kernel/git/next/linux-next.git/scripts/gcc-plugins, branch master

randstruct: report bad casts as warnings rather than notes

2026-09-03T23:27:21+00:00

find_bad_casts() reports a cast between two randomized structure pointer types with inform(), which renders as a "note:". It has done so since the plugin was originally added, while using error() freely for attribute misuse, UAPI structs, and version mismatches. Clang's implementation of the same check has always been stricter: it rejects such a cast as a full error. There is no reason for the GCC side to be effectively silent about the same problem. Build tested ARCH=x86_64 with CONFIG_RANDSTRUCT_FULL=y and GCC 14.2.0: allmodconfig clean, and defconfig clean under three different random seeds. A deliberate bad cast is still reported, now as a warning, at the correct line and column. Link: https://patch.msgid.link/20260903232438.60394-2-kees@kernel.org Signed-off-by: Kees Cook

randstruct: fix container_of() false positives after __mptr removal

2026-09-03T23:27:21+00:00

Commit f9e7a7564834 ("container_of: remove local __mptr variable") dropped the "void *__mptr" temporary from container_of(). The randstruct GCC plugin's find_bad_casts pass recognized the casts container_of() generates by that variable's name: const_tree ssa_name_var = SSA_NAME_VAR(rhs1); /* skip bogus type casts introduced by container_of */ if (ssa_name_var != NULL_TREE && DECL_NAME(ssa_name_var) && !strcmp(DECL_NAME_POINTER(ssa_name_var), "__mptr")) continue; With the variable gone the suppression never fires, so every container_of() whose container type is randomized now emits a note: include/linux/container_of.h:23:9: note: randstruct: casting between randomized structure pointer types (ssa): 'struct ocfs2_triggers' and 'struct jbd2_buffer_trigger_type' fs/ocfs2/journal.c:524:16: note: in expansion of macro 'container_of' The pass runs on GIMPLE, after folding, and for a member at offset 0 the whole expression collapses to a bare copy that is indistinguishable from an unsafe cast: to_ocfs2_trigger (struct jbd2_buffer_trigger_type * triggers) { _2 = triggers_1(D); /* void * cast and subtraction gone */ return _2; } Match the type relationship instead. A cast from A * to B * is a container_of() if B reaches a field of type A at offset 0 through a chain of by-value members. The chain matters: container_of()'s member argument may be a dotted path, as in ceph_inode(), which is container_of(inode, struct ceph_inode_info, netfs.inode) and needs two levels. The search is depth-bounded to 4 just in case, since real paths are generally one or two members deep. Requiring the cast happens at offset 0 is done because any other member offset the subtraction survives folding and the cast's rhs is still void *, which the pass already skips a few lines above. A cast between two randomized types with no containment relationship is still reported. Verified with: struct cred *f(struct file *f) { return (struct cred *)f; } which is still flagged with the patch applied. Clang's implementation is unaffected. It checks the cast as written, and both the old and new macros cast from void *, which is always permitted; a genuinely bad cast is rejected there as a hard error rather than a note. Build tested ARCH=x86_64 defconfig with CONFIG_RANDSTRUCT_FULL=y and GCC 14.2.0: randstruct notes 52 before, 0 after. Fixes: f9e7a7564834 ("container_of: remove local __mptr variable") Assisted-by: Claude:claude-opus-5[1m] Link: https://patch.msgid.link/20260903232438.60394-1-kees@kernel.org Signed-off-by: Kees Cook

gcc-plugins: Always define CONST_CAST_GIMPLE and CONST_CAST_TREE

2026-05-14T16:24:32+00:00

For gcc-16, the CONST_CAST macro family was removed. Add back what we were using in gcc-common.h, as they are simple wrappers. See GCC commits: c3d96ff9e916c02584aa081f03ab999292efbb50 458c7926d48959abcb2c1adaa22458e27459a551 Suggested-by: Ingo Saitz Link: https://lore.kernel.org/lkml/ab6OKoay0OWkywjK@spatz.zoo Fixes: 6b90bd4ba40b ("GCC plugin infrastructure") Tested-by: Ivan Bulatovic Tested-by: Christopher Cradock Signed-off-by: Kees Cook

gcc-plugins: Remove TODO_verify_il for GCC >= 16

2025-09-23T20:59:39+00:00

GCC now runs TODO_verify_il automatically[1], so it is no longer exposed to plugins. Only use the flag on GCC < 16. Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=9739ae9384dd7cd3bb1c7683d6b80b7a9116eaf8 [1] Suggested-by: Christopher Fore Link: https://lore.kernel.org/r/20250920234519.work.915-kees@kernel.org Signed-off-by: Kees Cook

stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth

2025-07-22T04:40:39+00:00

The Clang stack depth tracking implementation has a fixed name for the stack depth tracking callback, "__sanitizer_cov_stack_depth", so rename the GCC plugin function to match since the plugin has no external dependencies on naming. Link: https://lore.kernel.org/r/20250717232519.2984886-2-kees@kernel.org Signed-off-by: Kees Cook

Merge tag 'hardening-v6.16-rc1-fix1-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2025-06-01T18:37:01+00:00

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

randstruct: gcc-plugin: Fix attribute addition

2025-06-01T15:41:11+00:00

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

Merge tag 'gcc-minimum-version-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2025-05-31T15:16:52+00:00

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

randstruct: gcc-plugin: Remove bogus void member

2025-05-08T16:42:40+00:00

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

gcc-plugins: Force full rebuild when plugins change

2025-05-08T16:42:06+00:00

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 Reviewed-by: Nicolas Schier Signed-off-by: Kees Cook