- (djm) Ignore fix & patchlevel in OpenSSL version check. Patch from
solar@openwall.com
- (djm) Rework entropy code. If the OpenSSL PRNG is has not been
internally seeded, execute a subprogram "ssh-rand-helper" to obtain
some entropy for us. Rewrite the old in-process entropy collecter as
an example ssh-rand-helper.
- (djm) Always perform ssh_prng_cmds path lookups in configure, even if
we don't end up using ssh_prng_cmds (so we always get a valid file)
diff --git a/ChangeLog b/ChangeLog
index 7ce2187..4f4c843 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+20011222
+ - (djm) Ignore fix & patchlevel in OpenSSL version check. Patch from
+ solar@openwall.com
+ - (djm) Rework entropy code. If the OpenSSL PRNG is has not been
+ internally seeded, execute a subprogram "ssh-rand-helper" to obtain
+ some entropy for us. Rewrite the old in-process entropy collecter as
+ an example ssh-rand-helper.
+ - (djm) Always perform ssh_prng_cmds path lookups in configure, even if
+ we don't end up using ssh_prng_cmds (so we always get a valid file)
+
20011221
- (djm) Add option to gnome-ssh-askpass to stop it from grabbing the X
server. I have found this necessary to avoid server hangs with X input
@@ -7086,4 +7096,4 @@
- Wrote replacements for strlcpy and mkdtemp
- Released 1.0pre1
-$Id: ChangeLog,v 1.1705 2001/12/21 04:00:19 djm Exp $
+$Id: ChangeLog,v 1.1706 2001/12/23 14:41:47 djm Exp $
diff --git a/Makefile.in b/Makefile.in
index f484dc3..7a722b4 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1,4 +1,4 @@
-# $Id: Makefile.in,v 1.190 2001/11/11 23:34:23 djm Exp $
+# $Id: Makefile.in,v 1.191 2001/12/23 14:41:48 djm Exp $
prefix=@prefix@
exec_prefix=@exec_prefix@
@@ -23,7 +23,8 @@
-D_PATH_SSH_PROGRAM=\"$(SSH_PROGRAM)\" \
-D_PATH_SSH_ASKPASS_DEFAULT=\"$(ASKPASS_PROGRAM)\" \
-D_PATH_SFTP_SERVER=\"$(SFTP_SERVER)\" \
- -D_PATH_SSH_PIDDIR=\"$(piddir)\"
+ -D_PATH_SSH_PIDDIR=\"$(piddir)\" \
+ -DSSH_RAND_HELPER=\"$(libexecdir)/ssh-rand-helper\"
CC=@CC@
LD=@LD@
@@ -44,7 +45,7 @@
@NO_SFTP@SFTP_PROGS=sftp-server$(EXEEXT) sftp$(EXEEXT)
-TARGETS=ssh$(EXEEXT) sshd$(EXEEXT) ssh-add$(EXEEXT) ssh-keygen$(EXEEXT) ssh-keyscan${EXEEXT} ssh-agent$(EXEEXT) scp$(EXEEXT) $(SFTP_PROGS)
+TARGETS=ssh$(EXEEXT) sshd$(EXEEXT) ssh-add$(EXEEXT) ssh-keygen$(EXEEXT) ssh-keyscan${EXEEXT} ssh-agent$(EXEEXT) scp$(EXEEXT) ssh-rand-helper${EXEEXT} $(SFTP_PROGS)
LIBSSH_OBJS=atomicio.o authfd.o authfile.o bufaux.o buffer.o canohost.o channels.o cipher.o compat.o compress.o crc32.o deattack.o dh.o dispatch.o mac.o hostfile.o key.o kex.o kexdh.o kexgex.o log.o match.o misc.o mpaux.o nchan.o packet.o radix.o rijndael.o entropy.o readpass.o rsa.o scard.o ssh-dss.o ssh-rsa.o tildexpand.o ttymodes.o uidswap.o uuencode.o xmalloc.o
@@ -121,6 +122,9 @@
sftp$(EXEEXT): $(LIBCOMPAT) libssh.a sftp.o sftp-client.o sftp-int.o sftp-common.o sftp-glob.o
