* 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.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by Markus Friedl.
- * 4. The name of the author may not be used to endorse or promote products
- * derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
#include "includes.h"
+#include <openssl/rand.h>
+#include <openssl/sha.h>
+
+/* SunOS 4.4.4 needs this */
+#ifdef HAVE_FLOATINGPOINT_H
+# include <floatingpoint.h>
+#endif /* HAVE_FLOATINGPOINT_H */
+
#include "ssh.h"
#include "xmalloc.h"
-
-#ifdef HAVE_OPENSSL
-# include <openssl/rand.h>
-# include <openssl/sha.h>
-#endif
-#ifdef HAVE_SSL
-# include <ssl/rand.h>
-# include <ssl/sha.h>
-#endif
+#include "atomicio.h"
+#include "pathnames.h"
+#include "log.h"
RCSID("$Id$");
-#ifdef EGD_SOCKET
#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(EGD_SOCKET) || defined(RANDOM_POOL)
+
+#ifdef EGD_SOCKET
/* Collect entropy from EGD */
-void get_random_bytes(unsigned char *buf, int len)
+int get_random_bytes(unsigned char *buf, int len)
{
- static int egd_socket = -1;
- int c;
- char egd_message[2] = { 0x02, 0x00 };
+ int fd;
+ char msg[2];
struct sockaddr_un addr;
int addr_len;
- memset(&addr, '\0', sizeof(addr));
- addr.sun_family = AF_UNIX;
-
- /* FIXME: compile time check? */
+ /* Sanity checks */
if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path))
fatal("Random pool path is too long");
-
- strcpy(addr.sun_path, EGD_SOCKET);
-
- addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET);
-
- if (egd_socket == -1) {
- egd_socket = socket(AF_UNIX, SOCK_STREAM, 0);
- if (egd_socket == -1)
- fatal("Couldn't create AF_UNIX socket: %s", strerror(errno));
- if (connect(egd_socket, (struct sockaddr*)&addr, addr_len) == -1)
- fatal("Couldn't connect to EGD socket \"%s\": %s", addr.sun_path, strerror(errno));
- }
-
if (len > 255)
fatal("Too many bytes to read from EGD");
-
+
+ memset(&addr, '\0', sizeof(addr));
+ addr.sun_family = AF_UNIX;
+ strlcpy(addr.sun_path, EGD_SOCKET, sizeof(addr.sun_path));
+ addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET);
+
+ fd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (fd == -1) {
+ error("Couldn't create AF_UNIX socket: %s", strerror(errno));
+ return(0);
+ }
+
+ if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
+ error("Couldn't connect to EGD socket \"%s\": %s",
+ addr.sun_path, strerror(errno));
+ close(fd);
+ return(0);
+ }
+
/* Send blocking read request to EGD */
- egd_message[1] = len;
+ msg[0] = 0x02;
+ msg[1] = len;
+
+ if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) {
+ error("Couldn't write to EGD socket \"%s\": %s",
+ EGD_SOCKET, strerror(errno));
+ close(fd);
+ return(0);
+ }
+
+ if (atomicio(read, fd, buf, len) != len) {
+ error("Couldn't read from EGD socket \"%s\": %s",
+ EGD_SOCKET, strerror(errno));
+ close(fd);
+ return(0);
+ }
- c = atomicio(write, egd_socket, egd_message, sizeof(egd_message));
- if (c == -1)
- fatal("Couldn't write to EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno));
+ close(fd);
- c = atomicio(read, egd_socket, buf, len);
- if (c <= 0)
- fatal("Couldn't read from EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno));
-
- close(EGD_SOCKET);
+ return(1);
}
#else /* !EGD_SOCKET */
#ifdef RANDOM_POOL
/* Collect entropy from /dev/urandom or pipe */
-void get_random_bytes(unsigned char *buf, int len)
+int get_random_bytes(unsigned char *buf, int len)
{
- static int random_pool = -1;
- int c;
+ int random_pool;
+ random_pool = open(RANDOM_POOL, O_RDONLY);
if (random_pool == -1) {
- random_pool = open(RANDOM_POOL, O_RDONLY);
