/*
- * Copyright (c) 2001 Damien Miller. All rights reserved.
+ * Copyright (c) 2001-2002 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 <sys/types.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <string.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#ifdef HAVE_SYS_UN_H
+# include <sys/un.h>
+#endif
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <signal.h>
+#include <time.h>
+#include <unistd.h>
+
#include <openssl/rand.h>
#include <openssl/sha.h>
#include <openssl/crypto.h>
#include "pathnames.h"
#include "log.h"
-RCSID("$Id$");
+/* Number of bytes we write out */
+#define OUTPUT_SEED_SIZE 48
-#define RANDOM_SEED_SIZE 48
+/* Length of on-disk seedfiles */
+#define SEED_FILE_SIZE 1024
-#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 */
+/* Maximum number of command-line arguments to read from file */
+#define NUM_ARGS 10
+/* Minimum number of usable commands to be considered sufficient */
+#define MIN_ENTROPY_SOURCES 16
-#ifndef offsetof
-# define offsetof(type, member) ((size_t) &((type *)0)->member)
+/* Path to on-disk seed file (relative to user's home directory */
+#ifndef SSH_PRNG_SEED_FILE
+# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
#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
+/* Path to PRNG commands list */
+#ifndef SSH_PRNG_COMMAND_FILE
+# define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds"
+#endif
-/* Minimum number of commands to be considered valid */
-#define MIN_ENTROPY_SOURCES 16
+extern char *__progname;
#define WHITESPACE " \t\n"
# define RUSAGE_CHILDREN 0
#endif
-#if defined(PRNGD_SOCKET) || defined(PRNGD_PORT)
-# define USE_PRNGD
+#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
+# define USE_SEED_FILES
#endif
-#ifdef USE_PRNGD
-/* Collect entropy from PRNGD/EGD */
+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[NUM_ARGS]; /* XXX: arbitrary limit */
+ /* full command string (debug) */
+ char *cmdstring;
+} entropy_cmd_t;
+
+/* slow command timeouts (all in milliseconds) */
+/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
+static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
+
+/* this is initialised from a file, by prng_read_commands() */
+static entropy_cmd_t *entropy_cmds = NULL;
+
+/* Prototypes */
+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_command_output(entropy_cmd_t *src, unsigned char *hash);
+int get_random_bytes_prngd(unsigned char *buf, int len,
+ unsigned short tcp_port, char *socket_path);
+
+/*
+ * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
+ * listening either on 'tcp_port', or via Unix domain socket at *
+ * 'socket_path'.
+ * Either a non-zero tcp_port or a non-null socket_path must be
+ * supplied.
+ * Returns 0 on success, -1 on error
+ */
int
-get_random_bytes(unsigned char *buf, int len)
+get_random_bytes_prngd(unsigned char *buf, int len,
+ unsigned short tcp_port, char *socket_path)
{
- int fd;
- char msg[2];
-#ifdef PRNGD_PORT
- struct sockaddr_in addr;
-#else
- struct sockaddr_un addr;
-#endif
- int addr_len, rval, errors;
+ int fd, addr_len, rval, errors;
+ u_char msg[2];
+ struct sockaddr_storage addr;
+ struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
+ struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
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))
+ if (socket_path == NULL && tcp_port == 0)
+ fatal("You must specify a port or a socket");
+ if (socket_path != NULL &&
+ strlen(socket_path) >= sizeof(addr_un->sun_path))
fatal("Random pool path is too long");
+ if (len <= 0 || len > 255)
+ fatal("Too many bytes (%d) to read from PRNGD", len);
- 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
+ memset(&addr, '\0', sizeof(addr));
+
+ if (tcp_port != 0) {
+ addr_in->sin_family = AF_INET;
+ addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ addr_in->sin_port = htons(tcp_port);
+ addr_len = sizeof(*addr_in);
+ } else {
+ addr_un->sun_family = AF_UNIX;
+ strlcpy(addr_un->sun_path, socket_path,
+ sizeof(addr_un->sun_path));
+ addr_len = offsetof(struct sockaddr_un, sun_path) +
+ strlen(socket_path) + 1;
+ }
old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
- errors = rval = 0;
+ errors = 0;
+ rval = -1;
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);
+ fd = socket(addr.ss_family, SOCK_STREAM, 0);
