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Date:   Sun, 24 Sep 2023 19:06:25 +0200
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Subject: Re: [PATCH] scsi: target: tcmu: Annotate struct tcmu_tmr with
 __counted_by
To:     Kees Cook <keescook@chromium.org>
Cc:     "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, linux-hardening@vger.kernel.org
References: <20230922175300.work.148-kees@kernel.org>
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From:   Bodo Stroesser <bostroesser@gmail.com>
In-Reply-To: <20230922175300.work.148-kees@kernel.org>
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On 22.09.23 19:53, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct tcmu_tmr.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Bodo Stroesser <bostroesser@gmail.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: linux-scsi@vger.kernel.org
> Cc: target-devel@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>   drivers/target/target_core_user.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
> index 22cc6cac0ba2..7eb94894bd68 100644
> --- a/drivers/target/target_core_user.c
> +++ b/drivers/target/target_core_user.c
> @@ -201,7 +201,7 @@ struct tcmu_tmr {
>   
>   	uint8_t tmr_type;
>   	uint32_t tmr_cmd_cnt;
> -	int16_t tmr_cmd_ids[];
> +	int16_t tmr_cmd_ids[] __counted_by(tmr_cmd_cnt);
>   };
>   
>   /*

Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>

Thank you,
Bodo