in set_perms(), always call setuid(0) before changing the ruid/euid

so we always know it will succeed.

diff --git a/sudo.c b/sudo.c
index bf72ea2a8296d262bcfdf4f0bd3ceaadc8a07836..3480a774daa0498a074250d7d9ad54254b8663b9 100644 (file)
--- a/sudo.c
+++ b/sudo.c
@@ -893,43 +893,35 @@ set_perms(perm, sudo_mode)
 {
     struct passwd *pw;
 
-    switch (perm) {
-       case PERM_ROOT:
-                               if (setuid(0)) {
-                                   perror("setuid(0)");
-                                   exit(1);
-                               }
-                               break;
+    /*
+     * First, set real & effective uids to root.
+     * If perm is PERM_ROOT then we don't need to do anything else.
+     */
+    if (setuid(0)) {
+       perror("setuid(0)");
+       exit(1);
+    }
 
+    switch (perm) {
        case PERM_USER:
                                (void) setgid(user_gid);
 
-                               if (geteuid() != user_uid && seteuid(user_uid)) {
+                               if (seteuid(user_uid)) {
                                    perror("seteuid(user_uid)");
                                    exit(1);
                                }
                                break;
                                
        case PERM_FULL_USER:
-                               if (setuid(0)) {
-                                   perror("setuid(0)");
-                                   exit(1);
-                               }
-
                                (void) setgid(user_gid);
 
                                if (setuid(user_uid)) {
                                    perror("setuid(user_uid)");
                                    exit(1);
                                }
-
                                break;
+
        case PERM_RUNAS:
-                               if (setuid(0)) {
-                                   perror("setuid(0)");
-                                   exit(1);
-                               }
-                               
                                /* XXX - add group/gid support */
                                if (**user_runas == '#') {
                                    if (setuid(atoi(*user_runas + 1))) {
@@ -991,14 +983,9 @@ set_perms(perm, sudo_mode)
                                    if (sudo_mode & MODE_RESET_HOME)
                                        runas_homedir = pw->pw_dir;
                                }
-
                                break;
-       case PERM_SUDOERS:
-                               if (setuid(0)) {
-                                   perror("setuid(0)");
-                                   exit(1);
-                               }
 
+       case PERM_SUDOERS:
                                if (setgid(SUDOERS_GID)) {
                                    perror("setgid(SUDOERS_GID)");
                                    exit(1);
@@ -1022,7 +1009,6 @@ set_perms(perm, sudo_mode)
                                        exit(1);
                                    }
                                }
-
                                break;
     }
 }