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* gcc-plugins: randstruct: Remove GCC 4.7 or newer requirementThorsten Blum2024-08-051-4/+0
| | | | | | | | | Since the kernel currently requires GCC 5.1 as a minimum, remove the unnecessary GCC version >= 4.7 check. Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com> Link: https://lore.kernel.org/r/20240723165332.1947-1-thorsten.blum@toblux.com Signed-off-by: Kees Cook <kees@kernel.org>
* gcc-plugins: Remove duplicate included header file stringpool.hThorsten Blum2024-07-081-5/+0
| | | | | | | | | | | | | | | | | | | | | | The header file stringpool.h is included for GCC version >= 8 and then again for all versions. Since the header file stringpool.h was added in GCC 4.9 and the kernel currently requires GCC 5.1 as a minimum, remove the conditional include. Including the header file only once removes the following warning reported by make includecheck: stringpool.h is included more than once However, it's important to include stringpool.h before attribs.h because attribs.h uses some of its functions. Compile-tested with GCC 14. Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com> Link: https://lore.kernel.org/r/20240629233608.278028-2-thorsten.blum@toblux.com Signed-off-by: Kees Cook <kees@kernel.org>
* gcc-plugins/stackleak: Avoid .head.text sectionArd Biesheuvel2024-04-031-0/+2
| | | | | | | | | | | | | | The .head.text section carries the startup code that runs with the MMU off or with a translation of memory that deviates from the ordinary one. So avoid instrumentation with the stackleak plugin, which already avoids .init.text and .noinstr.text entirely. Fixes: 48204aba801f1b51 ("x86/sme: Move early SME kernel encryption handling into .head.text") Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202403221630.2692c998-oliver.sang@intel.com Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20240328064256.2358634-2-ardb+git@google.com Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: randstruct: Update code comment in relayout_struct()Gustavo A. R. Silva2023-11-281-2/+1
| | | | | | | | | | | | Update code comment to clarify that the only element whose layout is not randomized is a proper C99 flexible-array member. This update is complementary to commit 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays") Signed-off-by: "Gustavo A. R. Silva" <gustavoars@kernel.org> Link: https://lore.kernel.org/r/ZWJr2MWDjXLHE8ap@work Fixes: 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays") Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: latent_entropy: Fix typo (args -> argc) in plugin descriptionKonstantin Runov2023-11-141-2/+2
| | | | | | | | | Fix the typo in the plugin description comment. Clearly, "argc" should be used. Signed-off-by: Konstantin Runov <runebone1@gmail.com> Link: https://lore.kernel.org/r/20231030094508.245432-1-runebone1@gmail.com Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: randstruct: Only warn about true flexible arraysKees Cook2023-11-081-10/+0
| | | | | | | | | | | | | | | | | | | | The randstruct GCC plugin tried to discover "fake" flexible arrays to issue warnings about them in randomized structs. In the future LSM overhead reduction series, it would be legal to have a randomized struct with a 1-element array, and this should _not_ be treated as a flexible array, especially since commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3"). Disable the 0-sized and 1-element array discovery logic in the plugin, but keep the "true" flexible array check. Cc: KP Singh <kpsingh@kernel.org> Cc: linux-hardening@vger.kernel.org Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202311021532.iBwuZUZ0-lkp@intel.com/ Fixes: df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3") Reviewed-by: Bill Wendling <morbo@google.com> Acked-by: "Gustavo A. R. Silva" <gustavoars@kernel.org> Link: https://lore.kernel.org/r/20231104204334.work.160-kees@kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* randstruct: Fix gcc-plugin performance mode to stay in groupKees Cook2023-10-091-3/+8
| | | | | | | | | | | | | The performance mode of the gcc-plugin randstruct was shuffling struct members outside of the cache-line groups. Limit the range to the specified group indexes. Cc: linux-hardening@vger.kernel.org Cc: stable@vger.kernel.org Reported-by: Lukas Loidolt <e1634039@student.tuwien.ac.at> Closes: https://lore.kernel.org/all/f3ca77f0-e414-4065-83a5-ae4c4d25545d@student.tuwien.ac.at Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: Rename last_stmt() for GCC 14+Kees Cook2023-08-111-0/+4
