* 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 "ssh.h"
-#include "xmalloc.h"
-
#include <openssl/rand.h>
#include <openssl/sha.h>
+#include <openssl/crypto.h>
+
+/* SunOS 4.4.4 needs this */
+#ifdef HAVE_FLOATINGPOINT_H
+# include <floatingpoint.h>
+#endif /* HAVE_FLOATINGPOINT_H */
+
+#include "ssh.h"
+#include "misc.h"
+#include "xmalloc.h"
+#include "atomicio.h"
+#include "pathnames.h"
+#include "log.h"
RCSID("$Id$");
# define offsetof(type, member) ((size_t) &((type *)0)->member)
#endif
-/* Print lots of detail */
-/* #define DEBUG_ENTROPY */
-
/* Number of times to pass through command list gathering entropy */
#define NUM_ENTROPY_RUNS 1
# define RUSAGE_CHILDREN 0
#endif
+#if defined(_POSIX_SAVED_IDS) && !defined(BROKEN_SAVED_UIDS)
+# define SAVED_IDS_WORK_WITH_SETEUID
+#endif
+
+void check_openssl_version(void)
+{
+ if (SSLeay() != OPENSSL_VERSION_NUMBER)
+ fatal("OpenSSL version mismatch. Built against %x, you "
+ "have %x", OPENSSL_VERSION_NUMBER, SSLeay());
+}
+
+
#if defined(EGD_SOCKET) || defined(RANDOM_POOL)
#ifdef EGD_SOCKET
int fd;
char msg[2];
struct sockaddr_un addr;
- int addr_len;
+ int addr_len, rval, errors;
+ mysig_t old_sigpipe;
/* Sanity checks */
if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path))
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);
-
+
+ old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
+
+ errors = rval = 0;
+reopen:
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd == -1) {
error("Couldn't create AF_UNIX socket: %s", strerror(errno));
- return(0);
+ goto done;
}
if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
- error("Couldn't connect to EGD socket \"%s\": %s",
+ error("Couldn't connect to EGD socket \"%s\": %s",
addr.sun_path, strerror(errno));
- close(fd);
- return(0);
+ goto done;
}
/* Send blocking read request to EGD */
msg[1] = len;
if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) {
- error("Couldn't write to EGD socket \"%s\": %s",
+ if (errno == EPIPE && errors < 10) {
+ close(fd);
+ errors++;
+ goto reopen;
+ }
+ error("Couldn't write to EGD socket \"%s\": %s",
EGD_SOCKET, strerror(errno));
- close(fd);
- return(0);
+ goto done;
}
if (atomicio(read, fd, buf, len) != len) {
- error("Couldn't read from EGD socket \"%s\": %s",
+ if (errno == EPIPE && errors < 10) {
+ close(fd);
+ errors++;
+ goto reopen;
+ }
+ error("Couldn't read from EGD socket \"%s\": %s",
EGD_SOCKET, strerror(errno));
- close(fd);
- return(0);
+ goto done;
}
-
- close(fd);
-
- return(1);
+
+ rval = 1;
+done:
+ mysignal(SIGPIPE, old_sigpipe);
+ if (fd != -1)
+ close(fd);
+ return(rval);
}
#else /* !EGD_SOCKET */
#ifdef RANDOM_POOL
random_pool = open(RANDOM_POOL, O_RDONLY);
if (random_pool == -1) {
- error("Couldn't open random pool \"%s\": %s",
+ 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",
+ 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 */
seed_rng(void)
{
char buf[32];
-
+
debug("Seeding random number generator");
if (!get_random_bytes(buf, sizeof(buf))) {
} else {
RAND_add(buf, sizeof(buf), sizeof(buf));
}
-
+
memset(buf, '\0', sizeof(buf));
}
+void init_rng(void)
+{
+ check_openssl_version();
+}
+
#else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
-/*
+/*
* FIXME: proper entropy estimations. All current values are guesses
* FIXME: (ATL) do estimates at compile time?
