From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A1F4C6379F for ; Tue, 7 Feb 2023 12:58:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231727AbjBGM6H (ORCPT ); Tue, 7 Feb 2023 07:58:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229607AbjBGM6G (ORCPT ); Tue, 7 Feb 2023 07:58:06 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AE267DB1; Tue, 7 Feb 2023 04:58:05 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id C799838DBE; Tue, 7 Feb 2023 12:58:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1675774683; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=uC8rW1vgztaJvz1BqhV2czadU2bonbXSz3N1QcPJa1U=; b=egzoGaWrF7ZiPbTLSUnuRWuUOiK4NmApbxJ99o+fYrH7nIo1aXUaY1Kr3v5gct5xtt4N6Q cmQqhdOWjb7qiDgM313j3WWZUu0TSQykWy/ajQOdmv/6mQOYkRa0Iy/n6VrmjVoKL11EPS tWGIpsc6GVkbEQsucGB5jOYvk7KHsUs= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1675774683; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=uC8rW1vgztaJvz1BqhV2czadU2bonbXSz3N1QcPJa1U=; b=MxB3awFOepaml8JOfvlke7MoORYnY0pjji2cPlqapHBJJzFFrWKfCWcusBmbozj8MkEeyZ gDLGnp2TvNXPf7Ag== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 7189D13467; Tue, 7 Feb 2023 12:58:02 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 4HTcDtpK4mO1ZAAAMHmgww (envelope-from ); Tue, 07 Feb 2023 12:58:02 +0000 Date: Tue, 7 Feb 2023 09:57:59 -0300 From: Marcos Paulo de Souza To: Joe Lawrence Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org Subject: Re: [RFC PATCH v6 00/12] livepatch: klp-convert tool Message-ID: <20230207125759.xfcsnlma6ezehff7@daedalus> References: <20220216163940.228309-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220216163940.228309-1-joe.lawrence@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 16, 2022 at 11:39:28AM -0500, Joe Lawrence wrote: > This mostly a rebase update of the livepatch klp-convert tool used to > generate klp-relocation types (explained in the summary below). > > I'm marking this as an RFC as it hasn't been extensively tested for all > livepatch supported arches. There are may be a few symbol annotation > changes pending what may be implemented for the FGKASLR patchset, I've > left a few TODO and // question? marks in the code, etc. At the same > time, I think "CET/IBT support and live-patches" highlighted a potential > need for this tooling, so I'm posting it in its current format for > discussion. I'll reply to individual patches to highlight a few points > of interest. > > > Summary > ------- > > Livepatches may use symbols which are not contained in its own scope, > and, because of that, may end up compiled with relocations that will > only be resolved during module load. Yet, when the referenced symbols > are not exported, solving this relocation requires information on the > object that holds the symbol (either vmlinux or modules) and its > position inside the object, as an object may contain multiple symbols > with the same name. Providing such information must be done accordingly > to what is specified in Documentation/livepatch/module-elf-format.txt. > > Currently, there is no trivial way to embed the required information as > requested in the final livepatch elf object. klp-convert solves this > problem in two different forms: (i) by relying on a symbol map, which is > built during kernel compilation, to automatically infer the relocation > targeted symbol, and, when such inference is not possible (ii) by using > annotations in the elf object to convert the relocation accordingly to > the specification, enabling it to be handled by the livepatch loader. > > Given the above, add support for symbol mapping in the form of a > symbols.klp file; add klp-convert tool; integrate klp-convert tool into > kbuild; make livepatch modules discernible during kernel compilation > pipeline; add data-structure and macros to enable users to annotate > livepatch source code; make modpost stage compatible with livepatches; > update livepatch-sample and update documentation. > > The patch was tested under three use-cases: > > use-case 1: There is a relocation in the lp that can be automatically > resolved by klp-convert. For example. see the saved_command_line > variable in lib/livepatch/test_klp_convert2.c. > > use-case 2: There is a relocation in the lp that cannot be automatically > resolved, as the name of the respective symbol appears in multiple > objects. The livepatch contains an annotation to enable a correct > relocation. See the KLP_MODULE_RELOC / KLP_SYMPOS annotation sections > in lib/livepatch/test_klp_convert{1,2}.c. > > use-case 3: There is a relocation in the lp that cannot be automatically > resolved similarly as 2, but no annotation was provided in the > livepatch, triggering an error during compilation. Reproducible by > removing the KLP_MODULE_RELOC / KLP_SYMPOS annotation sections in > lib/livepatch/test_klp_convert{1,2}.c. > > Selftests have been added to exercise these klp-convert use-cases > through several tests. > > > Branches > -------- > > > Previous versions > ----------------- > > RFC: > https://lore.kernel.org/lkml/cover.1477578530.git.jpoimboe@redhat.com/ > v2: > https://lore.kernel.org/lkml/f52d29f7-7d1b-ad3d-050b-a9fa8878faf2@redhat.com/ > v3: > https://lore.kernel.org/lkml/20190410155058.9437-1-joe.lawrence@redhat.com/ > v4: > https://lore.kernel.org/lkml/20190509143859.9050-1-joe.lawrence@redhat.com/ > v5: > (not posted) > https://github.com/joe-lawrence/klp-convert-tree/tree/klp-convert-v5-devel > v6: > https://github.com/joe-lawrence/klp-convert-tree/tree/klp-convert-v6 > https://github.com/joe-lawrence/klp-convert-tree/tree/klp-convert-v6-devel Hi Joe, I send reviews to some patches of the v6 batch, but there is currently a v7 in your github profile. I believe that I sent Rb for patches that are the same between versions. The current version is almost one year older already. Do you plan to send v7 soon? Thanks a lot! Marcos > > > Summary of changes in v5 > ------------------------ > > [For/from Masahiro] > - rename Symbols.list to symbols.klp > - remove HOST_EXTRACFLAGS from klp-convert build > - kbuild tweaks from Masahiro Yamada > - SPDX instead of the license boilerplate > > [Joe] > - a bunch of small checkpatch, clang-check fixes > - klp-convert: account for symbols shared across sections > - klp-convert: sympos endianness for cross-compile > - klp-convert: implement rela section support list > - klp-convert: update group sections sh_link > - klp-convert: flag annotations without relocations > - klp-convert: allow .rela__jump_table to vmlinux > - livepatch/selftests: Add __asm__ symbol renaming examples > - livepatch/selftests: test multiple sections > - livepatch/selftests: add static keys test > > [Miroslav] > - klp-convert: use _safe list traversals only when required > - klp-convert: separate rela conversation from removal > > > Summary of changes in v6 > ------------------------ > > [For/from Christophe] > - klp-convert: Support for ppc32 ELF files > > [Joe] > - livepatch/selftests: add data relocations test > - klp-convert: move relas to klp_rela_sec tail > - rebase for v5.17-rc1 > > > Joao Moreira (2): > kbuild: Support for symbols.klp creation > documentation: Update on livepatch elf format > > Joe Lawrence (5): > livepatch/selftests: add klp-convert > livepatch/selftests: test multiple sections > livepatch/selftests: add __asm__ symbol renaming examples > livepatch/selftests: add data relocations test > livepatch/selftests: add static keys test > > Josh Poimboeuf (5): > livepatch: Create and include UAPI headers > livepatch: Add klp-convert tool > livepatch: Add klp-convert annotation helpers > modpost: Integrate klp-convert > livepatch: Add sample livepatch module > > .gitignore | 2 + > Documentation/dontdiff | 1 + > Documentation/livepatch/livepatch.rst | 3 + > Documentation/livepatch/module-elf-format.rst | 42 +- > MAINTAINERS | 2 + > Makefile | 12 +- > include/linux/livepatch.h | 13 + > include/uapi/linux/livepatch.h | 25 + > kernel/livepatch/core.c | 4 +- > lib/livepatch/Makefile | 12 + > lib/livepatch/test_klp_convert.h | 45 + > lib/livepatch/test_klp_convert1.c | 121 +++ > lib/livepatch/test_klp_convert2.c | 110 +++ > lib/livepatch/test_klp_convert_data.c | 190 ++++ > lib/livepatch/test_klp_convert_keys.c | 91 ++ > lib/livepatch/test_klp_convert_keys_mod.c | 52 + > lib/livepatch/test_klp_convert_mod_a.c | 31 + > lib/livepatch/test_klp_convert_mod_b.c | 19 + > lib/livepatch/test_klp_convert_mod_c.c | 36 + > lib/livepatch/test_klp_convert_sections.c | 120 +++ > samples/livepatch/Makefile | 1 + > .../livepatch/livepatch-annotated-sample.c | 93 ++ > scripts/Makefile | 1 + > scripts/Makefile.modfinal | 38 +- > scripts/Makefile.modpost | 5 + > scripts/livepatch/.gitignore | 1 + > scripts/livepatch/Makefile | 5 + > scripts/livepatch/elf.c | 813 ++++++++++++++++ > scripts/livepatch/elf.h | 74 ++ > scripts/livepatch/klp-convert.c | 885 ++++++++++++++++++ > scripts/livepatch/klp-convert.h | 47 + > scripts/livepatch/list.h | 391 ++++++++ > scripts/mod/modpost.c | 28 +- > scripts/mod/modpost.h | 1 + > .../selftests/livepatch/test-livepatch.sh | 405 ++++++++ > 35 files changed, 3708 insertions(+), 11 deletions(-) > create mode 100644 include/uapi/linux/livepatch.h > create mode 100644 lib/livepatch/test_klp_convert.h > create mode 100644 lib/livepatch/test_klp_convert1.c > create mode 100644 lib/livepatch/test_klp_convert2.c > create mode 100644 lib/livepatch/test_klp_convert_data.c > create mode 100644 lib/livepatch/test_klp_convert_keys.c > create mode 100644 lib/livepatch/test_klp_convert_keys_mod.c > create mode 100644 lib/livepatch/test_klp_convert_mod_a.c > create mode 100644 lib/livepatch/test_klp_convert_mod_b.c > create mode 100644 lib/livepatch/test_klp_convert_mod_c.c > create mode 100644 lib/livepatch/test_klp_convert_sections.c > create mode 100644 samples/livepatch/livepatch-annotated-sample.c > create mode 100644 scripts/livepatch/.gitignore > create mode 100644 scripts/livepatch/Makefile > create mode 100644 scripts/livepatch/elf.c > create mode 100644 scripts/livepatch/elf.h > create mode 100644 scripts/livepatch/klp-convert.c > create mode 100644 scripts/livepatch/klp-convert.h > create mode 100644 scripts/livepatch/list.h > > -- > 2.26.3 >