| | | | | | | | In GCC 14, last_stmt() was renamed to last_nondebug_stmt(). Add a helper macro to handle the renaming. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* Merge branch 'for-linus/hardening' into for-next/hardeningKees Cook2023-02-021-2/+2
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| * gcc-plugins: Reorganize gimple includes for GCC 13Kees Cook2023-01-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | The gimple-iterator.h header must be included before gimple-fold.h starting with GCC 13. Reorganize gimple headers to work for all GCC versions. Reported-by: Palmer Dabbelt <palmer@rivosinc.com> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/all/20230113173033.4380-1-palmer@rivosinc.com/ Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* | gcc-plugins: drop -std=gnu++11 to fix GCC 13 buildSam James2023-02-021-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | The latest GCC 13 snapshot (13.0.1 20230129) gives the following: ``` cc1: error: cannot load plugin ./scripts/gcc-plugins/randomize_layout_plugin.so :./scripts/gcc-plugins/randomize_layout_plugin.so: undefined symbol: tree_code_type ``` This ends up being because of https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=b0241ce6e37031 upstream in GCC which changes the visibility of some types used by the kernel's plugin infrastructure like tree_code_type. After discussion with the GCC folks, we found that the kernel needs to be building plugins with the same flags used to build GCC - and GCC defaults to gnu++17 right now. The minimum GCC version needed to build the kernel is GCC 5.1 and GCC 5.1 already defaults to gnu++14 anyway, so just drop the flag, as all GCCs that could be used to build GCC already default to an acceptable version which was >= the version we forced via flags until now. Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108634 Signed-off-by: Sam James <sam@gentoo.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230201230009.2252783-1-sam@gentoo.org
* treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_385.RULEThomas Gleixner2022-06-103-3/+3
| | | | | | | | | | | | | | | | Based on the normalized pattern: licensed under the gpl v2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference. Reviewed-by: Allison Randal <allison@lohutok.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* gcc-plugins: use KERNELVERSION for plugin versionMasahiro Yamada2022-05-246-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 61f60bac8c05 ("gcc-plugins: Change all version strings match kernel") broke parallel builds. Instead of adding the dependency between GCC plugins and utsrelease.h, let's use KERNELVERSION, which does not require any build artifact. Another reason why I want to avoid utsrelease.h is because it depends on CONFIG_LOCALVERSION(_AUTO) and localversion* files. (include/generated/utsrelease.h depends on include/config/kernel.release, which is generated by scripts/setlocalversion) I want to keep host tools independent of the kernel configuration. There is no good reason to rebuild GCC plugins just because of CONFIG_LOCALVERSION being changed. We just want to associate the plugin versions with the kernel source version. KERNELVERSION should be enough for our purpose. Fixes: 61f60bac8c05 ("gcc-plugins: Change all version strings match kernel") Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/linux-mm/202205230239.EZxeZ3Fv-lkp@intel.com Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220524135541.1453693-1-masahiroy@kernel.org
* gcc-plugins: randstruct: Remove cast exception handlingKees Cook2022-05-171-76/+3
| | | | | | | | | | | With all randstruct exceptions removed, remove all the exception handling code. Any future warnings are likely to be shared between this plugin and Clang randstruct, and will need to be addressed in a more wholistic fashion. Cc: Christoph Hellwig <hch@infradead.org> Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* af_unix: Silence randstruct GCC plugin warningKees Cook2022-05-171-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | While preparing for Clang randstruct support (which duplicated many of the warnings the randstruct GCC plugin warned about), one strange one remained only for the randstruct GCC plugin. Eliminating this rids the plugin of the last exception. It seems the plugin is happy to dereference individual members of a cross-struct cast, but it is upset about casting to a whole object pointer. This only manifests in one place in the kernel, so just replace the variable with individual member accesses. There is no change in executable instruction output. Drop the last exception from the randstruct GCC plugin. Cc: "David S. Miller" <davem@davemloft.net> Cc: Christoph Hellwig <hch@infradead.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Cong Wang <cong.wang@bytedance.