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Date:   Fri, 1 May 2020 14:58:37 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Julien Grall <julien.grall@arm.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ubsan: fix gcc-10 warnings
Message-ID: <202005011458.039084F70C@keescook>
References: <20200429185948.4189600-1-arnd@arndb.de>
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On Wed, Apr 29, 2020 at 08:59:35PM +0200, Arnd Bergmann wrote:
> The latest compiler expects slightly different function prototypes
> for the ubsan helpers:
> 
> lib/ubsan.c:192:6: error: conflicting types for built-in function '__ubsan_handle_add_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch]
>   192 | void __ubsan_handle_add_overflow(struct overflow_data *data,
>       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/ubsan.c:200:6: error: conflicting types for built-in function '__ubsan_handle_sub_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch]
>   200 | void __ubsan_handle_sub_overflow(struct overflow_data *data,
>       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/ubsan.c:207:6: error: conflicting types for built-in function '__ubsan_handle_mul_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch]
>   207 | void __ubsan_handle_mul_overflow(struct overflow_data *data,
>       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/ubsan.c:214:6: error: conflicting types for built-in function '__ubsan_handle_negate_overflow'; expected 'void(void *, void *)' [-Werror=builtin-declaration-mismatch]
>   214 | void __ubsan_handle_negate_overflow(struct overflow_data *data,
>       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/ubsan.c:234:6: error: conflicting types for built-in function '__ubsan_handle_divrem_overflow'; expected 'void(void *, void *, void *)' [-Werror=builtin-declaration-mismatch]
>   234 | void __ubsan_handle_divrem_overflow(struct overflow_data *data,
>       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Change the Linux implementation to match these, using a local
> typed pointer.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Thanks for that!

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  lib/ubsan.c | 33 +++++++++++++++++----------------
>  1 file changed, 17 insertions(+), 16 deletions(-)
> 
> diff --git a/lib/ubsan.c b/lib/ubsan.c
> index f8c0ccf35f29..cb9af3f6b77e 100644
> --- a/lib/ubsan.c
> +++ b/lib/ubsan.c
> @@ -189,7 +189,7 @@ static void handle_overflow(struct overflow_data *data, void *lhs,
>  	ubsan_epilogue();
>  }
>  
> -void __ubsan_handle_add_overflow(struct overflow_data *data,
> +void __ubsan_handle_add_overflow(void *data,
>  				void *lhs, void *rhs)
>  {
>  
> @@ -197,23 +197,23 @@ void __ubsan_handle_add_overflow(struct overflow_data *data,
>  }
>  EXPORT_SYMBOL(__ubsan_handle_add_overflow);
>  
> -void __ubsan_handle_sub_overflow(struct overflow_data *data,
> +void __ubsan_handle_sub_overflow(void *data,
>  				void *lhs, void *rhs)
>  {
>  	handle_overflow(data, lhs, rhs, '-');
>  }
>  EXPORT_SYMBOL(__ubsan_handle_sub_overflow);
>  
> -void __ubsan_handle_mul_overflow(struct overflow_data *data,
> +void __ubsan_handle_mul_overflow(void *data,
>  				void *lhs, void *rhs)
>  {
>  	handle_overflow(data, lhs, rhs, '*');
>  }
>  EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
>  
> -void __ubsan_handle_negate_overflow(struct overflow_data *data,
> -				void *old_val)
> +void __ubsan_handle_negate_overflow(void *_data, void *old_val)
>  {
> +	struct overflow_data *data = _data;
>  	char old_val_str[VALUE_LENGTH];
>  
>  	if (suppress_report(&data->location))
> @@ -231,9 +231,9 @@ void __ubsan_handle_negate_overflow(struct overflow_data *data,
>  EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
>  
>  
> -void __ubsan_handle_divrem_overflow(struct overflow_data *data,
> -				void *lhs, void *rhs)
> +void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)
>  {
> +	struct overflow_data *data = _data;
>  	char rhs_val_str[VALUE_LENGTH];
>  
>  	if (suppress_report(&data->location))
> @@ -326,10 +326,9 @@ void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
>  }
>  EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
>  
> -void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data,
> -				void *ptr)
> +void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr)
>  {
> -
> +	struct type_mismatch_data_v1 *data = _data;
>  	struct type_mismatch_data_common common_data = {
>  		.location = &data->location,
>  		.type = data->type,
> @@ -341,8 +340,9 @@ void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data,
>  }
>  EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
>  
> -void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, void *index)
> +void __ubsan_handle_out_of_bounds(void *_data, void *index)
>  {
> +	struct out_of_bounds_data *data = _data;
>  	char index_str[VALUE_LENGTH];
>  
>  	if (suppress_report(&data->location))
> @@ -357,9 +357,9 @@ void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, void *index)
>  }
>  EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
>  
> -void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
> -					void *lhs, void *rhs)
> +void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs)
>  {
> +	struct shift_out_of_bounds_data *data = _data;
>  	struct type_descriptor *rhs_type = data->rhs_type;
>  	struct type_descriptor *lhs_type = data->lhs_type;
>  	char rhs_str[VALUE_LENGTH];
> @@ -399,8 +399,9 @@ void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
>  EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
>  
>  
> -void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
> +void __ubsan_handle_builtin_unreachable(void *_data)
>  {
> +	struct unreachable_data *data = _data;
>  	ubsan_prologue(&data->location, "unreachable");
>  	pr_err("calling __builtin_unreachable()\n");
>  	ubsan_epilogue();
> @@ -408,9 +409,9 @@ void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
>  }
>  EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
>  
> -void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
> -				void *val)
> +void __ubsan_handle_load_invalid_value(void *_data, void *val)
>  {
> +	struct invalid_value_data *data = _data;
>  	char val_str[VALUE_LENGTH];
>  
>  	if (suppress_report(&data->location))
> -- 
> 2.26.0
> 

-- 
Kees Cook