Commit Graph

116 Commits

Author SHA1 Message Date
Thorsten Blum
f32e90c068 gcc-plugins: randstruct: Remove GCC 4.7 or newer requirement
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>
2024-08-05 14:34:23 -07:00
Thorsten Blum
18c18b1ff6 gcc-plugins: Remove duplicate included header file stringpool.h
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>
2024-07-08 12:20:32 -07:00
Ard Biesheuvel
e7d24c0aa8 gcc-plugins/stackleak: Avoid .head.text section
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: 48204aba80 ("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>
2024-04-03 14:35:49 -07:00
Gustavo A. R. Silva
d71f22365a gcc-plugins: randstruct: Update code comment in relayout_struct()
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>
2023-11-27 16:30:05 -08:00
Konstantin Runov
782ce43161 gcc-plugins: latent_entropy: Fix typo (args -> argc) in plugin description
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>
2023-11-14 09:32:47 -08:00
Kees Cook
1ee60356c2 gcc-plugins: randstruct: Only warn about true flexible arrays
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 df8fc4e934 ("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: df8fc4e934 ("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>
2023-11-08 14:18:57 -08:00
Kees Cook
381fdb73d1 randstruct: Fix gcc-plugin performance mode to stay in group
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: 313dd1b629 ("gcc-plugins: Add the randstruct plugin")
Signed-off-by: Kees Cook <keescook@chromium.org>
2023-10-08 22:46:05 -07:00
Kees Cook
2e3f65ccfe gcc-plugins: Rename last_stmt() for GCC 14+
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>
2023-08-10 23:10:09 -07:00
Kees Cook
5c0f220e1b Merge branch 'for-linus/hardening' into for-next/hardening 2023-02-02 18:43:28 +00:00
Sam James
5a6b64adc1 gcc-plugins: drop -std=gnu++11 to fix GCC 13 build
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
2023-02-02 16:31:23 +00:00
Kees Cook
e6a71160cc gcc-plugins: Reorganize gimple includes for GCC 13
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>
2023-01-25 12:24:48 -08:00
Thomas Gleixner
fa82cce7a6 treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_385.RULE
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>
2022-06-10 14:51:36 +02:00
Masahiro Yamada
d37aa2efc8 gcc-plugins: use KERNELVERSION for plugin version
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
2022-05-24 08:25:16 -07:00
Kees Cook
710e4ebfba gcc-plugins: randstruct: Remove cast exception handling
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>
2022-05-16 16:02:21 -07:00
Kees Cook
b146cbf2e3 af_unix: Silence randstruct GCC plugin warning
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>
2022-05-16 16:02:21 -07:00
Kees Cook
2dcfe9e2d3 niu: Silence randstruct warnings
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>
2022-05-16 16:02:21 -07:00
Kees Cook
c1298a3a11 big_keys: Use struct for internal payload
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>
2022-05-16 16:02:21 -07:00
Kees Cook
61f60bac8c gcc-plugins: Change all version strings match kernel
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>
2022-05-10 16:54:33 -07:00
Kees Cook
be2b34fa9b randstruct: Move seed generation into scripts/basic/
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
2022-05-08 01:33:07 -07:00
Kees Cook
595b893e20 randstruct: Reorganize Kconfigs and attribute macros
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
2022-05-08 01:33:06 -07:00
Bill Wendling
75c1182e18 security: don't treat structure as an array of struct hlist_head
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
2022-04-13 12:15:53 -07:00
Jason A. Donenfeld
c40160f299 gcc-plugins: latent_entropy: use /dev/urandom
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: 38addce8b6 ("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
2022-04-12 11:31:40 -07:00
Kees Cook
ae978009fc gcc-plugins/stackleak: Ignore .noinstr.text and .entry.text
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>
2022-02-06 10:55:03 -08:00
Kees Cook
27e9faf415 gcc-plugins/stackleak: Exactly match strings instead of prefixes
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>
2022-02-06 10:55:03 -08:00
Linus Torvalds
ab2e7f4b46 ARM development for 5.16:
- 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
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEuNNh8scc2k/wOAE+9OeQG+StrGQFAmGBEFIACgkQ9OeQG+St
 rGRbLw/9EQPEVAnx4obKSfQ7+H6JF8EZnSUvmFe0tK2zyR5T8dCoifh5bmdkdu51
 r2gtxse9gbCKzGyfAlhcR+p47P94ULt3/slRb+thc1E3USAkP9mDLH2gXlWraVOL
 TdBn6WD2zHdGWmLYB3RPjh/FpQy2IEKajQU9pFC+Rp0Hf8OKg7KH1E5Ap8W9kjz6
 o2HieVxsteuWKwCauQq95IDNZ/fpq/FuQi38fn11O52uB8PO4OC3LUR33/4qKBYj
 iykzt6hxHHnDLWKMrR9hbv0J6hSjflVgqTEirTuk1EpkKcIVoc6EOPTGENus7U1r
 GcrVbrnAs/obgYgT1DwTS0mreIAQ2dNpekbbICqD/SFrV4Rt/zOjImFXm17L4mxU
 2D0FG9iyTFgQIYOQBrbaUbeeDpH+Dxn4ldFYWZ0/PLukz901KK40xV6b9gpe52iY
 DJDmO8OVH55ZargQQXB13vcJ79ZYcHusEr+kBkU+kXXP7LzTBTZfj2a/xCR0H2hw
 urS5ocp8WXHQ+jSZGVLR82kIVK0TuqDmkuOSi+VXuCIAMC3ITaSs5X1/foVn7r2b
 SdBSoqa2R28HSWudtkP7Ki1QCqxzrrn4RWjCOyEa+aoHyKT/MXQ7E7qwrg8nWBXV
 Ep83wvL2TmE5ZaljfEcyXnjYnXTcStB+YAD4G/6dZERLXbJ1tms=
 =lDRU
 -----END PGP SIGNATURE-----

