diff mbox series

[v3,22/39] kasan: introduce CONFIG_KASAN_HW_TAGS

Message ID 76937ee6e88d0d1fc98003e503f31fe7b14a6a52.1600987622.git.andreyknvl@google.com
State New
Headers show
Series kasan: add hardware tag-based mode for arm64 | expand

Commit Message

Andrey Konovalov Sept. 24, 2020, 10:50 p.m. UTC
This patch adds a configuration option for a new KASAN mode called
hardware tag-based KASAN. This mode uses the memory tagging approach
like the software tag-based mode, but relies on arm64 Memory Tagging
Extension feature for tag management and access checking.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
Change-Id: I246c2def9fffa6563278db1bddfbe742ca7bdefe
---
 lib/Kconfig.kasan | 59 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 41 insertions(+), 18 deletions(-)

Comments

Marco Elver Oct. 1, 2020, 5:57 p.m. UTC | #1
On Fri, Sep 25, 2020 at 12:50AM +0200, Andrey Konovalov wrote:
> This patch adds a configuration option for a new KASAN mode called
> hardware tag-based KASAN. This mode uses the memory tagging approach
> like the software tag-based mode, but relies on arm64 Memory Tagging
> Extension feature for tag management and access checking.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

Reviewed-by: Marco Elver <elver@google.com>

> ---
> Change-Id: I246c2def9fffa6563278db1bddfbe742ca7bdefe
> ---
>  lib/Kconfig.kasan | 59 ++++++++++++++++++++++++++++++++---------------
>  1 file changed, 41 insertions(+), 18 deletions(-)
> 
> diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> index b4cf6c519d71..516d3a24f7d7 100644
> --- a/lib/Kconfig.kasan
> +++ b/lib/Kconfig.kasan
> @@ -6,7 +6,10 @@ config HAVE_ARCH_KASAN
>  config HAVE_ARCH_KASAN_SW_TAGS
>  	bool
>  
> -config	HAVE_ARCH_KASAN_VMALLOC
> +config HAVE_ARCH_KASAN_HW_TAGS
> +	bool
> +
> +config HAVE_ARCH_KASAN_VMALLOC
>  	bool
>  
>  config CC_HAS_KASAN_GENERIC
> @@ -20,11 +23,11 @@ config CC_HAS_WORKING_NOSANITIZE_ADDRESS
>  
>  menuconfig KASAN
>  	bool "KASAN: runtime memory debugger"
> -	depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
> -		   (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)
> +	depends on (((HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
> +		     (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)) && \
> +		    CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \
> +		   HAVE_ARCH_KASAN_HW_TAGS
>  	depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
> -	depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS
> -	select SLUB_DEBUG if SLUB

See my comment in the other patch about moving this line again.

>  	select CONSTRUCTORS
>  	select STACKDEPOT
>  	help
> @@ -38,17 +41,23 @@ choice
>  	prompt "KASAN mode"
>  	default KASAN_GENERIC
>  	help
> -	  KASAN has two modes: generic KASAN (similar to userspace ASan,
> -	  x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and
> -	  software tag-based KASAN (a version based on software memory
> -	  tagging, arm64 only, similar to userspace HWASan, enabled with
> -	  CONFIG_KASAN_SW_TAGS).
> +	  KASAN has three modes:
> +	  1. generic KASAN (similar to userspace ASan,
> +	     x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC),
> +	  2. software tag-based KASAN (arm64 only, based on software
> +	     memory tagging (similar to userspace HWASan), enabled with
> +	     CONFIG_KASAN_SW_TAGS), and
> +	  3. hardware tag-based KASAN (arm64 only, based on hardware
> +	     memory tagging, enabled with CONFIG_KASAN_HW_TAGS).
> +
> +	  All KASAN modes are strictly debugging features.
>  
> -	  Both generic and tag-based KASAN are strictly debugging features.
> +	  For better error reports enable CONFIG_STACKTRACE.
>  
>  config KASAN_GENERIC
>  	bool "Generic mode"
>  	depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
> +	select SLUB_DEBUG if SLUB
>  	help
>  	  Enables generic KASAN mode.
>  
> @@ -61,20 +70,21 @@ config KASAN_GENERIC
>  	  and introduces an overhead of ~x1.5 for the rest of the allocations.
>  	  The performance slowdown is ~x3.
>  
> -	  For better error detection enable CONFIG_STACKTRACE.
> -
>  	  Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
>  	  (the resulting kernel does not boot).
>  
>  config KASAN_SW_TAGS
>  	bool "Software tag-based mode"
>  	depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
> +	select SLUB_DEBUG if SLUB
>  	help
>  	  Enables software tag-based KASAN mode.
>  
> -	  This mode requires Top Byte Ignore support by the CPU and therefore
> -	  is only supported for arm64. This mode requires Clang version 7.0.0
> -	  or later.
> +	  This mode require software memory tagging support in the form of
> +	  HWASan-like compiler instrumentation.
> +
> +	  Currently this mode is only implemented for arm64 CPUs and relies on
> +	  Top Byte Ignore. This mode requires Clang version 7.0.0 or later.
>  
>  	  This mode consumes about 1/16th of available memory at kernel start
>  	  and introduces an overhead of ~20% for the rest of the allocations.
> @@ -82,15 +92,27 @@ config KASAN_SW_TAGS
>  	  casting and comparison, as it embeds tags into the top byte of each
>  	  pointer.
>  
> -	  For better error detection enable CONFIG_STACKTRACE.
> -
>  	  Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
>  	  (the resulting kernel does not boot).
>  
> +config KASAN_HW_TAGS
> +	bool "Hardware tag-based mode"
> +	depends on HAVE_ARCH_KASAN_HW_TAGS
> +	depends on SLUB
> +	help
> +	  Enables hardware tag-based KASAN mode.
> +
> +	  This mode requires hardware memory tagging support, and can be used
> +	  by any architecture that provides it.
> +
> +	  Currently this mode is only implemented for arm64 CPUs starting from
> +	  ARMv8.5 and relies on Memory Tagging Extension and Top Byte Ignore.
> +
>  endchoice
>  
>  choice
>  	prompt "Instrumentation type"
> +	depends on KASAN_GENERIC || KASAN_SW_TAGS
>  	default KASAN_OUTLINE
>  
>  config KASAN_OUTLINE
> @@ -114,6 +136,7 @@ endchoice
>  
>  config KASAN_STACK_ENABLE
>  	bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
> +	depends on KASAN_GENERIC || KASAN_SW_TAGS
>  	help
>  	  The LLVM stack address sanitizer has a know problem that
>  	  causes excessive stack usage in a lot of functions, see
> -- 
> 2.28.0.681.g6f77f65b4e-goog
>
diff mbox series