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: netdev@vger.kernel.org Cc: linux-hardening@vger.kernel.org Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Link: https://lore.kernel.org/lkml/20220511022217.58586-1-kuniyu@amazon.co.jp Acked-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/lkml/20220511151542.4cb3ff17@kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* niu: Silence randstruct warningsKees Cook2022-05-171-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clang randstruct gets upset when it sees struct addresspace (which is randomized) being assigned to a struct page (which is not randomized): drivers/net/ethernet/sun/niu.c:3385:12: error: casting from randomized structure pointer type 'struct address_space *' to 'struct page *' *link = (struct page *) page->mapping; ^ It looks like niu.c is looking for an in-line place to chain its allocated pages together and is overloading the "mapping" member, as it is unused. This is very non-standard, and is expected to be cleaned up in the future[1], but there is no "correct" way to handle it today. No meaningful machine code changes result after this change, and source readability is improved. Drop the randstruct exception now that there is no "confusing" cross-type assignment. [1] https://lore.kernel.org/lkml/YnqgjVoMDu5v9PNG@casper.infradead.org/ Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Du Cheng <ducheng2@gmail.com> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Nathan Chancellor <nathan@kernel.org> Cc: netdev@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-hardening@vger.kernel.org Acked-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/lkml/20220511151647.7290adbe@kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* big_keys: Use struct for internal payloadKees Cook2022-05-171-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | The randstruct GCC plugin gets upset when it sees struct path (which is randomized) being assigned from a "void *" (which it cannot type-check). There's no need for these casts, as the entire internal payload use is following a normal struct layout. Convert the enum-based void * offset dereferencing to the new big_key_payload struct. No meaningful machine code changes result after this change, and source readability is improved. Drop the randstruct exception now that there is no "confusing" cross-type assignment. Cc: David Howells <dhowells@redhat.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: linux-hardening@vger.kernel.org Cc: keyrings@vger.kernel.org Cc: linux-security-module@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: Change all version strings match kernelKees Cook2022-05-116-9/+10
| | | | | | | | | | It's not meaningful for the GCC plugins to track their versions separately from the rest of the kernel. Switch all versions to the kernel version. Fix mismatched indenting while we're at it. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* randstruct: Move seed generation into scripts/basic/Kees Cook2022-05-082-14/+10
| | | | | | | | | | | | To enable Clang randstruct support, move the structure layout randomization seed generation out of scripts/gcc-plugins/ into scripts/basic/ so it happens early enough that it can be used by either compiler implementation. The gcc-plugin still builds its own header file, but now does so from the common "randstruct.seed" file. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-6-keescook@chromium.org
* randstruct: Reorganize Kconfigs and attribute macrosKees Cook2022-05-081-38/+0
| | | | | | | | | | | | In preparation for Clang supporting randstruct, reorganize the Kconfigs, move the attribute macros, and generalize the feature to be named CONFIG_RANDSTRUCT for on/off, CONFIG_RANDSTRUCT_FULL for the full randomization mode, and CONFIG_RANDSTRUCT_PERFORMANCE for the cache-line sized mode. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220503205503.3054173-4-keescook@chromium.org
* security: don't treat structure as an array of struct hlist_headBill Wendling2022-04-131-2/+0
| | | | | | | | | | | | | | | | | The initialization of "security_hook_heads" is done by casting it to another structure pointer type, and treating it as an array of "struct hlist_head" objects. This requires an exception be made in "randstruct", because otherwise it will emit an error, reducing the effectiveness of the hardening technique. Instead of using a cast, initialize the individual struct hlist_head elements in security_hook_heads explicitly. This removes the need for the cast and randstruct exception. Signed-off-by: Bill Wendling <morbo@google.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220407175930.471870-1-morbo@google.com
