- (djm) Fix pam sprintf fix
- (djm) Cleanup entropy collection code a little more. Split initialisation
from seeding, perform intialisation immediatly at start, be careful with
uids. Based on problem report from Jim Watt <jimw@peisj.pebio.com>
diff --git a/entropy.c b/entropy.c
index d8eba65..8427609 100644
--- a/entropy.c
+++ b/entropy.c
@@ -35,7 +35,7 @@
#include <openssl/rand.h>
#include <openssl/sha.h>
-RCSID("$Id: entropy.c,v 1.16 2000/06/26 03:55:31 djm Exp $");
+RCSID("$Id: entropy.c,v 1.17 2000/07/09 12:42:33 djm Exp $");
#ifndef offsetof
# define offsetof(type, member) ((size_t) &((type *)0)->member)
@@ -168,6 +168,9 @@
memset(buf, '\0', sizeof(buf));
}
+/* No-op */
+void init_rng(void) {}
+
#else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
/*
@@ -180,9 +183,9 @@
/* 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
{
@@ -395,10 +398,10 @@
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;
@@ -432,38 +435,36 @@
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);
@@ -533,7 +534,7 @@
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()))
+ if (((st.st_mode & 0177) != 0) || !(st.st_uid == original_uid))
fatal("PRNG seedfile %.100s must be mode 0600, owned by uid %d",
filename, getuid());
@@ -551,12 +552,14 @@
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));
+ original_uid, strerror(errno));
/* Try to ensure that the parent directory is there */
snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
@@ -591,10 +594,10 @@
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));
+ original_uid, strerror(errno));
snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
SSH_PRNG_SEED_FILE);
@@ -755,7 +758,7 @@
/* 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);
}
@@ -777,35 +780,41 @@
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;
- }
+ 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("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());
+
+ 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.");
-
- 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)
+{
+ original_uid = getuid();
+
+ /* 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;
+ prng_read_seedfile();
+ fatal_add_cleanup(prng_seed_cleanup, NULL);
+ atexit(prng_write_seedfile);
+
+ prng_initialised = 1;
+}
+
#endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */