From fe3b81b446d4ecb954f1b9dd191164a78fd278ad Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 4 Apr 2017 17:08:42 -0700 Subject: [PATCH] NFS: Use ERR_CAST() to avoid cross-structure cast When the call to nfs_devname() fails, the error path attempts to retain the error via the mnt variable, but this requires a cast across very different types (char * to struct vfsmount *), which the upcoming structure layout randomization plugin flags as being potentially dangerous in the face of randomization. This is a false positive, but what this code actually wants to do is retain the error value, so this patch explicitly sets it, instead of using what seems to be an unexpected cast. Signed-off-by: Kees Cook Acked-by: Trond Myklebust Reviewed-by: Christoph Hellwig --- fs/nfs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index 1a224a33a6c2..e5686be67be8 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -246,7 +246,7 @@ struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh, devname = nfs_devname(dentry, page, PAGE_SIZE); if (IS_ERR(devname)) - mnt = (struct vfsmount *)devname; + mnt = ERR_CAST(devname); else mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata); -- 2.20.1