 
-       RAND_add(&pid, sizeof(&pid), 0.0);
-
+       close(devnull);
        close(p[1]);
 
-       /* Hash output from child */
-       SHA1_Init(&sha);
-       total_bytes_read = 0;
-
-       while (!error_abort && !cmd_eof) {
-               int ret;
-               struct timeval tv;
-               int msec_remaining;
-
-               (void) gettimeofday(&tv_current, 0);
-               msec_elapsed = _get_timeval_msec_difference(&tv_start, &tv_current);
-               if (msec_elapsed >= entropy_timeout_current) {
-                       error_abort=1;
-                       continue;
-               }
-               msec_remaining = entropy_timeout_current - msec_elapsed;
-
-               FD_ZERO(&rdset);
-               FD_SET(p[0], &rdset);
-               tv.tv_sec =  msec_remaining / 1000;
-               tv.tv_usec = (msec_remaining % 1000) * 1000;
-
-               ret = select(p[0]+1, &rdset, NULL, NULL, &tv);
-
-               RAND_add(&tv, sizeof(tv), 0.0);
-
-               switch (ret) {
-               case 0:
-                       /* timer expired */
-                       error_abort = 1;
-                       break;
-               case 1:
-                       /* command input */
-                       bytes_read = read(p[0], buf, sizeof(buf));
-                       RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
-                       if (bytes_read == -1) {
-                               error_abort = 1;
-                               break;
-                       } else if (bytes_read) {
-                               SHA1_Update(&sha, buf, bytes_read);
-                               total_bytes_read += bytes_read;
-                       } else {
-                               cmd_eof = 1;
-                       }
-                       break;
-               case -1:
-               default:
-                       /* error */
-                       debug("Command '%s': select() failed: %s", src->cmdstring,
-                             strerror(errno));
-                       error_abort = 1;
-                       break;
-               }
-       }
-
-       SHA1_Final(hash, &sha);
+       memset(buf, '\0', sizeof(buf));
+       ret = atomicio(read, p[0], buf, sizeof(buf));
+       if (ret == -1)
+               fatal("Couldn't read from ssh-rand-helper: %s",
+                   strerror(errno));
+       if (ret != sizeof(buf))
+               fatal("ssh-rand-helper child produced insufficient data");
 
        close(p[0]);
 