Patch

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index b4cf6c519d71..516d3a24f7d7 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -6,7 +6,10 @@  config HAVE_ARCH_KASAN
 config HAVE_ARCH_KASAN_SW_TAGS
 	bool
 
-config	HAVE_ARCH_KASAN_VMALLOC
+config HAVE_ARCH_KASAN_HW_TAGS
+	bool
+
+config HAVE_ARCH_KASAN_VMALLOC
 	bool
 
 config CC_HAS_KASAN_GENERIC
@@ -20,11 +23,11 @@  config CC_HAS_WORKING_NOSANITIZE_ADDRESS
 
 menuconfig KASAN
 	bool "KASAN: runtime memory debugger"
-	depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
-		   (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)
+	depends on (((HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
+		     (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)) && \
+		    CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \
+		   HAVE_ARCH_KASAN_HW_TAGS
 	depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
-	depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS
-	select SLUB_DEBUG if SLUB
 	select CONSTRUCTORS
 	select STACKDEPOT
 	help
@@ -38,17 +41,23 @@  choice
 	prompt "KASAN mode"
 	default KASAN_GENERIC
 	help
-	  KASAN has two modes: generic KASAN (similar to userspace ASan,
-	  x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and
-	  software tag-based KASAN (a version based on software memory
-	  tagging, arm64 only, similar to userspace HWASan, enabled with
-	  CONFIG_KASAN_SW_TAGS).
+	  KASAN has three modes:
+	  1. generic KASAN (similar to userspace ASan,
+	     x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC),
+	  2. software tag-based KASAN (arm64 only, based on software
+	     memory tagging (similar to userspace HWASan), enabled with
+	     CONFIG_KASAN_SW_TAGS), and
+	  3. hardware tag-based KASAN (arm64 only, based on hardware
+	     memory tagging, enabled with CONFIG_KASAN_HW_TAGS).
+
+	  All KASAN modes are strictly debugging features.
 
-	  Both generic and tag-based KASAN are strictly debugging features.
+	  For better error reports enable CONFIG_STACKTRACE.
 
 config KASAN_GENERIC
 	bool "Generic mode"
 	depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
+	select SLUB_DEBUG if SLUB
 	help
 	  Enables generic KASAN mode.
 
@@ -61,20 +70,21 @@  config KASAN_GENERIC
 	  and introduces an overhead of ~x1.5 for the rest of the allocations.
 	  The performance slowdown is ~x3.
 
-	  For better error detection enable CONFIG_STACKTRACE.
-
 	  Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
 	  (the resulting kernel does not boot).
 
 config KASAN_SW_TAGS
 	bool "Software tag-based mode"
 	depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
+	select SLUB_DEBUG if SLUB
 	help
 	  Enables software tag-based KASAN mode.
 
-	  This mode requires Top Byte Ignore support by the CPU and therefore
-	  is only supported for arm64. This mode requires Clang version 7.0.0
-	  or later.
+	  This mode require software memory tagging support in the form of
+	  HWASan-like compiler instrumentation.
+
+	  Currently this mode is only implemented for arm64 CPUs and relies on
+	  Top Byte Ignore. This mode requires Clang version 7.0.0 or later.
 
 	  This mode consumes about 1/16th of available memory at kernel start
 	  and introduces an overhead of ~20% for the rest of the allocations.
@@ -82,15 +92,27 @@  config KASAN_SW_TAGS
 	  casting and comparison, as it embeds tags into the top byte of each
 	  pointer.
 
-	  For better error detection enable CONFIG_STACKTRACE.
-
 	  Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
 	  (the resulting kernel does not boot).
 
+config KASAN_HW_TAGS
+	bool "Hardware tag-based mode"
+	depends on HAVE_ARCH_KASAN_HW_TAGS
+	depends on SLUB
+	help
+	  Enables hardware tag-based KASAN mode.
+
+	  This mode requires hardware memory tagging support, and can be used
+	  by any architecture that provides it.
+
+	  Currently this mode is only implemented for arm64 CPUs starting from
+	  ARMv8.5 and relies on Memory Tagging Extension and Top Byte Ignore.
+
 endchoice
 
 choice
 	prompt "Instrumentation type"
+	depends on KASAN_GENERIC || KASAN_SW_TAGS
 	default KASAN_OUTLINE
 
 config KASAN_OUTLINE
@@ -114,6 +136,7 @@  endchoice
 
 config KASAN_STACK_ENABLE
 	bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
+	depends on KASAN_GENERIC || KASAN_SW_TAGS
 	help
 	  The LLVM stack address sanitizer has a know problem that
 	  causes excessive stack usage in a lot of functions, see