| Message ID | 1467377767-12845-1-git-send-email-mszeredi@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 01, 2016 at 09:05:10AM -0400, Jeff Layton wrote: > 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 <eguan@redhat.com> > > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> > > Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") > > Cc: <stable@vger.kernel.org> > > Cc: Jeff Layton <jlayton@poochiereds.net> > > Cc: "J. Bruce Fields" <bfields@fieldses.org> > > --- > > 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 <jlayton@redhat.com> I'll take it and pass it along in a pull request later today, unless somebody tells me otherwise. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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;
(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 <eguan@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Cc: <stable@vger.kernel.org> Cc: Jeff Layton <jlayton@poochiereds.net> Cc: "J. Bruce Fields" <bfields@fieldses.org> --- fs/locks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)