> From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > Sent: Tuesday, July 27, 2021 6:13 PM > On Tue, Jul 27, 2021 at 04:09:37PM +0000, Roberto Sassu wrote: > > > From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > > > Sent: Tuesday, July 27, 2021 5:44 PM > > > On Tue, Jul 27, 2021 at 03:35:16PM +0000, Roberto Sassu wrote: > > > > > From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > > > > > Sent: Tuesday, July 27, 2021 4:44 PM > > > > > On Mon, Jul 26, 2021 at 06:36:50PM +0200, Roberto Sassu wrote: > > > > > > --- /dev/null > > > > > > +++ b/include/uapi/linux/diglim.h > > > > > > @@ -0,0 +1,51 @@ > > > > > > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ > > > > > > +/* > > > > > > + * Copyright (C) 2017-2021 Huawei Technologies Duesseldorf GmbH > > > > > > + * > > > > > > + * Author: Roberto Sassu <roberto.sassu@xxxxxxxxxx> > > > > > > + * > > > > > > + * DIGLIM definitions exported to user space, useful for generating > > > digest > > > > > > + * lists. > > > > > > + */ > > > > > > + > > > > > > +#ifndef _UAPI__LINUX_DIGLIM_H > > > > > > +#define _UAPI__LINUX_DIGLIM_H > > > > > > + > > > > > > +#include <linux/types.h> > > > > > > +#include <linux/hash_info.h> > > > > > > + > > > > > > +enum compact_types { COMPACT_KEY, COMPACT_PARSER, > > > > > COMPACT_FILE, > > > > > > + COMPACT_METADATA, COMPACT_DIGEST_LIST, > > > > > COMPACT__LAST }; > > > > > > + > > > > > > +enum compact_modifiers { COMPACT_MOD_IMMUTABLE, > > > > > COMPACT_MOD__LAST }; > > > > > > + > > > > > > +enum compact_actions { COMPACT_ACTION_IMA_MEASURED, > > > > > > + COMPACT_ACTION_IMA_APPRAISED, > > > > > > + COMPACT_ACTION_IMA_APPRAISED_DIGSIG, > > > > > > + COMPACT_ACTION__LAST }; > > > > > > + > > > > > > +enum ops { DIGEST_LIST_ADD, DIGEST_LIST_DEL, > > > DIGEST_LIST_OP__LAST }; > > > > > > + > > > > > > +/** > > > > > > + * struct compact_list_hdr - header of the following concatenated > > > digests > > > > > > + * @version: version of the digest list > > > > > > + * @_reserved: field reserved for future use > > > > > > + * @type: type of digest list among enum compact_types > > > > > > + * @modifiers: additional attributes among (1 << enum > > > compact_modifiers) > > > > > > > > > > I do not understand this description, what does it mean? > > > > > > > > Hi Greg > > > > > > > > yes, it is not very clear. > > > > > > > > @modifiers is a bitmask where each bit corresponds to a different > > > > attribute. enum compact_modifiers defines which bit position is > > > > assigned to each attribute. > > > > > > Watch out with endian issues and bitmasks... Anyway, please document > > > this. > > > > > > > > > > > > > + * @algo: digest algorithm > > > > > > > > > > Is this also a #define or an enum? Where is the list of them? > > > > > > > > @algo is an enum defined in include/uapi/linux/hash_info.h. > > > > > > Please say that. > > > > > > > > > + * @count: number of digests > > > > > > + * @datalen: length of concatenated digests > > > > > > > > > > Where does this count and length come into play as nothing else is in > > > > > this structure? > > > > > > > > Each digest list must begin with this structure. From it, the parser knows > > > > how much data it should expect afterwards. After the data, there could > be > > > > another or more blocks of this structure and following data. > > > > > > Ah, that was not obvious at all :) > > > > > > Why do you not have a __u8 data[]; type field as the last one here for > > > that memory so you can access it easier? > > > > After the digest list is parsed, I'm accessing the digest with the offset from > > the beginning of the digest list. If the offset was relative to the header, it > could > > have been useful. I could add the new field, but I'm afraid of the > incompatibility > > with existing tools that we have. > > What tools? This isn't a feature in the kernel yet, so we have no > legacy to support, right? Yes, right. We shouldn't be limited by previously written code. Thanks Roberto HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Li Jian, Shi Yanli > thanks, > > greg k-h
