svn commit: r332087 - head/sys/net

[Brooks Davis]

Author: brooks
Date: Thu Apr  5 21:58:28 2018
New Revision: 332087
URL: https://svnweb.freebsd.org/changeset/base/332087

Log:
  ifconf(): Always zero the whole struct ifreq.
  
  The previous split of zeroing ifr_name and ifr_addr seperately is safe
  on current architectures, but would be unsafe if pointers were larger
  than 8 bytes. Combining the zeroing adds no real cost (a few
  instructions) and makes the security property easier to verify.
  
  Reviewed by:	kib, emaste
  Obtained from:	CheriBSD
  MFC after:	3 days
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D14912

Modified:
  head/sys/net/if.c

Modified: head/sys/net/if.c
==============================================================================
--- head/sys/net/if.c	Thu Apr  5 20:31:45 2018	(r332086)
+++ head/sys/net/if.c	Thu Apr  5 21:58:28 2018	(r332087)
@@ -3129,10 +3129,10 @@ again:
 		int addrs;
 
 		/*
-		 * Zero the ifr_name buffer to make sure we don't
-		 * disclose the contents of the stack.
+		 * Zero the ifr to make sure we don't disclose the contents
+		 * of the stack.
 		 */
-		memset(ifr.ifr_name, 0, sizeof(ifr.ifr_name));
+		memset(&ifr, 0, sizeof(ifr));
 
 		if (strlcpy(ifr.ifr_name, ifp->if_xname, sizeof(ifr.ifr_name))
 		    >= sizeof(ifr.ifr_name)) {
@@ -3166,7 +3166,6 @@ again:
 		}
 		IF_ADDR_RUNLOCK(ifp);
 		if (addrs == 0) {
-			bzero((caddr_t)&ifr.ifr_addr, sizeof(ifr.ifr_addr));
 			sbuf_bcat(sb, &ifr, sizeof(ifr));
 			max_len += sizeof(ifr);