diff -up openssh-7.4p1/monitor_wrap.c.audit-race openssh-7.4p1/monitor_wrap.c --- openssh-7.4p1/monitor_wrap.c.audit-race 2016-12-23 16:35:52.694685771 +0100 +++ openssh-7.4p1/monitor_wrap.c 2016-12-23 16:35:52.697685772 +0100 @@ -1107,4 +1107,48 @@ mm_audit_destroy_sensitive_data(const ch mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_SERVER_KEY_FREE, &m); buffer_free(&m); } + +int mm_forward_audit_messages(int fdin) +{ + u_char buf[4]; + u_int blen, msg_len; + Buffer m; + int ret = 0; + + debug3("%s: entering", __func__); + buffer_init(&m); + do { + blen = atomicio(read, fdin, buf, sizeof(buf)); + if (blen == 0) /* closed pipe */ + break; + if (blen != sizeof(buf)) { + error("%s: Failed to read the buffer from child", __func__); + ret = -1; + break; + } + + msg_len = get_u32(buf); + if (msg_len > 256 * 1024) + fatal("%s: read: bad msg_len %d", __func__, msg_len); + buffer_clear(&m); + buffer_append_space(&m, msg_len); + if (atomicio(read, fdin, buffer_ptr(&m), msg_len) != msg_len) { + error("%s: Failed to read the the buffer content from the child", __func__); + ret = -1; + break; + } + if (atomicio(vwrite, pmonitor->m_recvfd, buf, blen) != blen || + atomicio(vwrite, pmonitor->m_recvfd, buffer_ptr(&m), msg_len) != msg_len) { + error("%s: Failed to write the message to the monitor", __func__); + ret = -1; + break; + } + } while (1); + buffer_free(&m); + return ret; +} +void mm_set_monitor_pipe(int fd) +{ + pmonitor->m_recvfd = fd; +} #endif /* SSH_AUDIT_EVENTS */ diff -up openssh-7.4p1/monitor_wrap.h.audit-race openssh-7.4p1/monitor_wrap.h --- openssh-7.4p1/monitor_wrap.h.audit-race 2016-12-23 16:35:52.694685771 +0100 +++ openssh-7.4p1/monitor_wrap.h 2016-12-23 16:35:52.698685772 +0100 @@ -83,6 +83,8 @@ void mm_audit_unsupported_body(int); void mm_audit_kex_body(int, char *, char *, char *, char *, pid_t, uid_t); void mm_audit_session_key_free_body(int, pid_t, uid_t); void mm_audit_destroy_sensitive_data(const char *, pid_t, uid_t); +int mm_forward_audit_messages(int); +void mm_set_monitor_pipe(int); #endif struct Session; diff -up openssh-7.4p1/session.c.audit-race openssh-7.4p1/session.c --- openssh-7.4p1/session.c.audit-race 2016-12-23 16:35:52.695685771 +0100 +++ openssh-7.4p1/session.c 2016-12-23 16:37:26.339730596 +0100 @@ -162,6 +162,10 @@ static Session *sessions = NULL; login_cap_t *lc; #endif +#ifdef SSH_AUDIT_EVENTS +int paudit[2]; +#endif + static int is_child = 0; static int in_chroot = 0; static int have_dev_log = 1; @@ -289,6 +293,8 @@ xauth_valid_string(const char *s) return 1; } +void child_destory_sensitive_data(); + #define USE_PIPES 1 /* * This is called to fork and execute a command when we have no tty. This @@ -424,6 +430,8 @@ do_exec_no_pty(Session *s, const char *c cray_init_job(s->pw); /* set up cray jid and tmpdir */ #endif + child_destory_sensitive_data(); + /* Do processing for the child (exec command etc). */ do_child(s, command); /* NOTREACHED */ @@ -547,6 +555,9 @@ do_exec_pty(Session *s, const char *comm /* Close the extra descriptor for the pseudo tty. */ close(ttyfd); + /* Do this early, so we will not block large MOTDs */ + child_destory_sensitive_data(); + /* record login, etc. similar to login(1) */ #ifdef _UNICOS cray_init_job(s->pw); /* set up cray jid and tmpdir */ @@ -717,6 +728,8 @@ do_exec(Session *s, const char *command) } if (s->command != NULL && s->ptyfd == -1) s->command_handle = PRIVSEP(audit_run_command(s->command)); + if (pipe(paudit) < 0) + fatal("pipe: %s", strerror(errno)); #endif if (s->ttyfd != -1) ret = do_exec_pty(s, command); @@ -732,6 +745,20 @@ do_exec(Session *s, const char *command) */ buffer_clear(&loginmsg); +#ifdef SSH_AUDIT_EVENTS + close(paudit[1]); + if (use_privsep && ret == 0) { + /* + * Read the audit messages from forked child and send them + * back to monitor. We don't want to communicate directly, + * because the messages might get mixed up. + * Continue after the pipe gets closed (all messages sent). + */ + ret = mm_forward_audit_messages(paudit[0]); + } + close(paudit[0]); +#endif /* SSH_AUDIT_EVENTS */ + return ret; } @@ -1538,6 +1565,33 @@ child_close_fds(void) endpwent(); } +void +child_destory_sensitive_data() +{ +#ifdef SSH_AUDIT_EVENTS + int pparent = paudit[1]; + close(paudit[0]); + /* Hack the monitor pipe to avoid race condition with parent */ + if (use_privsep) + mm_set_monitor_pipe(pparent); +#endif + + /* remove hostkey from the child's memory */ + destroy_sensitive_data(use_privsep); + /* + * We can audit this, because we hacked the pipe to direct the + * messages over postauth child. But this message requires answer + * which we can't do using one-way pipe. + */ + packet_destroy_all(0, 1); + +#ifdef SSH_AUDIT_EVENTS + /* Notify parent that we are done */ + close(pparent); +#endif + +} + /* * Performs common processing for the child, such as setting up the * environment, closing extra file descriptors, setting the user and group @@ -1554,12 +1608,6 @@ do_child(Session *s, const char *command struct passwd *pw = s->pw; int r = 0; - /* remove hostkey from the child's memory */ - destroy_sensitive_data(1); - /* Don't audit this - both us and the parent would be talking to the - monitor over a single socket, with no synchronization. */ - packet_destroy_all(0, 1); - /* Force a password change */ if (s->authctxt->force_pwchange) { do_setusercontext(pw);