$(LD) -o $@ sftp.o sftp-client.o sftp-common.o sftp-int.o sftp-glob.o $(LDFLAGS) -lssh -lopenbsd-compat $(LIBS)
+ssh-rand-helper${EXEEXT}: $(LIBCOMPAT) ssh-rand-helper.o
+ $(LD) -o $@ ssh-rand-helper.o atomicio.o log.o xmalloc.o $(LDFLAGS) -lopenbsd-compat $(LIBS)
+
# test driver for the loginrec code - not built by default
logintest: logintest.o $(LIBCOMPAT) libssh.a loginrec.o
$(LD) -o $@ logintest.o $(LDFLAGS) loginrec.o -lopenbsd-compat -lssh $(LIBS)
@@ -197,6 +201,7 @@
$(INSTALL) -m 0755 -s ssh-keygen $(DESTDIR)$(bindir)/ssh-keygen
$(INSTALL) -m 0755 -s ssh-keyscan $(DESTDIR)$(bindir)/ssh-keyscan
$(INSTALL) -m 0755 -s sshd $(DESTDIR)$(sbindir)/sshd
+ $(INSTALL) -m 0755 -s ssh-rand-helper $(DESTDIR)$(libexecdir)/ssh-rand-helper
@NO_SFTP@$(INSTALL) -m 0755 -s sftp $(DESTDIR)$(bindir)/sftp
@NO_SFTP@$(INSTALL) -m 0755 -s sftp-server $(DESTDIR)$(SFTP_SERVER)
$(INSTALL) -m 644 ssh.1.out $(DESTDIR)$(mandir)/$(mansubdir)1/ssh.1
diff --git a/configure.ac b/configure.ac
index ae2b6a7..35cda59 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-# $Id: configure.ac,v 1.6 2001/12/07 17:20:48 mouring Exp $
+i# $Id: configure.ac,v 1.7 2001/12/23 14:41:48 djm Exp $
AC_INIT
AC_CONFIG_SRCDIR([ssh.c])
@@ -1598,28 +1598,28 @@
INSTALL_SSH_PRNG_CMDS=""
rm -f prng_commands
if (test -z "$RANDOM_POOL" && test -z "$PRNGD") ; then
- # Use these commands to collect entropy
- OSSH_PATH_ENTROPY_PROG(PROG_LS, ls)
- OSSH_PATH_ENTROPY_PROG(PROG_NETSTAT, netstat)
- OSSH_PATH_ENTROPY_PROG(PROG_ARP, arp)
- OSSH_PATH_ENTROPY_PROG(PROG_IFCONFIG, ifconfig)
- OSSH_PATH_ENTROPY_PROG(PROG_JSTAT, jstat)
- OSSH_PATH_ENTROPY_PROG(PROG_PS, ps)
- OSSH_PATH_ENTROPY_PROG(PROG_SAR, sar)
- OSSH_PATH_ENTROPY_PROG(PROG_W, w)
- OSSH_PATH_ENTROPY_PROG(PROG_WHO, who)
- OSSH_PATH_ENTROPY_PROG(PROG_LAST, last)
- OSSH_PATH_ENTROPY_PROG(PROG_LASTLOG, lastlog)
- OSSH_PATH_ENTROPY_PROG(PROG_DF, df)
- OSSH_PATH_ENTROPY_PROG(PROG_VMSTAT, vmstat)
- OSSH_PATH_ENTROPY_PROG(PROG_UPTIME, uptime)
- OSSH_PATH_ENTROPY_PROG(PROG_IPCS, ipcs)
- OSSH_PATH_ENTROPY_PROG(PROG_TAIL, tail)
-
INSTALL_SSH_PRNG_CMDS="yes"
fi
AC_SUBST(INSTALL_SSH_PRNG_CMDS)
+# These programs are used to gather entropy from
+OSSH_PATH_ENTROPY_PROG(PROG_LS, ls)
+OSSH_PATH_ENTROPY_PROG(PROG_NETSTAT, netstat)
+OSSH_PATH_ENTROPY_PROG(PROG_ARP, arp)
+OSSH_PATH_ENTROPY_PROG(PROG_IFCONFIG, ifconfig)
+OSSH_PATH_ENTROPY_PROG(PROG_JSTAT, jstat)
+OSSH_PATH_ENTROPY_PROG(PROG_PS, ps)
+OSSH_PATH_ENTROPY_PROG(PROG_SAR, sar)
+OSSH_PATH_ENTROPY_PROG(PROG_W, w)
+OSSH_PATH_ENTROPY_PROG(PROG_WHO, who)
+OSSH_PATH_ENTROPY_PROG(PROG_LAST, last)
+OSSH_PATH_ENTROPY_PROG(PROG_LASTLOG, lastlog)
+OSSH_PATH_ENTROPY_PROG(PROG_DF, df)
+OSSH_PATH_ENTROPY_PROG(PROG_VMSTAT, vmstat)
+OSSH_PATH_ENTROPY_PROG(PROG_UPTIME, uptime)
+OSSH_PATH_ENTROPY_PROG(PROG_IPCS, ipcs)
+OSSH_PATH_ENTROPY_PROG(PROG_TAIL, tail)
