From 40f64e6fb7c314718708025e496781f5d43594d4 Mon Sep 17 00:00:00 2001 From: djm Date: Mon, 21 Jan 2002 12:44:12 +0000 Subject: [PATCH] - (djm) Rework ssh-rand-helper: - Reduce quantity of ifdef code, in preparation for ssh_rand_conf - Always seed from system calls, even when doing PRNGd seeding - Tidy and comment #define knobs - Remove unused facility for multiple runs through command list - KNF, cleanup, update copyright --- ChangeLog | 8 + ssh-rand-helper.c | 697 +++++++++++++++++++++++----------------------- 2 files changed, 357 insertions(+), 348 deletions(-) diff --git a/ChangeLog b/ChangeLog index 66ff2eeb..23417fd9 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +20020121 + - (djm) Rework ssh-rand-helper: + - Reduce quantity of ifdef code, in preparation for ssh_rand_conf + - Always seed from system calls, even when doing PRNGd seeding + - Tidy and comment #define knobs + - Remove unused facility for multiple runs through command list + - KNF, cleanup, update copyright + 20020114 - (djm) Bug #50 - make autoconf entropy path checks more robust diff --git a/ssh-rand-helper.c b/ssh-rand-helper.c index 6037dd5a..281a780c 100644 --- a/ssh-rand-helper.c +++ b/ssh-rand-helper.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2001 Damien Miller. All rights reserved. + * Copyright (c) 2001-2002 Damien Miller. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -39,37 +39,41 @@ #include "pathnames.h" #include "log.h" -#ifdef HAVE___PROGNAME -extern char *__progname; -#else -char *__progname; -#endif - RCSID("$Id$"); -#define RANDOM_SEED_SIZE 48 +/* Number of bytes we write out */ +#define OUTPUT_SEED_SIZE 48 + +/* Length of on-disk seedfiles */ +#define SEED_FILE_SIZE 1024 + +/* Maximum number of command-line arguments to read from file */ +#define NUM_ARGS 10 + +/* Minimum number of usable commands to be considered sufficient */ +#define MIN_ENTROPY_SOURCES 16 +/* Path to on-disk seed file (relative to user's home directory */ #ifndef SSH_PRNG_SEED_FILE # define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed" -#endif /* SSH_PRNG_SEED_FILE */ +#endif + +/* Path to PRNG commands list */ #ifndef SSH_PRNG_COMMAND_FILE # define SSH_PRNG_COMMAND_FILE ETCDIR "/ssh_prng_cmds" -#endif /* SSH_PRNG_COMMAND_FILE */ +#endif +#ifdef HAVE___PROGNAME +extern char *__progname; +#else +char *__progname; +#endif + #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 @@ -81,70 +85,104 @@ RCSID("$Id$"); #if defined(PRNGD_SOCKET) || defined(PRNGD_PORT) # define USE_PRNGD +#else +# define USE_SEED_FILES #endif -#ifdef USE_PRNGD -/* Collect entropy from PRNGD/EGD */ +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 */ + char *path; + /* argv to pass to executable */ + char *args[NUM_ARGS]; /* XXX: arbitrary limit */ + /* full command string (debug) */ + char *cmdstring; +} entropy_cmd_t; + +/* slow command timeouts (all in milliseconds) */ +/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ +static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; + +/* this is initialised from a file, by prng_read_commands() */ +static entropy_cmd_t *entropy_cmds = NULL; + +/* Prototypes */ +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_command_output(entropy_cmd_t *src, char *hash); +int get_random_bytes_prngd(unsigned char *buf, int len, + unsigned short tcp_port, char *socket_path); + +/* + * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon + * listening either on 'tcp_port', or via Unix domain socket at * + * 'socket_path'. + * Either a non-zero tcp_port or a non-null socket_path must be + * supplied. + * Returns 0 on success, -1 on error + */ int -get_random_bytes(unsigned char *buf, int len) +get_random_bytes_prngd(unsigned char *buf, int len, + unsigned short tcp_port, char *socket_path) { - int fd; + int fd, addr_len, rval, errors; char msg[2]; -#ifdef PRNGD_PORT - struct sockaddr_in addr; -#else - struct sockaddr_un addr; -#endif - int addr_len, rval, errors; + struct sockaddr_storage addr; + struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; + struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; mysig_t old_sigpipe; + /* Sanity checks */ + if (socket_path == NULL && tcp_port == 0) + fatal("You must specify a port or a socket"); + if (socket_path != NULL && + strlen(socket_path) >= sizeof(addr_un->sun_path)) + fatal("Random pool path is too long"); if (len > 255) fatal("Too many bytes to read from PRNGD"); memset(&addr, '\0', sizeof(addr)); -#ifdef PRNGD_PORT - addr.sin_family = AF_INET; - addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); - addr.sin_port = htons(PRNGD_PORT); - addr_len = sizeof(struct sockaddr_in); -#else /* use IP socket PRNGD_SOCKET instead */ - /* Sanity checks */ - if (sizeof(PRNGD_SOCKET) > sizeof(addr.sun_path)) - fatal("Random pool path is too long"); - - addr.sun_family = AF_UNIX; - strlcpy(addr.sun_path, PRNGD_SOCKET, sizeof(addr.sun_path)); - addr_len = offsetof(struct sockaddr_un, sun_path) + - sizeof(PRNGD_SOCKET); -#endif + if (tcp_port != 0) { + addr_in->sin_family = AF_INET; + addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); + addr_in->sin_port = htons(tcp_port); + addr_len = sizeof(*addr_in); + } else { + addr_un->sun_family = AF_UNIX; + strlcpy(addr_un->sun_path, socket_path, + sizeof(addr_un->sun_path)); + addr_len = offsetof(struct sockaddr_un, sun_path) + + strlen(socket_path) + 1; + } old_sigpipe = mysignal(SIGPIPE, SIG_IGN); - errors = rval = 0; + errors = 0; + rval = -1; reopen: -#ifdef PRNGD_PORT - fd = socket(addr.sin_family, SOCK_STREAM, 0); - if (fd == -1) { - error("Couldn't create AF_INET socket: %s", strerror(errno)); - goto done; - } -#else - fd = socket(addr.sun_family, SOCK_STREAM, 0); + fd = socket(addr.ss_family, SOCK_STREAM, 0); if (fd == -1) { - error("Couldn't create AF_UNIX socket: %s", strerror(errno)); + error("Couldn't create socket: %s", strerror(errno)); goto done; } -#endif if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { -#ifdef PRNGD_PORT - error("Couldn't connect to PRNGD port %d: %s", - PRNGD_PORT, strerror(errno)); -#else - error("Couldn't connect to PRNGD socket \"%s\": %s", - addr.sun_path, strerror(errno)); -#endif + if (tcp_port != 0) { + error("Couldn't connect to PRNGD port %d: %s", + tcp_port, strerror(errno)); + } else { + error("Couldn't connect to PRNGD socket \"%s\": %s", + addr_un->sun_path, strerror(errno)); + } goto done; } @@ -174,146 +212,12 @@ reopen: goto done; } - rval = 1; + rval = 0; done: mysignal(SIGPIPE, old_sigpipe); if (fd != -1) close(fd); - return(rval); -} - -static void -seed_openssl_rng(void) -{ - unsigned char buf[RANDOM_SEED_SIZE]; - - if (!get_random_bytes(buf, sizeof(buf))) - fatal("Entropy collection failed"); - - RAND_add(buf, sizeof(buf), sizeof(buf)); - memset(buf, '\0', sizeof(buf)); -} - -#else /* USE_PRNGD */ - -/* - * FIXME: proper entropy estimations. All current values are guesses - * FIXME: (ATL) do estimates at compile time? - * FIXME: More entropy sources - */ - -/* slow command timeouts (all in milliseconds) */ -/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ -static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; - -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 */ - char *path; - /* argv to pass to executable */ - char *args[5]; - /* full command string (debug) */ - char *cmdstring; -} entropy_source_t; - -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 -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; - - i = getuid(); - RAND_add(&i, sizeof(i), 0.0); - i = getgid(); - RAND_add(&i, sizeof(i), 0.0); - - total_entropy_estimate += stir_gettimeofday(1.0); - total_entropy_estimate += stir_clock(0.5); - total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); - - return(total_entropy_estimate); -} - -double -stir_from_programs(void) -{ - int i; - int c; - double entropy_estimate; - double total_entropy_estimate; - char hash[SHA_DIGEST_LENGTH]; - - total_entropy_estimate = 0; - for(i = 0; i < NUM_ENTROPY_RUNS; i++) { - c = 0; - while (entropy_sources[c].path != NULL) { - - 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); - } 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); + return rval; } double @@ -326,7 +230,7 @@ stir_gettimeofday(double entropy_estimate) RAND_add(&tv, sizeof(tv), entropy_estimate); - return(entropy_estimate); + return entropy_estimate; } double @@ -338,9 +242,9 @@ stir_clock(double entropy_estimate) c = clock(); RAND_add(&c, sizeof(c), entropy_estimate); - return(entropy_estimate); + return entropy_estimate; #else /* _HAVE_CLOCK */ - return(0); + return 0; #endif /* _HAVE_CLOCK */ } @@ -351,19 +255,19 @@ stir_rusage(int who, double entropy_estimate) struct rusage ru; if (getrusage(who, &ru) == -1) - return(0); + return 0; RAND_add(&ru, sizeof(ru), entropy_estimate); - return(entropy_estimate); + return entropy_estimate; #else /* _HAVE_GETRUSAGE */ - return(0); + return 0; #endif /* _HAVE_GETRUSAGE */ } - static int -_get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) { +timeval_diff(struct timeval *t1, struct timeval *t2) +{ int secdiff, usecdiff; secdiff = t2->tv_sec - t1->tv_sec; @@ -372,27 +276,24 @@ _get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) { } double -hash_output_from_command(entropy_source_t *src, char *hash) +hash_command_output(entropy_cmd_t *src, char *hash) { - static int devnull = -1; - int p[2]; + char buf[8192]; fd_set rdset; - int cmd_eof = 0, error_abort = 0; - struct timeval tv_start, tv_current; - int msec_elapsed = 0; + int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2]; + int status, total_bytes_read; + static int devnull = -1; pid_t pid; - int status; - char buf[16384]; - int bytes_read; - int total_bytes_read; SHA_CTX sha; + struct timeval tv_start, tv_current; 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)); + fatal("Couldn't open /dev/null: %s", + strerror(errno)); } if (pipe(p) == -1) @@ -415,8 +316,9 @@ hash_output_from_command(entropy_source_t *src, char *hash) close(devnull); execv(src->path, (char**)(src->args)); - debug("(child) Couldn't exec '%s': %s", src->cmdstring, - strerror(errno)); + + debug("(child) Couldn't exec '%s': %s", + src->cmdstring, strerror(errno)); _exit(-1); default: /* Parent */ break; @@ -428,15 +330,15 @@ hash_output_from_command(entropy_source_t *src, char *hash) /* Hash output from child */ SHA1_Init(&sha); - total_bytes_read = 0; + cmd_eof = error_abort = msec_elapsed = total_bytes_read = 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); + msec_elapsed = timeval_diff(&tv_start, &tv_current); if (msec_elapsed >= entropy_timeout_current) { error_abort=1; continue; @@ -445,10 +347,10 @@ hash_output_from_command(entropy_source_t *src, char *hash) FD_ZERO(&rdset); FD_SET(p[0], &rdset); - tv.tv_sec = msec_remaining / 1000; + tv.tv_sec = msec_remaining / 1000; tv.tv_usec = (msec_remaining % 1000) * 1000; - ret = select(p[0]+1, &rdset, NULL, NULL, &tv); + ret = select(p[0] + 1, &rdset, NULL, NULL, &tv); RAND_add(&tv, sizeof(tv), 0.0); @@ -476,8 +378,8 @@ hash_output_from_command(entropy_source_t *src, char *hash) case -1: default: /* error */ - debug("Command '%s': select() failed: %s", src->cmdstring, - strerror(errno)); + debug("Command '%s': select() failed: %s", + src->cmdstring, strerror(errno)); error_abort = 1; break; } @@ -490,93 +392,174 @@ hash_output_from_command(entropy_source_t *src, char *hash) debug3("Time elapsed: %d msec", msec_elapsed); if (waitpid(pid, &status, 0) == -1) { - error("Couldn't wait for child '%s' completion: %s", src->cmdstring, - strerror(errno)); - return(0.0); + error("Couldn't wait for child '%s' completion: %s", + src->cmdstring, strerror(errno)); + return 0.0; } RAND_add(&status, sizeof(&status), 0.0); 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 */ + /* + * 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); + return total_bytes_read; } if (WIFEXITED(status)) { - if (WEXITSTATUS(status)==0) { - return(total_bytes_read); + if (WEXITSTATUS(status) == 0) { + return total_bytes_read; } else { - debug2("Command '%s' exit status was %d", src->cmdstring, - WEXITSTATUS(status)); + debug2("Command '%s' exit status was %d", + src->cmdstring, WEXITSTATUS(status)); src->badness = src->sticky_badness = 128; - return (0.0); + return 0.0; } } else if (WIFSIGNALED(status)) { - debug2("Command '%s' returned on uncaught signal %d !", src->cmdstring, - status); + debug2("Command '%s' returned on uncaught signal %d !", + src->cmdstring, status); src->badness = src->sticky_badness = 128; - return(0.0); + return 0.0; } else - return(0.0); + return 0.0; +} + +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; + + i = getuid(); + RAND_add(&i, sizeof(i), 0.0); + i = getgid(); + RAND_add(&i, sizeof(i), 0.0); + + total_entropy_estimate += stir_gettimeofday(1.0); + total_entropy_estimate += stir_clock(0.5); + total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); + + return total_entropy_estimate; +} + +double +stir_from_programs(void) +{ + int c; + double entropy, total_entropy; + char hash[SHA_DIGEST_LENGTH]; + + total_entropy = 0; + for(c = 0; entropy_cmds[c].path != NULL; c++) { + if (!entropy_cmds[c].badness) { + /* Hash output from command */ + entropy = hash_command_output(&entropy_cmds[c], + hash); + + /* Scale back estimate by command's rate */ + entropy *= entropy_cmds[c].rate; + + /* Upper bound of entropy is SHA_DIGEST_LENGTH */ + if (entropy > SHA_DIGEST_LENGTH) + entropy = SHA_DIGEST_LENGTH; + + /* Stir it in */ + RAND_add(hash, sizeof(hash), entropy); + + debug3("Got %0.2f bytes of entropy from '%s'", + entropy, entropy_cmds[c].cmdstring); + + total_entropy += entropy; + + /* Execution time should be a bit unpredictable */ + total_entropy += stir_gettimeofday(0.05); + total_entropy += stir_clock(0.05); + total_entropy += stir_rusage(RUSAGE_SELF, 0.1); + total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1); + } else { + debug2("Command '%s' disabled (badness %d)", + entropy_cmds[c].cmdstring, + entropy_cmds[c].badness); + + if (entropy_cmds[c].badness > 0) + entropy_cmds[c].badness--; + } + } + + return total_entropy; } /* * prng seedfile functions */ int -prng_check_seedfile(char *filename) { - +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 */ + /* + * XXX raceable: eg replace seed between this stat and subsequent + * open. Not such a problem because we don't really trust the + * seed file anyway. + * XXX: use secure path checking as elsewhere in OpenSSH + */ 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); + debug("WARNING: Couldn't stat random seed file " + "\"%.100s\": %s", filename, strerror(errno)); + return 0; } /* regular file? */ if (!S_ISREG(st.st_mode)) - fatal("PRNG seedfile %.100s is not a regular file", 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())) { - debug("WARNING: PRNG seedfile %.100s must be mode 0600, owned by uid %d", - filename, getuid()); - return(0); + debug("WARNING: PRNG seedfile %.100s must be mode 0600, " + "owned by uid %d", filename, getuid()); + return 0; } - return(1); + return 1; } void -prng_write_seedfile(void) { +prng_write_seedfile(void) +{ int fd; - char seed[1024]; - char filename[1024]; + char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; struct passwd *pw; pw = getpwuid(getuid()); 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", getuid(), strerror(errno)); /* Try to ensure that the parent directory is there */ snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, - _PATH_SSH_USER_DIR); + _PATH_SSH_USER_DIR); mkdir(filename, 0700); snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, - SSH_PRNG_SEED_FILE); + SSH_PRNG_SEED_FILE); debug("writing PRNG seed to file %.100s", filename); @@ -586,27 +569,27 @@ prng_write_seedfile(void) { 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)); + 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)); + 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) { +prng_read_seedfile(void) +{ int fd; - char seed[1024]; - char filename[1024]; + char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; struct passwd *pw; pw = getpwuid(getuid()); 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", getuid(), strerror(errno)); snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, SSH_PRNG_SEED_FILE); @@ -614,19 +597,19 @@ prng_read_seedfile(void) { debug("loading PRNG seed from file %.100s", filename); if (!prng_check_seedfile(filename)) { - verbose("Random seed file not found or not valid, ignoring."); + verbose("Random seed file not found or invalid, 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)); + 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); + 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); @@ -642,81 +625,78 @@ prng_read_seedfile(void) { int prng_read_commands(char *cmdfilename) { - FILE *f; - char *cp; - char line[1024]; - char cmd[1024]; - char path[256]; - int linenum; - int num_cmds = 64; - int cur_cmd = 0; + char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE]; double est; - entropy_source_t *entcmd; + entropy_cmd_t *entcmd; + FILE *f; + int cur_cmd, linenum, num_cmds, arg; - f = fopen(cmdfilename, "r"); - if (!f) { + if ((f = fopen(cmdfilename, "r")) == NULL) { 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)); + num_cmds = 64; + entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t)); + memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t)); /* Read in file */ - linenum = 0; + cur_cmd = linenum = 0; while (fgets(line, sizeof(line), f)) { - int arg; - char *argv; - linenum++; - /* skip leading whitespace, test for blank line or comment */ + /* Skip leading whitespace, blank lines and comments */ cp = line + strspn(line, WHITESPACE); if ((*cp == 0) || (*cp == '#')) continue; /* done with this line */ - /* First non-whitespace char should be double quote delimiting */ - /* commandline */ + /* + * The first non-whitespace char should be a double quote + * delimiting the commandline + */ if (*cp != '"') { - error("bad entropy command, %.100s line %d", cmdfilename, - linenum); + error("bad entropy command, %.100s line %d", + cmdfilename, linenum); continue; } - /* first token, command args (incl. argv[0]) in double quotes */ + /* + * 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); + error("missing or bad command string, %.100s " + "line %d -- ignored", cmdfilename, linenum); continue; } strlcpy(cmd, cp, sizeof(cmd)); - /* second token, full command path */ + /* Second token, full command path */ if ((cp = strtok(NULL, WHITESPACE)) == NULL) { - error("missing command path, %.100s line %d -- ignored", - cmdfilename, linenum); + error("missing command path, %.100s " + "line %d -- ignored", cmdfilename, linenum); continue; } - /* did configure mark this as dead? */ + /* 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 */ + /* Third token, entropy rate estimate for this command */ if ((cp = strtok(NULL, WHITESPACE)) == NULL) { - error("missing entropy estimate, %.100s line %d -- ignored", - cmdfilename, linenum); + error("missing entropy estimate, %.100s " + "line %d -- ignored", cmdfilename, linenum); continue; } - est = strtod(cp, &argv); + est = strtod(cp, NULL); /* end of line */ if ((cp = strtok(NULL, WHITESPACE)) != NULL) { - error("garbage at end of line %d in %.100s -- ignored", linenum, - cmdfilename); + error("garbage at end of line %d in %.100s " + "-- ignored", linenum, cmdfilename); continue; } @@ -726,17 +706,14 @@ prng_read_commands(char *cmdfilename) /* 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; + entcmd[cur_cmd].args[arg] = xstrdup(cp); arg++; - } while ((arg < 5) && (cp = strtok(NULL, WHITESPACE))); + } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE))); if (strtok(NULL, WHITESPACE)) - error("ignored extra command elements (max 5), %.100s line %d", - cmdfilename, linenum); + error("ignored extra commands (max %d), %.100s " + "line %d", NUM_ARGS, cmdfilename, linenum); /* Copy the command path and rate estimate */ entcmd[cur_cmd].path = xstrdup(path); @@ -747,56 +724,80 @@ prng_read_commands(char *cmdfilename) 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 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)); + entcmd = xrealloc(entcmd, num_cmds * + sizeof(entropy_cmd_t)); } } /* zero the last entry */ - memset(&entcmd[cur_cmd], '\0', sizeof(entropy_source_t)); + memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t)); /* trim to size */ - entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t)); + entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) * + sizeof(entropy_cmd_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); + return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0; } -static void -seed_openssl_rng(void) -{ - /* Read in collection commands */ - if (!prng_read_commands(SSH_PRNG_COMMAND_FILE)) - fatal("PRNG initialisation failed -- exiting."); - - prng_read_seedfile(); - - 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()); - - prng_write_seedfile(); -} - -#endif /* USE_PRNGD */ - int main(int argc, char **argv) { - unsigned char buf[48]; + unsigned char buf[OUTPUT_SEED_SIZE]; int ret; __progname = get_progname(argv[0]); /* XXX: need some debugging mode */ log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1); - seed_openssl_rng(); +#ifdef USE_SEED_FILES + prng_read_seedfile(); +#endif + + /* + * Seed the RNG from wherever we can + */ + + /* Take whatever is on the stack, but don't credit it */ + RAND_add(buf, sizeof(buf), 0); + + debug("Seeded RNG with %i bytes from system calls", + (int)stir_from_system()); + +#ifdef PRNGD_PORT + if (get_random_bytes_prngd(buf, sizeof(buf), PRNGD_PORT, + NULL) == -1) + fatal("Entropy collection failed"); + RAND_add(buf, sizeof(buf), sizeof(buf)); +#elif PRNGD_SOCKET + if (get_random_bytes_prngd(buf, sizeof(buf), PRNGD_SOCKET, + NULL) == -1) + fatal("Entropy collection failed"); + RAND_add(buf, sizeof(buf), sizeof(buf)); +#else + /* Read in collection commands */ + if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1) + fatal("PRNG initialisation failed -- exiting."); + debug("Seeded RNG with %i bytes from programs", + (int)stir_from_programs()); +#endif + +#ifdef USE_SEED_FILES + prng_write_seedfile(); +#endif + + /* + * Write the seed to stdout + */ if (!RAND_status()) fatal("Not enough entropy in RNG"); -- 2.45.1