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

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
  ...
2021-11-02 11:33:15 -07:00
Ye Guojin
6425392acf gcc-plugins: remove duplicate include in gcc-common.h
'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
2021-10-21 08:41:51 -07:00
Kees Cook
b4d89579cc gcc-plugins: Remove cyc_complexity
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
2021-10-21 08:41:47 -07:00
Kees Cook
8bd51a2ba3 gcc-plugins: Explicitly document purpose and deprecation schedule
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
2021-10-21 08:41:38 -07:00
Ard Biesheuvel
4c78c7271f gcc-plugins: remove support for GCC 4.9 and older
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
2021-10-04 10:58:08 -07:00
Ard Biesheuvel
dfbdcda280 gcc-plugins: arm-ssp: Prepare for THREAD_INFO_IN_TASK support
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>
2021-09-27 16:54:01 +02:00
Masahiro Yamada
0058d07ec6 scripts: make some scripts executable
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 21917bded7 ("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>
2021-08-10 09:13:25 +09:00
Masahiro Yamada
9009b45581 .gitignore: prefix local generated files with a slash
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>
2021-05-02 00:43:35 +09:00
Masahiro Yamada
ce6ed1c4c9 kbuild: rebuild GCC plugins when the compiler is upgraded
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 8b59cd81dc ("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>
2021-03-11 14:40:50 +09:00
Jason Yan
5477edcaca gcc-plugins: latent_entropy: remove unneeded semicolon
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
2021-03-01 19:19:50 -08:00
Jason Yan
b924a8197a gcc-plugins: structleak: remove unneeded variable 'ret'
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
2021-03-01 19:19:44 -08:00
Valdis Klētnieks
67a5a68013 gcc-plugins: fix gcc 11 indigestion with plugins...
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
2021-01-06 15:08:23 -08:00
Masahiro Yamada
1e860048c5 gcc-plugins: simplify GCC plugin-dev capability test
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
2020-12-04 14:09:55 -08:00
Masahiro Yamada
af2d22254e gcc-plugins: remove code for GCC versions older than 4.9
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
2020-12-04 14:09:41 -08:00
Linus Torvalds
fc80c51fd4 Kbuild updates for v5.9
- 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
 -----BEGIN PGP SIGNATURE-----
 
 iQJJBAABCgAzFiEEbmPs18K1szRHjPqEPYsBB53g2wYFAl8wJXEVHG1hc2FoaXJv
 eUBrZXJuZWwub3JnAAoJED2LAQed4NsGMGEP/0jDq/WafbfPN0aU83EqEWLt/sKg
 bluzmf/6HGx3XVRnuAzsHNNqysUx77WJiDsU/jbC/zdH8Iox3Sc1diE2sELLNAfY
 iJmQ8NBPggyU74aYG3OJdpDjz8T9EX/nVaYrjyFlbuXElM+Qvo8Z4Fz6NpWqKWlA
 gU+yGxEPPdX6MLHcSPSIu1hGWx7UT4fgfx3zDFTI2qvbQgQjKtzyTjAH5Cm3o87h
 rfomvHSSoAUg+Fh1LediRh1tJlkdVO+w7c+LNwCswmdBtkZuxecj1bQGUTS8GaLl
 CCWOKYfWp0KsVf1veXNNNaX/ecbp+Y34WErFq3V9Fdq5RmVlp+FPSGMyjDMRiQ/p
 LGvzbJLPpG586MnK8of0dOj6Es6tVPuq6WH2HuvsyTGcZJDpFTTxRcK3HDkE8ig6
 ZtuM3owB/Mep8IzwY2yWQiDrc7TX5Fz8S4hzGPU1zG9cfj4VT6TBqHGAy1Eql/0l
 txj6vJpnbQSdXiIX8MIU3yH35Y7eW3JYWgspTZH5Woj1S/wAWwuG93Fuuxq6mQIJ
 q6LSkMavtOfuCjOA9vJBZewpKXRU6yo0CzWNL/5EZ6z/r/I+DGtfb/qka8oYUDjX
 9H0cecL37AQxDHRPTxCZDQF0TpYiFJ6bmnMftK9NKNuIdvsk9DF7UBa3EdUNIj38
 yKS3rI7Lw55xWuY3
 =bkNQ
 -----END PGP SIGNATURE-----

