On Fri, 2016-07-01 at 14:56 +0200, Miklos Szeredi wrote: > (Another one for the f_path debacle.) > > ltp fcntl33 testcase caused an Oops in selinux_file_send_sigiotask. > > The reason is that generic_add_lease() used filp->f_path.dentry->inode > while all the others use file_inode(). This makes a difference for files > opened on overlayfs since the former will point to the overlay inode the > latter to the underlying inode. > > So generic_add_lease() added the lease to the overlay inode and > generic_delete_lease() removed it from the underlying inode. When the file > was released the lease remained on the overlay inode's lock list, resulting > in use after free. > > Reported-by: Eryu Guan <[email protected]> > Signed-off-by: Miklos Szeredi <[email protected]> > Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and > f_inode to the underlay") > Cc: <[email protected]> > Cc: Jeff Layton <[email protected]> > Cc: "J. Bruce Fields" <[email protected]> > --- > fs/locks.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/locks.c b/fs/locks.c > index 7c5f91be9b65..ee1b15f6fc13 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -1628,7 +1628,7 @@ generic_add_lease(struct file *filp, long arg, struct > file_lock **flp, void **pr > { > struct file_lock *fl, *my_fl = NULL, *lease; > struct dentry *dentry = filp->f_path.dentry; > - struct inode *inode = dentry->d_inode; > + struct inode *inode = file_inode(filp); > struct file_lock_context *ctx; > bool is_deleg = (*flp)->fl_flags & FL_DELEG; > int error;
Looks good. Al or Bruce, if either of you have remaining patches this cycle then could one of you take this one? Otherwise, I can queue up a branch with it. Reviewed-by: Jeff Layton <[email protected]>