* gcc-plugins: latent_entropy: use /dev/urandomJason A. Donenfeld2022-04-121-17/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While the latent entropy plugin mostly doesn't derive entropy from get_random_const() for measuring the call graph, when __latent_entropy is applied to a constant, then it's initialized statically to output from get_random_const(). In that case, this data is derived from a 64-bit seed, which means a buffer of 512 bits doesn't really have that amount of compile-time entropy. This patch fixes that shortcoming by just buffering chunks of /dev/urandom output and doling it out as requested. At the same time, it's important that we don't break the use of -frandom-seed, for people who want the runtime benefits of the latent entropy plugin, while still having compile-time determinism. In that case, we detect whether gcc's set_random_seed() has been called by making a call to get_random_seed(noinit=true) in the plugin init function, which is called after set_random_seed() is called but before anything that calls get_random_seed(noinit=false), and seeing if it's zero or not. If it's not zero, we're in deterministic mode, and so we just generate numbers with a basic xorshift prng. Note that we don't detect if -frandom-seed is being used using the documented local_tick variable, because it's assigned via: local_tick = (unsigned) tv.tv_sec * 1000 + tv.tv_usec / 1000; which may well overflow and become -1 on its own, and so isn't reliable: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105171 [kees: The 256 byte rnd_buf size was chosen based on average (250), median (64), and std deviation (575) bytes of used entropy for a defconfig x86_64 build] Fixes: 38addce8b600 ("gcc-plugins: Add latent_entropy plugin") Cc: stable@vger.kernel.org Cc: PaX Team <pageexec@freemail.hu> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220405222815.21155-1-Jason@zx2c4.com
* gcc-plugins/stackleak: Ignore .noinstr.text and .entry.textKees Cook2022-02-061-0/+4
| | | | | | | | | | | | | | | | | | The .noinstr.text section functions may not have "current()" sanely available. Similarly true for .entry.text, though such a check is currently redundant. Add a check for both. In an x86_64 defconfig build, the following functions no longer receive stackleak instrumentation: __do_fast_syscall_32() do_int80_syscall_32() do_machine_check() do_syscall_64() exc_general_protection() fixup_bad_iret() Suggested-by: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Popov <alex.popov@linux.com> Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins/stackleak: Exactly match strings instead of prefixesKees Cook2022-02-061-4/+21
| | | | | | | | | | Since STRING_CST may not be NUL terminated, strncmp() was used for check for equality. However, this may lead to mismatches for longer section names where the start matches the tested-for string. Test for exact equality by checking for the presences of NUL termination. Cc: Alexander Popov <alex.popov@linux.com> Signed-off-by: Kees Cook <keescook@chromium.org>
* Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2021-11-021-21/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM updates from Russell King: - Rejig task/thread info to place thread info in task struct - Amba bus cleanups (removing unused functions) - Handle Amba device probe without IRQ domains - Parse linux,usable-memory-range in decompressor - Mark OCRAM as read-only after initialisation - Refactor page fault handling - Fix PXN handling with LPAE kernels - Warning and build fixes from Arnd * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (32 commits) ARM: 9151/1: Thumb2: avoid __builtin_thread_pointer() on Clang ARM: 9150/1: Fix PID_IN_CONTEXTIDR regression when THREAD_INFO_IN_TASK=y ARM: 9147/1: add printf format attribute to early_print() ARM: 9146/1: RiscPC needs older gcc version ARM: 9145/1: patch: fix BE32 compilation ARM: 9144/1: forbid ftrace with clang and thumb2_kernel ARM: 9143/1: add CONFIG_PHYS_OFFSET default values ARM: 9142/1: kasan: work around LPAE build warning ARM: 9140/1: allow compile-testing without machine record ARM: 9137/1: disallow CONFIG_THUMB with ARMv4 ARM: 9136/1: ARMv7-M uses BE-8, not BE-32 ARM: 9135/1: kprobes: address gcc -Wempty-body warning ARM: 9101/1: sa1100/assabet: convert LEDs to gpiod APIs ARM: 9131/1: mm: Fix PXN process with LPAE feature ARM: 9130/1: mm: Provide die_kernel_fault() helper ARM: 9126/1: mm: Kill page table base print in show_pte() ARM: 9127/1: mm: Cleanup access_error() ARM: 9129/1: mm: Kill task_struct argument for __do_page_fault() ARM: 9128/1: mm: Refactor the __do_page_fault() ARM: imx6: mark OCRAM mapping read-only ...
