- markus@cvs.openbsd.org 2002/03/21 21:23:34

     [sshd.c]
     add privsep_preauth() and remove 1 goto; ok provos@

1 files changed, 55 insertions, 43 deletions

diff --git a/sshd.c b/sshd.c
index 26124b777..c80dfc146 100644
--- a/sshd.c
+++ b/sshd.c
@@ -42,7 +42,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.236 2002/03/20 21:08:08 stevesk Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.237 2002/03/21 21:23:34 markus Exp $");
 
 #include <openssl/dh.h>
 #include <openssl/bn.h>
@@ -551,14 +551,51 @@ privsep_preauth_child(void)
         do_setusercontext(pw);
 }
 
-static void
-privsep_postauth(Authctxt *authctxt, pid_t pid)
+static Authctxt*
+privsep_preauth(void)
 {
-        extern Authctxt *x_authctxt;
+        Authctxt *authctxt = NULL;
         int status;
+        pid_t pid;
 
-        /* Wait for the child's exit status */
-        waitpid(pid, &status, 0);
+        /* Set up unprivileged child process to deal with network data */
+        monitor = monitor_init();
+        /* Store a pointer to the kex for later rekeying */
+        monitor->m_pkex = &xxx_kex;
+
+        pid = fork();
+        if (pid == -1) {
+                fatal("fork of unprivileged child failed");
+        } else if (pid != 0) {
+                debug2("Network child is on pid %d", pid);
+
+                close(monitor->m_recvfd);
+                authctxt = monitor_child_preauth(monitor);
+                close(monitor->m_sendfd);
+
+                /* Sync memory */
+                monitor_sync(monitor);
+
+                /* Wait for the child's exit status */
+                waitpid(pid, &status, 0);
+
+                return (authctxt);
+        } else {
+                /* child */
+
+                close(monitor->m_sendfd);
+
+                /* Demote the child */
+                if (getuid() == 0 || geteuid() == 0)
+                        privsep_preauth_child();
+        }
+        return (NULL);
+}
+
+static void
+privsep_postauth(Authctxt *authctxt)
+{
+        extern Authctxt *x_authctxt;
 
         /* XXX - Remote port forwarding */
         x_authctxt = authctxt;
@@ -584,7 +621,7 @@ privsep_postauth(Authctxt *authctxt, pid_t pid)
         if (monitor->m_pid == -1)
                 fatal("fork of unprivileged child failed");
         else if (monitor->m_pid != 0) {
-                debug2("User child is on pid %d", pid);
+                debug2("User child is on pid %d", monitor->m_pid);
                 close(monitor->m_recvfd);
                 monitor_child_postauth(monitor);
 
@@ -604,7 +641,6 @@ privsep_postauth(Authctxt *authctxt, pid_t pid)
         monitor_apply_keystate(monitor);
 }
 
-
 static char *
 list_hostkey_types(void)
 {
@@ -1379,36 +1415,9 @@ main(int ac, char **av)
 
         packet_set_nonblocking();
 
-        if (!use_privsep)
-                goto skip_privilegeseparation;
-
-        /* Set up unprivileged child process to deal with network data */
-        monitor = monitor_init();
-        /* Store a pointer to the kex for later rekeying */
-        monitor->m_pkex = &xxx_kex;
-
-        pid = fork();
-        if (pid == -1)
-                fatal("fork of unprivileged child failed");
-        else if (pid != 0) {
-                debug2("Network child is on pid %d", pid);
-
-                close(monitor->m_recvfd);
-                authctxt = monitor_child_preauth(monitor);
-                close(monitor->m_sendfd);
-
-                /* Sync memory */
-                monitor_sync(monitor);
-                goto authenticated;
-        } else {
-                close(monitor->m_sendfd);
-
-                /* Demote the child */
-                if (getuid() == 0 || geteuid() == 0)
-                        privsep_preauth_child();
-        }
-
- skip_privilegeseparation:
+        if (use_privsep)
+                if ((authctxt = privsep_preauth()) != NULL)
+                        goto authenticated;
 
         /* perform the key exchange */
         /* authenticate user and start session */
@@ -1419,12 +1428,14 @@ main(int ac, char **av)
                 do_ssh1_kex();
                 authctxt = do_authentication();
         }
-        if (use_privsep)
+        /*
+         * If we use privilege separation, the unprivileged child transfers
+         * the current keystate and exits
+         */
+        if (use_privsep) {
                 mm_send_keystate(monitor);
-
-        /* If we use privilege separation, the unprivileged child exits */
-        if (use_privsep)
                 exit(0);
+        }
 
  authenticated:
         /*
@@ -1432,7 +1443,8 @@ main(int ac, char **av)
          * file descriptor passing.
          */
         if (use_privsep) {
-                privsep_postauth(authctxt, pid);
+                privsep_postauth(authctxt);
+                /* the monitor process [priv] will not return */
                 if (!compat20)
                         destroy_sensitive_data();
         }