* FIXME: More entropy sources
/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
-static int prng_seed_loaded = 0;
static int prng_seed_saved = 0;
-static int prng_commands_loaded = 0;
+static int prng_initialised = 0;
+uid_t original_uid;
typedef struct
{
/* 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), 0.5);
total_entropy_estimate += 0.1;
-
+
i = getppid();
RAND_add(&i, sizeof(i), 0.5);
total_entropy_estimate += 0.1;
return(total_entropy_estimate);
}
-double
+double
stir_from_programs(void)
{
int i;
/* 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 */
+ /* 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);
-#ifdef DEBUG_ENTROPY
- debug("Got %0.2f bytes of entropy from '%s'", entropy_estimate,
+ debug3("Got %0.2f bytes of entropy from '%s'", entropy_estimate,
entropy_sources[c].cmdstring);
-#endif
total_entropy_estimate += entropy_estimate;
total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1);
total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1);
} else {
-#ifdef DEBUG_ENTROPY
- debug("Command '%s' disabled (badness %d)",
+ debug2("Command '%s' disabled (badness %d)",
entropy_sources[c].cmdstring, entropy_sources[c].badness);
-#endif
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)
return(0);
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));
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));
- src->badness = src->sticky_badness = 128;
_exit(-1);
default: /* Parent */
break;
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;
- }
- if (bytes_read) {
+ } else if (bytes_read) {
SHA1_Update(&sha, buf, bytes_read);
total_bytes_read += bytes_read;
- RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
- } else
+ } else {
cmd_eof = 1;
-
+ }
break;
-
case -1:
default:
+ /* error */
debug("Command '%s': select() failed: %s", src->cmdstring,
strerror(errno));
error_abort = 1;
break;
- } /* switch ret */
-
- RAND_add(&tv, sizeof(&tv), 0.0);
- } /* while !error_abort && !cmd_eof */
+ }
+ }
SHA1_Final(hash, &sha);
close(p[0]);
-#ifdef DEBUG_ENTROPY
- debug("Time elapsed: %d msec", msec_elapsed);
-#endif
-
+ debug3("Time elapsed: %d msec", msec_elapsed);
+
if (waitpid(pid, &status, 0) == -1) {
- debug("Couldn't wait for child '%s' completion: %s", src->cmdstring,
+ error("Couldn't wait for child '%s' completion: %s", src->cmdstring,
strerror(errno));
return(0.0);
}
/* closing p[0] on timeout causes the entropy command to
* SIGPIPE. Take whatever output we got, and mark this command
* as slow */
- debug("Command '%s' timed out", src->cmdstring);
+ debug2("Command '%s' timed out", src->cmdstring);
src->sticky_badness *= 2;
src->badness = src->sticky_badness;
return(total_bytes_read);
if (WEXITSTATUS(status)==0) {
return(total_bytes_read);
} else {
- debug("Command '%s' exit status was %d", src->cmdstring,
+ debug2("Command '%s' exit status was %d", src->cmdstring,
WEXITSTATUS(status));
src->badness = src->sticky_badness = 128;
return (0.0);
}
} else if (WIFSIGNALED(status)) {
- debug("Command '%s' returned on uncaught signal %d !", src->cmdstring,
+ debug2("Command '%s' returned on uncaught signal %d !", src->cmdstring,
status);
src->badness = src->sticky_badness = 128;
return(0.0);
/* 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) {
- /* Fail on hard errors */
+ /* Give up on hard errors */
if (errno != ENOENT)
- fatal("Couldn't stat random seed file \"%s\": %s", filename,
- strerror(errno));
+ debug("WARNING: Couldn't stat random seed file \"%s\": %s",
+ filename, strerror(errno));
return(0);
}
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()))
- fatal("PRNG seedfile %.100s must be mode 0600, owned by uid %d",
+ 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);
}
/* Don't bother if we have already saved a seed */
if (prng_seed_saved)
return;
-
+
+ setuid(original_uid);
+
prng_seed_saved = 1;
-
- pw = getpwuid(getuid());
+
+ pw = getpwuid(original_uid);
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 (%i): %s",
+ original_uid, strerror(errno));
+
/* Try to ensure that the parent directory is there */
- snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
- SSH_USER_DIR);
+ 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,
+ snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
SSH_PRNG_SEED_FILE);
