| Message ID | 202203251443.9BBADFD98@keescook (mailing list archive) |
|---|---|
| State | Mainlined |
| Headers | show |
| Series | [GIT,PULL] FORTIFY_SOURCE updates for v5.18-rc1 | expand |
On Fri, Mar 25, 2022 at 3:03 PM Kees Cook <keescook@chromium.org> wrote: > > 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]): So how much of this is _completely_ compile-time? Right now it looks to me like FORTIFY_SOURCE ends up doing two things - added runtime checking based on compile-time sizes - compile-time errors How hard would it be to separate the two issues out? Because if all the compiler issues and warnings have been sorted out, it sounds to me like the compile-time side could/should be done unconditionally if there are no runtime downsides. Hmm? Linus
On Sat, Mar 26, 2022 at 12:29 PM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > Because if all the compiler issues and warnings have been sorted out, > it sounds to me like the compile-time side could/should be done > unconditionally if there are no runtime downsides. .. or do the existing compiler warnings for the builtins already cover all cases, and the only reason the fortify-source code has compile-time warnings is that the option takes over the builtins? So maybe there's no upside to the fortify-source code for that case? Linus
The pull request you sent on Fri, 25 Mar 2022 15:03:43 -0700:
> https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git tags/memcpy-v5.18-rc1
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/4be240b18aa67b1144af546bea2d7cad1b75c19b
Thank you!
On Sat, Mar 26, 2022 at 12:40:18PM -0700, Linus Torvalds wrote: > On Sat, Mar 26, 2022 at 12:29 PM Linus Torvalds > <torvalds@linux-foundation.org> wrote: > > > > Because if all the compiler issues and warnings have been sorted out, > > it sounds to me like the compile-time side could/should be done > > unconditionally if there are no runtime downsides. Yeah, I'd like to do this. The way the header files are currently split up makes this slightly weird, and there have been issues with some arch/compiler combinations, so it's not quite as cut-and-dried as I'd like. I'll investigate what it could look like. > .. or do the existing compiler warnings for the builtins already cover > all cases, and the only reason the fortify-source code has > compile-time warnings is that the option takes over the builtins? This mostly depends on the compiler version, and they often overlap, but the new FORTIFY logic tends to be more strict (where possible) and is more consistent; I view the two diagnostic capabilities as complementary.
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