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 <kees@kernel.org>
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
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
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: 313dd1b629 ("gcc-plugins: Add the randstruct plugin")
Signed-off-by: Kees Cook <kees@kernel.org>
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>
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>
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>
Commit a3e8fe814a ("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>
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>
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 1ee60356c2 ("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: 1ee60356c2 ("gcc-plugins: randstruct: Only warn about true flexible arrays")
Signed-off-by: Kees Cook <keescook@chromium.org>
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
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>
Commit 61f60bac8c ("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: 61f60bac8c ("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
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>
