From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3E6C15B54A for ; Fri, 26 Sep 2025 03:02:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758855773; cv=none; b=IUB6NfV5ejKFpkBT3PdnfQeCi8H3R59RUoPJxQ83Vmzdd3PC4qwDPPJdlZoPGalj8UhIbRf+zMyuB+GvPmrqbYJsB3n7pa1h3nGpv/PDRnWdiCyELguaScISTk9F0YPX5F0Qx+vDotm6PLFSMTPTsXzrR4yWJSwFNzUJ2FaW61E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758855773; c=relaxed/simple; bh=CSihgRaHwPiAC1FL6Ql7OZ1vSHSrh2BqPxzXdNZOFKY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=APDvMVJXnPvX4E6jorCz/pLnioZrYpHPk974lKY2gokzGGAomfbjToWAXHc0Zh9gQ+5ZFsNRT5BbjX3m4990LPSuWsrw6GKLmaJJy7yST8iqozJJljvd2hRKtEndFIkW1ALNWqcB5hslqR7xyl0xaLmN+HQn2w0Sa+KaS6gLh84= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZWEVslzl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZWEVslzl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8062AC4CEF0; Fri, 26 Sep 2025 03:02:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758855772; bh=CSihgRaHwPiAC1FL6Ql7OZ1vSHSrh2BqPxzXdNZOFKY=; h=From:To:Cc:Subject:Date:From; b=ZWEVslzl4E+ejFHpKvBlbUMSykuLitiZnx/Sn4HOTCWSPKR2nLx9Cia92hEIAot0e hFOHwCJ3JKBOS6taRJslczByBwkTDd4CTc3Dyuz4F2G2d41K8zDm/4R31G5p7nx07H d5Xqa1aYPsqUOHyPGFmeDcJDGWbts2Rth6y8EwrIEO8bcXD6nPehTkpl9dnTfRUV/8 8i7KvrXbYroIDpFyPfnP0JnLwZl/Cc5c2OyEcWIzMKoNOHw0FnNRskd7iMtK+YyqmT pOnIRKwb3jISKuq9plOl8At7GQj1UbiRP0jIRCrj8cc7cNJrN0YTBA2R8JS74U/zmA ArW1xPm4xu3YQ== From: Kees Cook To: Qing Zhao Cc: Kees Cook , Andrew Pinski , Jakub Jelinek , Martin Uecker , Richard Biener , Joseph Myers , Peter Zijlstra , Ard Biesheuvel , Jeff Law , Jan Hubicka , Richard Earnshaw , Richard Sandiford , Marcus Shawcroft , Kyrylo Tkachov , Kito Cheng , Palmer Dabbelt , Andrew Waterman , Jim Wilson , Dan Li , Sami Tolvanen , Ramon de C Valle , Joao Moreira , Nathan Chancellor , Bill Wendling , gcc-patches@gcc.gnu.org, linux-hardening@vger.kernel.org Subject: [PATCH v4 0/7] Introduce Kernel Control Flow Integrity ABI [PR107048] Date: Thu, 25 Sep 2025 20:02:42 -0700 Message-Id: <20250926023737.it.616-kees@kernel.org> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=8801; i=kees@kernel.org; h=from:subject:message-id; bh=CSihgRaHwPiAC1FL6Ql7OZ1vSHSrh2BqPxzXdNZOFKY=; b=owGbwMvMwCVmps19z/KJym7G02pJDBnXmMJeWDyfadVvln5q8ZxzZnrh10IVVxw6fjk22OdYQ Zyc3AP7jlIWBjEuBlkxRZYgO/c4F4+37eHucxVh5rAygQxh4OIUgIms+M/wP33CZZZCD9ntySod kR+yvk96y7boq7ebofbzXX2vlVx1fRn+Fxvduy3gYbHkWE6I56Wr0x50pt5pnGK0un1v7N3ZLB9 /sAIA X-Developer-Key: i=kees@kernel.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit Hi, Here is v4! :) This series implements[1][2] the Linux Kernel Control Flow Integrity ABI, which provides a function prototype based forward edge control flow integrity protection by instrumenting every indirect call to check for a hash value before the target function address. If the hash at the call site and the hash at the target do not match, execution will trap. Changes since v3[3]: - Clarified commit logs and kcfi.cc design docs further. - Switched to KCFI-specific global label counter. - Refactored patchable function entry and alignment padding calculations and added extensive comments. - Moved option validation into early option processing. - Switched arm to using eor sequence suggested by Ard Biesheuvel. - Switched