- djm@cvs.openbsd.org 2011/06/17 21:44:31

     [log.c log.h monitor.c monitor.h monitor_wrap.c monitor_wrap.h sshd.c]
     make the pre-auth privsep slave log via a socketpair shared with the
     monitor rather than /var/empty/dev/log; ok dtucker@ deraadt@ markus@

1 files changed, 114 insertions, 14 deletions

diff --git a/monitor.c b/monitor.c
index 2c9254182..bb8003c67 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor.c,v 1.113 2011/05/23 03:30:07 djm Exp $ */
+/* $OpenBSD: monitor.c,v 1.114 2011/06/17 21:44:30 djm Exp $ */
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * Copyright 2002 Markus Friedl <markus@openbsd.org>
@@ -44,6 +44,13 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#else
+# ifdef HAVE_SYS_POLL_H
+#  include <sys/poll.h>
+# endif
+#endif
 
 #ifdef SKEY
 #include <skey.h>
@@ -52,6 +59,7 @@
 #include <openssl/dh.h>
 
 #include "openbsd-compat/sys-queue.h"
+#include "atomicio.h"
 #include "xmalloc.h"
 #include "ssh.h"
 #include "key.h"
@@ -179,6 +187,8 @@ int mm_answer_audit_event(int, Buffer *);
 int mm_answer_audit_command(int, Buffer *);
 #endif
 
+static int monitor_read_log(struct monitor *);
+
 static Authctxt *authctxt;
 static BIGNUM *ssh1_challenge = NULL;   /* used for ssh1 rsa auth */
 
@@ -346,6 +356,10 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 
         debug3("preauth child monitor started");
 
+        close(pmonitor->m_recvfd);
+        close(pmonitor->m_log_sendfd);
+        pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1;
+
         authctxt = _authctxt;
         memset(authctxt, 0, sizeof(*authctxt));
 
@@ -405,6 +419,10 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
 #endif
         }
 
+        /* Drain any buffered messages from the child */
+        while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0)
+                ;
+
         if (!authctxt->valid)
                 fatal("%s: authenticated invalid user", __func__);
         if (strcmp(auth_method, "unknown") == 0)
@@ -414,6 +432,10 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor)
             __func__, authctxt->user);
 
         mm_get_keystate(pmonitor);
+
+        close(pmonitor->m_sendfd);
+        close(pmonitor->m_log_recvfd);
+        pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1;
 }
 
 static void
@@ -431,6 +453,9 @@ monitor_child_handler(int sig)
 void
 monitor_child_postauth(struct monitor *pmonitor)
 {
+        close(pmonitor->m_recvfd);
+        pmonitor->m_recvfd = -1;
+
         monitor_set_child_handler(pmonitor->m_pid);
         signal(SIGHUP, &monitor_child_handler);
         signal(SIGTERM, &monitor_child_handler);
@@ -454,6 +479,9 @@ monitor_child_postauth(struct monitor *pmonitor)
 
         for (;;)
                 monitor_read(pmonitor, mon_dispatch, NULL);
+
+        close(pmonitor->m_sendfd);
+        pmonitor->m_sendfd = -1;
 }
 
