> From: Mauro Carvalho Chehab [mailto:mchehab+huawei@xxxxxxxxxx] > Sent: Wednesday, July 28, 2021 1:39 PM > Em Mon, 26 Jul 2021 18:36:51 +0200 > Roberto Sassu <roberto.sassu@xxxxxxxxxx> escreveu: > > > Define the objects to manage digest lists: > > > > - digest_list_item: a digest list loaded into the kernel; > > - digest_list_item_ref: a reference to a digest list; > > - digest_item: a digest of a digest list. > > > > Also define some helpers for the objects. More information can be found in > > Documentation/security/diglim/implementation.rst. > > > > Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx> > > --- > > .../security/diglim/implementation.rst | 105 ++++++++++++++ > > MAINTAINERS | 1 + > > security/integrity/diglim/diglim.h | 134 ++++++++++++++++++ > > 3 files changed, 240 insertions(+) > > create mode 100644 security/integrity/diglim/diglim.h > > > > diff --git a/Documentation/security/diglim/implementation.rst > b/Documentation/security/diglim/implementation.rst > > index 59a180b3bb3f..6002049612a1 100644 > > --- a/Documentation/security/diglim/implementation.rst > > +++ b/Documentation/security/diglim/implementation.rst > > @@ -95,3 +95,108 @@ with digest lists: > > > > - ``DIGEST_LIST_ADD``: the digest list is being added; > > - ``DIGEST_LIST_DEL``: the digest list is being deleted. > > + > > + > > +Objects > > +------- > > + > > +This section defines the objects to manage digest lists. > > + > > +.. kernel-doc:: security/integrity/diglim/diglim.h > > + > > +They are represented in the following class diagram: > > + > > +:: > > + > > + digest_offset, > > + hdr_offset---------------+ > > + | > > + | > > + +------------------+ | +----------------------+ > > + | digest_list_item |--- N:1 ---| digest_list_item_ref | > > + +------------------+ +----------------------+ > > + | > > + 1:N > > + | > > + +-------------+ > > + | digest_item | > > + +-------------+ > > + > > +A ``digest_list_item`` is associated to one or multiple > > +``digest_list_item_ref``, one for each digest it contains. However, > > +a ``digest_list_item_ref`` is associated to only one ``digest_list_item``, > > +as it represents a single location within a specific digest list. > > + > > +Given that a ``digest_list_item_ref`` represents a single location, it is > > +associated to only one ``digest_item``. However, a ``digest_item`` can have > > +multiple references (as it might appears multiple times within the same > > +digest list or in different digest lists, if it is duplicated). > > + > > +All digest list references are stored for a given digest, so that a query > > +result can include the OR of the modifiers and actions of each referenced > > +digest list. > > + > > +The relationship between the described objects can be graphically > > +represented as: > > + > > +:: > > Just merge "::" at the previous line (everywhere). Ok. > > + > > + Hash table +-------------+ +-------------+ > > + PARSER +-----+ | digest_item | | digest_item | > > + FILE | key |-->| |-->...-->| | > > + METADATA +-----+ |ref0|...|refN| |ref0|...|refN| > > + +-------------+ +-------------+ > > + ref0: | | refN: > > + digest_offset | +-----------------------------+ digest_offset > > + hdr_offset | | hdr_offset > > + | | > > + V V > > + +--------------------+ > > + | digest_list_item | > > + | | > > + | size, buf, actions | > > + +--------------------+ > > + ^ > > + | > > + Hash table +-------------+ +-------------+ > > + DIGEST_LIST +-----+ |ref0 | |ref0 | > > + | key |-->| |-->...-->| | > > + +-----+ | digest_item | | digest_item | > > + +-------------+ +-------------+ > > + > > +The reference for the digest of the digest list differs from the references > > +for the other digest types. ``digest_offset`` and ``hdr_offset`` are set to > > +zero, so that the digest of the digest list is retrieved from the > > +``digest_list_item`` structure directly (see ``get_digest()`` below). > > + > > +Finally, this section defines useful helpers to access a digest or the > > +header the digest belongs to. For example: > > + > > +:: > > + > > + static inline struct compact_list_hdr *get_hdr( > > + struct digest_list_item *digest_list, > > + loff_t hdr_offset) > > I would write this to avoid ending a line with an open parenthesis. You could, > for instance, write it as: > > static inline struct compact_list_hdr * > get_hdr(struct digest_list_item *digest_list, > off_t hdr_offset) > > if you also want to avoid to have a line bigger than 80 columns. Ok. > > + { > > + return (struct compact_list_hdr *)(digest_list->buf + hdr_offset); > > + } > > + > > +the header can be obtained by summing the address of the digest list buffer > > +in the ``digest_list_item`` structure with ``hdr_offset``. > > + > > +Similarly: > > + > > +:: > > + > > + static inline u8 *get_digest(struct digest_list_item *digest_list, > > + loff_t digest_offset, loff_t hdr_offset) > > + { > > + /* Digest list digest is stored in a