Commit cea9125d authored by Nick Mathewson's avatar Nick Mathewson 🌉
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Implement two flavors of authentication for control connections: one for...

Implement two flavors of authentication for control connections: one for trusted FS, one for untrusted FS.


svn:r2664
parent 871bf904
......@@ -1575,6 +1575,47 @@ base32_encode(char *dest, size_t destlen, const char *src, size_t srclen)
dest[i] = '\0';
}
/** Implement RFC2440-style iterated-salted S2K conversion: convert the
* <b>secret_len</b>-byte <b>secret</b> into a <b>key_out_len</b> byte
* <b>key_out</b>. As in RFC2440, the first 8 bytes of s2k_specifier
* are a salt; the 9th byte describes how much iteration to do.
* Does not support <b>key_out_len</b> &gt; DIGEST_LEN.
*/
void
secret_to_key(char *key_out, size_t key_out_len, const char *secret,
size_t secret_len, const char *s2k_specifier)
{
crypto_digest_env_t *d;
uint8_t c;
size_t count;
char *tmp;
#define EXPBIAS 6
c = s2k_specifier[8];
count = ((uint32_t)16 + (c & 15)) << ((c >> 4) + EXPBIAS);
#undef EXPBIAS
tor_assert(key_out_len <= DIGEST_LEN);
d = crypto_new_digest_env();
tmp = tor_malloc(8+secret_len);
memcpy(tmp,s2k_specifier,8);
memcpy(tmp+8,secret,secret_len);
secret_len += 8;
while (count) {
if (count >= secret_len) {
crypto_digest_add_bytes(d, tmp, secret_len);
count -= secret_len;
} else {
crypto_digest_add_bytes(d, tmp, count);
count = 0;
}
}
crypto_digest_get_digest(d, key_out, key_out_len);
tor_free(tmp);
crypto_free_digest_env(d);
}
/*
Local Variables:
mode:c
......
......@@ -153,6 +153,10 @@ int base64_decode(char *dest, size_t destlen, const char *src, size_t srclen);
#define BASE32_CHARS "abcdefghijklmnopqrstuvwxyz234567"
void base32_encode(char *dest, size_t destlen, const char *src, size_t srclen);
#define S2K_SPECIFIER_LEN 9
void secret_to_key(char *key_out, size_t key_out_len, const char *secret,
size_t secret_len, const char *s2k_specifier);
#endif
/*
......
......@@ -101,6 +101,7 @@ static config_var_t config_vars[] = {
VAR("MyFamily", STRING, MyFamily, NULL),
VAR("NodeFamily", LINELIST, NodeFamilies, NULL),
VAR("Group", STRING, Group, NULL),
VAR("HashedControlPassword",STRING, HashedControlPassword, NULL),
VAR("HttpProxy", STRING, HttpProxy, NULL),
VAR("HiddenServiceDir", LINELIST, RendConfigLines, NULL),
VAR("HiddenServicePort", LINELIST, RendConfigLines, NULL),
......@@ -183,12 +184,13 @@ config_get_commandlines(int argc, char **argv)
int i = 1;
while (i < argc-1) {
if (!strcmp(argv[i],"-f")) {
// log(LOG_DEBUG,"Commandline: skipping over -f.");
i += 2; /* this is the config file option. ignore it. */
if (!strcmp(argv[i],"-f") ||
!strcmp(argv[i],"--hash-password")) {
i += 2; /* command-line option with argument. ignore them. */
continue;
} else if (!strcmp(argv[i],"--list-fingerprint")) {
i += 1; /* command-line option. ignore it. */
continue;
}
new = tor_malloc(sizeof(struct config_line_t));
......@@ -803,7 +805,12 @@ getconfig(int argc, char **argv, or_options_t *options)
++i;
} else if (!strcmp(argv[i],"--list-fingerprint")) {
options->command = CMD_LIST_FINGERPRINT;
} else if (!strcmp(argv[i],"--hash-password")) {
options->command = CMD_HASH_PASSWORD;
options->command_arg = tor_strdup(argv[i+1]);
++i;
}
}
if (using_default_torrc) {
......
