diff mbox series

[2/2] kbuild: rust: Enable KASAN support

Message ID 20240725232126.1996981-3-mmaurer@google.com (mailing list archive)
State New
Headers show
Series [1/2] kbuild: rust: Define probing macros for rustc | expand

Commit Message

Matthew Maurer July 25, 2024, 11:20 p.m. UTC
Rust supports KASAN via LLVM, but prior to this patch, the flags aren't
set properly.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Matthew Maurer <mmaurer@google.com>
---
 scripts/Makefile.kasan | 46 +++++++++++++++++++++++++++++++++++++++++-
 scripts/Makefile.lib   |  3 +++
 2 files changed, 48 insertions(+), 1 deletion(-)

Comments

Andrey Konovalov July 25, 2024, 11:57 p.m. UTC | #1
On Fri, Jul 26, 2024 at 1:21 AM Matthew Maurer <mmaurer@google.com> wrote:
>
> Rust supports KASAN via LLVM, but prior to this patch, the flags aren't
> set properly.
>
> Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> Signed-off-by: Matthew Maurer <mmaurer@google.com>

Hi Matthew,

>  CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
> +RUSTFLAGS_KASAN_MINIMAL := -Zsanitizer=kernel-address -Zsanitizer-recover=kernel-address

If I recall correctly, the reason we need CFLAGS_KASAN_MINIMAL is
because older compilers don't support some of the additional options.
With Rust, this shouldn't be needed, as it requires a modern compiler
that does support all needed options. E.g., for CONFIG_KASAN_SW_TAGS,
we also don't have the MINIMAL thing for the same reason. (Possibly,
we also already don't need this for GENERIC KASAN, as the GCC version
requirement was raised a few times since KASAN was introduced.)

>         # Now add all the compiler specific options that are valid standalone
>         CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
>          $(call cc-param,asan-globals=1) \
>          $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
>          $(call cc-param,asan-instrument-allocas=1)
> +       ifdef CONFIG_RUST
> +               RUSTFLAGS_KASAN := $(RUSTFLAGS_KASAN_SHADOW) \
> +                $(call rustc-param,asan-globals=1) \
> +                $(call rustc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
> +                $(call rustc-param,asan-instrument-allocas=1)

I'm wondering if there's a way to avoid duplicating all options for
Rust. Perhaps, some kind of macro?

Thanks!
Dmitry Vyukov July 26, 2024, 10:23 a.m. UTC | #2
On Fri, 26 Jul 2024 at 01:57, Andrey Konovalov <andreyknvl@gmail.com> wrote:
>
> On Fri, Jul 26, 2024 at 1:21 AM Matthew Maurer <mmaurer@google.com> wrote:
> >
> > Rust supports KASAN via LLVM, but prior to this patch, the flags aren't
> > set properly.

This is great, thanks, Matthew!

Does Rust support KUnit tests?
It would be good to add at least a simple positive test similar to the
existing ones so that the support does not get rotten soon.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/kasan/kasan_test.c



> > Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> > Signed-off-by: Matthew Maurer <mmaurer@google.com>
>
> Hi Matthew,
>
> >  CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
> > +RUSTFLAGS_KASAN_MINIMAL := -Zsanitizer=kernel-address -Zsanitizer-recover=kernel-address
>
> If I recall correctly, the reason we need CFLAGS_KASAN_MINIMAL is
> because older compilers don't support some of the additional options.
> With Rust, this shouldn't be needed, as it requires a modern compiler
> that does support all needed options. E.g., for CONFIG_KASAN_SW_TAGS,
> we also don't have the MINIMAL thing for the same reason. (Possibly,
> we also already don't need this for GENERIC KASAN, as the GCC version
> requirement was raised a few times since KASAN was introduced.)
>
> >         # Now add all the compiler specific options that are valid standalone
> >         CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
> >          $(call cc-param,asan-globals=1) \
> >          $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
> >          $(call cc-param,asan-instrument-allocas=1)
> > +       ifdef CONFIG_RUST
> > +               RUSTFLAGS_KASAN := $(RUSTFLAGS_KASAN_SHADOW) \
> > +                $(call rustc-param,asan-globals=1) \
> > +                $(call rustc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
> > +                $(call rustc-param,asan-instrument-allocas=1)
>
> I'm wondering if there's a way to avoid duplicating all options for
> Rust. Perhaps, some kind of macro?
>
> Thanks!
Miguel Ojeda July 26, 2024, 12:36 p.m. UTC | #3
On Fri, Jul 26, 2024 at 12:23 PM Dmitry Vyukov <dvyukov@google.com> wrote:
>
> This is great, thanks, Matthew!
>
> Does Rust support KUnit tests?
> It would be good to add at least a simple positive test similar to the
> existing ones so that the support does not get rotten soon.
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/kasan/kasan_test.c

