| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 36/68] locks: use file_inode() | Date | Mon, 8 Aug 2016 21:11:11 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Miklos Szeredi <mszeredi@redhat.com>
commit 6343a2120862f7023006c8091ad95c1f16a32077 upstream.
(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> Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/locks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/locks.c +++ b/fs/locks.c @@ -1602,7 +1602,7 @@ generic_add_lease(struct file *filp, lon { 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;
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