Re: [PATCH 1/2] crypto: drivers - avoid memcpy size warning

[Herbert Xu]

On Mon, Jul 24, 2023 at 03:53:01PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> Some configurations with gcc-12 or gcc-13 produce a warning for the source
> and destination of a memcpy() in atmel_sha_hmac_compute_ipad_hash() potentially
> overlapping:
> 
> In file included from include/linux/string.h:254,
>                  from drivers/crypto/atmel-sha.c:15:
> drivers/crypto/atmel-sha.c: In function 'atmel_sha_hmac_compute_ipad_hash':
> include/linux/fortify-string.h:57:33: error: '__builtin_memcpy' accessing 129 or more bytes at offsets 408 and 280 overlaps 1 or more bytes at offset 408 [-Werror=restrict]
>    57 | #define __underlying_memcpy     __builtin_memcpy
>       |                                 ^
> include/linux/fortify-string.h:648:9: note: in expansion of macro '__underlying_memcpy'
>   648 |         __underlying_##op(p, q, __fortify_size);                        \
>       |         ^~~~~~~~~~~~~
> include/linux/fortify-string.h:693:26: note: in expansion of macro '__fortify_memcpy_chk'
>   693 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
>       |                          ^~~~~~~~~~~~~~~~~~~~
> drivers/crypto/atmel-sha.c:1773:9: note: in expansion of macro 'memcpy'
>  1773 |         memcpy(hmac->opad, hmac->ipad, bs);
>       |         ^~~~~~
> 
> The same thing happens in two more drivers that have the same logic:

Please send me the configurations which triggers these warnings.
As these are false positives, I'd like to enable them only on the
configurations where they actually cause a problem.

Thanks,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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