/* random.c - A single-file translator providing random data Copyright (C) 1998, 1999, 2001, 2017 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "mach_debug_U.h" /* Entropy pool. We use one of the SHAKE algorithms from the Keccak family. Being a sponge construction, it allows the extraction of arbitrary amounts of pseudorandom data. */ static gcry_md_hd_t pool; enum gcry_md_algos hash_algo = GCRY_MD_SHAKE128; /* Protected by this lock. */ static pthread_mutex_t pool_lock = PTHREAD_MUTEX_INITIALIZER; /* A map of the Mach time device. Used for quick stirring. */ volatile struct mapped_time_value *mtime; static void pool_initialize (void) { error_t err; gcry_error_t cerr; if (! gcry_check_version ("1.8.0")) error (1, 0, "libgcrypt version mismatch\n"); cerr = gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0); if (cerr) error (1, 0, "Finalizing gcrypt failed: %s", gcry_strerror (cerr)); cerr = gcry_md_open (&pool, hash_algo, GCRY_MD_FLAG_SECURE); if (cerr) error (1, 0, "Initializing hash failed: %s", gcry_strerror (cerr)); err = maptime_map (0, NULL, &mtime); if (err) err = maptime_map (1, NULL, &mtime); if (err) error (1, err, "Failed to map time device"); } /* Mix data into the pool. */ static void pool_add_entropy (const void *buffer, size_t length) { pthread_mutex_lock (&pool_lock); gcry_md_write (pool, buffer, length); pthread_mutex_unlock (&pool_lock); } /* Extract data from the pool. */ static error_t pool_randomize (void *buffer, size_t length) { gcry_error_t cerr; pthread_mutex_lock (&pool_lock); /* Quickly stir the the time device into the pool. Do not even bother with synchronization. */ gcry_md_write (pool, (void *) mtime, sizeof *mtime); cerr = gcry_md_extract (pool, hash_algo, buffer, length); pthread_mutex_unlock (&pool_lock); return cerr ? EIO : 0; } /* Name of file to use as seed. */ static char *seed_file; /* Size of the seed file. */ size_t seed_size = 600; static error_t update_random_seed_file (void) { error_t err; int fd; void *map; if (seed_file == NULL) return 0; fd = open (seed_file, O_RDWR|O_CREAT, 0600); if (fd < 0) return errno; if (ftruncate (fd, seed_size)) { err = errno; goto out; } map = mmap (NULL, seed_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); if (map == MAP_FAILED) { err = errno; goto out; } err = pool_randomize (map, seed_size); munmap (map, seed_size); out: close (fd); return err; } static error_t read_random_seed_file (void) { error_t err; int fd; struct stat s; void *map; if (seed_file == NULL) return 0; fd = open (seed_file, O_RDWR); if (fd < 0) return errno; if (fstat (fd, &s)) { err = errno; goto out; } /* XXX should check file permissions. */ map = mmap (NULL, s.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); if (map == MAP_FAILED) { err = errno; goto out; } pool_add_entropy (map, s.st_size); /* Immediately update it, to minimize the chance that the same state is read twice. */ pool_randomize (map, s.st_size); munmap (map, s.st_size); out: close (fd); return err; } static void gather_slab_info (void) { error_t err; cache_info_array_t cache_info; mach_msg_type_number_t cache_info_count; cache_info = NULL; cache_info_count = 0; err = host_slab_info (mach_host_self(), &cache_info, &cache_info_count); if (err) return; pool_add_entropy (cache_info, cache_info_count * sizeof *cache_info); vm_deallocate (mach_task_self (), (vm_address_t) cache_info, cache_info_count * sizeof *cache_info); } static void gather_vm_statistics (void) { error_t err; struct vm_statistics vmstats; err = vm_statistics (mach_task_self (), &vmstats); if (err) return; pool_add_entropy (&vmstats, sizeof vmstats); } static void gather_vm_cache_statistics (void) { error_t err; struct vm_cache_statistics cache_stats; err = vm_cache_statistics (mach_task_self (), &cache_stats); if (err) return; pool_add_entropy (&cache_stats, sizeof cache_stats); } static void * gather_thread (void *args) { while (1) { gather_slab_info (); gather_vm_statistics (); gather_vm_cache_statistics (); usleep ( (useconds_t) (1000000. * (1. + (float) random () / (float) RAND_MAX))); } assert_backtrace (! "reached"); } error_t start_gather_thread (void) { error_t err; pthread_t thread; err = pthread_create (&thread, NULL, gather_thread, NULL); if (err) return err; err = pthread_detach (thread); return err; } const char *argp_program_version = STANDARD_HURD_VERSION (random); /* Our control port. */ struct trivfs_control *fsys; /* Trivfs hooks. */ int trivfs_fstype = FSTYPE_MISC; int trivfs_fsid = 0; int trivfs_allow_open = O_READ | O_WRITE; int trivfs_support_read = 1; int trivfs_support_write = 1; int trivfs_support_exec = 0; void trivfs_modify_stat (struct trivfs_protid *cred, struct stat *st) { /* Mark the node as a read-only plain file. */ st->st_mode &= ~((unsigned) S_IFMT); st->st_mode |= (S_IFCHR); st->st_size = 0; } error_t trivfs_goaway (struct trivfs_control *cntl, int