diff mbox series

[v3,2/4] kbuild: rust: Enable KASAN support

Message ID 20240819213534.4080408-3-mmaurer@google.com (mailing list archive)
State New
Headers show
Series Rust KASAN Support | expand

Commit Message

Matthew Maurer Aug. 19, 2024, 9:35 p.m. UTC 
Rust supports KASAN via LLVM, but prior to this patch, the flags aren't
set properly.

Rust hasn't yet enabled software-tagged KWHASAN (only regular HWASAN),
so explicitly prevent Rust from being selected when it is enabled.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Matthew Maurer <mmaurer@google.com>
---
 scripts/Makefile.kasan          | 54 +++++++++++++++++++++++----------
 scripts/Makefile.lib            |  3 ++
 scripts/generate_rust_target.rs |  1 +
 3 files changed, 42 insertions(+), 16 deletions(-)

Comments

Andrey Konovalov Aug. 20, 2024, 5:30 p.m. UTC | #1 
On Mon, Aug 19, 2024 at 11:35 PM Matthew Maurer <mmaurer@google.com> wrote:
>
> Rust supports KASAN via LLVM, but prior to this patch, the flags aren't
> set properly.
>
> Rust hasn't yet enabled software-tagged KWHASAN (only regular HWASAN),
> so explicitly prevent Rust from being selected when it is enabled.

This is done in the next patch, not in this one.

> Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> Signed-off-by: Matthew Maurer <mmaurer@google.com>
> ---
>  scripts/Makefile.kasan          | 54 +++++++++++++++++++++++----------
>  scripts/Makefile.lib            |  3 ++
>  scripts/generate_rust_target.rs |  1 +
>  3 files changed, 42 insertions(+), 16 deletions(-)
>
> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> index aab4154af00a..163640fdefa0 100644
> --- a/scripts/Makefile.kasan
> +++ b/scripts/Makefile.kasan
> @@ -12,6 +12,11 @@ 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
> @@ -41,39 +46,56 @@ CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
>                 $(call cc-option, -fsanitize=kernel-address \
>                 -mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
>
> -# Now, add other parameters enabled similarly in both GCC and Clang.
> -# As some of them are not supported by older compilers, use cc-param.
> -CFLAGS_KASAN += $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
> -               $(call cc-param,asan-stack=$(stack_enable)) \
> -               $(call cc-param,asan-instrument-allocas=1) \
> -               $(call cc-param,asan-globals=1)
> +# The minimum supported `rustc` version has a minimum supported LLVM
> +# version late enough that we can assume support for -asan-mapping-offset

Nit: dot at the end.

> +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.
> -CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1)
> +kasan_params += asan-kernel-mem-intrinsic-prefix=1
>
>  endif # CONFIG_KASAN_GENERIC
>
>  ifdef CONFIG_KASAN_SW_TAGS
>
>  ifdef CONFIG_KASAN_INLINE
> -       instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
> +       kasan_params += hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
>  else
> -       instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1)
> +       kasan_params += hwasan-instrument-with-calls=1
>  endif
>
> -CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
> -               $(call cc-param,hwasan-instrument-stack=$(stack_enable)) \
> -               $(call cc-param,hwasan-use-short-granules=0) \
> -               $(call cc-param,hwasan-inline-all-checks=0) \
> -               $(instrumentation_flags)
> +kasan_params += hwasan-instrument-stack=$(stack_enable) \
> +               hwasan-use-short-granules=0 \
> +               hwasan-inline-all-checks=0

Let's put these kasan_params parts after CFLAGS_KASAN.

> +
> +CFLAGS_KASAN := -fsanitize=kernel-hwaddress
> +RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress \
> +                  -Zsanitizer-recover=kernel-hwaddress

What's the intention of defining RUSTFLAGS_KASAN for SW_TAGS if it's
not supported by Rust? Should this be removed?

If this is just a foundation for potential future support of
Rust+SW_TAGS, please add a comment explaining this. And also please
put the patch that disallows Rust+SW_TAGS before this one, if you keep
RUSTFLAGS_KASAN.

>  # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
>  ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
> -       CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
> +       kasan_params += hwasan-kernel-mem-intrinsic-prefix=1
>  endif
>
>  endif # CONFIG_KASAN_SW_TAGS
>
> -export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE
> +# Add all as-supported KASAN LLVM parameters requested by the configuration

Nit: dot at the end.


