Date:   Fri, 25 Mar 2022 15:03:43 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org, George Burgess IV <gbiv@...gle.com>,
        Kees Cook <keescook@...omium.org>,
        linux-hardening@...r.kernel.org, llvm@...ts.linux.dev,
        Miguel Ojeda <ojeda@...nel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: [GIT PULL] FORTIFY_SOURCE updates for v5.18-rc1

Hi Linus,

Please pull these FORTIFY_SOURCE updates for v5.18-rc1.

This series consists of two halves:

- strict compile-time buffer size checking under FORTIFY_SOURCE for
  the memcpy()-family of functions (for extensive details and rationale,
  see the first commit),

- enabling FORTIFY_SOURCE for Clang, which has had many overlapping bugs
  that we've finally worked past.

It looks like all the dependent trees with related buffer fixes have been
merged (I was waiting for the scsi tree to get pulled). This has been
in -next for almost 2 development cycles, and I did overnight build
testing merged against your tree under the following combinations,
with no new warnings (there is one Clang 14+ specific issue in
drivers/net/ethernet/huawei/hinic that we're still tracking down as a
likely compiler regression[1]):

gcc   11.2.1 (Fedora 35)    defconfig:    x86_64 i386 arm64
gcc   11.2.1 (Fedora 35)    allmodconfig: x86_64 i386 arm64
gcc   11.2.0 (Ubuntu 21.10) defconfig:    x86_64 i386 arm64
gcc   11.2.0 (Ubuntu 21.10) allmodconfig: x86_64 i386 arm64
gcc   10.3.0 (Ubuntu 21.10) defconfig:    x86_64 i386 arm64
gcc   10.3.0 (Ubuntu 21.10) allmodconfig: x86_64 i386 arm64
gcc    9.4.0 (Ubuntu 21.10) defconfig:    x86_64 i386 arm64
gcc    9.4.0 (Ubuntu 21.10) allmodconfig: x86_64 i386 arm64
gcc    8.5.0 (Ubuntu 21.10) defconfig:    x86_64 i386 arm64
gcc    8.5.0 (Ubuntu 21.10) allmodconfig: x86_64 i386 arm64
clang 15.0.0 (local build)  defconfig:    x86_64 i386 arm64
clang 14.0.0 (Ubuntu 22.04) defconfig:    x86_64 i386 arm64
clang 13.0.0 (Fedora 35)    defconfig:    x86_64 i386 arm64
clang 12.0.1 (Ubuntu 21.10) defconfig:    x86_64 i386 arm64
clang 13.0.0 (Ubuntu 21.10) allmodconfig: x86_64 i386
clang 12.0.1 (Ubuntu 21.10) allmodconfig: x86_64 i386

There is also still 1 runtime fix pending for the comedi driver's
selftests[2], which is living in my "pending-fixes" tree (for fixes that
maintainers appear to have picked up, but haven't appeared in -next yet).

Beyond that, as far as I've been able to track, all the other architecture
also build cleanly; we've been fixing any issues as they are reported
by various builders, and when we find them in our builds.

Thanks!

-Kees

[1] https://github.com/ClangBuiltLinux/linux/issues/1592
[2] https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=for-next/pending-fixes&id=77cc24d543c46076d753348b6178473eb16fc788

The following changes since commit dfd42facf1e4ada021b939b4e19c935dcdd55566:

  Linux 5.17-rc3 (2022-02-06 12:20:50 -0800)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git tags/memcpy-v5.18-rc1

for you to fetch changes up to 281d0c962752fb40866dd8d4cade68656f34bd1f:

  fortify: Add Clang support (2022-02-13 16:50:07 -0800)

----------------------------------------------------------------
memcpy updates for v5.18-rc1

- Enable strict FORTIFY_SOURCE compile-time validation of memcpy buffers

- Add Clang features needed for FORTIFY_SOURCE support

- Enable FORTIFY_SOURCE for Clang where possible

----------------------------------------------------------------
Kees Cook (12):
      fortify: Detect struct member overflows in memcpy() at compile-time
      fortify: Detect struct member overflows in memmove() at compile-time
      fortify: Detect struct member overflows in memset() at compile-time
      fortify: Update compile-time tests for Clang 14
      fortify: Replace open-coded __gnu_inline attribute
      Compiler Attributes: Add __pass_object_size for Clang
      Compiler Attributes: Add __overloadable for Clang
      Compiler Attributes: Add __diagnose_as for Clang
      fortify: Make pointer arguments const
      fortify: Use __diagnose_as() for better diagnostic coverage
      fortify: Make sure strlen() may still be used as a constant expression
      fortify: Add Clang support

 arch/x86/boot/compressed/misc.c                 |   3 +-
 arch/x86/lib/memcpy_32.c                        |   1 +
 include/linux/compiler_attributes.h             |  39 ++++
 include/linux/fortify-string.h                  | 238 +++++++++++++++++++-----
 lib/Makefile                                    |   3 +-
 lib/string_helpers.c                            |   6 +
 lib/test_fortify/read_overflow2_field-memcpy.c  |   5 +
 lib/test_fortify/read_overflow2_field-memmove.c |   5 +
 lib/test_fortify/write_overflow_field-memcpy.c  |   5 +
 lib/test_fortify/write_overflow_field-memmove.c |   5 +
 lib/test_fortify/write_overflow_field-memset.c  |   5 +
 scripts/test_fortify.sh                         |   8 +-
 security/Kconfig                                |   5 +-
 13 files changed, 272 insertions(+), 56 deletions(-)
 create mode 100644 lib/test_fortify/read_overflow2_field-memcpy.c
 create mode 100644 lib/test_fortify/read_overflow2_field-memmove.c
 create mode 100644 lib/test_fortify/write_overflow_field-memcpy.c
 create mode 100644 lib/test_fortify/write_overflow_field-memmove.c
 create mode 100644 lib/test_fortify/write_overflow_field-memset.c

-- 
Kees Cook

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