- if (random_pool == -1)
- fatal("Couldn't open random pool \"%s\": %s", RANDOM_POOL, strerror(errno));
+ 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);
}
-
- c = atomicio(read, random_pool, buf, len);
- if (c <= 0)
- fatal("Couldn't read from random pool \"%s\": %s", RANDOM_POOL, strerror(errno));
+
+ close(random_pool);
+
+ return(1);
}
#endif /* RANDOM_POOL */
#endif /* EGD_SOCKET */
-#if !defined(EGD_SOCKET) && !defined(RANDOM_POOL)
-/*
+/*
+ * Seed OpenSSL's random number pool from Kernel random number generator
+ * or EGD
+ */
+void
+seed_rng(void)
+{
+ char buf[32];
+
+ debug("Seeding random number generator");
+
+ if (!get_random_bytes(buf, sizeof(buf))) {
+ if (!RAND_status())
+ fatal("Entropy collection failed and entropy exhausted");
+ } else {
+ RAND_add(buf, sizeof(buf), sizeof(buf));
+ }
+
+ memset(buf, '\0', sizeof(buf));
+}
+
+/* No-op */
+void init_rng(void) {}
+
+#else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
+
+/*
* FIXME: proper entropy estimations. All current values are guesses
- * FIXME: Need timeout for slow moving programs
+ * FIXME: (ATL) do estimates at compile time?
* FIXME: More entropy sources
*/
-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(const char *path, const char **args, char *hash);
+/* 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 */
- const char *path;
+ char *path;
/* argv to pass to executable */
- const char *args[5];
+ char *args[5];
+ /* full command string (debug) */
+ char *cmdstring;
} entropy_source_t;
-entropy_source_t entropy_sources[] = {
-#ifdef PROG_LS
- { 0.002, PROG_LS, { "ls", "-alni", "/var/log", NULL } },
- { 0.002, PROG_LS, { "ls", "-alni", "/var/adm", NULL } },
- { 0.002, PROG_LS, { "ls", "-alni", "/var/mail", NULL } },
- { 0.002, PROG_LS, { "ls", "-alni", "/var/spool/mail", NULL } },
- { 0.002, PROG_LS, { "ls", "-alni", "/proc", NULL } },
- { 0.002, PROG_LS, { "ls", "-alni", "/tmp", NULL } },
-#endif
-#ifdef PROG_NETSTAT
- { 0.005, PROG_NETSTAT, { "netstat","-an", NULL, NULL } },
- { 0.010, PROG_NETSTAT, { "netstat","-in", NULL, NULL } },
- { 0.002, PROG_NETSTAT, { "netstat","-rn", NULL, NULL } },
- { 0.002, PROG_NETSTAT, { "netstat","-s", NULL, NULL } },
-#endif
-#ifdef PROG_ARP
- { 0.002, PROG_ARP, { "arp","-a","-n", NULL } },
-#endif
-#ifdef PROG_IFCONFIG
- { 0.002, PROG_IFCONFIG, { "ifconfig", "-a", NULL, NULL } },
-#endif
-#ifdef PROG_PS
- { 0.003, PROG_PS, { "ps", "laxww", NULL, NULL } },
- { 0.003, PROG_PS, { "ps", "-al", NULL, NULL } },
- { 0.003, PROG_PS, { "ps", "-efl", NULL, NULL } },
-#endif
-#ifdef PROG_W
- { 0.005, PROG_W, { "w", NULL, NULL, NULL } },
-#endif
-#ifdef PROG_WHO
- { 0.001, PROG_WHO, { "who","-i", NULL, NULL } },
-#endif
-#ifdef PROG_LAST
- { 0.001, PROG_LAST, { "last", NULL, NULL, NULL } },
-#endif
-#ifdef PROG_LASTLOG
- { 0.001, PROG_LASTLOG, { "lastlog", NULL, NULL, NULL } },
-#endif
-#ifdef PROG_DF
- { 0.010, PROG_DF, { "df", NULL, NULL, NULL } },
- { 0.010, PROG_DF, { "df", "-i", NULL, NULL } },
-#endif
-#ifdef PROG_VMSTAT
- { 0.010, PROG_VMSTAT, { "vmstat", NULL, NULL, NULL } },
-#endif
-#ifdef PROG_UPTIME
- { 0.001, PROG_UPTIME, { "uptime", NULL, NULL, NULL } },
-#endif
-#ifdef PROG_IPCS
- { 0.001, PROG_IPCS, { "-a", NULL, NULL, NULL } },
-#endif
-#ifdef PROG_TAIL
- { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/messages", NULL, NULL } },
- { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/syslog", NULL, NULL } },
- { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/messages", NULL, NULL } },
- { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/syslog", NULL, NULL } },
- { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/maillog", NULL, NULL } },
- { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/maillog", NULL, NULL } },
-#endif
- { 0.000, NULL, { NULL, NULL, NULL, NULL, NULL } },
-};
+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
+double
stir_from_system(void)
{
double total_entropy_estimate;
long int i;
-
+
total_entropy_estimate = 0;
-
+
i = getpid();
- RAND_add(&i, sizeof(i), 0.1);
+ RAND_add(&i, sizeof(i), 0.5);
total_entropy_estimate += 0.1;
-
+
i = getppid();
- RAND_add(&i, sizeof(i), 0.1);
+ RAND_add(&i, sizeof(i), 0.5);
total_entropy_estimate += 0.1;
i = getuid();
RAND_add(&i, sizeof(i), 0.0);
total_entropy_estimate += stir_gettimeofday(1.0);
- total_entropy_estimate += stir_clock(0.2);
+ total_entropy_estimate += stir_clock(0.5);
total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
return(total_entropy_estimate);
}
-double
+double
stir_from_programs(void)
{
int i;
double total_entropy_estimate;
char hash[SHA_DIGEST_LENGTH];
- /*
- * Run through list of programs twice to catch differences
- */
total_entropy_estimate = 0;
- for(i = 0; i < 2; i++) {
+ for(i = 0; i < NUM_ENTROPY_RUNS; i++) {
c = 0;
while (entropy_sources[c].path != NULL) {
- /* Hash output from command */
- entropy_estimate = hash_output_from_command(entropy_sources[c].path,
- entropy_sources[c].args, 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 /= 10.0 * (i + 1.0);
-
- /* Stir it in */
- RAND_add(hash, sizeof(hash), entropy_estimate);
-
-/* FIXME: turn this off later */
-#if 1
- debug("Got %0.2f bytes of entropy from %s", entropy_estimate,
- entropy_sources[c].path);
-#endif
- total_entropy_estimate += entropy_estimate;
+ 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);
-
+ 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);
}
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);
}
{
#ifdef HAVE_CLOCK
clock_t c;
-
+
c = clock();
RAND_add(&c, sizeof(c), entropy_estimate);
-
+
return(entropy_estimate);
#else /* _HAVE_CLOCK */
return(0);
{
#ifdef HAVE_GETRUSAGE
struct rusage ru;
-
- if (getrusage(who, &ru) == -1)
- fatal("Couldn't getrusage: %s", strerror(errno));
- RAND_add(&ru, sizeof(ru), 0.1);
+ if (getrusage(who, &ru) == -1)
+ return(0);
+
+ RAND_add(&ru, sizeof(ru), entropy_estimate);
return(entropy_estimate);
#else /* _HAVE_GETRUSAGE */
#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(const char *path, const char **args, char *hash)
+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[2048];
+ 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]);
fatal("Couldn't fork: %s", strerror(errno));
/* NOTREACHED */
case 0: /* Child */
- close(0);
- close(1);
- close(2);
- dup2(devnull, 0);
- dup2(p[1], 1);
- dup2(p[1], 2);
+ dup2(devnull, STDIN_FILENO);
+ dup2(p[1], STDOUT_FILENO);
+ dup2(p[1], STDERR_FILENO);
close(p[0]);
close(p[1]);
close(devnull);
- execv(path, (char**)args);
- debug("(child) Couldn't exec '%s': %s", path, strerror(errno));
+ 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;
/* Hash output from child */
SHA1_Init(&sha);
total_bytes_read = 0;
- while ((bytes_read = read(p[0], buf, sizeof(buf))) > 0) {
- SHA1_Update(&sha, buf, bytes_read);
- total_bytes_read += bytes_read;
- RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
+
+ while (!error_abort && !cmd_eof) {
+ int ret;
+ struct timeval tv;
+ int msec_remaining;
+
+ (void) gettimeofday(&tv_current, 0);
+ msec_elapsed = _get_timeval_msec_difference(&tv_start, &tv_current);
+ if (msec_elapsed >= entropy_timeout_current) {
+ error_abort=1;
