Hi! Here is v2, which is substantially changed compared to the RFC[1].
This series implements[2][3] 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. The major change here is getting (what seems to be) proper KCFI RTL working on the back end so that expansion Just Works. This meant all the strange hacks I had for handling corner cases mostly went away, and I was left with an optimizer that actually wanted to help me. :) I revamped the mangler to do the hashing directly, and incorporated design details into kcfi.cc (rather than putting it all in the commit log). I'm using proper target hooks. I've tested all 4 architectures now, and everything is working for me. I'm still unsure about the arm32 and riscv RTL expansion: it seems strange that I have to extract the CALL from PARALLEL patterns, but everything I tried to match an PARALLEL kept failling. For the commits, I ended up hand-building the ChangeLog trailers... I assume there is a better way to do this, but I think I was just too dense to find it. :P Thanks! -Kees [1] https://lore.kernel.org/linux-hardening/20250821064202.work.893-k...@kernel.org/ [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107048 [3] https://github.com/KSPP/linux/issues/369 Kees Cook (7): mangle: Introduce C typeinfo mangling API kcfi: Add core Kernel Control Flow Integrity infrastructure 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 kcfi: Add regression test suite gcc/kcfi.h | 47 + gcc/kcfi.cc | 764 ++++++++++++ gcc/Makefile.in | 2 + 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/flag-types.h | 2 + gcc/gimple.h | 21 + gcc/mangle.h | 32 + gcc/tree-pass.h | 3 + gcc/testsuite/gcc.dg/kcfi/kcfi-adjacency.c | 73 ++ gcc/testsuite/gcc.dg/kcfi/kcfi-basics.c | 101 ++ gcc/testsuite/gcc.dg/kcfi/kcfi-call-sharing.c | 85 ++ .../gcc.dg/kcfi/kcfi-cold-partition.c | 137 +++ .../gcc.dg/kcfi/kcfi-complex-addressing.c | 125 ++ .../gcc.dg/kcfi/kcfi-ipa-robustness.c | 55 + .../gcc.dg/kcfi/kcfi-move-preservation.c | 56 + .../gcc.dg/kcfi/kcfi-no-sanitize-inline.c | 101 ++ gcc/testsuite/gcc.dg/kcfi/kcfi-no-sanitize.c | 41 + .../gcc.dg/kcfi/kcfi-offset-validation.c | 50 + .../gcc.dg/kcfi/kcfi-patchable-basic.c | 71 ++ .../gcc.dg/kcfi/kcfi-patchable-entry-only.c | 64 + .../gcc.dg/kcfi/kcfi-patchable-large.c | 52 + .../gcc.dg/kcfi/kcfi-patchable-medium.c | 61 + .../gcc.dg/kcfi/kcfi-patchable-prefix-only.c | 61 + .../gcc.dg/kcfi/kcfi-pic-addressing.c | 105 ++ .../gcc.dg/kcfi/kcfi-retpoline-r11.c | 51 + gcc/testsuite/gcc.dg/kcfi/kcfi-tail-calls.c | 143 +++ .../gcc.dg/kcfi/kcfi-trap-encoding.c | 56 + gcc/testsuite/gcc.dg/kcfi/kcfi-trap-section.c | 43 + .../gcc.dg/kcfi/kcfi-type-mangling.c | 1064 +++++++++++++++++ gcc/c-family/c-attribs.cc | 12 + gcc/config/aarch64/aarch64.cc | 115 ++ gcc/config/aarch64/aarch64.md | 64 +- gcc/config/arm/arm.cc | 144 +++ gcc/config/arm/arm.md | 62 + gcc/config/i386/i386-expand.cc | 21 +- gcc/config/i386/i386.cc | 118 ++ gcc/config/i386/i386.md | 62 +- gcc/config/riscv/riscv.cc | 147 +++ gcc/config/riscv/riscv.md | 74 +- gcc/df-scan.cc | 6 + gcc/doc/invoke.texi | 102 ++ gcc/doc/tm.texi | 31 + gcc/doc/tm.texi.in | 12 + gcc/final.cc | 3 + gcc/mangle.cc | 512 ++++++++ gcc/opts.cc | 1 + gcc/passes.cc | 1 + gcc/passes.def | 3 + gcc/rtl.def | 6 + gcc/rtlanal.cc | 5 + gcc/target.def | 38 + gcc/testsuite/gcc.dg/kcfi/kcfi.exp | 36 + gcc/toplev.cc | 11 + gcc/tree-inline.cc | 10 + gcc/varasm.cc | 46 +- 59 files changed, 5092 insertions(+), 32 deletions(-) create mode 100644 gcc/kcfi.h create mode 100644 gcc/kcfi.cc create mode 100644 gcc/mangle.h create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-adjacency.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-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-basic.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-patchable-entry-only.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-pic-addressing.c create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi-retpoline-r11.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-type-mangling.c create mode 100644 gcc/mangle.cc create mode 100644 gcc/testsuite/gcc.dg/kcfi/kcfi.exp -- 2.34.1
