From 322ee5b36eac42e762526b0df7fa432beba6e7a0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 15 Feb 2008 14:37:24 -0800 Subject: [PATCH] check for null vfsmount in dentry_open() Make sure no-one calls dentry_open with a NULL vfsmount argument and crap out with a stacktrace otherwise. A NULL file->f_vfsmnt has always been problematic, but with the per-mount r/o tracking we can't accept anymore at all. [AV] the last place that passed NULL had been eliminated by the previous patch (reiserfs xattr stuff) Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Al Viro --- fs/open.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'fs') diff --git a/fs/open.c b/fs/open.c index 5419853..a4b1202 100644 --- a/fs/open.c +++ b/fs/open.c @@ -903,6 +903,18 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags) int error; struct file *f; + /* + * We must always pass in a valid mount pointer. Historically + * callers got away with not passing it, but we must enforce this at + * the earliest possible point now to avoid strange problems deep in the + * filesystem stack. + */ + if (!mnt) { + printk(KERN_WARNING "%s called with NULL vfsmount\n", __func__); + dump_stack(); + return ERR_PTR(-EINVAL); + } + error = -ENFILE; f = get_empty_filp(); if (f == NULL) { -- cgit v1.1