arm scratch register to ip with r3 fallback. - Removed redundant aarch64 clobbers. - Added KCFI availability function for regression tests. - Refactored regression tests to use check-function-bodies. - Split arch-specific regresion test patterns into per-arch patches (I don't like having fully separate test source files be per-arch since the conditions being tested are usually arch-agnostic). - Added more complete function interface comments. - Added -ffixed-$reg option checking and associated tests. - Various other small cleanups. Thanks! -Kees [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107048 [2] https://github.com/KSPP/linux/issues/369 [3] https://lore.kernel.org/linux-hardening/20250913231256.make.519-kees@kernel.org/ Kees Cook (7): typeinfo: Introduce KCFI typeinfo mangling API kcfi: Add core Kernel Control Flow Integrity infrastructure kcfi: Add regression test suite x86: Add x86_64 Kernel Control Flow Integrity implementation aarch64: Add AArch64 Kernel Control Flow Integrity implementation arm: Add ARM 32-bit Kernel Control Flow Integrity implementation riscv: Add RISC-V Kernel Control Flow Integrity implementation gcc/kcfi.h | 55 ++ gcc/kcfi.cc | 670 ++++++++++++++++++ gcc/config/aarch64/aarch64-protos.h | 5 + gcc/config/arm/arm-protos.h | 4 + gcc/config/i386/i386-protos.h | 1 + gcc/config/i386/i386.h | 3 +- gcc/config/riscv/riscv-protos.h | 3 + gcc/config/aarch64/aarch64.md | 64 +- gcc/config/arm/arm.md | 62 ++ gcc/config/i386/i386.md | 62 +- gcc/config/riscv/riscv.md | 76 +- gcc/config/aarch64/aarch64.cc | 111 +++ gcc/config/arm/arm.cc | 170 +++++ gcc/config/i386/i386-expand.cc | 22 +- gcc/config/i386/i386-options.cc | 11 + gcc/config/i386/i386.cc | 128 ++++ gcc/config/riscv/riscv.cc | 169 +++++ gcc/doc/extend.texi | 132 ++++ gcc/doc/invoke.texi | 104 +++ gcc/doc/tm.texi | 31 + gcc/testsuite/gcc.dg/kcfi/kcfi.exp | 42 ++ gcc/testsuite/lib/target-supports.exp | 14 + .../gcc.dg/builtin-typeinfo-errors.c | 28 + gcc/testsuite/gcc.dg/builtin-typeinfo.c | 350 +++++++++ .../gcc.dg/kcfi/kcfi-aarch64-fixed-x16.c | 17 + .../gcc.dg/kcfi/kcfi-aarch64-fixed-x17.c | 17 + gcc/testsuite/gcc.dg/kcfi/kcfi-adjacency.c | 114 +++ gcc/testsuite/gcc.dg/kcfi/kcfi-arm-fixed-ip.c | 15 + .../gcc.dg/kcfi/kcfi-arm-fixed-r12.c | 15 + gcc/testsuite/gcc.dg/kcfi/kcfi-basics.c | 149 ++++ gcc/testsuite/gcc.dg/kcfi/kcfi-call-sharing.c | 90 +++ .../gcc.dg/kcfi/kcfi-cold-partition.c | 126 ++++ .../gcc.dg/kcfi/kcfi-complex-addressing.c | 203 ++++++ .../gcc.dg/kcfi/kcfi-complex-addressing.s | 0 .../gcc.dg/kcfi/kcfi-ipa-robustness.c | 54 ++ .../gcc.dg/kcfi/kcfi-move-preservation.c | 118 +++ .../gcc.dg/kcfi/kcfi-no-sanitize-inline.c | 100 +++ gcc/testsuite/gcc.dg/kcfi/kcfi-no-sanitize.c | 39 + .../gcc.dg/kcfi/kcfi-offset-validation.c | 38 + .../gcc.dg/kcfi/kcfi-patchable-entry-only.c | 64 ++ .../gcc.dg/kcfi/kcfi-patchable-incompatible.c | 7 + .../gcc.dg/kcfi/kcfi-patchable-large.c | 54 ++ .../gcc.dg/kcfi/kcfi-patchable-medium.c | 60 ++ .../gcc.dg/kcfi/kcfi-patchable-prefix-only.c | 61 ++ .../gcc.dg/kcfi/kcfi-riscv-fixed-t1.c | 17 + .../gcc.dg/kcfi/kcfi-riscv-fixed-t2.c | 17 + .../gcc.dg/kcfi/kcfi-riscv-fixed-t3.c | 17 + gcc/testsuite/gcc.dg/kcfi/kcfi-runtime.c | 276 ++++++++ gcc/testsuite/gcc.dg/kcfi/kcfi-tail-calls.c | 