| * gcc-plugins: arm-ssp: Prepare for THREAD_INFO_IN_TASK supportArd Biesheuvel2021-09-271-21/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We will be enabling THREAD_INFO_IN_TASK support for ARM, which means that we can no longer load the stack canary value by masking the stack pointer and taking the copy that lives in thread_info. Instead, we will be able to load it from the task_struct directly, by using the TPIDRURO register which will hold the current task pointer when THREAD_INFO_IN_TASK is in effect. This is much more straight-forward, and allows us to declutter this code a bit while at it. Note that this means that ARMv6 (non-v6K) SMP systems can no longer use this feature, but those are quite rare to begin with, so this is a reasonable trade off. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
* | gcc-plugins: remove duplicate include in gcc-common.hYe Guojin2021-10-211-1/+0
| | | | | | | | | | | | | | | | | | | | 'tree-ssa-operands.h' included in 'gcc-common.h' is duplicated. it's also included at line 56. Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20211019082910.998257-1-ye.guojin@zte.com.cn
* | gcc-plugins: Remove cyc_complexityKees Cook2021-10-212-85/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This plugin has no impact on the resulting binary, is disabled under COMPILE_TEST, and is not enabled on any builds I'm aware of. Additionally, given the clarified purpose of GCC plugins in the kernel, remove cyc_complexity. Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-hardening@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-doc@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20211020173554.38122-3-keescook@chromium.org
* | gcc-plugins: Explicitly document purpose and deprecation scheduleKees Cook2021-10-211-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GCC plugins should only exist when some compiler feature needs to be proven but does not exist in either GCC nor Clang. For example, if a desired feature is already in Clang, it should be added to GCC upstream. Document this explicitly. Additionally, mark the plugins with matching upstream GCC features as removable past their respective GCC versions. Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: linux-hardening@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: llvm@lists.linux.dev Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20211020173554.38122-2-keescook@chromium.org
* | gcc-plugins: remove support for GCC 4.9 and olderArd Biesheuvel2021-10-046-208/+1
|/ | | | | | | | | The minimum GCC version has been bumped to 5.1, so we can get rid of all the compatibility code for anything older than that. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210922182632.633394-1-ardb@kernel.org
* scripts: make some scripts executableMasahiro Yamada2021-08-101-0/+0
| | | | | | | | | | | | | | | | Set the x bit to some scripts to make them directly executable. Especially, scripts/checkdeclares.pl is not hooked by anyone. It should be executable since it is tedious to type 'perl scripts/checkdeclares.pl'. The original patch [1] set the x bit properly, but it was lost when it was merged as commit 21917bded72c ("scripts: a new script for checking duplicate struct declaration"). [1] https://lore.kernel.org/lkml/20210401110943.1010796-1-wanjiabing@vivo.com/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* .gitignore: prefix local generated files with a slashMasahiro Yamada2021-05-011-1/+1
| | | | | | | | | | | | The pattern prefixed with '/' matches files in the same directory, but not ones in sub-directories. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Andra Paraschiv <andraprs@amazon.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Gabriel Krisman Bertazi <krisman@collabora.com>
* kbuild: rebuild GCC plugins when the compiler is upgradedMasahiro Yamada2021-03-111-0/+1
| | | | | | | | | | | | | | | | | | | | | Linus reported a build error due to the GCC plugin incompatibility when the compiler is upgraded. [1] GCC plugins are tied to a particular GCC version. So, they must be rebuilt when the compiler is upgraded. This seems to be a long-standing flaw since the initial support of GCC plugins. Extend commit 8b59cd81dc5e ("kbuild: ensure full rebuild when the compiler is updated"), so that GCC plugins are covered by the compiler upgrade detection. [1]: https://lore.kernel.org/lkml/CAHk-=wieoN5ttOy7SnsGwZv+Fni3R6m-Ut=oxih6bbZ28G+4dw@mail.gmail.com/ Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: latent_entropy: remove unneeded semicolonJason Yan2021-03-021-1/+1
| | | | | | | | | | | Fix the following coccicheck warning: scripts/gcc-plugins/latent_entropy_plugin.c:539:2-3: Unneeded semicolon Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200418070521.10931-1-yanaijie@huawei.com
* gcc-plugins: structleak: remove unneeded variable 'ret'Jason Yan2021-03-021-2/+1
