user/sven/linux.git/scripts/gcc-plugins, branch v5.4.300

randstruct: gcc-plugin: Fix attribute addition

2025-09-09T16:44:01Z

[ Upstream commit f39f18f3c3531aa802b58a20d39d96e82eb96c14 ] 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 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 Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1104745 Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Tested-by: Thiago Jung Bauermann Link: https://lore.kernel.org/r/20250530221824.work.623-kees@kernel.org Signed-off-by: Kees Cook Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

randstruct: gcc-plugin: Remove bogus void member

2025-09-09T16:44:01Z

[ Upstream commit e136a4062174a9a8d1c1447ca040ea81accfa6a8 ] 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" Closes: https://lore.kernel.org/lkml/Z_PRaKx7q70MKgCA@gallifrey/ Reported-by: Mark Brown Closes: https://lore.kernel.org/lkml/20250407-kbuild-disable-gcc-plugins-v1-1-5d46ae583f5e@kernel.org/ Reported-by: WangYuli 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 Stable-dep-of: f39f18f3c353 ("randstruct: gcc-plugin: Fix attribute addition") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

gcc-plugins: Rename last_stmt() for GCC 14+

2024-07-27T08:38:28Z

commit 2e3f65ccfe6b0778b261ad69c9603ae85f210334 upstream. 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 Cc: Thomas Meyer Signed-off-by: Greg Kroah-Hartman

randstruct: Fix gcc-plugin performance mode to stay in group

2023-11-28T16:50:17Z

commit 381fdb73d1e2a48244de7260550e453d1003bb8e upstream. 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 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 Signed-off-by: Greg Kroah-Hartman

gcc-plugins: latent_entropy: use /dev/urandom

2022-04-20T07:19:38Z

commit c40160f2998c897231f8454bf797558d30a20375 upstream. 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 Signed-off-by: Jason A. Donenfeld Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220405222815.21155-1-Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman

gcc-plugins/stackleak: Exactly match strings instead of prefixes

2022-04-15T12:18:22Z

[ Upstream commit 27e9faf415dbf94af19b9c827842435edbc1fbbc ] 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 Signed-off-by: Kees Cook Signed-off-by: Sasha Levin

gcc-common.h: Update for GCC 10

2020-05-27T15:46:24Z

[ Upstream commit c7527373fe28f97d8a196ab562db5589be0d34b9 ] 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 :1: ./gcc-plugins/gcc-common.h:852:13: error: redefinition of ‘static bool is_a_helper::test(U*) [with U = const gimple; T = const ggoto*]’ 852 | inline bool is_a_helper::test(const_gimple gs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ./gcc-plugins/gcc-common.h:125, from :1: /usr/lib/gcc/x86_64-redhat-linux/10/plugin/include/gimple.h:1037:1: note: ‘static bool is_a_helper::test(U*) [with U = const gimple; T = const ggoto*]’ previously declared here 1037 | is_a_helper ::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) 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 Signed-off-by: Sasha Levin

gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS again

2020-01-09T09:19:57Z

commit a5b0dc5a46c221725c43bd9b01570239a4cd78b1 upstream. I noticed that randconfig builds with gcc no longer produce a lot of ccache hits, unlike with clang, and traced this back to plugins now being enabled unconditionally if they are supported. I am now working around this by adding export CCACHE_COMPILERCHECK=/usr/bin/size -A %compiler% to my top-level Makefile. This changes the heuristic that ccache uses to determine whether the plugins are the same after a 'make clean'. However, it also seems that being able to just turn off the plugins is generally useful, at least for build testing it adds noticeable overhead but does not find a lot of bugs additional bugs, and may be easier for ccache users than my workaround. Fixes: 9f671e58159a ("security: Create "kernel hardening" config area") Signed-off-by: Arnd Bergmann Acked-by: Ard Biesheuvel Reviewed-by: Masahiro Yamada Link: https://lore.kernel.org/r/20191211133951.401933-1-arnd@arndb.de Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

randstruct: Check member structs in is_pure_ops_struct()

2019-07-31T20:13:22Z

While no uses in the kernel triggered this case, it was possible to have a false negative where a struct contains other structs which contain only function pointers because of unreachable code in is_pure_ops_struct(). Signed-off-by: Joonwon Kang Link: https://lore.kernel.org/r/20190727155841.GA13586@host Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook

docs: move gcc_plugins.txt to core-api and rename to .rst

2019-07-15T12:20:27Z

The gcc_plugins.txt file is already a ReST file. Move it to the core-api book while renaming it. Signed-off-by: Mauro Carvalho Chehab Acked-by: Kees Cook