From: Scott Branden <scott.branden@broadcom.com>
To: Mimi Zohar <zohar@kernel.org>,
Luis Chamberlain <mcgrof@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
David Brown <david.brown@linaro.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Shuah Khan <shuah@kernel.org>,
bjorn.andersson@linaro.org,
Shuah Khan <skhan@linuxfoundation.org>,
Arnd Bergmann <arnd@arndb.de>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
Olof Johansson <olof@lixom.net>,
Andrew Morton <akpm@linux-foundation.org>,
Dan Carpenter <dan.carpenter@oracle.com>,
Colin Ian King <colin.king@canonical.com>,
Kees Cook <keescook@chromium.org>, Takashi Iwai <tiwai@suse.de>,
linux-kselftest@vger.kernel.org, Andy Gross <agross@kernel.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
linux-integrity <linux-integrity@vger.kernel.org>
Subject: Re: [PATCH v5 1/7] fs: introduce kernel_pread_file* support
Date: Wed, 13 May 2020 11:57:09 -0700 [thread overview]
Message-ID: <104a1eea-6b55-d857-04b9-d13aed9a36fd@broadcom.com> (raw)
In-Reply-To: <0e6b5f65-8c61-b02e-7d35-b4ae52aebcf3@broadcom.com>
On 2020-05-13 11:53 a.m., Scott Branden wrote:
> Hi Mimi,
>
> On 2020-05-13 11:39 a.m., Mimi Zohar wrote:
>> [Cc'ing linux-security-module, linux-integrity]
>>
>> On Thu, 2020-05-07 at 17:27 -0700, Scott Branden wrote:
>>> Add kernel_pread_file* support to kernel to allow for partial read
>>> of files with an offset into the file. Existing kernel_read_file
>>> functions call new kernel_pread_file functions with offset=0 and
>>> flags=KERNEL_PREAD_FLAG_WHOLE.
>>>
>>> Signed-off-by: Scott Branden <scott.branden@broadcom.com>
>>> ---
>> <snip>
>>
>>> @@ -941,14 +955,16 @@ int kernel_read_file(struct file *file, void
>>> **buf, loff_t *size,
> The checkpatch shows this as kernel_read_file when it is actually the
> new function kernel_pread_file.
typo: "checkpatch" should be "patch diff"
> Please see the call to kernel_pread_file from kernel_read_file in the
> complete patch rather this snippet.
>>> if (bytes == 0)
>>> break;
>>> +
>>> + buf_pos += bytes;
>>> }
>>> - if (pos != i_size) {
>>> + if (pos != read_end) {
>>> ret = -EIO;
>>> goto out_free;
>>> }
>>> - ret = security_kernel_post_read_file(file, *buf, i_size, id);
>>> + ret = security_kernel_post_read_file(file, *buf, alloc_size, id);
>>> if (!ret)
>>> *size = pos;
>> Prior to the patch set that introduced this security hook, firmware
>> would be read twice, once for measuring/appraising the firmware and
>> again reading the file contents into memory. Partial reads will break
>> both IMA's measuring the file and appraising the file signatures.
> The partial file read support is needed for request_firmware_into_buf
> from drivers. The EXPORT_SYMBOL_GPL is being removed so that
> there can be no abuse of the partial file read support. Such file
> integrity checks are not needed for this use case. The partial file
> (firmware image) is actually downloaded in portions and verified on
> the device it is loaded to.
>
> Regards,
> Scott
next prev parent reply other threads:[~2020-05-13 18:57 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-08 0:27 [PATCH v5 0/7] firmware: add partial read support in request_firmware_into_buf Scott Branden
2020-05-08 0:27 ` [PATCH v5 1/7] fs: introduce kernel_pread_file* support Scott Branden
2020-05-13 0:27 ` Luis Chamberlain
2020-05-13 6:23 ` Scott Branden
2020-05-13 6:51 ` Greg Kroah-Hartman
2020-05-13 8:16 ` Scott Branden
2020-05-13 18:39 ` Mimi Zohar
2020-05-13 18:53 ` Scott Branden
2020-05-13 18:57 ` Scott Branden [this message]
2020-05-13 19:03 ` Mimi Zohar
2020-05-13 19:18 ` Scott Branden
2020-05-13 19:39 ` Mimi Zohar
2020-05-13 19:41 ` Scott Branden
2020-05-13 21:20 ` Mimi Zohar
2020-05-13 21:28 ` Luis Chamberlain
2020-05-13 22:12 ` Mimi Zohar
2020-05-13 22:48 ` Scott Branden
2020-05-13 23:00 ` Mimi Zohar
2020-05-13 23:34 ` Kees Cook
2020-05-13 23:58 ` Mimi Zohar
2020-05-08 0:27 ` [PATCH v5 2/7] firmware: add offset to request_firmware_into_buf Scott Branden
2020-05-13 0:33 ` Luis Chamberlain
2020-05-13 18:35 ` Scott Branden
2020-05-15 20:44 ` Luis Chamberlain
2020-05-08 0:27 ` [PATCH v5 3/7] test_firmware: add partial read support for request_firmware_into_buf Scott Branden
2020-05-13 0:35 ` Luis Chamberlain
2020-05-08 0:27 ` [PATCH v5 4/7] firmware: test partial file reads of request_firmware_into_buf Scott Branden
2020-05-08 0:27 ` [PATCH v5 5/7] bcm-vk: add bcm_vk UAPI Scott Branden
2020-05-08 0:27 ` [PATCH v5 7/7] MAINTAINERS: bcm-vk: add maintainer for Broadcom VK Driver Scott Branden
[not found] ` <20200508002739.19360-7-scott.branden@broadcom.com>
2020-05-13 0:38 ` [PATCH v5 6/7] misc: bcm-vk: add Broadcom VK driver Luis Chamberlain
2020-05-13 6:31 ` Scott Branden
2020-05-13 6:50 ` Greg Kroah-Hartman
2020-05-13 12:30 ` Luis Chamberlain
2020-05-13 18:39 ` Scott Branden
2020-05-13 16:23 ` [PATCH v5 0/7] firmware: add partial read support in request_firmware_into_buf Mimi Zohar
2020-05-15 20:47 ` Luis Chamberlain
2020-05-15 23:28 ` Scott Branden
2020-05-16 1:05 ` Luis Chamberlain
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