| | | | | | | | | | | | Fix the following coccicheck warning: scripts/gcc-plugins/structleak_plugin.c:177:14-17: Unneeded variable: "ret". Return "0" on line 207 Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200418070505.10715-1-yanaijie@huawei.com
* gcc-plugins: fix gcc 11 indigestion with plugins...Valdis Klētnieks2021-01-071-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Fedora Rawhide has started including gcc 11,and the g++ compiler throws a wobbly when it hits scripts/gcc-plugins: HOSTCXX scripts/gcc-plugins/latent_entropy_plugin.so In file included from /usr/include/c++/11/type_traits:35, from /usr/lib/gcc/x86_64-redhat-linux/11/plugin/include/system.h:244, from /usr/lib/gcc/x86_64-redhat-linux/11/plugin/include/gcc-plugin.h:28, from scripts/gcc-plugins/gcc-common.h:7, from scripts/gcc-plugins/latent_entropy_plugin.c:78: /usr/include/c++/11/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options. 32 | #error This file requires compiler and library support \ In fact, it works just fine with c++11, which has been in gcc since 4.8, and we now require 4.9 as a minimum. Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/82487.1609006918@turing-police
* gcc-plugins: simplify GCC plugin-dev capability testMasahiro Yamada2020-12-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linus pointed out a third of the time in the Kconfig parse stage comes from the single invocation of cc1plus in scripts/gcc-plugin.sh [1], and directly testing plugin-version.h for existence cuts down the overhead a lot. [2] This commit takes one step further to kill the build test entirely. The small piece of code was probably intended to test the C++ designated initializer, which was not supported until C++20. In fact, with -pedantic option given, both GCC and Clang emit a warning. $ echo 'class test { public: int test; } test = { .test = 1 };' | g++ -x c++ -pedantic - -fsyntax-only <stdin>:1:43: warning: C++ designated initializers only available with '-std=c++2a' or '-std=gnu++2a' [-Wpedantic] $ echo 'class test { public: int test; } test = { .test = 1 };' | clang++ -x c++ -pedantic - -fsyntax-only <stdin>:1:43: warning: designated initializers are a C++20 extension [-Wc++20-designator] class test { public: int test; } test = { .test = 1 }; ^ 1 warning generated. Otherwise, modern C++ compilers should be able to build the code, and hopefully skipping this test should not make any practical problem. Checking the existence of plugin-version.h is still needed to ensure the plugin-dev package is installed. The test code is now small enough to be embedded in scripts/gcc-plugins/Kconfig. [1] https://lore.kernel.org/lkml/CAHk-=wjU4DCuwQ4pXshRbwDCUQB31ScaeuDo1tjoZ0_PjhLHzQ@mail.gmail.com/ [2] https://lore.kernel.org/lkml/CAHk-=whK0aQxs6Q5ijJmYF1n2ch8cVFSUzU5yUM_HOjig=+vnw@mail.gmail.com/ Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201203125700.161354-1-masahiroy@kernel.org
* gcc-plugins: remove code for GCC versions older than 4.9Masahiro Yamada2020-12-0410-505/+1
| | | | | | | | | Documentation/process/changes.rst says the minimal GCC version is 4.9. Hence, BUILDING_GCC_VERSION is greater than or equal to 4009. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201202134929.99883-1-masahiroy@kernel.org
* Merge tag 'kbuild-v5.9' of ↵Linus Torvalds2020-08-091-11/+50
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - run the checker (e.g. sparse) after the compiler - remove unneeded cc-option tests for old compiler flags - fix tar-pkg to install dtbs - introduce ccflags-remove-y and asflags-remove-y syntax - allow to trace functions in sub-directories of lib/ - introduce hostprogs-always-y and userprogs-always-y syntax - various Makefile cleanups * tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled kbuild: introduce hostprogs-always-y and userprogs-always-y kbuild: sort hostprogs before passing it to ifneq kbuild: move host .so build rules to scripts/gcc-plugins/Makefile kbuild: Replace HTTP links with HTTPS ones kbuild: trace functions in subdirectories of lib/ kbuild: introduce ccflags-remove-y and asflags-remove-y kbuild: do not export LDFLAGS_vmlinux kbuild: always create directories of targets powerpc/boot: add DTB to 'targets' kbuild: buildtar: add dtbs support kbuild: remove cc-option test of -ffreestanding kbuild: remove cc-option test of -fno-stack-protector Revert "kbuild: Create directory for target DTB" kbuild: run the checker after the compiler
| * kbuild: move host .so build rules to scripts/gcc-plugins/MakefileMasahiro Yamada2020-08-091-11/+50
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The host shared library rules are currently implemented in scripts/Makefile.host, but actually GCC-plugin is the only user of them. (The VDSO .so files are built for the target by different build rules) Hence, they do not need to be treewide available. Move all the relevant build rules to scripts/gcc-plugins/Makefile. I also optimized the build steps so *.so is directly built from .c because every upstream plugin is compiled from a single source file. I am still keeping the multi-file plugin support, which Kees Cook mentioned might be needed by out-of-tree plugins. (https://lkml.org/lkml/2019/1/11/1107) If the plugin, foo.so, is compiled from two files foo.c and foo2.c, then you can do like follows: foo-objs := foo.o foo2.o Single-file plugins do not need the *-objs notation. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
