static void
privsep_preauth_child(void)
{
u_int32_t rand[256];
gid_t gidset[2];
struct passwd *pw;
int i;
/* Enable challenge-response authentication for privilege separation */
privsep_challenge_enable();
for (i = 0; i < 256; i++)
rand[i] = arc4random();
RAND_seed(rand, sizeof(rand));
/* Demote the private keys to public keys. */
demote_sensitive_data();
if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
fatal("Privilege separation user %s does not exist",
SSH_PRIVSEP_USER);
memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
endpwent();
/* Change our root directory*/
if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
strerror(errno));
if (chdir("/") == -1)
fatal("chdir(\"/\"): %s", strerror(errno));
/* Drop our privileges */
debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
(u_int)pw->pw_gid);
#if 0
/* XXX not ready, to heavy after chroot */
do_setusercontext(pw);
#else
gidset[0] = pw->pw_gid;
if (setgid(pw->pw_gid) < 0)
fatal("setgid failed for %u", pw->pw_gid );
if (setgroups(1, gidset) < 0)
fatal("setgroups: %.100s", strerror(errno));
permanently_set_uid(pw);
#endif
}
static void
privsep_postauth(Authctxt *authctxt)
{
#ifdef DISABLE_FD_PASSING
if (1) {
#else
if (authctxt->pw->pw_uid == 0 || options.use_login) {
#endif
/* File descriptor passing is broken or root login */
monitor_apply_keystate(pmonitor);
use_privsep = 0;
return;
}
/* Authentication complete */
alarm(0);
if (startup_pipe != -1) {
close(startup_pipe);
startup_pipe = -1;
}
/* New socket pair */
monitor_reinit(pmonitor);
pmonitor->m_pid = fork();
if (pmonitor->m_pid == -1)
fatal("fork of unprivileged child failed");
else if (pmonitor->m_pid != 0) {
debug2("User child is on pid %ld", (long)pmonitor->m_pid);
close(pmonitor->m_recvfd);
buffer_clear(&loginmsg);
monitor_child_postauth(pmonitor);
/* NEVERREACHED */
exit(0);
}
close(pmonitor->m_sendfd);
/* Demote the private keys to public keys. */
demote_sensitive_data();
/* Drop privileges */
do_setusercontext(authctxt->pw);
/* It is safe now to apply the key state */
monitor_apply_keystate(pmonitor);
}
static char *
list_hostkey_types(void)
{
Buffer b;
const char *p;
char *ret;
int i;
buffer_init(&b);
for (i = 0; i < options.num_host_key_files; i++) {
Key *key = sensitive_data.host_keys[i];
if (key == NULL)
continue;
switch (key->type) {
case KEY_RSA:
case KEY_DSA:
if (buffer_len(&b) > 0)
buffer_append(&b, ",", 1);
p = key_ssh_name(key);
buffer_append(&b, p, strlen(p));
break;
}
}
buffer_append(&b, "\0", 1);
ret = xstrdup(buffer_ptr(&b));
buffer_free(&b);
debug("list_hostkey_types: %s", ret);
return ret;
}