Merge tag 'kbuild-v5.9' of 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
2020-08-09 14:10:26 -07:00
Masahiro Yamada
42640b134b kbuild: move host .so build rules to scripts/gcc-plugins/Makefile
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>
2020-08-10 01:32:59 +09:00
Linus Torvalds
3e4a12a1ba GCC plugins updates for v5.9-rc1
- Update URLs for HTTPS scheme where available (Alexander A. Klimov)
 - Improve STACKLEAK code generation on x86 (Alexander Popov)
 -----BEGIN PGP SIGNATURE-----
 
 iQJKBAABCgA0FiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAl8oXDwWHGtlZXNjb29r
 QGNocm9taXVtLm9yZwAKCRCJcvTf3G3AJk+oD/0VHjn3KWSMtJmBkABzbWnzi6m6
 O3J5IJ1qb7b7AriD04/YAx1YaIPknsircv5hJNAiB4c8f9QoVcnufQlp0lsSW/FR
 3bQ8B7zwuw19bq2nITndc9HvjVbNg5aie6I4umeIbkzWzaHfXPuQ/wF0arSDDB7I
 Kmq1gxsSj9wHl5rly06dPW536zTehRfrHiB4nFQnGk1HKBOlhosJ4bNpC9wkbrii
 0TKcOoGw9aAT1m/RYQdaLKDThuEZFdYK8xcNP1gUrH5gHuntpZprVRT4jCZuEMLx
 sEpcabjvfILBGn8/74g/ld1UOjti+5sNUPqHt8poViMlM06YReZlH3QcxJwa+mSY
 spWx54IJs7FXRw42Sj4HEmQQPcffdvFLkes26h3colAhFKJWwRs3vWZRW8ahyLE2
 U/TbkhAWeKpCaLUf6oPST76TdYKGxKxypVG9xaE31YVacjwbHIBE9uP6iNFR974R
 caWoSmMp6ImtxUNAwQGK4zJHJe1x/V5msh85y9TihwX6DNJJp12WuiN6OX5DL4do
 wYhVFDD71v8F6zzYAwI22yPd77P44fQZ40Aayw8Yaa7A6yuB0Pru/paiEttfIBqo
 knVAczXetZKWBogmXply4vqwLXx6wIAgslQLzxDBAaNjQ62DZ63ZbxKjaa317hL6
 mKucFRyn4LXA2i3Dsw==
 =X+DU
 -----END PGP SIGNATURE-----

Merge tag 'gcc-plugins-v5.9-rc1' of 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
2020-08-04 13:26:06 -07:00
Alexander A. Klimov
496b24ec6d gcc-plugins: Replace HTTP links with HTTPS ones
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>
2020-07-13 09:29:09 -07:00
Masahiro Yamada
6975031a31 gcc-plugins: fix gcc-plugins directory path in documentation
Fix typos "plgins" -> "plugins".

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
2020-06-28 12:16:55 +09:00
Alexander Popov
8dd70543f7 gcc-plugins/stackleak: Add 'verbose' plugin parameter
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>
2020-06-24 07:48:44 -07:00
Alexander Popov
feee1b8c49 gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving
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>
2020-06-24 07:48:28 -07:00
Linus Torvalds
4152d146ee Merge branch 'rwonce/rework' of 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
2020-06-10 14:46:54 -07:00
Masahiro Yamada
827365ffda gcc-plugins: remove always-false $(if ...) in Makefile
This is the remnant of commit c17d6179ad ("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>
2020-05-26 00:03:16 +09:00
Will Deacon
5429ef62bc compiler/gcc: Raise minimum GCC version for kernel builds to 4.8
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>
2020-04-15 21:36:20 +01:00
Frédéric Pierret (fepitre)
c7527373fe gcc-common.h: Update for GCC 10
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>
2020-04-13 10:19:20 -07:00
Kees Cook
8d97fb393c gcc-plugins/stackleak: Avoid assignment for unused macro argument
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>
2020-04-13 10:17:44 -07:00