* | Merge tag 'gcc-plugins-v5.9-rc1' of ↵Linus Torvalds2020-08-044-34/+220
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc plugin updates from Kees Cook: "Primarily improvements to STACKLEAK from Alexander Popov, along with some additional cleanups. - Update URLs for HTTPS scheme where available (Alexander A. Klimov) - Improve STACKLEAK code generation on x86 (Alexander Popov)" * tag 'gcc-plugins-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: gcc-plugins: Replace HTTP links with HTTPS ones gcc-plugins/stackleak: Add 'verbose' plugin parameter gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving ARM: vdso: Don't use gcc plugins for building vgettimeofday.c gcc-plugins/stackleak: Don't instrument itself
| * gcc-plugins: Replace HTTP links with HTTPS onesAlexander A. Klimov2020-07-133-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Deterministic algorithm: For each file: If not .svg: For each line: If doesn't contain `\bxmlns\b`: For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`: If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`: If both the HTTP and HTTPS versions return 200 OK and serve the same content: Replace HTTP with HTTPS. Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de> Link: https://lore.kernel.org/r/20200713135018.34708-1-grandmaster@al2klimov.de Signed-off-by: Kees Cook <keescook@chromium.org>
| * gcc-plugins/stackleak: Add 'verbose' plugin parameterAlexander Popov2020-06-241-5/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add 'verbose' plugin parameter for stackleak gcc plugin. It can be used for printing additional info about the kernel code instrumentation. For using it add the following to scripts/Makefile.gcc-plugins: gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ += -fplugin-arg-stackleak_plugin-verbose Signed-off-by: Alexander Popov <alex.popov@linux.com> Link: https://lore.kernel.org/r/20200624123330.83226-6-alex.popov@linux.com Signed-off-by: Kees Cook <keescook@chromium.org>
| * gcc-plugins/stackleak: Use asm instrumentation to avoid useless register savingAlexander Popov2020-06-241-28/+177
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel code instrumentation in stackleak gcc plugin works in two stages. At first, stack tracking is added to GIMPLE representation of every function (except some special cases). And later, when stack frame size info is available, stack tracking is removed from the RTL representation of the functions with small stack frame. There is an unwanted side-effect for these functions: some of them do useless work with caller-saved registers. As an example of such case, proc_sys_write without() instrumentation: 55 push %rbp 41 b8 01 00 00 00 mov $0x1,%r8d 48 89 e5 mov %rsp,%rbp e8 11 ff ff ff callq ffffffff81284610 <proc_sys_call_handler> 5d pop %rbp c3 retq 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 00 00 00 proc_sys_write() with instrumentation: 55 push %rbp 48 89 e5 mov %rsp,%rbp 41 56 push %r14 41 55 push %r13 41 54 push %r12 53 push %rbx 49 89 f4 mov %rsi,%r12 48 89 fb mov %rdi,%rbx 49 89 d5 mov %rdx,%r13 49 89 ce mov %rcx,%r14 4c 89 f1 mov %r14,%rcx 4c 89 ea mov %r13,%rdx 4c 89 e6 mov %r12,%rsi 48 89 df mov %rbx,%rdi 41 b8 01 00 00 00 mov $0x1,%r8d e8 f2 fe ff ff callq ffffffff81298e80 <proc_sys_call_handler> 5b pop %rbx 41 5c pop %r12 41 5d pop %r13 41 5e pop %r14 5d pop %rbp c3 retq 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1) 00 00 Let's improve the instrumentation to avoid this: 1. Make stackleak_track_stack() save all register that it works with. Use no_caller_saved_registers attribute for that function. This attribute is available for x86_64 and i386 starting from gcc-7. 2. Insert calling stackleak_track_stack() in asm: asm volatile("call stackleak_track_stack" :: "r" (current_stack_pointer)) Here we use ASM_CALL_CONSTRAINT trick from arch/x86/include/asm/asm.h. The input constraint is taken into account during gcc shrink-wrapping optimization. It is needed to be sure that stackleak_track_stack() call is inserted after the prologue of the containing function, when the stack frame is prepared. This work is a deep reengineering of the idea described on grsecurity blog https://grsecurity.net/resolving_an_unfortunate_stackleak_interaction Signed-off-by: Alexander Popov <alex.popov@linux.com> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Link: https://lore.kernel.org/r/20200624123330.83226-5-alex.popov@linux.com Signed-off-by: Kees Cook <keescook@chromium.org>
* | gcc-plugins: fix gcc-plugins directory path in documentationMasahiro Yamada2020-06-281-1/+1
|/ | | | | | | Fix typos "plgins" -> "plugins". Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
