Fail when dropping root privileges is not successful.

https://bugzilla.novell.com/show_bug.cgi?id=347822
https://bugzilla.redhat.com/show_bug.cgi?id=425481

Lubomir Kundrak <lkundrak@redhat.com>

Index: src/daemon/main.c
===================================================================
--- src/daemon/main.c	(revision 2098)
+++ src/daemon/main.c	(working copy)
@@ -372,7 +372,8 @@
         pa_limit_caps();
 
         /* Drop priviliges, but keep CAP_SYS_NICE */
-        pa_drop_root();
+        if (pa_drop_root() < 0)
+            goto finish;
 
         /* After dropping root, the effective set is reset, hence,
          * let's raise it again */
@@ -443,7 +444,8 @@
              * let's give it up early */
 
             pa_drop_caps();
-            pa_drop_root();
+            if (pa_drop_root() < 0)
+                goto finish;
             suid_root = real_root = FALSE;
 
             if (conf->high_priority || conf->realtime_scheduling)
@@ -497,7 +499,8 @@
 
         if (drop)  {
             pa_drop_caps();
-            pa_drop_root();
+            if (pa_drop_root() < 0)
+                goto finish;
             suid_root = real_root = FALSE;
         }
     }
Index: src/daemon/caps.c
===================================================================
--- src/daemon/caps.c	(revision 2098)
+++ src/daemon/caps.c	(working copy)
@@ -54,27 +54,36 @@
 #ifdef HAVE_GETUID
 
 /* Drop root rights when called SUID root */
-void pa_drop_root(void) {
+int pa_drop_root(void) {
     uid_t uid = getuid();
+    int error = 0;
 
     if (uid == 0 || geteuid() != 0)
-        return;
+        return 0;
 
     pa_log_info("Dropping root priviliges.");
 
 #if defined(HAVE_SETRESUID)
-    setresuid(uid, uid, uid);
+    error += setresuid(uid, uid, uid);
 #elif defined(HAVE_SETREUID)
-    setreuid(uid, uid);
+    error += setreuid(uid, uid);
 #else
-    setuid(uid);
-    seteuid(uid);
+    error += setuid(uid);
+    error += seteuid(uid);
 #endif
+
+    if (error != 0) {
+        pa_log_error("Could not drop root priviliges.");
+        return -1;
+    }
+
+    return 0;
 }
 
 #else
 
-void pa_drop_root(void) {
+int pa_drop_root(void) {
+    return 0;
 }
 
 #endif
@@ -142,8 +151,7 @@
 }
 
 int pa_drop_caps(void) {
-    pa_drop_root();
-    return 0;
+    return pa_drop_root();
 }
 
 #endif
Index: src/daemon/caps.h
===================================================================
--- src/daemon/caps.h	(revision 2098)
+++ src/daemon/caps.h	(working copy)
@@ -24,7 +24,7 @@
   USA.
 ***/
 
-void pa_drop_root(void);
+int pa_drop_root(void);
 int pa_limit_caps(void);
 int pa_drop_caps(void);