+
AC_ARG_WITH(mantype,
[ --with-mantype=man|cat|doc Set man page type],
diff --git a/entropy.c b/entropy.c
index d9760cc..86ea81a 100644
--- 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
@@ -25,14 +25,8 @@
#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"
@@ -40,878 +34,108 @@
#include "pathnames.h"
#include "log.h"
-RCSID("$Id: entropy.c,v 1.38 2001/08/06 06:51:49 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
-
-static 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 */
-static 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
+ * 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.
*/
+
+#define RANDOM_SEED_SIZE 48
+
+RCSID("$Id: entropy.c,v 1.39 2001/12/23 14:41:48 djm Exp $");
+
+static uid_t original_uid, original_euid;
+
void
seed_rng(void)
{
- unsigned char buf[32];
+ int devnull;
+ int p[2];
+ pid_t pid;
+ int ret;
+ unsigned char buf[RANDOM_SEED_SIZE];
- 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));
+ if (RAND_status() == 1) {
+ debug3("RNG is ready, skipping seeding");
+ return;
}
+ debug3("Seeing PRNG from %s", SSH_RAND_HELPER);
+
+ 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));
+
+ 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 &&
+ setuid(original_uid) == -1) {
+ fprintf(stderr, "(rand child) setuid: %s\n",
+ strerror(errno));
+ _exit(1);
+ }
+
+ 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);
+ }
+
+ close(devnull);
+ close(p[1]);
+
+ 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]);
+
+ if (waitpid(pid, &ret, 0) == -1)
+ fatal("Couldn't wait for ssh-rand-helper completion: %s",
+ strerror(errno));
+
+ /* 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);
+
+ 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 */
- do {
- bytes_read = read(p[0], buf, sizeof(buf));
- } while (bytes_read == -1 && errno == EINTR);
- 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.
+ * OpenSSL version numbers: MNNFFPPS: major minor fix patch status
+ * We match major, minor, fix and status (not patch)
*/
- 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 */
+ if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L)
+ fatal("OpenSSL version mismatch. Built against %lx, you "
+ "have %lx", OPENSSL_VERSION_NUMBER, SSLeay());
- 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;
+ if ((original_uid = getuid()) == -1)
+ fatal("getuid: %s", strerror(errno));
+ if ((original_euid = geteuid()) == -1)
+ fatal("geteuid: %s", strerror(errno));
}
-
-#endif /* defined(USE_PRNGD) || defined(RANDOM_POOL) */
diff --git a/pathnames.h b/pathnames.h
index 1b223e3..feb2d0c 100644
--- a/pathnames.h
+++ b/pathnames.h
@@ -154,13 +154,3 @@
#ifndef ASKPASS_PROGRAM
#define ASKPASS_PROGRAM "/usr/lib/ssh/ssh-askpass"
#endif /* ASKPASS_PROGRAM */
-
-/*
- * Relevant only when using builtin PRNG.