> +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, $(kasan_params))
> +endif # CONFIG_RUST
> +
> +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 9f06f6aaf7fc..4a58636705e0 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -167,6 +167,9 @@ ifneq ($(CONFIG_KASAN_HW_TAGS),y)
>  _c_flags += $(if $(patsubst n%,, \
>                 $(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
>                 $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
> +_rust_flags += $(if $(patsubst n%,, \
> +               $(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
> +               $(RUSTFLAGS_KASAN))
>  endif
>  endif
>
> diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
> index ced405d35c5d..c24c2abd67db 100644
> --- a/scripts/generate_rust_target.rs
> +++ b/scripts/generate_rust_target.rs
> @@ -192,6 +192,7 @@ fn main() {
>          }
>          ts.push("features", features);
>          ts.push("llvm-target", "x86_64-linux-gnu");
> +        ts.push("supported-sanitizers", ["kernel-address"]);
>          ts.push("target-pointer-width", "64");
>      } else if cfg.has("LOONGARCH") {
>          panic!("loongarch uses the builtin rustc loongarch64-unknown-none-softfloat target");
> --
> 2.46.0.184.g6999bdac58-goog
>
diff mbox series

Patch

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index aab4154af00a..163640fdefa0 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -12,6 +12,11 @@  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
@@ -41,39 +46,56 @@  CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
 		$(call cc-option, -fsanitize=kernel-address \
 		-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
 
-# Now, add other parameters enabled similarly in both GCC and Clang.
-# As some of them are not supported by older compilers, use cc-param.
-CFLAGS_KASAN += $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
-		$(call cc-param,asan-stack=$(stack_enable)) \
-		$(call cc-param,asan-instrument-allocas=1) \
-		$(call cc-param,asan-globals=1)
+# The minimum supported `rustc` version has a minimum supported LLVM
+# version late enough that we can assume support for -asan-mapping-offset
+RUSTFLAGS_KASAN := -Zsanitizer=kernel-address \
+		   -Zsanitizer-recover=kernel-address \
+		   -Cllvm-args=-asan-mapping-offset=$(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.
-CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1)
+kasan_params += asan-kernel-mem-intrinsic-prefix=1
 
 endif # CONFIG_KASAN_GENERIC
 
 ifdef CONFIG_KASAN_SW_TAGS
 
 ifdef CONFIG_KASAN_INLINE
-	instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
+	kasan_params += hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
 else
-	instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1)
+	kasan_params += hwasan-instrument-with-calls=1
 endif
 
-CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
-		$(call cc-param,hwasan-instrument-stack=$(stack_enable)) \
-		$(call cc-param,hwasan-use-short-granules=0) \
-		$(call cc-param,hwasan-inline-all-checks=0) \
-		$(instrumentation_flags)
+kasan_params += hwasan-instrument-stack=$(stack_enable) \
+		hwasan-use-short-granules=0 \
+		hwasan-inline-all-checks=0
+
+CFLAGS_KASAN := -fsanitize=kernel-hwaddress
+RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress \
+		   -Zsanitizer-recover=kernel-hwaddress
 
 # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
 ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
-	CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
+	kasan_params += hwasan-kernel-mem-intrinsic-prefix=1
 endif
 
 endif # CONFIG_KASAN_SW_TAGS
 
-export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE
+# 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, $(kasan_params))
+endif # CONFIG_RUST
+
+export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 9f06f6aaf7fc..4a58636705e0 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -167,6 +167,9 @@  ifneq ($(CONFIG_KASAN_HW_TAGS),y)
 _c_flags += $(if $(patsubst n%,, \
 		$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
 		$(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
+_rust_flags += $(if $(patsubst n%,, \
+		$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
+		$(RUSTFLAGS_KASAN))
 endif
 endif
 
diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
index ced405d35c5d..c24c2abd67db 100644
--- a/scripts/generate_rust_target.rs
+++ b/scripts/generate_rust_target.rs
@@ -192,6 +192,7 @@  fn main() {
         }
         ts.push("features", features);
         ts.push("llvm-target", "x86_64-linux-gnu");
+        ts.push("supported-sanitizers", ["kernel-address"]);
         ts.push("target-pointer-width", "64");
     } else if cfg.has("LOONGARCH") {
         panic!("loongarch uses the builtin rustc loongarch64-unknown-none-softfloat target");