if (fd == -1) {
- error("Couldn't create AF_UNIX socket: %s", strerror(errno));
+ error("Couldn't create 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
+ if (tcp_port != 0) {
+ error("Couldn't connect to PRNGD port %d: %s",
+ tcp_port, strerror(errno));
+ } else {
+ error("Couldn't connect to PRNGD socket \"%s\": %s",
+ addr_un->sun_path, strerror(errno));
+ }
goto done;
}
msg[0] = 0x02;
msg[1] = len;
- if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) {
+ if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
if (errno == EPIPE && errors < 10) {
close(fd);
errors++;
goto done;
}
- if (atomicio(read, fd, buf, len) != len) {
+ if (atomicio(read, fd, buf, len) != (size_t)len) {
if (errno == EPIPE && errors < 10) {
close(fd);
errors++;
goto done;
}
- rval = 1;
+ rval = 0;
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);
+ return rval;
}
-double
-stir_from_programs(void)
+static int
+seed_from_prngd(unsigned char *buf, size_t bytes)
{
- 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);
+#ifdef PRNGD_PORT
+ debug("trying egd/prngd port %d", PRNGD_PORT);
+ if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
+ return 0;
+#endif
+#ifdef PRNGD_SOCKET
+ debug("trying egd/prngd socket %s", PRNGD_SOCKET);
+ if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
+ return 0;
+#endif
+ return -1;
}
double
RAND_add(&tv, sizeof(tv), entropy_estimate);
- return(entropy_estimate);
+ return entropy_estimate;
}
double
c = clock();
RAND_add(&c, sizeof(c), entropy_estimate);
- return(entropy_estimate);
+ return entropy_estimate;
#else /* _HAVE_CLOCK */
- return(0);
+ return 0;
#endif /* _HAVE_CLOCK */
}
struct rusage ru;
if (getrusage(who, &ru) == -1)
- return(0);
+ return 0;
RAND_add(&ru, sizeof(ru), entropy_estimate);
- return(entropy_estimate);
+ return entropy_estimate;
#else /* _HAVE_GETRUSAGE */
- return(0);
+ return 0;
#endif /* _HAVE_GETRUSAGE */
}
-
static int
-_get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) {
+timeval_diff(struct timeval *t1, struct timeval *t2)
+{
int secdiff, usecdiff;
secdiff = t2->tv_sec - t1->tv_sec;
}
double
-hash_output_from_command(entropy_source_t *src, char *hash)
+hash_command_output(entropy_cmd_t *src, unsigned char *hash)
{
- static int devnull = -1;
- int p[2];
+ char buf[8192];
fd_set rdset;
- int cmd_eof = 0, error_abort = 0;
- struct timeval tv_start, tv_current;
- int msec_elapsed = 0;
+ int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
+ int status, total_bytes_read;
+ static int devnull = -1;
pid_t pid;
- int status;
- char buf[16384];
- int bytes_read;
- int total_bytes_read;
SHA_CTX sha;
+ struct timeval tv_start, tv_current;
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));
+ fatal("Couldn't open /dev/null: %s",
+ strerror(errno));
}
if (pipe(p) == -1)
close(devnull);
execv(src->path, (char**)(src->args));
- debug("(child) Couldn't exec '%s': %s", src->cmdstring,
- strerror(errno));
+
+ debug("(child) Couldn't exec '%s': %s",
+ src->cmdstring, strerror(errno));
_exit(-1);
default: /* Parent */
break;
/* Hash output from child */
SHA1_Init(&sha);
- total_bytes_read = 0;
+ cmd_eof = error_abort = msec_elapsed = 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);
+ msec_elapsed = timeval_diff(&tv_start, &tv_current);
if (msec_elapsed >= entropy_timeout_current) {
error_abort=1;
continue;
FD_ZERO(&rdset);
FD_SET(p[0], &rdset);
- tv.tv_sec = msec_remaining / 1000;
+ tv.tv_sec = msec_remaining / 1000;
tv.tv_usec = (msec_remaining % 1000) * 1000;
- ret = select(p[0]+1, &rdset, NULL, NULL, &tv);
+ ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
RAND_add(&tv, sizeof(tv), 0.0);
case 0:
/* timer expired */
error_abort = 1;
+ kill(pid, SIGINT);
break;
case 1:
/* command input */
case -1:
default:
/* error */
- debug("Command '%s': select() failed: %s", src->cmdstring,
- strerror(errno));
+ debug("Command '%s': select() failed: %s",
+ src->cmdstring, strerror(errno));
error_abort = 1;
break;
}
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);
+ 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 */
+ /*
+ * 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);
+ return total_bytes_read;
}
if (WIFEXITED(status)) {
- if (WEXITSTATUS(status)==0) {
- return(total_bytes_read);