......@@ -47,6 +47,10 @@ extern or_options_t options;
static uint32_t global_event_mask = 0;
#define AUTHENTICATION_COOKIE_LEN 32
static int authentication_cookie_is_set = 0;
static char authentication_cookie[AUTHENTICATION_COOKIE_LEN];
static void update_global_event_mask(void);
static void send_control_message(connection_t *conn, uint16_t type,
uint16_t len, const char *body);
......@@ -216,13 +220,34 @@ static int handle_control_setevents(connection_t *conn, uint16_t len,
static int handle_control_authenticate(connection_t *conn, uint16_t len,
const char *body)
{
if (0/* XXXX009 NM */) {
send_control_done(conn);
conn->state = CONTROL_CONN_STATE_OPEN;
} else {
send_control_error(conn, ERR_FAILED_AUTHENTICATION,"Authentication failed");
if (len == AUTHENTICATION_COOKIE_LEN &&
authentication_cookie_is_set &&
!memcmp(authentication_cookie, body, len)) {
goto ok;
} else if (options.HashedControlPassword) {
char expected[S2K_SPECIFIER_LEN+DIGEST_LEN];
char received[DIGEST_LEN];
if (base64_decode(expected,sizeof(expected),
options.HashedControlPassword,
strlen(options.HashedControlPassword))<0) {
/* XXXX009 NM we should warn sooner. */
log_fn(LOG_WARN,"Couldn't decode HashedControlPassword: invalid base64");
goto err;
}
secret_to_key(received,DIGEST_LEN,body,len,expected);
if (!memcmp(expected+S2K_SPECIFIER_LEN, received, DIGEST_LEN))
goto ok;
}
err:
send_control_error(conn, ERR_FAILED_AUTHENTICATION,"Authentication failed");
return 0;
ok:
log_fn(LOG_INFO, "Authenticated control connection (%d)", conn->s);
send_control_done(conn);
conn->state = CONTROL_CONN_STATE_OPEN;
return 0;
}
int connection_control_finished_flushing(connection_t *conn) {
......@@ -391,6 +416,25 @@ void control_event_logmsg(int severity, const char *msg)
send_control_event(EVENT_WARNING, (uint16_t)(len+1), msg);
}
int init_cookie_authentication(void)
{
char fname[512];
/* XXXX009 NM add config option to disable this. */
tor_snprintf(fname, sizeof(fname), "%s/control_auth_cookie",
get_data_directory(&options));
crypto_rand(authentication_cookie, AUTHENTICATION_COOKIE_LEN);
authentication_cookie_is_set = 1;
if (write_bytes_to_file(fname, authentication_cookie,
AUTHENTICATION_COOKIE_LEN, 1)) {
log_fn(LOG_WARN,"Error writing authentication cookie.");
return -1;
}
return 0;
}
/*
Local Variabls:
mode:c
......
......@@ -1373,6 +1373,25 @@ static void do_list_fingerprint(void)
}
}
/** DOCDOC **/
static void do_hash_password(void)
{
char output[256];
char key[S2K_SPECIFIER_LEN+DIGEST_LEN];
crypto_rand(key, S2K_SPECIFIER_LEN-1);
key[S2K_SPECIFIER_LEN-1] = (uint8_t)96; /* Hash 64 K of data. */
secret_to_key(key+S2K_SPECIFIER_LEN, DIGEST_LEN,
options.command_arg, strlen(options.command_arg),
key);
if (base64_encode(output, sizeof(output), key, sizeof(key))<0) {
log_fn(LOG_ERR, "Unable to compute base64");
} else {
printf("%s",output);
}
}
#ifdef MS_WINDOWS_SERVICE
void nt_service_control(DWORD request)
{
......@@ -1449,6 +1468,9 @@ int tor_main(int argc, char *argv[]) {
case CMD_LIST_FINGERPRINT:
do_list_fingerprint();
break;
case CMD_HASH_PASSWORD:
do_hash_password();
break;
default:
log_fn(LOG_ERR, "Illegal command number %d: internal error.",
options.command);
......
......@@ -852,8 +852,10 @@ typedef struct exit_redirect_t {
typedef struct {
/** What should the tor process actually do? */
enum {
CMD_RUN_TOR=0, CMD_LIST_FINGERPRINT
CMD_RUN_TOR=0, CMD_LIST_FINGERPRINT, CMD_HASH_PASSWORD,
} command;
const char *command_arg; /**< Argument for command-line option. */
struct config_line_t *LogOptions; /**< List of configuration lines
* for logfiles */
......@@ -949,6 +951,8 @@ typedef struct {
int AccountingMaxKB; /**< How many KB do we allow per accounting
* interval before hibernation? 0 for "never
* hibernate." */
char *HashedControlPassword; /**< Base64-encoded hash of a password for
* the control system. */
} or_options_t;
/* XXX are these good enough defaults? */
......@@ -1241,6 +1245,8 @@ int control_event_or_conn_status(connection_t *conn, or_conn_status_event_t e);
int control_event_bandwidth_used(uint32_t n_read, uint32_t n_written);
void control_event_logmsg(int severity, const char *msg);
int init_cookie_authentication(void);
/********************************* cpuworker.c *****************************/
void cpu_init(void);
......
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