different place. */ > > + if (!digest_offset) > > + return digest_list->digest; > > + return digest_list->buf + digest_offset; > > + } > > + > > +the digest can be obtained by summing the address of the digest list buffer > > +with ``digest_offset`` (except for the digest lists, where the digest is > > +stored in the ``digest`` field of the ``digest_list_item`` structure). > > diff --git a/MAINTAINERS b/MAINTAINERS > > index f61f5239468a..f7592d41367d 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -5462,6 +5462,7 @@ F: > Documentation/security/diglim/implementation.rst > > F: Documentation/security/diglim/index.rst > > F: Documentation/security/diglim/introduction.rst > > F: include/uapi/linux/diglim.h > > +F: security/integrity/diglim/diglim.h > > > > DIOLAN U2C-12 I2C DRIVER > > M: Guenter Roeck <linux@xxxxxxxxxxxx> > > diff --git a/security/integrity/diglim/diglim.h > b/security/integrity/diglim/diglim.h > > new file mode 100644 > > index 000000000000..578253d7e1d1 > > --- /dev/null > > +++ b/security/integrity/diglim/diglim.h > > @@ -0,0 +1,134 @@ > > +/* 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> > > + * > > + * Definitions only used inside DIGLIM. > > + */ > > + > > +#ifndef __DIGLIM_INTERNAL_H > > +#define __DIGLIM_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/diglim.h> > > + > > +#define MAX_DIGEST_SIZE 64 > > +#define HASH_BITS 10 > > +#define DIGLIM_HTABLE_SIZE (1 << HASH_BITS) > > + > > +/** > > + * struct digest_list_item - a digest list loaded into the kernel > > + * > > + * @size: size of the digest list buffer > > + * @buf: digest list buffer > > + * @digest: digest of the digest list > > + * @label: label used to identify the digest list (e.g. file name) > > + * @actions: actions performed on the digest list > > + * @algo: digest algorithm > > + */ > > +struct digest_list_item { > > + loff_t size; > > + u8 *buf; > > + u8 digest[64]; > > + const char *label; > > + u8 actions; > > + enum hash_algo algo; > > +}; > > + > > +/** > > + * struct digest_list_item_ref - a reference to a digest list > > + * > > + * @list: linked list pointers > > + * @digest_list: pointer to struct digest_list_item > > + * @digest_offset: offset of the digest in the referenced digest list > > + * @hdr_offset: offset of the header the digest refers to in the digest list > > + */ > > +struct digest_list_item_ref { > > + struct list_head list; > > + struct digest_list_item *digest_list; > > + u32 digest_offset; > > + u32 hdr_offset; > > +}; > > + > > +/** > > + * struct digest_item - a digest of a digest list > > + * > > + * @hnext: pointers of the hash table > > + * @refs: linked list of struct digest_list_item_ref > > + */ > > +struct digest_item { > > + struct hlist_node hnext; > > + struct list_head refs; > > +}; > > + > > > > +struct h_table { > > + unsigned long len; > > + struct hlist_head queue[DIGLIM_HTABLE_SIZE]; > > +}; > > + > > +static inline unsigned int hash_key(u8 *digest) > > +{ > > + return (digest[0] | digest[1] << 8) % DIGLIM_HTABLE_SIZE; > > +} > > + > > +static inline struct compact_list_hdr *get_hdr( > > + struct digest_list_item *digest_list, > > + loff_t hdr_offset) > > Same here with regards to open parenthesis. > > > +{ > > + return (struct compact_list_hdr *)(digest_list->buf + hdr_offset); > > +} > > + > > +static inline enum hash_algo get_algo(struct digest_list_item *digest_list, > > + loff_t digest_offset, loff_t hdr_offset) > > +{ > > + /* Digest list digest algorithm is stored in a different place. */ > > + if (!digest_offset) > > + return digest_list->algo; > > + > > + return get_hdr(digest_list, hdr_offset)->algo; > > +} > > + > > +static inline u8 *get_digest(struct digest_list_item *digest_list, > > + loff_t digest_offset, loff_t hdr_offset) > > +{ > > + /* Digest list digest is stored in a different place. */ > > + if (!digest_offset) > > + return digest_list->digest; > > + > > + return digest_list->buf + digest_offset; > > +} > > + > > +static inline struct compact_list_hdr *get_hdr_ref( > > + struct digest_list_item_ref *ref) > > +{ > > + return get_hdr(ref->digest_list, ref->hdr_offset); > > +} > > + > > +static inline enum hash_algo get_algo_ref(struct digest_list_item_ref *ref) > > +{ > > + /* Digest list digest algorithm is stored in a different place. */ > > + if (!ref->digest_offset) > > + return ref->digest_list->algo; > > + > > + return get_hdr_ref(ref)->algo; > > +} > > + > > +static inline u8 *get_digest_ref(struct digest_list_item_ref *ref) > > +{ > > + /* Digest list digest is stored in a different place. */ > > + if (!ref->digest_offset) > > + return ref->digest_list->digest; > > + > > + return ref->digest_list->buf + ref->digest_offset; > > +} > > I would also document the above static inline functions and > struct h_table. Ok. Thanks Roberto HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Li Jian, Shi Yanli > > +#endif /*__DIGLIM_INTERNAL_H*/ > > > > Thanks, > Mauro