-       debug3("Time elapsed: %d msec", msec_elapsed);
-
-       if (waitpid(pid, &status, 0) == -1) {
-              error("Couldn't wait for child '%s' completion: %s", src->cmdstring,
-                    strerror(errno));
-               return(0.0);
-       }
-
-       RAND_add(&status, sizeof(&status), 0.0);
-
-       if (error_abort) {
-               /* closing p[0] on timeout causes the entropy command to
-                * SIGPIPE. Take whatever output we got, and mark this command
-                * as slow */
-               debug2("Command '%s' timed out", src->cmdstring);
-               src->sticky_badness *= 2;
-               src->badness = src->sticky_badness;
-               return(total_bytes_read);
-       }
-
-       if (WIFEXITED(status)) {
-               if (WEXITSTATUS(status)==0) {
-                       return(total_bytes_read);
-               } else {
-                       debug2("Command '%s' exit status was %d", src->cmdstring,
-                               WEXITSTATUS(status));
-                       src->badness = src->sticky_badness = 128;
-                       return (0.0);
-               }
-       } else if (WIFSIGNALED(status)) {
-               debug2("Command '%s' returned on uncaught signal %d !", src->cmdstring,
-                       status);
-               src->badness = src->sticky_badness = 128;
-               return(0.0);
-       } else
-               return(0.0);
-}
-
-/*
- * prng seedfile functions
- */
-int
-prng_check_seedfile(char *filename) {
-
-       struct stat st;
-
-       /* FIXME raceable: eg replace seed between this stat and subsequent open */
-       /* Not such a problem because we don't trust the seed file anyway */
-       if (lstat(filename, &st) == -1) {
-               /* Give up on hard errors */
-               if (errno != ENOENT)
-                       debug("WARNING: Couldn't stat random seed file \"%s\": %s",
-                          filename, strerror(errno));
-
-               return(0);
-       }
-
-       /* regular file? */
-       if (!S_ISREG(st.st_mode))
-               fatal("PRNG seedfile %.100s is not a regular file", filename);
-
-       /* mode 0600, owned by root or the current user? */
-       if (((st.st_mode & 0177) != 0) || !(st.st_uid == original_uid)) {
-               debug("WARNING: PRNG seedfile %.100s must be mode 0600, owned by uid %d",
-                        filename, getuid());
-               return(0);
-       }
-
-       return(1);
-}
-
-void
-prng_write_seedfile(void) {
-       int fd;
-       char seed[1024];
-       char filename[1024];
-       struct passwd *pw;
-
-       /* Don't bother if we have already saved a seed */
-       if (prng_seed_saved)
-               return;
-
-       setuid(original_uid);
-
-       prng_seed_saved = 1;
-
-       pw = getpwuid(original_uid);
-       if (pw == NULL)
-               fatal("Couldn't get password entry for current user (%i): %s",
-                       original_uid, strerror(errno));
-
-       /* Try to ensure that the parent directory is there */
-       snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
-               _PATH_SSH_USER_DIR);
-       mkdir(filename, 0700);
-
-       snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
-               SSH_PRNG_SEED_FILE);
-
-       debug("writing PRNG seed to file %.100s", filename);
-
-       RAND_bytes(seed, sizeof(seed));
-
-       /* Don't care if the seed doesn't exist */
-       prng_check_seedfile(filename);
-
-       if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) {
-               debug("WARNING: couldn't access PRNG seedfile %.100s (%.100s)",
-                  filename, strerror(errno));
-       } else {
-               if (atomicio(write, fd, &seed, sizeof(seed)) != sizeof(seed))
-                       fatal("problem writing PRNG seedfile %.100s (%.100s)", filename,
-                                strerror(errno));
-
-               close(fd);
-       }
-}
-
-void
-prng_read_seedfile(void) {
-       int fd;
-       char seed[1024];
-       char filename[1024];
-       struct passwd *pw;
-
-       pw = getpwuid(original_uid);
-       if (pw == NULL)
-               fatal("Couldn't get password entry for current user (%i): %s",
-                       original_uid, strerror(errno));
+       if (waitpid(pid, &ret, 0) == -1)
+               fatal("Couldn't wait for ssh-rand-helper completion: %s",
+                   strerror(errno));
+       signal(SIGCHLD, old_sigchld);
 
-       snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
-               SSH_PRNG_SEED_FILE);
-
-       debug("loading PRNG seed from file %.100s", filename);
-
-       if (!prng_check_seedfile(filename)) {
-               verbose("Random seed file not found or not valid, ignoring.");
-               return;
-       }
+       /* We don't mind if the child exits upon a SIGPIPE */
+       if (!WIFEXITED(ret) &&
+           (!WIFSIGNALED(ret) || WTERMSIG(ret) != SIGPIPE))
+               fatal("ssh-rand-helper terminated abnormally");
+       if (WEXITSTATUS(ret) != 0)
+               fatal("ssh-rand-helper exit with exit status %d", ret);
 
