diff mbox series

[v2,2/3] kbuild: rust: Enable KASAN support

Message ID 20240812232910.2026387-3-mmaurer@google.com (mailing list archive)
State New
Headers show
Series [v2,1/3] kbuild: rust: Define probing macros for rustc | expand

Commit Message

Matthew Maurer Aug. 12, 2024, 11:29 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          | 51 +++++++++++++++++++++++----------
 scripts/Makefile.lib            |  3 ++
 scripts/generate_rust_target.rs |  1 +
 3 files changed, 40 insertions(+), 15 deletions(-)

Comments

Andrey Konovalov Aug. 13, 2024, 10:53 p.m. UTC | #1 
On Tue, Aug 13, 2024 at 1:29 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>
> ---
>  scripts/Makefile.kasan          | 51 +++++++++++++++++++++++----------
>  scripts/Makefile.lib            |  3 ++
>  scripts/generate_rust_target.rs |  1 +
>  3 files changed, 40 insertions(+), 15 deletions(-)
>
> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> index 390658a2d5b7..bfd37be9cc45 100644
> --- a/scripts/Makefile.kasan
> +++ b/scripts/Makefile.kasan
> @@ -12,6 +12,9 @@ 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)))
>
>  ifdef CONFIG_KASAN_STACK
>         stack_enable := 1
> @@ -28,6 +31,7 @@ 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 \
> @@ -35,44 +39,61 @@ CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
>                         $(call cc-option, -fsanitize=kernel-address \
>                         -mllvm -asan-mapping-offset=$(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_SHADOW := $(RUSTFLAGS_KASAN_MINIMAL) \
> +                         -Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET)
> +
> +KASAN_PARAMS :=
> +
>  ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
>         CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
> +       # We still need to consider this case for Rust because we want Rust code
> +       # to match the behavior of possibly old C compilers when linked together.
> +       ifdef CONFIG_RUST
> +               RUSTFLAGS_KASAN := $(RUSTFLAGS_KASAN_MINIMAL)
> +       endif

Eh, this is getting ugly. I sent a patch that simplifies the KASAN
Makefile, please rebase your changes on top of it.

>  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)) \
> -        $(call cc-param,asan-instrument-allocas=1)
> +       KASAN_PARAMS += asan-globals=1 asan-instrumentation-with-call-threshold=$(call_threshold) asan-instrument-allocas=1
> +       CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW)
> +       ifdef CONFIG_RUST
> +               RUSTFLAGS_KASAN := $(RUSTFLAGS_KASAN_SHADOW)
> +       endif
>  endif
>
> -CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable))
> +KASAN_PARAMS += asan-stack=$(stack_enable)
>
>  # 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 $(instrumentation_params)

What are instrumentation_params? instrumentation_flags? They are not
defined in the Makefile anymore.

> +CFLAGS_KASAN := -fsanitize=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)
>  endif
>
> +ifdef CONFIG_RUST
> +       RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress -Zsanitizer-recover=kernel-hwaddress
> +endif

Let's change the order of the definitions to:

1. CFLAGS_KASAN
2. RUSTFLAGS_KASAN
3. KASAN_PARAMS


> +
>  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))
> +RUSTFLAGS_KASAN += $(call check-args, rustc-param, $(KASAN_PARAMS))
> +
> +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index fe3668dc4954..27999da3d382 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -167,6 +167,9 @@ ifneq ($(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 8a0644c0beed..1a4d468c575f 100644
> --- a/scripts/generate_rust_target.rs
> +++ b/scripts/generate_rust_target.rs
> @@ -187,6 +187,7 @@ 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("X86_32") {
>          // This only works on UML, as i386 otherwise needs regparm support in rustc
> --
> 2.46.0.76.ge559c4bf1a-goog
>
diff mbox series

Patch

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 390658a2d5b7..bfd37be9cc45 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -12,6 +12,9 @@  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)))
 
 ifdef CONFIG_KASAN_STACK
 	stack_enable := 1
@@ -28,6 +31,7 @@  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 \
@@ -35,44 +39,61 @@  CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
 			$(call cc-option, -fsanitize=kernel-address \
 			-mllvm -asan-mapping-offset=$(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_SHADOW := $(RUSTFLAGS_KASAN_MINIMAL) \
+			  -Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET)
+
+KASAN_PARAMS :=
+
 ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
 	CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
+	# We still need to consider this case for Rust because we want Rust code
+	# to match the behavior of possibly old C compilers when linked together.
+	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)) \
-	 $(call cc-param,asan-instrument-allocas=1)
+	KASAN_PARAMS += asan-globals=1 asan-instrumentation-with-call-threshold=$(call_threshold) asan-instrument-allocas=1
+	CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW)
+	ifdef CONFIG_RUST
+		RUSTFLAGS_KASAN := $(RUSTFLAGS_KASAN_SHADOW)
+	endif
 endif
 
-CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable))
+KASAN_PARAMS += asan-stack=$(stack_enable)
 
 # 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 $(instrumentation_params)
+CFLAGS_KASAN := -fsanitize=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)
 endif
 
+ifdef CONFIG_RUST
+	RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress -Zsanitizer-recover=kernel-hwaddress
+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))
+RUSTFLAGS_KASAN += $(call check-args, rustc-param, $(KASAN_PARAMS))
+
+export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index fe3668dc4954..27999da3d382 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -167,6 +167,9 @@  ifneq ($(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 8a0644c0beed..1a4d468c575f 100644
--- a/scripts/generate_rust_target.rs
+++ b/scripts/generate_rust_target.rs
@@ -187,6 +187,7 @@  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("X86_32") {
         // This only works on UML, as i386 otherwise needs regparm support in rustc