140 ++++ .../gcc.dg/kcfi/kcfi-trap-encoding.c | 69 ++ gcc/testsuite/gcc.dg/kcfi/kcfi-trap-section.c | 29 + .../gcc.dg/kcfi/kcfi-x86-fixed-r10.c | 17 + .../gcc.dg/kcfi/kcfi-x86-fixed-r11.c | 17 + .../gcc.dg/kcfi/kcfi-x86-retpoline-r11.c | 40 ++ gcc/Makefile.in | 2 + gcc/c-family/c-common.h | 1 + gcc/flag-types.h | 2 + gcc/gimple.h | 22 + gcc/kcfi-typeinfo.h | 32 + gcc/tree-pass.h | 1 + gcc/c-family/c-attribs.cc | 17 +- gcc/c-family/c-common.cc | 2 + gcc/c/c-parser.cc | 72 ++ gcc/df-scan.cc | 7 + gcc/doc/tm.texi.in | 12 + gcc/final.cc | 3 + gcc/kcfi-typeinfo.cc | 472 ++++++++++++ gcc/opts.cc | 1 + gcc/passes.cc | 1 + gcc/passes.def | 1 + gcc/rtl.def | 6 + gcc/rtlanal.cc | 5 + gcc/target.def | 38 + gcc/toplev.cc | 10 + gcc/tree-inline.cc | 10 + gcc/varasm.cc | 37 +- 76 files changed, 5018 insertions(+), 33 deletions(-) create mode 100644 gcc/kcfi.h create mode 100644 gcc/kcfi.cc create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi.exp create mode 100644 gcc/testsuite/gcc.dg/builtin-typeinfo-errors.c create mode 100644 gcc/testsuite/gcc.dg/builtin-typeinfo.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-aarch64-fixed-x16.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-aarch64-fixed-x17.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-adjacency.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-arm-fixed-ip.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-arm-fixed-r12.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-basics.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-call-sharing.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-cold-partition.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-complex-addressing.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-complex-addressing.s create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-ipa-robustness.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-move-preservation.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-no-sanitize-inline.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-no-sanitize.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-offset-validation.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-patchable-entry-only.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-patchable-incompatible.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-patchable-large.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-patchable-medium.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-patchable-prefix-only.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-riscv-fixed-t1.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-riscv-fixed-t2.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-riscv-fixed-t3.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-runtime.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-tail-calls.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-trap-encoding.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-trap-section.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-x86-fixed-r10.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-x86-fixed-r11.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-x86-retpoline-r11.c create mode 100644 gcc/kcfi-typeinfo.h create mode 100644 gcc/kcfi-typeinfo.cc -- 2.34.1