svn commit: r287345 - head/usr.bin/bluetooth/btsockstat

[Xin LI]

Author: delphij
Date: Tue Sep  1 06:28:16 2015
New Revision: 287345
URL: https://svnweb.freebsd.org/changeset/base/287345

Log:
  Drop group privileges after opening the kvm descriptor, otherwise, the code
  would not drop privileges as expected.
  
  While there also add checks for the drop and bail out immediately if we
  failed.
  
  MFC after:	3 days

Modified:
  head/usr.bin/bluetooth/btsockstat/btsockstat.c

Modified: head/usr.bin/bluetooth/btsockstat/btsockstat.c
==============================================================================
--- head/usr.bin/bluetooth/btsockstat/btsockstat.c	Tue Sep  1 06:21:12 2015	(r287344)
+++ head/usr.bin/bluetooth/btsockstat/btsockstat.c	Tue Sep  1 06:28:16 2015	(r287345)
@@ -154,9 +154,9 @@ main(int argc, char *argv[])
 	 * Discard setgid privileges if not the running kernel so that
 	 * bad guys can't print interesting stuff from kernel memory.
 	 */
-
 	if (memf != NULL)
-		setgid(getgid());
+		if (setgid(getgid()) != 0)
+			err(1, "setgid");
 
 	kvmd = kopen(memf);
 	if (kvmd == NULL)
@@ -583,15 +583,9 @@ kopen(char const *memf)
 	kvm_t	*kvmd = NULL;
 	char	 errbuf[_POSIX2_LINE_MAX];
 
-	/*
-	 * Discard setgid privileges if not the running kernel so that 
-	 * bad guys can't print interesting stuff from kernel memory.
-	 */
-
-	if (memf != NULL)
-		setgid(getgid());   
-
 	kvmd = kvm_openfiles(NULL, memf, NULL, O_RDONLY, errbuf);
+	if (setgid(getgid()) != 0)
+		err(1, "setgid");
 	if (kvmd == NULL) {
 		warnx("kvm_openfiles: %s", errbuf);
 		return (NULL);