Lose the CAP_NET_ADMIN at every fork, instead of at startup. Otherwise, if

Asterisk runs as a non-root user and the administrator does a 'restart now',
Asterisk loses the ability to set QOS on packets.
(closes issue #14004)
 Reported by: nemo
 Patches: 
       20090105__bug14004.diff.txt uploaded by Corydon76 (license 14)
 Tested by: Corydon76


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@172438 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_ices.c

@@ -25,6 +25,10 @@
  * \ingroup applications
  */
  
+/*** MODULEINFO
+	<depend>working_fork</depend>
+ ***/
+
 #include "asterisk.h"
 
 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
@@ -37,6 +41,9 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include <fcntl.h>
 #include <sys/time.h>
 #include <errno.h>
+#ifdef HAVE_CAP
+#include <sys/capability.h>
+#endif /* HAVE_CAP */
 
 #include "asterisk/lock.h"
 #include "asterisk/file.h"
@@ -65,6 +72,9 @@ static int icesencode(char *filename, int fd)
 	int res;
 	int x;
 	sigset_t fullset, oldset;
+#ifdef HAVE_CAP
+	cap_t cap;
+#endif
 
 	sigfillset(&fullset);
 	pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
@@ -81,6 +91,16 @@ static int icesencode(char *filename, int fd)
 	signal(SIGPIPE, SIG_DFL);
 	pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
 
+#ifdef HAVE_CAP
+	cap = cap_from_text("cap_net_admin-eip");
+
+	if (cap_set_proc(cap)) {
+		/* Careful with order! Logging cannot happen after we close FDs */
+		ast_log(LOG_WARNING, "Unable to remove capabilities.\n");
+	}
+	cap_free(cap);
+#endif
+
 	if (ast_opt_high_priority)
 		ast_set_priority(0);
 	dup2(fd, STDIN_FILENO);