flags) { error_t err; err = update_random_seed_file (); if (err) error (0, err, "Warning: Failed to save random seed to %s", seed_file); exit (0); } /* Read data from an IO object. If offset is -1, read from the object maintained file pointer. If the object is not seekable, offset is ignored. The amount desired to be read is in AMOUNT. */ error_t trivfs_S_io_read (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, data_t *data, mach_msg_type_number_t *data_len, loff_t offs, mach_msg_type_number_t amount) { error_t err; void *buf = NULL; size_t length = 0; if (! cred) return EOPNOTSUPP; else if (! (cred->po->openmodes & O_READ)) return EBADF; if (amount > 0) { /* Possibly allocate a new buffer. */ if (*data_len < amount) { *data = mmap (0, amount, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); if (*data == MAP_FAILED) { err = errno; goto errout; } /* Keep track of our map in case of errors. */ buf = *data, length = amount; /* Update DATA_LEN to reflect the new buffers size. */ *data_len = amount; } err = pool_randomize (*data, amount); if (err) goto errout; } *data_len = amount; trivfs_set_atime (fsys); return 0; errout: if (buf) munmap (buf, length); return err; } /* Write data to an IO object. If offset is -1, write at the object maintained file pointer. If the object is not seekable, offset is ignored. The amount successfully written is returned in amount. A given user should not have more than one outstanding io_write on an object at a time; servers implement congestion control by delaying responses to io_write. Servers may drop data (returning ENOBUFS) if they receive more than one write when not prepared for it. */ error_t trivfs_S_io_write (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t replytype, data_t data, mach_msg_type_number_t datalen, loff_t offset, mach_msg_type_number_t *amount) { /* Deny access if they have bad credentials. */ if (! cred) return EOPNOTSUPP; else if (! (cred->po->openmodes & O_WRITE)) return EBADF; pool_add_entropy (data, datalen); *amount = datalen; trivfs_set_mtime (fsys); return 0; } /* Tell how much data can be read from the object without blocking for a "long time" (this should be the same meaning of "long time" used by the nonblocking flag. */ kern_return_t trivfs_S_io_readable (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t replytype, mach_msg_type_number_t *amount) { /* Deny access if they have bad credentials. */ if (! cred) return EOPNOTSUPP; else if (! (cred->po->openmodes & O_READ)) return EBADF; /* We allow an infinite amount of data to be extracted. We need to return something here, so just go with the page size. */ *amount = PAGE_SIZE; return 0; } /* SELECT_TYPE is the bitwise OR of SELECT_READ, SELECT_WRITE, and SELECT_URG. Block until one of the indicated types of i/o can be done "quickly", and return the types that are then available. ID_TAG is returned as passed; it is just for the convenience of the user in matching up reply messages with specific requests sent. */ error_t trivfs_S_io_select (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, int *type) { if (!cred) return EOPNOTSUPP; /* We only deal with SELECT_READ and SELECT_WRITE here. */ if (*type & ~(SELECT_READ | SELECT_WRITE)) return EINVAL; /* We allow an infinite amount of data to be extracted and stored. Just return success. */ return 0; } /* Change current read/write offset */ error_t trivfs_S_io_seek (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, loff_t offs, int whence, loff_t *new_offs) { if (! cred) return EOPNOTSUPP; /* Not seekable. */ return ESPIPE; } /* Change the size of the file. If the size increases, new blocks are zero-filled. After successful return, it is safe to reference mapped areas of the file up to NEW_SIZE. */ error_t trivfs_S_file_set_size (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, loff_t size) { if (!cred) return EOPNOTSUPP; return size == 0 ? 0 : EINVAL; } /* These four routines modify the O_APPEND, O_ASYNC, O_FSYNC, and O_NONBLOCK bits for the IO object. In addition, io_get_openmodes will tell you which of O_READ, O_WRITE, and O_EXEC the object can be used for. The O_ASYNC bit affects icky async I/O; good async I/O is done through io_async which is orthogonal to these calls. */ error_t trivfs_S_io_set_all_openmodes(struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, int mode) { if (!cred) return EOPNOTSUPP; return 0; } error_t trivfs_S_io_set_some_openmodes (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, int bits) { if (!cred) return EOPNOTSUPP; return 0; } error_t trivfs_S_io_get_owner (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, pid_t *owner) { if (!cred) return EOPNOTSUPP; *owner = 0; return 0; } error_t trivfs_S_io_mod_owner (struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, pid_t owner) { if (!cred) return EOPNOTSUPP; return EINVAL; } /* Return objects mapping the data