Re: [PATCH] NFS: possible NULL pointer deref in nfs_sillyrename()

[Jesper Juhl]

On 17/08/06, Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote:
> On Thu, 2006-08-17 at 00:22 +0200, Jesper Juhl wrote:
> > The coverity checker spotted this as bug #1013.
> >
> > If we get a NULL dentry->d_inode, then regardless of
> > NFS_PARANOIA or no NFS_PARANOIA, then if
> >    if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
> > turns out to be false we'll end up dereferencing
> > that NULL d_inode in two places below.
> >
> > And since the check for "(!dentry->d_inode)" even exists
> > (although inside #ifdef NFS_PARANOIA) I take that to mean
> > that this is a possibility.
>
> Sorry, but it isn't possible. See the checks in may_delete() (which is
> called before ->unlink()) and nfs_rename().
Thanks, that was useful info.

> IOW: Feel free to kill the NFS_PARANOIA crap. It looks like legacy code
> from a debugging session about a decade or so ago.
Sure thing, I'll cook up a patch to do that.

--
Jesper Juhl <jesper.juhl@xxxxxxxxx>
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