Messages in this thread Patch in this message | | | Date | Tue, 4 Apr 2017 17:12:06 -0700 | From | Kees Cook <> | Subject | [PATCH] NFS: Avoid cross-structure casting |
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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 <keescook@chromium.org> --- fs/nfs/namespace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index 786f17580582..89f50bf12f52 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -259,9 +259,10 @@ struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh, if (page == NULL) goto out; devname = nfs_devname(dentry, page, PAGE_SIZE); - mnt = (struct vfsmount *)devname; - if (IS_ERR(devname)) + if (IS_ERR(devname)) { + mnt = ERR_PTR(PTR_ERR(devname)); goto free_page; + } mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata); free_page: free_page((unsigned long)page); -- 2.7.4
-- Kees Cook Pixel Security
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