Fwd: OpenSSH on Ultrix?
Lutz Jaenicke
Lutz.Jaenicke at aet.TU-Cottbus.DE
Sat Mar 3 01:26:48 EST 2001
On Sat, Mar 03, 2001 at 12:17:33AM +1100, Damien Miller wrote:
> I think this is exactly what I will do :) Can you give the below patch
> a try for both Unix domain and localhost sockets? It replaces the
> current --with-egd-pool configure option with --with-prngd-port and
> --with-prngd-socket options.
Ok. I have rewritten entropy.c to a more "defensive" handling :-)
With this version, it works with both Unix and TCP socket.
I have attached the complete file, since my CVS checkout is from the
public server which seems not to be completely in sync with your
archive, so, to be on the safe side...
> BTW You should apply to the IANA to get a well known port number
> assigned for PRNGd.
I'll have a look into the procedure.
Best regards,
Lutz
--
Lutz Jaenicke Lutz.Jaenicke at aet.TU-Cottbus.DE
BTU Cottbus http://www.aet.TU-Cottbus.DE/personen/jaenicke/
Lehrstuhl Allgemeine Elektrotechnik Tel. +49 355 69-4129
Universitaetsplatz 3-4, D-03044 Cottbus Fax. +49 355 69-4153
-------------- next part --------------
/*
* Copyright (c) 2000 Damien Miller. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#include <openssl/rand.h>
#include <openssl/sha.h>
#include <openssl/crypto.h>
/* SunOS 4.4.4 needs this */
#ifdef HAVE_FLOATINGPOINT_H
# include <floatingpoint.h>
#endif /* HAVE_FLOATINGPOINT_H */
#include "ssh.h"
#include "misc.h"
#include "xmalloc.h"
#include "atomicio.h"
#include "pathnames.h"
#include "log.h"
RCSID("$Id: entropy.c,v 1.34 2001/02/27 00:00:52 djm Exp $");
#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"
#ifndef RUSAGE_SELF
# define RUSAGE_SELF 0
#endif
#ifndef RUSAGE_CHILDREN
# define RUSAGE_CHILDREN 0
#endif
#if defined(_POSIX_SAVED_IDS) && !defined(BROKEN_SAVED_UIDS)
# define SAVED_IDS_WORK_WITH_SETEUID
#endif
void check_openssl_version(void)
{
if (SSLeay() != OPENSSL_VERSION_NUMBER)
fatal("OpenSSL version mismatch. Built against %lx, you "
"have %lx", OPENSSL_VERSION_NUMBER, SSLeay());
}
#if defined(PRNGD_SOCKET) || defined(PRNGD_PORT)
# define USE_PRNGD
#endif
#if defined(USE_PRNGD) || defined(RANDOM_POOL)
#ifdef USE_PRNGD
/* Collect entropy from PRNGD/EGD */
int get_random_bytes(unsigned char *buf, int len)
{
int fd;
char msg[2];
#ifdef PRNGD_PORT
struct sockaddr_in addr;
#else
struct sockaddr_un addr;
#endif
int addr_len, rval, errors;
mysig_t old_sigpipe;
memset(&addr, '\0', sizeof(addr));
#ifdef PRNGD_PORT
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
addr.sin_port = htons(PRNGD_PORT);
addr_len = sizeof(struct sockaddr_in);
#else /* use IP socket PRNGD_SOCKET instead */
/* Sanity checks */
if (sizeof(PRNGD_SOCKET) > sizeof(addr.sun_path))
fatal("Random pool path is too long");
if (len > 255)
fatal("Too many bytes to read from PRNGD");
addr.sun_family = AF_UNIX;
strlcpy(addr.sun_path, PRNGD_SOCKET, sizeof(addr.sun_path));
addr_len = offsetof(struct sockaddr_un, sun_path) +
sizeof(PRNGD_SOCKET);
#endif
old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
errors = rval = 0;
reopen:
#ifdef PRNGD_PORT
fd = socket(addr.sin_family, SOCK_STREAM, 0);
if (fd == -1) {
error("Couldn't create AF_INET socket: %s", strerror(errno));
goto done;
}
#else
fd = socket(addr.sun_family, SOCK_STREAM, 0);
if (fd == -1) {
error("Couldn't create AF_UNIX socket: %s", strerror(errno));
goto done;
}
#endif
if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
#ifdef PRNGD_PORT
