From 7e61560628d17ea6b1d8ee370f6d42694cff8758 Mon Sep 17 00:00:00 2001 From: Ulises Mendez Martinez Date: Fri, 4 Sep 2026 15:07:09 +0000 Subject: objtool: Validate disassembler headers in libopcodes probe commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") tested for libopcodes availability by linking a test snippet with a forward declaration of disassemble_init_for_target(). However, testing symbol linkage with an extern declaration only verifies the presence of the library (.so/.a) and bypasses checking for development headers (binutils-dev). On systems where libopcodes is present without development headers installed, the probe succeeds, enabling BUILD_DISAS. Subsequent compilation of objtool then fails: fatal error: 'bfd.h' file not found 113 | #include Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring any sysroot or include flags specified for the host compiler. Fix this by including and directly in the test snippet, passing $(HOSTCFLAGS) so host compiler options are respected, and defining PACKAGE="objtool" to satisfy the configuration check in . Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check") Reported-by: Alice Ryhl Assisted-by: Antigravity:Gemini-Next Signed-off-by: Ulises Mendez Martinez Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com Signed-off-by: Josh Poimboeuf --- scripts/Makefile.kasan | 106 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 scripts/Makefile.kasan (limited to 'scripts/Makefile.kasan') diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan new file mode 100644 index 000000000..91504e812 --- /dev/null +++ b/scripts/Makefile.kasan @@ -0,0 +1,106 @@ +# SPDX-License-Identifier: GPL-2.0 + +ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX +# Safe for compiler to generate meminstrinsic calls in uninstrumented files. +CFLAGS_KASAN_NOSANITIZE := +else +# Don't let compiler generate memintrinsic calls in uninstrumented files +# because they are instrumented. +CFLAGS_KASAN_NOSANITIZE := -fno-builtin +endif + +KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) + +cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1))) +rustc-param = $(call rustc-option, -Cllvm-args=-$(1),) + +check-args = $(foreach arg,$(2),$(call $(1),$(arg))) + +kasan_params := + +ifdef CONFIG_KASAN_STACK + stack_enable := 1 +else + stack_enable := 0 +endif + +ifdef CONFIG_KASAN_GENERIC + +ifdef CONFIG_KASAN_INLINE + # When the number of memory accesses in a function is less than this + # call threshold number, the compiler will use inline instrumentation. + # 10000 is chosen offhand as a sufficiently large number to make all + # kernel functions to be instrumented inline. + call_threshold := 10000 +else + call_threshold := 0 +endif + +# First, enable -fsanitize=kernel-address together with providing the shadow +# mapping offset, as for GCC, -fasan-shadow-offset fails without -fsanitize +# (GCC accepts the shadow mapping offset via -fasan-shadow-offset instead of +# a --param like the other KASAN parameters). +# Instead of ifdef-checking the compiler, rely on cc-option. +CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \ + -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \ + $(call cc-option, -fsanitize=kernel-address \ + -mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET))) + +# The minimum supported `rustc` version has a minimum supported LLVM +# version late enough that we can assume support for -asan-mapping-offset. +RUSTFLAGS_KASAN := -Zsanitizer=kernel-address \ + -Zsanitizer-recover=kernel-address \ + -Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET) + +# Now, add other parameters enabled similarly in GCC, Clang, and rustc. +# As some of them are not supported by older compilers, these will be filtered +# through `cc-param` or `rust-param` as applicable. +kasan_params += asan-instrumentation-with-call-threshold=$(call_threshold) \ + asan-stack=$(stack_enable) \ + asan-instrument-allocas=1 \ + asan-globals=1 + +# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*() +# instead. With compilers that don't support this option, compiler-inserted +# memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures. +kasan_params += asan-kernel-mem-intrinsic-prefix=1 + +endif # CONFIG_KASAN_GENERIC + +ifdef CONFIG_KASAN_SW_TAGS + +CFLAGS_KASAN := -fsanitize=kernel-hwaddress + +RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress \ + -Zsanitizer-recover=kernel-hwaddress + +ifdef CONFIG_KASAN_INLINE + kasan_params += hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET) +else + kasan_params += hwasan-instrument-with-calls=1 +endif + +kasan_params += hwasan-instrument-stack=$(stack_enable) \ + hwasan-use-short-granules=0 \ + hwasan-inline-all-checks=0 + +# Instrument memcpy/memset/memmove calls by using instrumented __(hw)asan_mem*(). +ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX + ifdef CONFIG_CC_IS_GCC + kasan_params += asan-kernel-mem-intrinsic-prefix=1 + else + kasan_params += hwasan-kernel-mem-intrinsic-prefix=1 + endif +endif # CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX + +endif # CONFIG_KASAN_SW_TAGS + +# Add all as-supported KASAN LLVM parameters requested by the configuration. +CFLAGS_KASAN += $(call check-args, cc-param, $(kasan_params)) + +ifdef CONFIG_RUST + # Avoid calling `rustc-param` unless Rust is enabled. + RUSTFLAGS_KASAN += $(call check-args, rustc-param, $(kasan_params)) +endif # CONFIG_RUST + +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN -- cgit v1.3.1