From f9b625c36e3dea521c02919e90ac2ddcfd19b06a Mon Sep 17 00:00:00 2001 From: Damien Miller Date: Sun, 9 Jul 2000 22:42:32 +1000 Subject: - (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 --- entropy.c | 89 +++++++++++++++++++++++++++++++++++---------------------------- 1 file changed, 49 insertions(+), 40 deletions(-) (limited to 'entropy.c') diff --git a/entropy.c b/entropy.c index d8eba654..84276099 100644 --- a/entropy.c +++ b/entropy.c @@ -35,7 +35,7 @@ #include #include -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 @@ seed_rng(void) memset(buf, '\0', sizeof(buf)); } +/* No-op */ +void init_rng(void) {} + #else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ /* @@ -180,9 +183,9 @@ seed_rng(void) /* 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 @@ hash_output_from_command(entropy_source_t *src, char *hash) 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 @@ hash_output_from_command(entropy_source_t *src, char *hash) 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 @@ prng_check_seedfile(char *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())) + 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 @@ prng_write_seedfile(void) { 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 @@ prng_read_seedfile(void) { 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 @@ prng_read_commands(char *cmdfilename) /* 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 @@ 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; - } + 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) */ -- cgit v1.2.3