* Merge branch 'rwonce/rework' of ↵Linus Torvalds2020-06-101-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/will/linux Pull READ/WRITE_ONCE rework from Will Deacon: "This the READ_ONCE rework I've been working on for a while, which bumps the minimum GCC version and improves code-gen on arm64 when stack protector is enabled" [ Side note: I'm _really_ tempted to raise the minimum gcc version to 4.9, so that we can just say that we require _Generic() support. That would allow us to more cleanly handle a lot of the cases where we depend on very complex macros with 'sizeof' or __builtin_choose_expr() with __builtin_types_compatible_p() etc. This branch has a workaround for sparse not handling _Generic(), either, but that was already fixed in the sparse development branch, so it's really just gcc-4.9 that we'd require. - Linus ] * 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux: compiler_types.h: Use unoptimized __unqual_scalar_typeof for sparse compiler_types.h: Optimize __unqual_scalar_typeof compilation time compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long) compiler-types.h: Include naked type in __pick_integer_type() match READ_ONCE: Fix comment describing 2x32-bit atomicity gcov: Remove old GCC 3.4 support arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros READ_ONCE: Drop pointer qualifiers when reading from scalar types READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() arm64: csum: Disable KASAN for do_csum() fault_inject: Don't rely on "return value" from WRITE_ONCE() net: tls: Avoid assigning 'const' pointer to non-const pointer netfilter: Avoid assigning 'const' pointer to non-const pointer compiler/gcc: Raise minimum GCC version for kernel builds to 4.8
| * compiler/gcc: Raise minimum GCC version for kernel builds to 4.8Will Deacon2020-04-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is very rare to see versions of GCC prior to 4.8 being used to build the mainline kernel. These old compilers are also know to have codegen issues which can lead to silent miscompilation: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 Raise the minimum GCC version for kernel build to 4.8 and remove some tautological Kconfig dependencies as a consequence. Cc: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
* | gcc-plugins: remove always-false $(if ...) in MakefileMasahiro Yamada2020-05-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | This is the remnant of commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR"). The conditional $(if $(findstring /,$(p)),...) is always false because none of plugins contains '/' in the file name. Clean up the code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org>
* | gcc-common.h: Update for GCC 10Frédéric Pierret (fepitre)2020-04-132-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove "params.h" include, which has been dropped in GCC 10. Remove is_a_helper() macro, which is now defined in gimple.h, as seen when running './scripts/gcc-plugin.sh g++ g++ gcc': In file included from <stdin>:1: ./gcc-plugins/gcc-common.h:852:13: error: redefinition of ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ 852 | inline bool is_a_helper<const ggoto *>::test(const_gimple gs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ./gcc-plugins/gcc-common.h:125, from <stdin>:1: /usr/lib/gcc/x86_64-redhat-linux/10/plugin/include/gimple.h:1037:1: note: ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ previously declared here 1037 | is_a_helper <const ggoto *>::test (const gimple *gs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ Add -Wno-format-diag to scripts/gcc-plugins/Makefile to avoid meaningless warnings from error() formats used by plugins: scripts/gcc-plugins/structleak_plugin.c: In function ‘int plugin_init(plugin_name_args*, plugin_gcc_version*)’: scripts/gcc-plugins/structleak_plugin.c:253:12: warning: unquoted sequence of 2 consecutive punctuation characters ‘'-’ in format [-Wformat-diag] 253 | error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Frédéric Pierret (fepitre) <frederic.pierret@qubes-os.org> Link: https://lore.kernel.org/r/20200407113259.270172-1-frederic.pierret@qubes-os.org [kees: include -Wno-format-diag for plugin builds] Signed-off-by: Kees Cook <keescook@chromium.org>
* | gcc-plugins/stackleak: Avoid assignment for unused macro argumentKees Cook2020-04-131-3/+2
|/ | | | | | | | | | | | | | | | | With GCC version >= 8, the cgraph_create_edge() macro argument using "frequency" goes unused. Instead of assigning a temporary variable for the argument, pass the compute_call_stmt_bb_frequency() call directly as the macro argument so that it will just not be called when it is not wanted by the macros. Silences the warning: scripts/gcc-plugins/stackleak_plugin.c:54:6: warning: variable ‘frequency’ set but not used [-Wunused-but-set-variable] Now builds cleanly with gcc-7 and gcc-9. Both boot and pass STACKLEAK_ERASING LKDTM test. Signed-off-by: Kees Cook <keescook@chromium.org>