-       /* open the file and read in the seed */
-       fd = open(filename, O_RDONLY);
-       if (fd == -1)
-               fatal("could not open PRNG seedfile %.100s (%.100s)", filename,
-                       strerror(errno));
-
-       if (atomicio(read, fd, &seed, sizeof(seed)) != sizeof(seed)) {
-               verbose("invalid or short read from PRNG seedfile %.100s - ignoring",
-                       filename);
-               memset(seed, '\0', sizeof(seed));
-       }
-       close(fd);
-
-       /* stir in the seed, with estimated entropy zero */
-       RAND_add(&seed, sizeof(seed), 0.0);
-}
-
-
-/*
- * entropy command initialisation functions
- */
-int
-prng_read_commands(char *cmdfilename)
-{
-       FILE *f;
-       char *cp;
-       char line[1024];
-       char cmd[1024];
-       char path[256];
-       int linenum;
-       int num_cmds = 64;
-       int cur_cmd = 0;
-       double est;
-       entropy_source_t *entcmd;
-
-       f = fopen(cmdfilename, "r");
-       if (!f) {
-               fatal("couldn't read entropy commands file %.100s: %.100s",
-                   cmdfilename, strerror(errno));
-       }
-
-       entcmd = (entropy_source_t *)xmalloc(num_cmds * sizeof(entropy_source_t));
-       memset(entcmd, '\0', num_cmds * sizeof(entropy_source_t));
-
-       /* Read in file */
-       linenum = 0;
-       while (fgets(line, sizeof(line), f)) {
-               int arg;
-               char *argv;
-
-               linenum++;
-
-               /* skip leading whitespace, test for blank line or comment */
-               cp = line + strspn(line, WHITESPACE);
-               if ((*cp == 0) || (*cp == '#'))
-                       continue; /* done with this line */
-
-               /* First non-whitespace char should be double quote delimiting */
-               /* commandline */
-               if (*cp != '"') {
-                       error("bad entropy command, %.100s line %d", cmdfilename,
-                            linenum);
-                       continue;
-               }
-
-               /* first token, command args (incl. argv[0]) in double quotes */
-               cp = strtok(cp, "\"");
-               if (cp == NULL) {
-                       error("missing or bad command string, %.100s line %d -- ignored",
-                             cmdfilename, linenum);
-                       continue;
-               }
-               strlcpy(cmd, cp, sizeof(cmd));
-
-               /* second token, full command path */
-               if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
-                       error("missing command path, %.100s line %d -- ignored",
-                             cmdfilename, linenum);
-                       continue;
-               }
-
-               /* did configure mark this as dead? */
-               if (strncmp("undef", cp, 5) == 0)
-                       continue;
-
-               strlcpy(path, cp, sizeof(path));
-
-               /* third token, entropy rate estimate for this command */
-               if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
-                       error("missing entropy estimate, %.100s line %d -- ignored",
-                             cmdfilename, linenum);
-                       continue;
-               }
-               est = strtod(cp, &argv);
-
-               /* end of line */
-               if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
-                       error("garbage at end of line %d in %.100s -- ignored", linenum,
-                               cmdfilename);
-                       continue;
-               }
-
-               /* save the command for debug messages */
-               entcmd[cur_cmd].cmdstring = xstrdup(cmd);
-
-               /* split the command args */
-               cp = strtok(cmd, WHITESPACE);
-               arg = 0;
-               argv = NULL;
-               do {
-                       char *s = (char*)xmalloc(strlen(cp) + 1);
-                       strncpy(s, cp, strlen(cp) + 1);
-                       entcmd[cur_cmd].args[arg] = s;
-                       arg++;
-               } while ((arg < 5) && (cp = strtok(NULL, WHITESPACE)));
-
-               if (strtok(NULL, WHITESPACE))
-                       error("ignored extra command elements (max 5), %.100s line %d",
-                             cmdfilename, linenum);
-
-               /* Copy the command path and rate estimate */
-               entcmd[cur_cmd].path = xstrdup(path);
-               entcmd[cur_cmd].rate = est;
-
-               /* Initialise other values */
-               entcmd[cur_cmd].sticky_badness = 1;
-
-               cur_cmd++;
-
-               /* If we've filled the array, reallocate it twice the size */
-               /* Do this now because even if this we're on the last command,
-                  we need another slot to mark the last entry */
-               if (cur_cmd == num_cmds) {
-                       num_cmds *= 2;
-                       entcmd = xrealloc(entcmd, num_cmds * sizeof(entropy_source_t));
-               }
-       }
-
-       /* zero the last entry */
-       memset(&entcmd[cur_cmd], '\0', sizeof(entropy_source_t));
-
-       /* trim to size */
-       entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t));
-
-       debug("Loaded %d entropy commands from %.100s", cur_cmd, cmdfilename);
+       RAND_add(buf, sizeof(buf), sizeof(buf));
+       memset(buf, '\0', sizeof(buf));
 
