5 files changed, 26 insertions, 30 deletions

diff --git a/ChangeLog b/ChangeLog
index ed52bdc96..48a67cb04 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -100,6 +100,10 @@
    - markus@cvs.openbsd.org 2002/03/19 15:31:47
      [auth.c]
      check for NULL; from provos@
+   - stevesk@cvs.openbsd.org 2002/03/20 19:12:25
+     [servconf.c servconf.h ssh.h sshd.c]
+     for unprivileged user, group do:
+     pw=getpwnam(SSH_PRIVSEP_USER); do_setusercontext(pw).  ok provos@
 
 20020317
  - (tim) [configure.ac] Assume path given with --with-pid-dir=PATH is wanted,
@@ -7946,4 +7950,4 @@
  - Wrote replacements for strlcpy and mkdtemp
  - Released 1.0pre1
 
-$Id: ChangeLog,v 1.1953 2002/03/22 03:08:30 mouring Exp $
+$Id: ChangeLog,v 1.1954 2002/03/22 03:11:49 mouring Exp $
diff --git a/servconf.c b/servconf.c
index 085854908..8e6ee5bb3 100644
--- a/servconf.c
+++ b/servconf.c
@@ -10,7 +10,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: servconf.c,v 1.104 2002/03/19 03:03:43 stevesk Exp $");
+RCSID("$OpenBSD: servconf.c,v 1.105 2002/03/20 19:12:24 stevesk Exp $");
 
 #if defined(KRB4) || defined(KRB5)
 #include <krb.h>
@@ -113,9 +113,6 @@ initialize_server_options(ServerOptions *options)
         options->authorized_keys_file = NULL;
         options->authorized_keys_file2 = NULL;
 
-        options->unprivileged_user = -1;
-        options->unprivileged_group = -1;
-
         /* Needs to be accessable in many places */
         use_privsep = -1;
 }
@@ -247,10 +244,6 @@ fill_default_server_options(ServerOptions *options)
         /* Turn privilege separation _off_ by default */
         if (use_privsep == -1)
                 use_privsep = 0;
-        if (options->unprivileged_user == -1)
-                options->unprivileged_user = 32767;
-        if (options->unprivileged_group == -1)
-                options->unprivileged_group = 32767;
 }
 
 /* Keyword tokens. */
@@ -283,7 +276,7 @@ typedef enum {
         sBanner, sVerifyReverseMapping, sHostbasedAuthentication,
         sHostbasedUsesNameFromPacketOnly, sClientAliveInterval,
         sClientAliveCountMax, sAuthorizedKeysFile, sAuthorizedKeysFile2,
-        sUsePrivilegeSeparation, sUnprivUser, sUnprivGroup,
+        sUsePrivilegeSeparation,
         sDeprecated
 } ServerOpCodes;
 
@@ -360,8 +353,6 @@ static struct {
         { "authorizedkeysfile", sAuthorizedKeysFile },
         { "authorizedkeysfile2", sAuthorizedKeysFile2 },
         { "useprivilegeseparation", sUsePrivilegeSeparation},
-        { "unprivuser", sUnprivUser},
-        { "unprivgroup", sUnprivGroup},
         { NULL, sBadOption }
 };
 
@@ -742,14 +733,6 @@ parse_flag:
                 intptr = &use_privsep;
                 goto parse_flag;
 
-        case sUnprivUser:
-                intptr = &options->unprivileged_user;
-                goto parse_int;
-
-        case sUnprivGroup:
-                intptr = &options->unprivileged_group;
-                goto parse_int;
-
         case sAllowUsers:
                 while ((arg = strdelim(&cp)) && *arg != '\0') {
                         if (options->num_allow_users >= MAX_ALLOW_USERS)
diff --git a/servconf.h b/servconf.h
index 06afaa3c8..c4e5b5f42 100644
--- a/servconf.h
+++ b/servconf.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: servconf.h,v 1.56 2002/03/19 03:03:43 stevesk Exp $   */
+/*      $OpenBSD: servconf.h,v 1.57 2002/03/20 19:12:25 stevesk Exp $   */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -130,9 +130,6 @@ typedef struct {
         char   *authorized_keys_file;   /* File containing public keys */
         char   *authorized_keys_file2;
         int     pam_authentication_via_kbd_int;
-
-        int     unprivileged_user;      /* User unprivileged child uses */
-        int     unprivileged_group;     /* Group unprivileged child uses */
 }       ServerOptions;
 
 void     initialize_server_options(ServerOptions *);
diff --git a/ssh.h b/ssh.h
index fdf554df0..078c9f7c7 100644
--- a/ssh.h
+++ b/ssh.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: ssh.h,v 1.64 2002/03/04 17:27:39 stevesk Exp $        */
+/*      $OpenBSD: ssh.h,v 1.65 2002/03/20 19:12:25 stevesk Exp $        */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -99,4 +99,11 @@
 /* Used to identify ``EscapeChar none'' */
 #define SSH_ESCAPECHAR_NONE             -2
 
+/*
+ * unprivileged user when UsePrivilegeSeparation=yes;
+ * sshd will change its pivileges to this user and its
+ * primary group.
+ */
+#define SSH_PRIVSEP_USER                "nobody"
+
 #endif                          /* SSH_H */
diff --git a/sshd.c b/sshd.c
index b6e71d84a..dc109815f 100644
--- a/sshd.c
+++ b/sshd.c
@@ -42,7 +42,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.234 2002/03/19 10:49:35 markus Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.235 2002/03/20 19:12:25 stevesk Exp $");
 
 #include <openssl/dh.h>
 #include <openssl/bn.h>
@@ -521,6 +521,7 @@ privsep_preauth_child(void)
 {
         u_int32_t rand[256];
         int i;
+        struct passwd *pw;
 
         /* Enable challenge-response authentication for privilege separation */
         privsep_challenge_enable();
@@ -532,6 +533,11 @@ privsep_preauth_child(void)
         /* Demote the private keys to public keys. */
         demote_sensitive_data();
 
+        if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
+                fatal("%s: no user", 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,
@@ -540,10 +546,9 @@ privsep_preauth_child(void)
                 fatal("chdir(/)");
 
         /* Drop our privileges */
-        setegid(options.unprivileged_group);
-        setgid(options.unprivileged_group);
-        seteuid(options.unprivileged_user);
-        setuid(options.unprivileged_user);
+        debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
+            (u_int)pw->pw_gid);
+        do_setusercontext(pw);
 }
 
 static void