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12 daysMerge tag 'hardening-v6.16-rc1-fix1-take2' of ↵HEADmasterLinus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening fixes from Kees Cook: - randstruct: gcc-plugin: Fix attribute addition with GCC 15 - ubsan: integer-overflow: depend on BROKEN to keep this out of CI - overflow: Introduce __DEFINE_FLEX for having no initializer - wifi: iwlwifi: mld: Work around Clang loop unrolling bug [ Take two after a jump scare due to some repo rewriting by 'b4' - Linus ] * tag 'hardening-v6.16-rc1-fix1-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: randstruct: gcc-plugin: Fix attribute addition overflow: Introduce __DEFINE_FLEX for having no initializer ubsan: integer-overflow: depend on BROKEN to keep this out of CI wifi: iwlwifi: mld: Work around Clang loop unrolling bug
12 daysrandstruct: gcc-plugin: Fix attribute additionKees Cook
Based on changes in the 2021 public version of the randstruct out-of-tree GCC plugin[1], more carefully update the attributes on resulting decls, to avoid tripping checks in GCC 15's comptypes_check_enum_int() when it has been configured with "--enable-checking=misc": arch/arm64/kernel/kexec_image.c:132:14: internal compiler error: in comptypes_check_enum_int, at c/c-typeck.cc:1519 132 | const struct kexec_file_ops kexec_image_ops = { | ^~~~~~~~~~~~~~ internal_error(char const*, ...), at gcc/gcc/diagnostic-global-context.cc:517 fancy_abort(char const*, int, char const*), at gcc/gcc/diagnostic.cc:1803 comptypes_check_enum_int(tree_node*, tree_node*, bool*), at gcc/gcc/c/c-typeck.cc:1519 ... Link: https://archive.org/download/grsecurity/grsecurity-3.1-5.10.41-202105280954.patch.gz [1] Reported-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org> Closes: https://github.com/KSPP/linux/issues/367 Closes: https://lore.kernel.org/lkml/20250530000646.104457-1-thiago.bauermann@linaro.org/ Reported-by: Ingo Saitz <ingo@hannover.ccc.de> Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1104745 Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Tested-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org> Link: https://lore.kernel.org/r/20250530221824.work.623-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
13 daysMerge tag 'gcc-minimum-version-6.16' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull compiler version requirement update from Arnd Bergmann: "Require gcc-8 and binutils-2.30 x86 already uses gcc-8 as the minimum version, this changes all other architectures to the same version. gcc-8 is used is Debian 10 and Red Hat Enterprise Linux 8, both of which are still supported, and binutils 2.30 is the oldest corresponding version on those. Ubuntu Pro 18.04 and SUSE Linux Enterprise Server 15 both use gcc-7 as the system compiler but additionally include toolchains that remain supported. With the new minimum toolchain versions, a number of workarounds for older versions can be dropped, in particular on x86_64 and arm64. Importantly, the updated compiler version allows removing two of the five remaining gcc plugins, as support for sancov and structeak features is already included in modern compiler versions. I tried collecting the known changes that are possible based on the new toolchain version, but expect that more cleanups will be possible. Since this touches multiple architectures, I merged the patches through the asm-generic tree." * tag 'gcc-minimum-version-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: Makefile.kcov: apply needed compiler option unconditionally in CFLAGS_KCOV Documentation: update binutils-2.30 version reference gcc-plugins: remove SANCOV gcc plugin Kbuild: remove structleak gcc plugin arm64: drop binutils version checks raid6: skip avx512 checks kbuild: require gcc-8 and binutils-2.30
2025-05-08randstruct: gcc-plugin: Remove bogus void memberKees Cook
When building the randomized replacement tree of struct members, the randstruct GCC plugin would insert, as the first member, a 0-sized void member. This appears as though it was done to catch non-designated ("unnamed") static initializers, which wouldn't be stable since they depend on the original struct layout order. This was accomplished by having the side-effect of the "void member" tripping an assert in GCC internals (count_type_elements) if the member list ever needed to be counted (e.g. for figuring out the order of members during a non-designated initialization), which would catch impossible type (void) in the struct: security/landlock/fs.c: In function ‘hook_file_ioctl_common’: security/landlock/fs.c:1745:61: internal compiler error: in count_type_elements, at expr.cc:7075 1745 | .u.op = &(struct lsm_ioctlop_audit) { | ^ static HOST_WIDE_INT count_type_elements (const_tree type, bool for_ctor_p) { switch (TREE_CODE (type)) ... case VOID_TYPE: default: gcc_unreachable (); } } However this is a redundant safety measure since randstruct uses the __designated_initializer attribute both internally and within the __randomized_layout attribute macro so that this would be enforced by the compiler