- */
-#ifndef SSH_PRNG_SEED_FILE
-# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
-#endif /* SSH_PRNG_SEED_FILE */
-#ifndef SSH_PRNG_COMMAND_FILE
-# define SSH_PRNG_COMMAND_FILE ETCDIR "/ssh_prng_cmds"
-#endif /* SSH_PRNG_COMMAND_FILE */
diff --git a/ssh-rand-helper.c b/ssh-rand-helper.c
new file mode 100644
index 0000000..5b7a9fc
--- /dev/null
+++ b/ssh-rand-helper.c
@@ -0,0 +1,805 @@
+/*
+ * 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
+ * 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 "misc.h"
+#include "xmalloc.h"
+#include "atomicio.h"
+#include "pathnames.h"
+#include "log.h"
+
+RCSID("$Id: ssh-rand-helper.c,v 1.1 2001/12/23 14:41:48 djm Exp $");
+
+#define RANDOM_SEED_SIZE 48
+
+#ifndef SSH_PRNG_SEED_FILE
+# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
+#endif /* SSH_PRNG_SEED_FILE */
+#ifndef SSH_PRNG_COMMAND_FILE
+# define SSH_PRNG_COMMAND_FILE ETCDIR "/ssh_prng_cmds"
+#endif /* SSH_PRNG_COMMAND_FILE */
+
+
+#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(PRNGD_SOCKET) || defined(PRNGD_PORT)
+# define USE_PRNGD
+#endif
+
+#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;
+
+ if (len > 255)
+ fatal("Too many bytes to read from PRNGD");
+
+ 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");
+
+ 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);
+}
+
+static void
+seed_openssl_rng(void)
+{
+ unsigned char buf[RANDOM_SEED_SIZE];
+
+ if (!get_random_bytes(buf, sizeof(buf)))
+ fatal("Entropy collection failed");
+
+ RAND_add(buf, sizeof(buf), sizeof(buf));
+ memset(buf, '\0', sizeof(buf));
+}
+
+#else /* USE_PRNGD */
+
+/*
+ * 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;
+
+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);
+
+ 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 */
+ do {
+ bytes_read = read(p[0], buf, sizeof(buf));
+ } while (bytes_read == -1 && errno == EINTR);
+ 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 == getuid())) {
+ 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;
+
+ pw = getpwuid(getuid());
+ if (pw == NULL)
+ fatal("Couldn't get password entry for current user (%i): %s",
+ getuid(), 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(getuid());
+ if (pw == NULL)
+ fatal("Couldn't get password entry for current user (%i): %s",
+ getuid(), 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);
+}
+
+static void
+seed_openssl_rng(void)
+{
+ /* Read in collection commands */
+ if (!prng_read_commands(SSH_PRNG_COMMAND_FILE))
+ fatal("PRNG initialisation failed -- exiting.");
+
+ prng_read_seedfile();
+
+ 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());
+
+ prng_write_seedfile();
+}
+
+#endif /* USE_PRNGD */
+
+int
+main(int argc, char **argv)
+{
+ unsigned char buf[48];
+ int ret;
+
+ /* XXX: need some debugging mode */
+ log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
+
+ seed_openssl_rng();
+
+ if (!RAND_status())
+ fatal("Not enough entropy in RNG");
+
+ RAND_bytes(buf, sizeof(buf));
+
+ ret = atomicio(write, STDOUT_FILENO, buf, sizeof(buf));
+
+ memset(buf, '\0', sizeof(buf));
+
+ return ret == sizeof(buf) ? 0 : 1;
+}
+