A bad bug in clang's implementation of -fzero-call-used-regs can result
in NULL pointer dereferences (see the links above the check for more
information). Restrict CONFIG_CC_HAS_ZERO_CALL_USED_REGS to either a
supported GCC version or a clang newer than 15.0.6, which will catch
both a theoretical 15.0.7 and the upcoming 16.0.0, which will both have
the bug fixed.
Cc: [email protected] # v5.15+
Signed-off-by: Nathan Chancellor <[email protected]>
---
security/Kconfig.hardening | 3 +++
1 file changed, 3 insertions(+)
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index d766b7d0ffd1..53baa95cb644 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -257,6 +257,9 @@ config INIT_ON_FREE_DEFAULT_ON
config CC_HAS_ZERO_CALL_USED_REGS
def_bool $(cc-option,-fzero-call-used-regs=used-gpr)
+ # https://github.com/ClangBuiltLinux/linux/issues/1766
+ # https://github.com/llvm/llvm-project/issues/59242
+ depends on !CC_IS_CLANG || CLANG_VERSION > 150006
config ZERO_CALL_USED_REGS
bool "Enable register zeroing on function exit"
base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476
--
2.39.0
On Wed, 14 Dec 2022 16:26:03 -0700, Nathan Chancellor wrote:
> A bad bug in clang's implementation of -fzero-call-used-regs can result
> in NULL pointer dereferences (see the links above the check for more
> information). Restrict CONFIG_CC_HAS_ZERO_CALL_USED_REGS to either a
> supported GCC version or a clang newer than 15.0.6, which will catch
> both a theoretical 15.0.7 and the upcoming 16.0.0, which will both have
> the bug fixed.
>
> [...]
Applied to for-next/hardening, thanks! (And I'll send it for v6.2-rc1 too.)
[1/1] security: Restrict CONFIG_ZERO_CALL_USED_REGS to gcc or clang > 15.0.6
https://git.kernel.org/kees/c/d6a9fb87e9d1
--
Kees Cook