directly even when randstruct was not enabled (via -Wdesignated-init). A recent change in Landlock ended up tripping the same member counting routine when using a full-struct copy initializer as part of an anonymous initializer. This, however, is a false positive as the initializer is copying between identical structs (and hence identical layouts). The "path" member is "struct path", a randomized struct, and is being copied to from another "struct path", the "f_path" member: landlock_log_denial(landlock_cred(file->f_cred), &(struct landlock_request) { .type = LANDLOCK_REQUEST_FS_ACCESS, .audit = { .type = LSM_AUDIT_DATA_IOCTL_OP, .u.op = &(struct lsm_ioctlop_audit) { .path = file->f_path, .cmd = cmd, }, }, ... As can be seen with the coming randstruct KUnit test, there appears to be no behavioral problems with this kind of initialization when the void member is removed from the randstruct GCC plugin, so remove it. Reported-by: "Dr. David Alan Gilbert" <linux@treblig.org> Closes: https://lore.kernel.org/lkml/Z_PRaKx7q70MKgCA@gallifrey/ Reported-by: Mark Brown <broonie@kernel.org> Closes: https://lore.kernel.org/lkml/20250407-kbuild-disable-gcc-plugins-v1-1-5d46ae583f5e@kernel.org/ Reported-by: WangYuli <wangyuli@uniontech.com> Closes: https://lore.kernel.org/lkml/337D5D4887277B27+3c677db3-a8b9-47f0-93a4-7809355f1381@uniontech.com/ Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Signed-off-by: Kees Cook <kees@kernel.org>
2025-05-08gcc-plugins: Force full rebuild when plugins changeKees Cook
There was no dependency between the plugins changing and the rest of the kernel being built. This could cause strange behaviors as instrumentation could vary between targets depending on when they were built. Generate a new header file, gcc-plugins.h, any time the GCC plugins change. Include the header file in compiler-version.h when its associated feature name, GCC_PLUGINS, is defined. This will be picked up by fixdep and force rebuilds where needed. Add a generic "touch" kbuild command, which will be used again in a following patch. Add a "normalize_path" string helper to make the "TOUCH" output less ugly. Link: https://lore.kernel.org/r/20250503184623.2572355-1-kees@kernel.org Tested-by: Nicolas Schier <n.schier@avm.de> Reviewed-by: Nicolas Schier <n.schier@avm.de> Signed-off-by: Kees Cook <kees@kernel.org>
2025-04-30gcc-plugins: remove SANCOV gcc pluginArnd Bergmann
With the minimum gcc version raised to 8.1, all supported compilers now understand the -fsanitize-coverage=trace-pc option, and there is no longer a need for the separate compiler plugin. Since only gcc-5 was able to use the plugin for several year now, it was already likely unused. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-04-30Kbuild: remove structleak gcc pluginArnd Bergmann
gcc-12 and higher support the -ftrivial-auto-var-init= flag, after gcc-8 is the minimum version, this is half of the supported ones, and the vast majority of the versions that users are actually likely to have, so it seems like a good time to stop having the fallback plugin implementation Older toolchains are still able to build kernels normally without this plugin, but won't be able to use variable initialization.. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-04-30kbuild: require gcc-8 and binutils-2.30Arnd Bergmann
Commit a3e8fe814ad1 ("x86/build: Raise the minimum GCC version to 8.1") raised the minimum compiler version as enforced by Kbuild to gcc-8.1 and clang-15 for x86. This is actually the same gcc version that has been discussed as the minimum for all architectures several times in the past, with little objection. A previous concern was the kernel for SLE15-SP7 needing to be built with gcc-7. As this ended up still using linux-6.4 and there is no plan for an SP8, this is no longer a problem. Change it for all architectures and adjust the documentation accordingly. A few version checks can be removed in the process. The binutils version 2.30 is the lowest version used in combination with gcc-8 on common distros, so use that as the corresponding minimum. Link: https://lore.kernel.org/lkml/20240925150059.3955569-32-ardb+git@google.com/ Link: https://lore.kernel.org/lkml/871q7yxrgv.wl-tiwai@suse.de/ Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2025-04-28gcc-plugins: Remove ARM_SSP_PER_TASK pluginKees Cook
As part of trying to remove GCC plugins from Linux, drop the ARM_SSP_PER_TASK plugin. The feature is available upstream since GCC 12, so anyone needing newer kernels with per-task ssp can update their compiler[1]. Suggested-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/all/08393aa3-05a3-4e3f-8004-f374a3ec4b7e@app.fastmail.com/ [1] Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20250409160409.work.168-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2024-08-05gcc-plugins: randstruct: Remove GCC 4.7 or newer requirementThorsten Blum
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>
2024-07-08gcc-plugins: Remove duplicate included header file stringpool.hThorsten Blum
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>