+ continue;
+ }
+ msec_remaining = entropy_timeout_current - msec_elapsed;
+
+ FD_ZERO(&rdset);
+ FD_SET(p[0], &rdset);
+ tv.tv_sec = msec_remaining / 1000;
+ tv.tv_usec = (msec_remaining % 1000) * 1000;
+
+ ret = select(p[0]+1, &rdset, NULL, NULL, &tv);
+
+ RAND_add(&tv, sizeof(tv), 0.0);
+
+ switch (ret) {
+ case 0:
+ /* timer expired */
+ error_abort = 1;
+ break;
+ case 1:
+ /* command input */
+ bytes_read = read(p[0], buf, sizeof(buf));
+ RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
+ if (bytes_read == -1) {
+ error_abort = 1;
+ break;
+ } else if (bytes_read) {
+ SHA1_Update(&sha, buf, bytes_read);
+ total_bytes_read += bytes_read;
+ } else {
+ cmd_eof = 1;
+ }
+ break;
+ case -1:
+ default:
+ /* error */
+ debug("Command '%s': select() failed: %s", src->cmdstring,
+ strerror(errno));
+ error_abort = 1;
+ break;
+ }
}
+
SHA1_Final(hash, &sha);
close(p[0]);
-
+
+ debug3("Time elapsed: %d msec", msec_elapsed);
+
if (waitpid(pid, &status, 0) == -1) {
- error("Couldn't wait for child '%s' completion: %s", path,
- strerror(errno));
- return(-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 (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
- return(0.0);
- else
+ 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);
}
-#endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
-#if defined(EGD_SOCKET) || defined(RANDOM_POOL)
/*
- * Seed OpenSSL's random number pool from Kernel random number generator
- * or EGD
+ * 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
-seed_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)
{
- char buf[32];
-
- debug("Seeding random number generator");
- get_random_bytes(buf, sizeof(buf));
- RAND_add(buf, sizeof(buf), sizeof(buf));
- memset(buf, '\0', sizeof(buf));
+ 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);
}
-#else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
+
+/*
+ * Write a keyfile at exit
+ */
+void
+prng_seed_cleanup(void *junk)
+{
+ prng_write_seedfile();
+}
+
/*
- * Conditionally Seed OpenSSL's random number pool syscalls and program output
+ * Conditionally Seed OpenSSL's random number pool from
+ * syscalls and program output
*/
void
seed_rng(void)
{
- debug("Seeding random number generator.");
- debug("OpenSSL random status is now %i\n", RAND_status());
- debug("%i bytes from system calls", (int)stir_from_system());
- debug("%i bytes from programs", (int)stir_from_programs());
- debug("OpenSSL random status is now %i\n", RAND_status());
+ void *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 = signal(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");
+
+ signal(SIGCHLD, old_sigchld_handler);
+
+ if (!RAND_status())
+ fatal("Couldn't initialise builtin random number generator -- exiting.");
+}
+
+void init_rng(void)
+{
+ int original_euid;
+
+ original_uid = getuid();
+ original_euid = geteuid();
+
+ /* Read in collection commands */
+ if (!prng_read_commands(SSH_PRNG_COMMAND_FILE))
+ fatal("PRNG initialisation failed -- exiting.");
+
+ /* Set ourselves up to save a seed upon exit */
+ prng_seed_saved = 0;
+
+ /* Give up privs while reading seed file */
+ if ((original_uid != original_euid) && (seteuid(original_uid) == -1))
+ fatal("Couldn't give up privileges");
+
+ prng_read_seedfile();
+
+ if ((original_uid != original_euid) && (seteuid(original_euid) == -1))
+ fatal("Couldn't restore privileges");
+
+ fatal_add_cleanup(prng_seed_cleanup, NULL);
+ atexit(prng_write_seedfile);
+
+ prng_initialised = 1;
}
+
#endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
andersk / openssh.git / blobdiff