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From: Sven Schnelle <svens@linux.ibm.com>
To: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Kees Cook <keescook@chromium.org>, linux-hardening@vger.kernel.org,
        Heiko Carstens <hca@linux.ibm.com>, Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Nico Boehr
 <nrb@linux.ibm.com>, Philipp Rudo <prudo@redhat.com>,
        Baoquan He
 <bhe@redhat.com>, Tao Liu <ltao@redhat.com>,
        Alexander Egorenkov
 <egorenar@linux.ibm.com>,
        linux-s390@vger.kernel.org,
        "Gustavo A. R.
 Silva" <gustavoars@kernel.org>,
        Bill Wendling <morbo@google.com>,
        Justin
 Stitt <justinstitt@google.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 30/82] s390/kexec_file: Refactor intentional wrap-around
 calculation
In-Reply-To: <ZbpXieRZz3BQ6jBH@li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com>
	(Alexander Gordeev's message of "Wed, 31 Jan 2024 15:22:01 +0100")
References: <20240122235208.work.748-kees@kernel.org>
	<20240123002814.1396804-30-keescook@chromium.org>
	<ZbpXieRZz3BQ6jBH@li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com>
Date: Wed, 31 Jan 2024 15:40:31 +0100
Message-ID: <yt9d4jetmuqo.fsf@linux.ibm.com>
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Alexander Gordeev <agordeev@linux.ibm.com> writes:

> On Mon, Jan 22, 2024 at 04:27:05PM -0800, Kees Cook wrote:
>> diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c
>> index 8d207b82d9fe..e5e925423061 100644
>> --- a/arch/s390/kernel/machine_kexec_file.c
>> +++ b/arch/s390/kernel/machine_kexec_file.c
>> @@ -238,6 +238,7 @@ void *kexec_file_add_components(struct kimage *image,
>>  	unsigned long max_command_line_size = LEGACY_COMMAND_LINE_SIZE;
>>  	struct s390_load_data data = {0};
>>  	unsigned long minsize;
>> +	unsigned long sum;
>
> Please, use min_kernel_buf_len instead of sum.
>
> @Sven, could you please correct me if (minsize + max_command_line_size)
> means something else.

Your understanding is correct, minsize + max_command_line_size is the
minimum required size of the kernel image.