debug("writing PRNG seed to file %.100s", filename);
/* 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)
- fatal("couldn't access PRNG seedfile %.100s (%.100s)", filename,
- strerror(errno));
-
- if (atomicio(write, fd, &seed, sizeof(seed)) != sizeof(seed))
- fatal("problem writing PRNG seedfile %.100s (%.100s)", filename,
- strerror(errno));
- close(fd);
+ 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
char seed[1024];
char filename[1024];
struct passwd *pw;
-
- pw = getpwuid(getuid());
+
+ pw = getpwuid(original_uid);
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,
+ 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, creating new");
- prng_write_seedfile();
-
- /* Reseed immediatly */
- (void)stir_from_system();
- (void)stir_from_programs();
+ 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,
+ fatal("could not open PRNG seedfile %.100s (%.100s)", filename,
strerror(errno));
if (atomicio(read, fd, &seed, sizeof(seed)) != sizeof(seed)) {
error("bad entropy command, %.100s line %d", cmdfilename,
linenum);
continue;
- }
+ }
/* first token, command args (incl. argv[0]) in double quotes */
cp = strtok(cp, "\"");
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",
if (strncmp("undef", cp, 5) == 0)
continue;
- strlcpy(path, cp, sizeof(path));
+ strlcpy(path, cp, sizeof(path));
/* third token, entropy rate estimate for this command */
if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
/* end of line */
if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
- error("garbage at end of line %d in %.100s -- ignored", linenum,
+ 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;
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);
/* trim to size */
entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t));
- debug("loaded %d entropy commands from %.100s", cur_cmd, cmdfilename);
+ 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)
{
void
seed_rng(void)
{
- void *old_sigchld_handler;
-
- if (!prng_commands_loaded) {
- if (!prng_read_commands(SSH_PRNG_COMMAND_FILE))
- fatal("PRNG initialisation failed -- exiting.");
- prng_commands_loaded = 1;
- }
+ 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 = signal(SIGCHLD, SIG_DFL);
+ old_sigchld_handler = mysignal(SIGCHLD, SIG_DFL);
- 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());
+ 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());
- signal(SIGCHLD, old_sigchld_handler);
+ 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.");
+}
- if (!prng_seed_loaded)
- {
- prng_seed_loaded = 1;
- prng_seed_saved = 0;
- prng_read_seedfile();
- fatal_add_cleanup(prng_seed_cleanup, NULL);
- atexit(prng_write_seedfile);
- }
+void init_rng(void)
+{
+ int original_euid;
+
+ check_openssl_version();
+
+ original_uid = getuid();
+ original_euid = geteuid();
+
+ /* Read in collection commands */
+ if (!prng_read_commands(SSH_PRNG_COMMAND_FILE))
+ fatal("PRNG initialisation failed -- exiting.");
+
+ /* Set ourselves up to save a seed upon exit */
+ prng_seed_saved = 0;
+
+ /* Give up privs while reading seed file */
+#ifdef SAVED_IDS_WORK_WITH_SETEUID
+ if ((original_uid != original_euid) && (seteuid(original_uid) == -1))
+ fatal("Couldn't give up privileges");
+#else /* SAVED_IDS_WORK_WITH_SETEUID */
+ /*
+ * Propagate the privileged uid to all of our uids.
+ * Set the effective uid to the given (unprivileged) uid.
+ */
+ if (original_uid != original_euid && (setuid(original_euid) == -1 ||
+ seteuid(original_uid) == -1))
+ fatal("Couldn't give up privileges");
+#endif /* SAVED_IDS_WORK_WITH_SETEUID */
+
+ prng_read_seedfile();
+
+#ifdef SAVED_IDS_WORK_WITH_SETEUID
+ if ((original_uid != original_euid) && (seteuid(original_euid) == -1))
+ fatal("Couldn't restore privileges");
+#else /* SAVED_IDS_WORK_WITH_SETEUID */
+ /*
+ * We are unable to restore the real uid to its unprivileged value.
+ * Propagate the real uid (usually more privileged) to effective uid
+ * as well.
+ */
+ if (original_uid != original_euid && (seteuid(original_euid) == -1 ||
+ setuid(original_uid) == -1))
+ fatal("Couldn't restore privileges");
+#endif /* SAVED_IDS_WORK_WITH_SETEUID */
+
+ fatal_add_cleanup(prng_seed_cleanup, NULL);
+ atexit(prng_write_seedfile);
+
+ prng_initialised = 1;
}
+
#endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
andersk / openssh.git / blobdiff