On LP64 struct ifid is 64-bit aligned while struct fid is 32-bit aligned

so on architectures with strict alignment requirements we can't just simply
cast the latter to the former but need to copy it bytewise instead.

PR:		143010
MFC after:	3 days

2 files changed, 17 insertions, 10 deletions

diff --git a/sys/fs/cd9660/cd9660_vfsops.c b/sys/fs/cd9660/cd9660_vfsops.c
index b4c65e1..e27daf8 100644
--- a/sys/fs/cd9660/cd9660_vfsops.c
+++ b/sys/fs/cd9660/cd9660_vfsops.c
@@ -589,17 +589,19 @@ cd9660_fhtovp(mp, fhp, vpp)
 	struct fid *fhp;
 	struct vnode **vpp;
 {
-	struct ifid *ifhp = (struct ifid *)fhp;
+	struct ifid ifh;
 	struct iso_node *ip;
 	struct vnode *nvp;
 	int error;
 
+	memcpy(&ifh, fhp, sizeof(ifh));
+
 #ifdef	ISOFS_DBG
 	printf("fhtovp: ino %d, start %ld\n",
-	       ifhp->ifid_ino, ifhp->ifid_start);
+	    ifh.ifid_ino, ifh.ifid_start);
 #endif
 
-	if ((error = VFS_VGET(mp, ifhp->ifid_ino, LK_EXCLUSIVE, &nvp)) != 0) {
+	if ((error = VFS_VGET(mp, ifh.ifid_ino, LK_EXCLUSIVE, &nvp)) != 0) {
 		*vpp = NULLVP;
 		return (error);
 	}
diff --git a/sys/fs/cd9660/cd9660_vnops.c b/sys/fs/cd9660/cd9660_vnops.c
index 55ea46b..5f4780f 100644
--- a/sys/fs/cd9660/cd9660_vnops.c
+++ b/sys/fs/cd9660/cd9660_vnops.c
@@ -819,20 +819,25 @@ cd9660_vptofh(ap)
 		struct fid *a_fhp;
 	} */ *ap;
 {
+	struct ifid ifh;
 	struct iso_node *ip = VTOI(ap->a_vp);
-	struct ifid *ifhp;
 
-	ifhp = (struct ifid *)ap->a_fhp;
-	ifhp->ifid_len = sizeof(struct ifid);
+	ifh.ifid_len = sizeof(struct ifid);
 
-	ifhp->ifid_ino = ip->i_number;
-	ifhp->ifid_start = ip->iso_start;
+	ifh.ifid_ino = ip->i_number;
+	ifh.ifid_start = ip->iso_start;
+	/*
+	 * This intentionally uses sizeof(ifh) in order to not copy stack
+	 * garbage on ILP32.
+	 */
+	memcpy(ap->a_fhp, &ifh, sizeof(ifh));
 
 #ifdef	ISOFS_DBG
 	printf("vptofh: ino %d, start %ld\n",
-	       ifhp->ifid_ino,ifhp->ifid_start);
+	    ifh.ifid_ino, ifh.ifid_start);
 #endif
-	return 0;
+
+	return (0);
 }
 
 /*