/*
- * Copyright (c) 2001 Damien Miller. All rights reserved.
+ * 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
#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 "pathnames.h"
#include "log.h"
-/*
- * 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.
- */
-
RCSID("$Id$");
-#ifndef OPENSSL_PRNG_ONLY
-#define RANDOM_SEED_SIZE 48
-static uid_t original_uid, original_euid;
+#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
+ */
void
seed_rng(void)
{
-#ifndef OPENSSL_PRNG_ONLY
- int devnull;
+ 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 ret;
- unsigned char buf[RANDOM_SEED_SIZE];
- mysig_t old_sigchld;
+ int status;
+ char buf[16384];
+ int bytes_read;
+ int total_bytes_read;
+ SHA_CTX sha;
- if (RAND_status() == 1) {
- debug3("RNG is ready, skipping seeding");
- return;
- }
+ debug3("Reading output from \'%s\'", src->cmdstring);
- debug3("Seeding PRNG from %s", SSH_RAND_HELPER);
+ if (devnull == -1) {
+ devnull = open("/dev/null", O_RDWR);
+ if (devnull == -1)
+ fatal("Couldn't open /dev/null: %s", strerror(errno));
+ }
- if ((devnull = open("/dev/null", O_RDWR)) == -1)
- fatal("Couldn't open /dev/null: %s", strerror(errno));
if (pipe(p) == -1)
- fatal("pipe: %s", strerror(errno));
-
- old_sigchld = mysignal(SIGCHLD, SIG_DFL);
- if ((pid = fork()) == -1)
- fatal("Couldn't fork: %s", strerror(errno));
- if (pid == 0) {
- dup2(devnull, STDIN_FILENO);
- dup2(p[1], STDOUT_FILENO);
- /* Keep stderr open for errors */
- close(p[0]);
- close(p[1]);
- close(devnull);
-
- if (original_uid != original_euid &&
- ( seteuid(getuid()) == -1 ||
- setuid(original_uid) == -1) ) {
- fprintf(stderr, "(rand child) setuid(%d): %s\n",
- original_uid, 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);
+ 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;
}
- close(devnull);
+ RAND_add(&pid, sizeof(&pid), 0.0);
+
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");
+ /* 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]);
- if (waitpid(pid, &ret, 0) == -1)
- fatal("Couldn't wait for ssh-rand-helper completion: %s",
- strerror(errno));
- mysignal(SIGCHLD, old_sigchld);
+ debug3("Time elapsed: %d msec", msec_elapsed);
- /* 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);
+ if (waitpid(pid, &status, 0) == -1) {
+ error("Couldn't wait for child '%s' completion: %s", src->cmdstring,
+ strerror(errno));
+ return(0.0);
+ }
- RAND_add(buf, sizeof(buf), sizeof(buf));
- memset(buf, '\0', sizeof(buf));
+ 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);
+ }
-#endif /* OPENSSL_PRNG_ONLY */
- if (RAND_status() != 1)
- fatal("PRNG is not seeded");
+ return(1);
}
void
-init_rng(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 */
/*
- * OpenSSL version numbers: MNNFFPPS: major minor fix patch status
- * We match major, minor, fix and status (not patch)
+ * Propagate the privileged uid to all of our uids.
+ * Set the effective uid to the given (unprivileged) uid.
*/
- if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L)
- fatal("OpenSSL version mismatch. Built against %lx, you "
- "have %lx", OPENSSL_VERSION_NUMBER, SSLeay());
+ 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 */
-#ifndef OPENSSL_PRNG_ONLY
- if ((original_uid = getuid()) == -1)
- fatal("getuid: %s", strerror(errno));
- if ((original_euid = geteuid()) == -1)
- fatal("geteuid: %s", strerror(errno));
-#endif
+ 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) */
andersk / gssapi-openssh.git / blobdiff