> From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > Sent: Sunday, June 27, 2021 12:56 PM > On Fri, Jun 25, 2021 at 06:56:06PM +0200, Roberto Sassu wrote: > > +++ 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@xxxxxxxxxx> > > + * > > + * 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? Hi Greg I meant not placed in include/linux. > > + */ > > + > > +#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? Yes, it shouldn't be. There are not concurrent updates. > > + 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? We had a discussion before: https://lore.kernel.org/linux-integrity/1587739544.5190.14.camel@xxxxxxxxxxxxx/ It seems there is no real advantage in hashing a digest. > > + > > +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? Maybe, I could change digest_list_item_ref to: struct digest_list_item_ref { struct digest_list_item *digest_list; u8 *digest; struct compact_list_hdr *hdr; }; where digest and hdr are calculated in the same way. Or you have a different suggestion? Thanks Roberto HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Li Jian, Shi Yanli > thanks, > > greg k-h
