lib: Fix privs when using HAVE_CAPABILITIES

If your daemon does not need any special privileges
and you are compiling with HAVE_CAPABILIES, the
zprivs->change pointer will end up NULL due
to the way zprivs_caps_init.  So as a check
let's add a NULL check for zprivs->change
and set it to a function that will do nothing.

This change prevents a crash if you raise privileges
when your daemon needs no special privileges.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

diff --git a/lib/privs.c b/lib/privs.c
index cfe7d6d6f81bdf802191e2559f1438ab7c985e98..7c99742d3407bf3454b30ac2c50436b226a8d79f 100644 (file)
--- a/lib/privs.c
+++ b/lib/privs.c
@@ -824,6 +824,19 @@ void zprivs_init(struct zebra_privs_t *zprivs)
 
 #ifdef HAVE_CAPABILITIES
        zprivs_caps_init(zprivs);
+
+       /*
+        * If we have initialized the system with no requested
+        * capabilities, change will not have been set
+        * to anything by zprivs_caps_init, As such
+        * we should make sure that when we attempt
+        * to raize privileges that we actually have
+        * a do nothing function to call instead of a
+        * crash :).
+        */
+       if (!zprivs->change)
+               zprivs->change = zprivs_change_null;
+
 #else  /* !HAVE_CAPABILITIES */
        /* we dont have caps. we'll need to maintain rid and saved uid
         * and change euid back to saved uid (who we presume has all neccessary