+ if (WEXITSTATUS(status) == 0) {
+ return total_bytes_read;
} else {
- debug2("Command '%s' exit status was %d", src->cmdstring,
- WEXITSTATUS(status));
+ debug2("Command '%s' exit status was %d",
+ src->cmdstring, WEXITSTATUS(status));
src->badness = src->sticky_badness = 128;
- return (0.0);
+ return 0.0;
}
} else if (WIFSIGNALED(status)) {
- debug2("Command '%s' returned on uncaught signal %d !", src->cmdstring,
- status);
+ debug2("Command '%s' returned on uncaught signal %d !",
+ src->cmdstring, status);
src->badness = src->sticky_badness = 128;
- return(0.0);
+ return 0.0;
} else
- return(0.0);
+ return 0.0;
+}
+
+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 c;
+ double entropy, total_entropy;
+ unsigned char hash[SHA_DIGEST_LENGTH];
+
+ total_entropy = 0;
+ for(c = 0; entropy_cmds[c].path != NULL; c++) {
+ if (!entropy_cmds[c].badness) {
+ /* Hash output from command */
+ entropy = hash_command_output(&entropy_cmds[c],
+ hash);
+
+ /* Scale back estimate by command's rate */
+ entropy *= entropy_cmds[c].rate;
+
+ /* Upper bound of entropy is SHA_DIGEST_LENGTH */
+ if (entropy > SHA_DIGEST_LENGTH)
+ entropy = SHA_DIGEST_LENGTH;
+
+ /* Stir it in */
+ RAND_add(hash, sizeof(hash), entropy);
+
+ debug3("Got %0.2f bytes of entropy from '%s'",
+ entropy, entropy_cmds[c].cmdstring);
+
+ total_entropy += entropy;
+
+ /* Execution time should be a bit unpredictable */
+ total_entropy += stir_gettimeofday(0.05);
+ total_entropy += stir_clock(0.05);
+ total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
+ total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
+ } else {
+ debug2("Command '%s' disabled (badness %d)",
+ entropy_cmds[c].cmdstring,
+ entropy_cmds[c].badness);
+
+ if (entropy_cmds[c].badness > 0)
+ entropy_cmds[c].badness--;
+ }
+ }
+
+ return total_entropy;
}
/*
* prng seedfile functions
*/
int
-prng_check_seedfile(char *filename) {
-
+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 */
+ /*
+ * XXX raceable: eg replace seed between this stat and subsequent
+ * open. Not such a problem because we don't really trust the
+ * seed file anyway.
+ * XXX: use secure path checking as elsewhere in OpenSSH
+ */
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);
+ debug("WARNING: Couldn't stat random seed file "
+ "\"%.100s\": %s", filename, strerror(errno));
+ return 0;
}
/* regular file? */
if (!S_ISREG(st.st_mode))
- fatal("PRNG seedfile %.100s is not a regular file", filename);
+ 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);
+ debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
+ "owned by uid %li", filename, (long int)getuid());
+ return 0;
}
- return(1);
+ return 1;
}
void
-prng_write_seedfile(void) {
- int fd;
- char seed[1024];
- char filename[1024];
+prng_write_seedfile(void)
+{
+ int fd, save_errno;
+ unsigned char seed[SEED_FILE_SIZE];
+ char filename[MAXPATHLEN], tmpseed[MAXPATHLEN];
struct passwd *pw;
+ mode_t old_umask;
pw = getpwuid(getuid());
if (pw == NULL)
- fatal("Couldn't get password entry for current user (%i): %s",
- getuid(), strerror(errno));
+ fatal("Couldn't get password entry for current user "
+ "(%li): %s", (long int)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);
+ _PATH_SSH_USER_DIR);
+ if (mkdir(filename, 0700) < 0 && errno != EEXIST)
+ fatal("mkdir %.200s: %s", filename, strerror(errno));
snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
- SSH_PRNG_SEED_FILE);
+ SSH_PRNG_SEED_FILE);
- debug("writing PRNG seed to file %.100s", filename);
+ strlcpy(tmpseed, filename, sizeof(tmpseed));
+ if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >=
+ sizeof(tmpseed))
+ fatal("PRNG seed filename too long");
- RAND_bytes(seed, sizeof(seed));
+ if (RAND_bytes(seed, sizeof(seed)) <= 0)
+ fatal("PRNG seed extraction failed");
/* 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));
+ old_umask = umask(0177);
+
+ if ((fd = mkstemp(tmpseed)) == -1) {
+ debug("WARNING: couldn't make temporary PRNG seedfile %.100s "
+ "(%.100s)", tmpseed, strerror(errno));
} else {
- if (atomicio(write, fd, &seed, sizeof(seed)) != sizeof(seed))
- fatal("problem writing PRNG seedfile %.100s (%.100s)", filename,
- strerror(errno));
+ debug("writing PRNG seed to file %.100s", tmpseed);
+ if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) {
