NFS: Remove superfluous kmap in nfs_readdir_xdr_to_array

Array is mapped by nfs_readdir_get_array(), the further kmap is a result
of a bad merge and should be removed.

This resource leakage can be exploited for DoS by receptively reading
a content of a directory on NFS (e.g. by running ls).

Fixes: 67a56e9743171 ("NFS: Fix memory leaks and corruption in readdir")
Signed-off-by: Petr Malat <oss@malat.biz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index c2665d9..2517fcd 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -678,8 +678,6 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
                goto out_label_free;
        }
 
-       array = kmap(page);
-
        status = nfs_readdir_alloc_pages(pages, array_size);
        if (status < 0)
                goto out_release_array;