mountd: fix segfault in add_name with newer gcc compilers

Signed-off-by: Steve Dickson <steved@redhat.com>

nfs-utils-1.3.0-mound-newgcc.patch

@@ -0,0 +1,61 @@
+From 25e83c2270b2d2966c992885faed0b79be09f474 Mon Sep 17 00:00:00 2001
+From: Jeff Layton <jlayton@poochiereds.net>
+Date: Thu, 1 May 2014 11:15:16 -0400
+Subject: [PATCH] mountd: fix segfault in add_name with newer gcc compilers
+
+I hit a segfault in add_name with a mountd built with gcc-4.9.0. Some
+NULL pointer checks got reordered such that a pointer was dereferenced
+before checking to see whether it was NULL. The problem was due to
+nfs-utils relying on undefined behavior, which tricked gcc into assuming
+that the pointer would never be NULL.
+
+At first I assumed that this was a compiler bug, but Jakub Jelinek and
+Jeff Law pointed out:
+
+"If old is NULL, then:
+
+	strncpy(new, old, cp-old);
+
+is undefined behavior (even when cp == old == NULL in that case),
+therefore gcc assumes that old is never NULL, as otherwise it would be
+invalid.
+
+Just guard
+	strncpy(new, old, cp-old);
+	new[cp-old] = 0;
+with if (old) { ... }."
+
+This patch does that. If old is NULL though, then we still need to
+ensure that new is NULL terminated, lest the subsequent strcats walk off
+the end of it.
+
+Cc: Jeff Law <law@redhat.com>
+Cc: Jakub Jelinek <jakub@redhat.com>
+Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
+Signed-off-by: Steve Dickson <steved@redhat.com>
+---
+ support/export/client.c | 8 ++++++--
+ 1 file changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/support/export/client.c b/support/export/client.c
+index dbf47b9..f85e11c 100644
+--- a/support/export/client.c
++++ b/support/export/client.c
+@@ -482,8 +482,12 @@ add_name(char *old, const char *add)
+ 		else
+ 			cp = cp + strlen(cp);
+ 	}
+-	strncpy(new, old, cp-old);
+-	new[cp-old] = 0;
++	if (old) {
++		strncpy(new, old, cp-old);
++		new[cp-old] = 0;
++	} else {
++		new[0] = 0;
++	}
+ 	if (cp != old && !*cp)
+ 		strcat(new, ",");
+ 	strcat(new, add);
+-- 
+1.9.0
+

nfs-utils.spec

@@ -2,7 +2,7 @@ Summary: NFS utilities and supporting clients and daemons for the kernel NFS ser
 Name: nfs-utils
 URL: http://sourceforge.net/projects/nfs
 Version: 1.3.0
-Release: 1.1%{?dist}
+Release: 1.2%{?dist}
 Epoch: 1
 
 # group all 32bit related archs
@@ -16,6 +16,7 @@ Source3: nfs-utils_env.sh
 
 Patch001: nfs-utils-1.3.1-rc1.patch
 Patch002: nfs-utils-1.3.0-start-statd.patch
+Patch003: nfs-utils-1.3.0-mound-newgcc.patch
 
 Patch100: nfs-utils-1.2.1-statdpath-man.patch
 Patch101: nfs-utils-1.2.1-exp-subtree-warn-off.patch
@@ -75,6 +76,7 @@ This package also contains the mount.nfs and umount.nfs program.
 
 %patch001 -p1
 %patch002 -p1
+%patch003 -p1
 
 %patch100 -p1
 %patch101 -p1
@@ -283,6 +285,9 @@ fi
 /sbin/umount.nfs4
 
 %changelog
+* Thu May  1 2014 Steve Dickson <steved@redhat.com> 1.3.0-1.2
+- mountd: fix segfault in add_name with newer gcc compilers
+
 * Thu May  1 2014 Steve Dickson <steved@redhat.com> 1.3.0-1.1
 - start-statd: rpc.statd's systemd unit changed names