2024-04-24 22:40:41

by Kees Cook

Subject: [PATCH v2] ubsan: Avoid i386 UBSAN handler crashes with Clang

When generating Runtime Calls, Clang doesn't respect the -mregparm=3
option used on i386. Hopefully this will be fixed correctly in Clang 19:
https://github.com/llvm/llvm-project/pull/89707
but we need to fix this for earlier Clang versions today. Force the
calling convention to use non-register arguments.

Reported-by: Erhard Furtner <[email protected]>
Closes: https://github.com/KSPP/linux/issues/350
Signed-off-by: Kees Cook <[email protected]>
---
Cc: Marco Elver <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Bill Wendling <[email protected]>
Cc: Justin Stitt <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
v2:
- use email address in Reported-by
- link to upstream llvm bug in ubsan.h comment
- drop needless /**/
- explicitly test Clang version
v1: https://lore.kernel.org/lkml/[email protected]/
---
lib/ubsan.h | 41 +++++++++++++++++++++++++++--------------
1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/lib/ubsan.h b/lib/ubsan.h
index 50ef50811b7c..07e37d4429b4 100644
--- a/lib/ubsan.h
+++ b/lib/ubsan.h
@@ -124,19 +124,32 @@ typedef s64 s_max;
typedef u64 u_max;
#endif

-void __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
-void __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
-void __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
-void __ubsan_handle_negate_overflow(void *_data, void *old_val);
-void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
-void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
-void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
-void __ubsan_handle_out_of_bounds(void *_data, void *index);
-void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
-void __ubsan_handle_builtin_unreachable(void *_data);
-void __ubsan_handle_load_invalid_value(void *_data, void *val);
-void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
- unsigned long align,
- unsigned long offset);
+/*
+ * When generating Runtime Calls, Clang doesn't respect the -mregparm=3
+ * option used on i386: https://github.com/llvm/llvm-project/issues/89670
+ * Fix this for earlier Clang versions by forcing the calling convention
+ * to use non-register arguments.
+ */
+#if defined(CONFIG_X86_32) && \
+ defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 190000
+# define ubsan_linkage asmlinkage
+#else
+# define ubsan_linkage
+#endif
+
+void ubsan_linkage __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_negate_overflow(void *_data, void *old_val);
+void ubsan_linkage __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
+void ubsan_linkage __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
+void ubsan_linkage __ubsan_handle_out_of_bounds(void *_data, void *index);
+void ubsan_linkage __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_builtin_unreachable(void *_data);
+void ubsan_linkage __ubsan_handle_load_invalid_value(void *_data, void *val);
+void ubsan_linkage __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
+ unsigned long align,
+ unsigned long offset);

#endif
--
2.34.1

2024-04-26 17:49:54

by Nathan Chancellor

Subject: Re: [PATCH v2] ubsan: Avoid i386 UBSAN handler crashes with Clang

On Wed, Apr 24, 2024 at 03:40:29PM -0700, Kees Cook wrote:
> When generating Runtime Calls, Clang doesn't respect the -mregparm=3
> option used on i386. Hopefully this will be fixed correctly in Clang 19:
> https://github.com/llvm/llvm-project/pull/89707
> but we need to fix this for earlier Clang versions today. Force the
> calling convention to use non-register arguments.
>
> Reported-by: Erhard Furtner <[email protected]>
> Closes: https://github.com/KSPP/linux/issues/350
> Signed-off-by: Kees Cook <[email protected]>