+ save_errno = errno;
+ close(fd);
+ unlink(tmpseed);
+ fatal("problem writing PRNG seedfile %.100s "
+ "(%.100s)", filename, strerror(save_errno));
+ }
close(fd);
+ debug("moving temporary PRNG seed to file %.100s", filename);
+ if (rename(tmpseed, filename) == -1) {
+ save_errno = errno;
+ unlink(tmpseed);
+ fatal("problem renaming PRNG seedfile from %.100s "
+ "to %.100s (%.100s)", tmpseed, filename,
+ strerror(save_errno));
+ }
}
+ umask(old_umask);
}
void
-prng_read_seedfile(void) {
+prng_read_seedfile(void)
+{
int fd;
- char seed[1024];
- char filename[1024];
+ char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
struct passwd *pw;
pw = getpwuid(getuid());
if (pw == NULL)
- fatal("Couldn't get password entry for current user (%i): %s",
- getuid(), strerror(errno));
+ fatal("Couldn't get password entry for current user "
+ "(%li): %s", (long int)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.");
+ verbose("Random seed file not found or invalid, 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));
+ 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);
+ 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);
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;
+ char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
double est;
- entropy_source_t *entcmd;
+ entropy_cmd_t *entcmd;
+ FILE *f;
+ int cur_cmd, linenum, num_cmds, arg;
- f = fopen(cmdfilename, "r");
- if (!f) {
+ if ((f = fopen(cmdfilename, "r")) == NULL) {
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));
+ num_cmds = 64;
+ entcmd = xcalloc(num_cmds, sizeof(entropy_cmd_t));
/* Read in file */
- linenum = 0;
+ cur_cmd = linenum = 0;
while (fgets(line, sizeof(line), f)) {
- int arg;
- char *argv;
-
linenum++;
- /* skip leading whitespace, test for blank line or comment */
+ /* Skip leading whitespace, blank lines and comments */
cp = line + strspn(line, WHITESPACE);
if ((*cp == 0) || (*cp == '#'))
continue; /* done with this line */
- /* First non-whitespace char should be double quote delimiting */
- /* commandline */
+ /*
+ * The first non-whitespace char should be a double quote
+ * delimiting the commandline
+ */
if (*cp != '"') {
- error("bad entropy command, %.100s line %d", cmdfilename,
- linenum);
+ error("bad entropy command, %.100s line %d",
+ cmdfilename, linenum);
continue;
}
- /* first token, command args (incl. argv[0]) in double quotes */
+ /*
+ * 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);
+ error("missing or bad command string, %.100s "
+ "line %d -- ignored", cmdfilename, linenum);
continue;
}
strlcpy(cmd, cp, sizeof(cmd));
- /* second token, full command path */
+ /* Second token, full command path */
if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
- error("missing command path, %.100s line %d -- ignored",
- cmdfilename, linenum);
+ error("missing command path, %.100s "
+ "line %d -- ignored", cmdfilename, linenum);
continue;
}
- /* did configure mark this as dead? */
+ /* 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 */
+ /* Third token, entropy rate estimate for this command */
if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
- error("missing entropy estimate, %.100s line %d -- ignored",
- cmdfilename, linenum);
+ error("missing entropy estimate, %.100s "
+ "line %d -- ignored", cmdfilename, linenum);
continue;
}
- est = strtod(cp, &argv);
+ est = strtod(cp, NULL);
/* end of line */
if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
- error("garbage at end of line %d in %.100s -- ignored", linenum,
- cmdfilename);
+ error("garbage at end of line %d in %.100s "
+ "-- ignored", linenum, cmdfilename);
continue;
}
/* 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;
+ entcmd[cur_cmd].args[arg] = xstrdup(cp);
arg++;
- } while ((arg < 5) && (cp = strtok(NULL, WHITESPACE)));
+ } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
if (strtok(NULL, WHITESPACE))
- error("ignored extra command elements (max 5), %.100s line %d",
- cmdfilename, linenum);
+ error("ignored extra commands (max %d), %.100s "
+ "line %d", NUM_ARGS, cmdfilename, linenum);
/* Copy the command path and rate estimate */
entcmd[cur_cmd].path = xstrdup(path);
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 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));
