Re: [RFC][PATCH 04/12] digest_lists: Objects
flat view
From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-06-27 10:56:21
Also in:
linux-integrity, linux-kselftest, linux-security-module, lkml
On Fri, Jun 25, 2021 at 06:56:06PM +0200, Roberto Sassu wrote:
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+++ b/security/integrity/digest_lists/digest_lists.h@@ -0,0 +1,117 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2005,2006,2007,2008 IBM Corporation + * Copyright (C) 2017-2021 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu <roberto.sassu@huawei.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + * + * File: digest_lists.h + * Unexported definitions for digest lists.
Unexported to whom?
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+ */ + +#ifndef __DIGEST_LISTS_INTERNAL_H +#define __DIGEST_LISTS_INTERNAL_H + +#include <linux/types.h> +#include <linux/crypto.h> +#include <linux/fs.h> +#include <linux/security.h> +#include <linux/hash.h> +#include <linux/tpm.h> +#include <linux/audit.h> +#include <crypto/hash_info.h> +#include <linux/hash_info.h> +#include <uapi/linux/digest_lists.h> + +#define MAX_DIGEST_SIZE 64 +#define HASH_BITS 10 +#define MEASURE_HTABLE_SIZE (1 << HASH_BITS) + +struct digest_list_item { + loff_t size; + u8 *buf; + u8 actions; + u8 digest[64]; + enum hash_algo algo; + const char *label; +}; + +struct digest_list_item_ref { + struct digest_list_item *digest_list; + loff_t digest_offset; + loff_t hdr_offset; +}; + +struct digest_item { + /* hash table pointers */ + struct hlist_node hnext; + /* digest list references (protected by RCU) */ + struct digest_list_item_ref *refs; +}; + +struct h_table { + atomic_long_t len;
Why is this atomic? Why would that matter?
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+ struct hlist_head queue[MEASURE_HTABLE_SIZE]; +}; + +static inline unsigned int hash_key(u8 *digest) +{ + return (digest[0] | digest[1] << 8) % MEASURE_HTABLE_SIZE; +}
Don't we have hashing functions in the kernel already?
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+ +static inline struct compact_list_hdr *get_hdr( + struct digest_list_item *digest_list, + loff_t hdr_offset) +{ + return (struct compact_list_hdr *)(digest_list->buf + hdr_offset); +}
pointer math feels rough, are you shure you want to do this this way? thanks, greg k-h