 void
@@ -465,6 +493,52 @@ monitor_sync(struct monitor *pmonitor)
         }
 }
 
+static int
+monitor_read_log(struct monitor *pmonitor)
+{
+        Buffer logmsg;
+        u_int len, level;
+        char *msg;
+
+        buffer_init(&logmsg);
+
+        /* Read length */
+        buffer_append_space(&logmsg, 4);
+        if (atomicio(read, pmonitor->m_log_recvfd,
+            buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg)) {
+                if (errno == EPIPE) {
+                        debug("%s: child log fd closed", __func__);
+                        close(pmonitor->m_log_recvfd);
+                        pmonitor->m_log_recvfd = -1;
+                        return -1;
+                }
+                fatal("%s: log fd read: %s", __func__, strerror(errno));
+        }
+        len = buffer_get_int(&logmsg);
+        if (len <= 4 || len > 8192)
+                fatal("%s: invalid log message length %u", __func__, len);
+
+        /* Read severity, message */
+        buffer_clear(&logmsg);
+        buffer_append_space(&logmsg, len);
+        if (atomicio(read, pmonitor->m_log_recvfd,
+            buffer_ptr(&logmsg), buffer_len(&logmsg)) != buffer_len(&logmsg))
+                fatal("%s: log fd read: %s", __func__, strerror(errno));
+
+        /* Log it */
+        level = buffer_get_int(&logmsg);
+        msg = buffer_get_string(&logmsg, NULL);
+        if (log_level_name(level) == NULL)
+                fatal("%s: invalid log level %u (corrupted message?)",
+                    __func__, level);
+        do_log2(level, "%s [preauth]", msg);
+
+        buffer_free(&logmsg);
+        xfree(msg);
+
+        return 0;
+}
+
 int
 monitor_read(struct monitor *pmonitor, struct mon_table *ent,
     struct mon_table **pent)
@@ -472,6 +546,27 @@ monitor_read(struct monitor *pmonitor, struct mon_table *ent,
         Buffer m;
         int ret;
         u_char type;
+        struct pollfd pfd[2];
+
+        for (;;) {
+                bzero(&pfd, sizeof(pfd));
+                pfd[0].fd = pmonitor->m_sendfd;
+                pfd[0].events = POLLIN;
+                pfd[1].fd = pmonitor->m_log_recvfd;
+                pfd[1].events = pfd[1].fd == -1 ? 0 : POLLIN;
+                if (poll(pfd, pfd[1].fd == -1 ? 1 : 2, -1) == -1)
+                        fatal("%s: poll: %s", __func__, strerror(errno));
+                if (pfd[1].revents) {
+                        /*
+                         * Drain all log messages before processing next
+                         * monitor request.
+                         */
+                        monitor_read_log(pmonitor);
+                        continue;
+                }
+                if (pfd[0].revents)
+                        break;  /* Continues below */
+        }
 
         buffer_init(&m);
 
@@ -1851,12 +1946,26 @@ mm_init_compression(struct mm_master *mm)
 } while (0)
 
 static void
-monitor_socketpair(int *pair)
+monitor_openfds(struct monitor *mon, int do_logfds)
 {
+        int pair[2];
+
         if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1)
-                fatal("%s: socketpair", __func__);
+                fatal("%s: socketpair: %s", __func__, strerror(errno));
         FD_CLOSEONEXEC(pair[0]);
         FD_CLOSEONEXEC(pair[1]);
+        mon->m_recvfd = pair[0];
+        mon->m_sendfd = pair[1];
+
+        if (do_logfds) {
+                if (pipe(pair) == -1)
+                        fatal("%s: pipe: %s", __func__, strerror(errno));
+                FD_CLOSEONEXEC(pair[0]);
+                FD_CLOSEONEXEC(pair[1]);
+                mon->m_log_recvfd = pair[0];
+                mon->m_log_sendfd = pair[1];
+        } else
+                mon->m_log_recvfd = mon->m_log_sendfd = -1;
 }
 
 #define MM_MEMSIZE      65536
@@ -1865,14 +1974,10 @@ struct monitor *
 monitor_init(void)
 {
         struct monitor *mon;
-        int pair[2];
 
         mon = xcalloc(1, sizeof(*mon));
 
-        monitor_socketpair(pair);
-
-        mon->m_recvfd = pair[0];
-        mon->m_sendfd = pair[1];
+        monitor_openfds(mon, 1);
 
         /* Used to share zlib space across processes */
         if (options.compression) {
@@ -1889,12 +1994,7 @@ monitor_init(void)
 void
 monitor_reinit(struct monitor *mon)
 {
-        int pair[2];
-
-        monitor_socketpair(pair);
-
-        mon->m_recvfd = pair[0];
-        mon->m_sendfd = pair[1];
+        monitor_openfds(mon, 0);
 }
 
 #ifdef GSSAPI