-       return (cur_cmd >= MIN_ENTROPY_SOURCES);
+#endif /* OPENSSL_PRNG_ONLY */
+       if (RAND_status() != 1)
+               fatal("PRNG is not seeded");
 }
 
-/*
- * Write a keyfile at exit
- */
 void
-prng_seed_cleanup(void *junk)
+init_rng(void)
 {
-       prng_write_seedfile();
+       /*
+        * OpenSSL version numbers: MNNFFPPS: major minor fix patch status
+        * We match major, minor, fix and status (not patch)
+        */
+       if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L)
+               fatal("OpenSSL version mismatch. Built against %lx, you "
+                   "have %lx", OPENSSL_VERSION_NUMBER, SSLeay());
+
+#ifndef OPENSSL_PRNG_ONLY
+       original_uid = getuid();
+       original_euid = geteuid();
+#endif
 }
 
-/*
- * Conditionally Seed OpenSSL's random number pool from
- * syscalls and program output
- */
+#ifndef OPENSSL_PRNG_ONLY
 void
-seed_rng(void)
+rexec_send_rng_seed(Buffer *m)
 {
-       mysig_t old_sigchld_handler;
-
-       if (!prng_initialised)
-               fatal("RNG not initialised");
-
-       /* Make sure some other sigchld handler doesn't reap our entropy */
-       /* commands */
-       old_sigchld_handler = mysignal(SIGCHLD, SIG_DFL);
-
-       debug("Seeded RNG with %i bytes from programs", (int)stir_from_programs());
-       debug("Seeded RNG with %i bytes from system calls", (int)stir_from_system());
-
-       if (!RAND_status())
-               fatal("Not enough entropy in RNG");
+       u_char buf[RANDOM_SEED_SIZE];
 
-       mysignal(SIGCHLD, old_sigchld_handler);
-
-       if (!RAND_status())
-               fatal("Couldn't initialise builtin random number generator -- exiting.");
+       if (RAND_bytes(buf, sizeof(buf)) <= 0) {
+               error("Couldn't obtain random bytes (error %ld)",
+                   ERR_get_error());
+               buffer_put_string(m, "", 0);
+       } else 
+               buffer_put_string(m, buf, sizeof(buf));
 }
 
-void init_rng(void)
+void
+rexec_recv_rng_seed(Buffer *m)
 {
-       int original_euid;
-
-       original_uid = getuid();
-       original_euid = geteuid();
-
-       /* Read in collection commands */
-       if (!prng_read_commands(SSH_PRNG_COMMAND_FILE))
-               fatal("PRNG initialisation failed -- exiting.");
-
-       /* Set ourselves up to save a seed upon exit */
-       prng_seed_saved = 0;
+       u_char *buf;
+       u_int len;
 
-       /* Give up privs while reading seed file */
-       if ((original_uid != original_euid) && (seteuid(original_uid) == -1))
-               fatal("Couldn't give up privileges");
-
-       prng_read_seedfile();
-
-       if ((original_uid != original_euid) && (seteuid(original_euid) == -1))
-               fatal("Couldn't restore privileges");
-
-       fatal_add_cleanup(prng_seed_cleanup, NULL);
-       atexit(prng_write_seedfile);
-
-       prng_initialised = 1;
+       buf = buffer_get_string_ret(m, &len);
+       if (buf != NULL) {
+               debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len);
+               RAND_add(buf, len, len);
+       }
 }
-
-#endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
+#endif
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