error("Couldn't connect to PRNGD port %d: %s",
PRNGD_PORT, strerror(errno));
#else
error("Couldn't connect to PRNGD socket \"%s\": %s",
addr.sun_path, strerror(errno));
#endif
goto done;
}
/* Send blocking read request to PRNGD */
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 PRNGD socket: %s",
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 PRNGD socket: %s",
strerror(errno));
goto done;
}
rval = 1;
done:
mysignal(SIGPIPE, old_sigpipe);
if (fd != -1)
close(fd);
return(rval);
}
#else /* !USE_PRNGD */
#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 /* USE_PRNGD */
/*
* Seed OpenSSL's random number pool from Kernel random number generator
* or PRNGD/EGD
*/
void
seed_rng(void)
{
unsigned 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));
}
void init_rng(void)
{
check_openssl_version();
}
#else /* defined(USE_PRNGD) || 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;
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);
if (devnull == -1) {
devnull = open("/dev/null", O_RDWR);
if (devnull == -1)
fatal("Couldn't open /dev/null: %s", strerror(errno));
}
if (pipe(p) == -1)
fatal("Couldn't open pipe: %s", strerror(errno));
(void)gettimeofday(&tv_start, NULL); /* record start time */
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);
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;
}
RAND_add(&pid, sizeof(&pid), 0.0);
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);
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));
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;
}
/* 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);
return (cur_cmd >= MIN_ENTROPY_SOURCES);
}
/*
* Write a keyfile at exit
*/
void
prng_seed_cleanup(void *junk)
{
prng_write_seedfile();
}
/*
* Conditionally Seed OpenSSL's random number pool from
* syscalls and program output
*/
void
seed_rng(void)
{
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");
mysignal(SIGCHLD, old_sigchld_handler);
if (!RAND_status())
fatal("Couldn't initialise builtin random number generator -- exiting.");
}
void init_rng(void)
{
int original_euid;
check_openssl_version();
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;
/* Give up privs while reading seed file */
#ifdef SAVED_IDS_WORK_WITH_SETEUID
if ((original_uid != original_euid) && (seteuid(original_uid) == -1))
fatal("Couldn't give up privileges");
#else /* SAVED_IDS_WORK_WITH_SETEUID */
/*
* Propagate the privileged uid to all of our uids.
* Set the effective uid to the given (unprivileged) uid.
*/
if (original_uid != original_euid && (setuid(original_euid) == -1 ||
seteuid(original_uid) == -1))
fatal("Couldn't give up privileges");
#endif /* SAVED_IDS_WORK_WITH_SETEUID */
prng_read_seedfile();
#ifdef SAVED_IDS_WORK_WITH_SETEUID
if ((original_uid != original_euid) && (seteuid(original_euid) == -1))
fatal("Couldn't restore privileges");
#else /* SAVED_IDS_WORK_WITH_SETEUID */
/*
* We are unable to restore the real uid to its unprivileged value.
* Propagate the real uid (usually more privileged) to effective uid
* as well.
*/
if (original_uid != original_euid && (seteuid(original_euid) == -1 ||
setuid(original_uid) == -1))
fatal("Couldn't restore privileges");
#endif /* SAVED_IDS_WORK_WITH_SETEUID */
fatal_add_cleanup(prng_seed_cleanup, NULL);
atexit(prng_write_seedfile);
prng_initialised = 1;
}
#endif /* defined(USE_PRNGD) || defined(RANDOM_POOL) */
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