+ entcmd = xrealloc(entcmd, num_cmds,
+ sizeof(entropy_cmd_t));
}
}
/* zero the last entry */
- memset(&entcmd[cur_cmd], '\0', sizeof(entropy_source_t));
+ memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
/* trim to size */
- entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t));
+ entropy_cmds = xrealloc(entcmd, (cur_cmd + 1),
+ sizeof(entropy_cmd_t));
+
+ debug("Loaded %d entropy commands from %.100s", cur_cmd,
+ cmdfilename);
- debug("Loaded %d entropy commands from %.100s", cur_cmd, cmdfilename);
+ fclose(f);
+ return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
+}
- return (cur_cmd >= MIN_ENTROPY_SOURCES);
+void
+usage(void)
+{
+ fprintf(stderr, "Usage: %s [options]\n", __progname);
+ fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
+ fprintf(stderr, " Multiple -v increases verbosity.\n");
+ fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n");
+ fprintf(stderr, " -X Force output in binary\n");
+ fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
+ OUTPUT_SEED_SIZE);
}
-static void
-seed_openssl_rng(void)
+int
+main(int argc, char **argv)
{
- /* Read in collection commands */
- if (!prng_read_commands(SSH_PRNG_COMMAND_FILE))
- fatal("PRNG initialisation failed -- exiting.");
+ unsigned char *buf;
+ int ret, ch, debug_level, output_hex, bytes;
+ extern char *optarg;
+ LogLevel ll;
+
+ __progname = ssh_get_progname(argv[0]);
+ log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
+
+ ll = SYSLOG_LEVEL_INFO;
+ debug_level = output_hex = 0;
+ bytes = OUTPUT_SEED_SIZE;
+
+ /* Don't write binary data to a tty, unless we are forced to */
+ if (isatty(STDOUT_FILENO))
+ output_hex = 1;
+
+ while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
+ switch (ch) {
+ case 'v':
+ if (debug_level < 3)
+ ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
+ break;
+ case 'x':
+ output_hex = 1;
+ break;
+ case 'X':
+ output_hex = 0;
+ break;
+ case 'b':
+ if ((bytes = atoi(optarg)) <= 0)
+ fatal("Invalid number of output bytes");
+ break;
+ case 'h':
+ usage();
+ exit(0);
+ default:
+ error("Invalid commandline option");
+ usage();
+ exit(1);
+ }
+ }
+ log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
+
+ if (argc != optind) {
+ error("Unexpected commandline arguments.");
+ usage();
+ exit(1);
+ }
+#ifdef USE_SEED_FILES
prng_read_seedfile();
+#endif
- 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());
+ buf = xmalloc(bytes);
- prng_write_seedfile();
-}
+ /*
+ * Seed the RNG from wherever we can
+ */
-#endif /* USE_PRNGD */
+ /* Take whatever is on the stack, but don't credit it */
+ RAND_add(buf, bytes, 0);
-int
-main(int argc, char **argv)
-{
- unsigned char buf[48];
- int ret;
+ debug("Seeded RNG with %i bytes from system calls",
+ (int)stir_from_system());
- /* XXX: need some debugging mode */
- log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
+ /* try prngd, fall back to commands if prngd fails or not configured */
+ if (seed_from_prngd(buf, bytes) == 0) {
+ RAND_add(buf, bytes, bytes);
+ } else {
+ /* Read in collection commands */
+ if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
+ fatal("PRNG initialisation failed -- exiting.");
+ debug("Seeded RNG with %i bytes from programs",
+ (int)stir_from_programs());
+ }
+
+#ifdef USE_SEED_FILES
+ prng_write_seedfile();
+#endif
- seed_openssl_rng();
+ /*
+ * Write the seed to stdout
+ */
if (!RAND_status())
fatal("Not enough entropy in RNG");
- RAND_bytes(buf, sizeof(buf));
+ if (RAND_bytes(buf, bytes) <= 0)
+ fatal("Couldn't extract entropy from PRNG");
+
+ if (output_hex) {
+ for(ret = 0; ret < bytes; ret++)
+ printf("%02x", (unsigned char)(buf[ret]));
+ printf("\n");
+ } else
+ ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
+
+ memset(buf, '\0', bytes);
+ xfree(buf);
- ret = atomicio(write, STDOUT_FILENO, buf, sizeof(buf));
-
- memset(buf, '\0', sizeof(buf));
-
- return ret == sizeof(buf) ? 0 : 1;
+ return ret == bytes ? 0 : 1;
}
+/*
+ * We may attempt to re-seed during mkstemp if we are using the one in the
+ * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we
+ * need our own seed_rng(). We must also check that we have enough entropy.
+ */
+void
+seed_rng(void)
+{
+ if (!RAND_status())
+ fatal("Not enough entropy in RNG");
+}
andersk / openssh.git / blobdiff