2024-04-03gcc-plugins/stackleak: Avoid .head.text sectionArd Biesheuvel
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>
2023-11-27gcc-plugins: randstruct: Update code comment in relayout_struct()Gustavo A. R. Silva
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>
2023-11-14gcc-plugins: latent_entropy: Fix typo (args -> argc) in plugin descriptionKonstantin Runov
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>
2023-11-08gcc-plugins: randstruct: Only warn about true flexible arraysKees Cook
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>
2023-10-08randstruct: Fix gcc-plugin performance mode to stay in groupKees Cook
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>
2023-08-10gcc-plugins: Rename last_stmt() for GCC 14+Kees Cook
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>
2023-02-02Merge branch 'for-linus/hardening' into for-next/hardeningKees Cook
2023-02-02gcc-plugins: drop -std=gnu++11 to fix GCC 13 buildSam James
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
2023-01-25gcc-plugins: Reorganize gimple includes for GCC 13Kees Cook
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>
2022-06-10treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_385.RULEThomas Gleixner
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>
2022-05-24gcc-plugins: use KERNELVERSION for plugin versionMasahiro Yamada
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
2022-05-16gcc-plugins: randstruct: Remove cast exception handlingKees Cook
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>
2022-05-16af_unix: Silence randstruct GCC plugin warningKees Cook
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>
2022-05-16niu: Silence randstruct warningsKees Cook
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>
2022-05-16big_keys: Use struct for internal payloadKees Cook
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>
2022-05-10gcc-plugins: Change all version strings match kernelKees Cook
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>
2022-05-08randstruct: Move seed generation into scripts/basic/Kees Cook
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
2022-05-08randstruct: Reorganize Kconfigs and attribute macrosKees Cook
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
2022-04-13security: don't treat structure as an array of struct hlist_headBill Wendling
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
2022-04-12gcc-plugins: latent_entropy: use /dev/urandomJason A. Donenfeld
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
2022-02-06gcc-plugins/stackleak: Ignore .noinstr.text and .entry.textKees Cook
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>
2022-02-06gcc-plugins/stackleak: Exactly match strings instead of prefixesKees Cook
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>
2021-11-02Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds
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 ...
2021-10-21gcc-plugins: remove duplicate include in gcc-common.hYe Guojin
'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
2021-10-21gcc-plugins: Remove cyc_complexityKees Cook
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
2021-10-21gcc-plugins: Explicitly document purpose and deprecation scheduleKees Cook
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
2021-10-04gcc-plugins: remove support for GCC 4.9 and olderArd Biesheuvel
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
2021-09-27gcc-plugins: arm-ssp: Prepare for THREAD_INFO_IN_TASK supportArd Biesheuvel
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>
2021-08-10scripts: make some scripts executableMasahiro Yamada
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>
2021-05-02.gitignore: prefix local generated files with a slashMasahiro Yamada
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>
2021-03-11kbuild: rebuild GCC plugins when the compiler is upgradedMasahiro Yamada
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>
2021-03-01gcc-plugins: latent_entropy: remove unneeded semicolonJason Yan
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
2021-03-01gcc-plugins: structleak: remove unneeded variable 'ret'Jason Yan
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
2021-01-06gcc-plugins: fix gcc 11 indigestion with plugins...Valdis Klētnieks
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
2020-12-04gcc-plugins: simplify GCC plugin-dev capability testMasahiro Yamada
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
2020-12-04gcc-plugins: remove code for GCC versions older than 4.9Masahiro Yamada
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
2020-08-09Merge tag 'kbuild-v5.9' of ↵Linus Torvalds
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
2020-08-10kbuild: move host .so build rules to scripts/gcc-plugins/MakefileMasahiro Yamada
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>
2020-08-04Merge tag 'gcc-plugins-v5.9-rc1' of ↵Linus Torvalds
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
generated by cgit (git 2.34.1) at 2025-06-13 16:40:16 +0000