Acked-by: Nathan Chancellor <[email protected]>

> ---
> Cc: Marco Elver <[email protected]>
> Cc: Andrey Konovalov <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Nathan Chancellor <[email protected]>
> Cc: Nick Desaulniers <[email protected]>
> Cc: Bill Wendling <[email protected]>
> Cc: Justin Stitt <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> v2:
> - use email address in Reported-by
> - link to upstream llvm bug in ubsan.h comment
> - drop needless /**/
> - explicitly test Clang version
> v1: https://lore.kernel.org/lkml/[email protected]/
> ---
> lib/ubsan.h | 41 +++++++++++++++++++++++++++--------------
> 1 file changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/lib/ubsan.h b/lib/ubsan.h
> index 50ef50811b7c..07e37d4429b4 100644
> --- a/lib/ubsan.h
> +++ b/lib/ubsan.h
> @@ -124,19 +124,32 @@ typedef s64 s_max;
> typedef u64 u_max;
> #endif
>
> -void __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
> -void __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
> -void __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
> -void __ubsan_handle_negate_overflow(void *_data, void *old_val);
> -void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
> -void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
> -void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
> -void __ubsan_handle_out_of_bounds(void *_data, void *index);
> -void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
> -void __ubsan_handle_builtin_unreachable(void *_data);
> -void __ubsan_handle_load_invalid_value(void *_data, void *val);
> -void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
> - unsigned long align,
> - unsigned long offset);
> +/*
> + * When generating Runtime Calls, Clang doesn't respect the -mregparm=3
> + * option used on i386: https://github.com/llvm/llvm-project/issues/89670
> + * Fix this for earlier Clang versions by forcing the calling convention
> + * to use non-register arguments.
> + */
> +#if defined(CONFIG_X86_32) && \
> + defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 190000
> +# define ubsan_linkage asmlinkage
> +#else
> +# define ubsan_linkage
> +#endif
> +
> +void ubsan_linkage __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_negate_overflow(void *_data, void *old_val);
> +void ubsan_linkage __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
> +void ubsan_linkage __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
> +void ubsan_linkage __ubsan_handle_out_of_bounds(void *_data, void *index);
> +void ubsan_linkage __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_builtin_unreachable(void *_data);
> +void ubsan_linkage __ubsan_handle_load_invalid_value(void *_data, void *val);
> +void ubsan_linkage __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
> + unsigned long align,
> + unsigned long offset);
>
> #endif
> --
> 2.34.1
>

2024-04-26 20:28:13

by Justin Stitt

Subject: Re: [PATCH v2] ubsan: Avoid i386 UBSAN handler crashes with Clang

Hi,

On Wed, Apr 24, 2024 at 03:40:29PM -0700, Kees Cook wrote:
> When generating Runtime Calls, Clang doesn't respect the -mregparm=3
> option used on i386. Hopefully this will be fixed correctly in Clang 19:
> https://github.com/llvm/llvm-project/pull/89707
> but we need to fix this for earlier Clang versions today. Force the
> calling convention to use non-register arguments.
>
> Reported-by: Erhard Furtner <[email protected]>
> Closes: https://github.com/KSPP/linux/issues/350
> Signed-off-by: Kees Cook <[email protected]>
> ---
> Cc: Marco Elver <[email protected]>
> Cc: Andrey Konovalov <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Nathan Chancellor <[email protected]>
> Cc: Nick Desaulniers <[email protected]>
> Cc: Bill Wendling <[email protected]>
> Cc: Justin Stitt <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> v2:
> - use email address in Reported-by
> - link to upstream llvm bug in ubsan.h comment
> - drop needless /**/
> - explicitly test Clang version
> v1: https://lore.kernel.org/lkml/[email protected]/
> ---
> lib/ubsan.h | 41 +++++++++++++++++++++++++++--------------
> 1 file changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/lib/ubsan.h b/lib/ubsan.h
> index 50ef50811b7c..07e37d4429b4 100644
> --- a/lib/ubsan.h
> +++ b/lib/ubsan.h
> @@ -124,19 +124,32 @@ typedef s64 s_max;
> typedef u64 u_max;
> #endif
>
> -void __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
> -void __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
> -void __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
> -void __ubsan_handle_negate_overflow(void *_data, void *old_val);
> -void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
> -void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
> -void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
> -void __ubsan_handle_out_of_bounds(void *_data, void *index);
> -void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
> -void __ubsan_handle_builtin_unreachable(void *_data);
> -void __ubsan_handle_load_invalid_value(void *_data, void *val);
> -void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
> - unsigned long align,
> - unsigned long offset);
> +/*
> + * When generating Runtime Calls, Clang doesn't respect the -mregparm=3
> + * option used on i386: https://github.com/llvm/llvm-project/issues/89670
> + * Fix this for earlier Clang versions by forcing the calling convention
> + * to use non-register arguments.
> + */
> +#if defined(CONFIG_X86_32) && \
> + defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 190000
> +# define ubsan_linkage asmlinkage

Clever.

Acked-by: Justin Stitt <[email protected]>

> +#else
> +# define ubsan_linkage
> +#endif
> +
> +void ubsan_linkage __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_negate_overflow(void *_data, void *old_val);
> +void ubsan_linkage __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
> +void ubsan_linkage __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
> +void ubsan_linkage __ubsan_handle_out_of_bounds(void *_data, void *index);
> +void ubsan_linkage __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
> +void ubsan_linkage __ubsan_handle_builtin_unreachable(void *_data);
> +void ubsan_linkage __ubsan_handle_load_invalid_value(void *_data, void *val);
> +void ubsan_linkage __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
> + unsigned long align,
> + unsigned long offset);
>
> #endif
> --
> 2.34.1
>

Thanks
Justin