From: "Arnd Bergmann" <arnd@arndb.de>
To: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Arnd Bergmann" <arnd@kernel.org>
Cc: "Udipto Goswami" <quic_ugoswami@quicinc.com>,
"John Keeping" <john@keeping.me.uk>,
"Linyu Yuan" <quic_linyyuan@quicinc.com>,
"Dan Carpenter" <error27@gmail.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: functionfs: avoid memcpy() field overflow warning
Date: Mon, 03 Jul 2023 15:05:14 +0200 [thread overview]
Message-ID: <8af6715a-8dc9-4cd4-9a83-acc27e539c54@app.fastmail.com> (raw)
In-Reply-To: <2023070309-outlook-predator-c3dc@gregkh>
On Mon, Jul 3, 2023, at 14:45, Greg Kroah-Hartman wrote:
> On Mon, Jul 03, 2023 at 02:30:32PM +0200, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>>
>> __ffs_func_bind_do_os_desc() copies both the CompatibleID and SubCompatibleID
>> fields of the usb_ext_compat_desc structure into an array, which triggers
>> a warning in the fortified memcpy():
>>
>> In file included from drivers/usb/gadget/function/f_fs.c:17:
>> In file included from include/linux/string.h:254:
>> include/linux/fortify-string.h:592:4: error: call to '__read_overflow2_field' declared with 'warning' attribute: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Werror,-Wattribute-warning]
>> __read_overflow2_field(q_size_field, size);
>>
>> Usually we can avoid this by using a struct_group() inside of the structure
>> definition, but this might cause problems in userspace since it is in a uapi
>> header.
>
> We use this in other uapi .h files, what is unique about these fields
> that makes it so that they can not be used? Because it's not the last
> field?
It's probably ok, and I was overly cautious. I'll send a new version after
some more testing.
Arnd
prev parent reply other threads:[~2023-07-03 13:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-03 12:30 Arnd Bergmann
2023-07-03 12:45 ` Greg Kroah-Hartman
2023-07-03 13:05 ` Arnd Bergmann [this message]
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