Yeah, we have Rust doctests converted into KUnit tests, as well as
upcoming `#[test]`s support (also handled as KUnit tests). For this, I
assume the latter would make more sense, but we have to merge it.

Cheers,
Miguel
diff mbox series

Patch

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 390658a2d5b7..84572c473e23 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -12,6 +12,7 @@  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),)
 
 ifdef CONFIG_KASAN_STACK
 	stack_enable := 1
@@ -28,6 +29,7 @@  else
 endif
 
 CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
+RUSTFLAGS_KASAN_MINIMAL := -Zsanitizer=kernel-address -Zsanitizer-recover=kernel-address
 
 # -fasan-shadow-offset fails without -fsanitize
 CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
@@ -36,13 +38,36 @@  CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
 			-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
 
 ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
+	KASAN_SHADOW_SUPPORTED := n
+else
+	KASAN_SHADOW_SUPPORTED := y
+endif
+
+ifdef CONFIG_RUST
+	RUSTFLAGS_KASAN_SHADOW := $(call rustc-option $(RUSTFLAGS_KASAN_MINIMAL) \
+				  -Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET))
+	ifeq ($(strip $(RUSTFLAGS_KASAN_SHADOW)),)
+		KASAN_SHADOW_SUPPORTED := n
+	endif
+endif
+
+ifeq ($(KASAN_SHADOW_SUPPORTED),y)
 	CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
+	ifdef CONFIG_RUST
+		RUSTFLAGS_KASAN := $(RUSTFLAGS_KASAN_MINIMAL)
+	endif
 else
 	# Now add all the compiler specific options that are valid standalone
 	CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
 	 $(call cc-param,asan-globals=1) \
 	 $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
 	 $(call cc-param,asan-instrument-allocas=1)
+	ifdef CONFIG_RUST
+		RUSTFLAGS_KASAN := $(RUSTFLAGS_KASAN_SHADOW) \
+		 $(call rustc-param,asan-globals=1) \
+		 $(call rustc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
+		 $(call rustc-param,asan-instrument-allocas=1)
+	endif
 endif
 
 CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable))
@@ -52,6 +77,11 @@  CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable))
 # memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures.
 CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1)
 
+ifdef CONFIG_RUST
+	RUSTFLAGS_KASAN += $(call rustc-param,asan-stack=$(stack_enable))
+	RUSTFLAGS_KASAN += $(call rustc-param,asan-kernel-mem-intrinsic-prefix=1)
+endif
+
 endif # CONFIG_KASAN_GENERIC
 
 ifdef CONFIG_KASAN_SW_TAGS
@@ -73,6 +103,20 @@  ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
 CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
 endif
 
+ifdef CONFIG_RUST
+	ifdef CONFIG_KASAN_INLINE
+		rust_instrumentation_flags := $(call rustc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
+	else
+		rust_instrumentation_flags := $(call rustc-param,hwasan-instrument-with-calls=1)
+	endif
+	RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress -Zsanitizer-recover=kernel-hwaddress \
+			   $(call rustc-param,hwasan-instrument-stack=$(stack_enable)) \
+			   $(call rustc-param,hwasan-use-short-granules=0) \
+			   $(call rustc-param,hwasan-inline-all-checks=0) \
+			   $(call rustc-param,hwasan-kernel-mem-intrinsic-prefix=1) \
+			   $(instrumentation_flags)
+endif
+
 endif # CONFIG_KASAN_SW_TAGS
 
-export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE
+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