underlying this memory object. If the object can be read then memobjrd will be provided; if the object can be written then memobjwr will be provided. For objects where read data and write data are the same, these objects will be equal, otherwise they will be disjoint. Servers are permitted to implement io_map but not io_map_cntl. Some objects do not provide mapping; they will set none of the ports and return an error. Such objects can still be accessed by io_read and io_write. */ error_t trivfs_S_io_map(struct trivfs_protid *cred, mach_port_t reply, mach_msg_type_name_t reply_type, mach_port_t *rdobj, mach_msg_type_name_t *rdtype, mach_port_t *wrobj, mach_msg_type_name_t *wrtype) { if (!cred) return EOPNOTSUPP; return EINVAL; } int random_demuxer (mach_msg_header_t *inp, mach_msg_header_t *outp) { extern int startup_notify_server (mach_msg_header_t *, mach_msg_header_t *); return (trivfs_demuxer (inp, outp) || startup_notify_server (inp, outp)); } /* Options processing. We accept the same options on the command line and from fsys_set_options. */ static const struct argp_option options[] = { {"fast", 'f', 0, 0, "(ignored)"}, {"secure", 's', 0, 0, "(ignored)"}, {"seed-file", 'S', "FILE", 0, "Use FILE to remember the seed"}, {0} }; static error_t parse_opt (int opt, char *arg, struct argp_state *state) { switch (opt) { default: return ARGP_ERR_UNKNOWN; case ARGP_KEY_INIT: case ARGP_KEY_SUCCESS: case ARGP_KEY_ERROR: break; case 'f': case 's': /* Ignored. */ break; case 'S': seed_file = strdup (arg); break; } return 0; } /* This will be called from libtrivfs to help construct the answer to an fsys_get_options RPC. */ error_t trivfs_append_args (struct trivfs_control *fsys, char **argz, size_t *argz_len) { error_t err = 0; char *opt; if (seed_file) { if (asprintf (&opt, "--seed-file=%s", seed_file) < 0) err = ENOMEM; else { err = argz_add (argz, argz_len, opt); free (opt); } } return err; } static struct argp random_argp = { options, parse_opt, 0, "A translator providing random output." }; /* Setting this variable makes libtrivfs use our argp to parse options passed in an fsys_set_options RPC. */ struct argp *trivfs_runtime_argp = &random_argp; struct port_class *shutdown_notify_class; /* The system is going down; destroy all the extant port rights. That will cause net channels and such to close promptly. */ error_t S_startup_dosync (mach_port_t handle) { error_t err; struct port_info *inpi = ports_lookup_port (fsys->pi.bucket, handle, shutdown_notify_class); if (!inpi) return EOPNOTSUPP; err = update_random_seed_file (); if (err) error (0, err, "Warning: Failed to save random seed to %s", seed_file); return 0; } void sigterm_handler (int signo) { error_t err; err = update_random_seed_file (); if (err) error (0, err, "Warning: Failed to save random seed to %s", seed_file); signal (SIGTERM, SIG_DFL); raise (SIGTERM); } static error_t arrange_shutdown_notification () { error_t err; mach_port_t initport, notify; struct port_info *pi; shutdown_notify_class = ports_create_class (0, 0); if (signal (SIGTERM, sigterm_handler) == SIG_ERR) return errno; /* Arrange to get notified when the system goes down, but if we fail for some reason, just silently give up. No big deal. */ err = ports_create_port (shutdown_notify_class, fsys->pi.bucket, sizeof (struct port_info), &pi); if (err) return err; initport = file_name_lookup (_SERVERS_STARTUP, 0, 0); if (! MACH_PORT_VALID (initport)) return errno; notify = ports_get_send_right (pi); ports_port_deref (pi); err = startup_request_notification (initport, notify, MACH_MSG_TYPE_MAKE_SEND, program_invocation_short_name); mach_port_deallocate (mach_task_self (), notify); mach_port_deallocate (mach_task_self (), initport); return err; } int main (int argc, char **argv) { error_t err; unsigned int seed; mach_port_t bootstrap; /* We use the same argp for options available at startup as for options we'll accept in an fsys_set_options RPC. */ argp_parse (&random_argp, argc, argv, 0, 0, 0); pool_initialize (); err = read_random_seed_file (); if (err) error (0, err, "Warning: Failed to read random seed file %s", seed_file); /* Initialize the libcs PRNG. */ pool_randomize (&seed, sizeof seed); srandom (seed); task_get_bootstrap_port (mach_task_self (), &bootstrap); if (bootstrap == MACH_PORT_NULL) error (1, 0, "Must be started as a translator"); /* Reply to our parent */ err = trivfs_startup (bootstrap, 0, 0, 0, 0, 0, &fsys); mach_port_deallocate (mach_task_self (), bootstrap); if (err) error (3, err, "trivfs_startup"); err = arrange_shutdown_notification (); if (err) error (0, err, "Warning: Cannot request shutdown notification"); err = start_gather_thread (); if (err) error (1, err, "Starting gather thread failed"); /* Launch. */ ports_manage_port_operations_multithread (fsys->pi.bucket, random_demuxer, 10 * 1000, /* idle thread */ 10 * 60 * 1000, /* idle server */ 0); return 0; }