From: Mimi Zohar <zohar@linux.ibm.com>
To: Scott Branden <scott.branden@broadcom.com>,
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-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH v6 8/8] ima: add FIRMWARE_PARTIAL_READ support
Date: Fri, 05 Jun 2020 19:48:15 -0400 [thread overview]
Message-ID: <1591400895.4615.45.camel@linux.ibm.com> (raw)
In-Reply-To: <824407ae-8ab8-0fe3-bd72-270fce960ac5@broadcom.com>
On Fri, 2020-06-05 at 16:31 -0700, Scott Branden wrote:
> Hi Mimi,
>
> On 2020-06-05 4:19 p.m., Mimi Zohar wrote:
> > Hi Scott,
> >
> > On Fri, 2020-06-05 at 15:59 -0700, Scott Branden wrote:
> >> @@ -648,6 +667,9 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
> >> enum ima_hooks func;
> >> u32 secid;
> >>
> >> + if (!file && read_id == READING_FIRMWARE_PARTIAL_READ)
> >> + return 0;
> > The file should be measured on the pre security hook, not here on the
> > post security hook. Here, whether "file" is defined or not, is
> > irrelevant. The test should just check "read_id".
> OK, will remove the !file from here.
thanks!
> >
> > Have you tested measuring the firmware by booting a system with
> > "ima_policy=tcb" specified on the boot command line and compared the
> > measurement entry in the IMA measurement list with the file hash (eg.
> > sha1sum, sha256sum)?
> Yes, I enabled IMA in my kernel and added ima_policy=tsb to the boot
> command line,
>
> Here are the entries from
> /sys/kernel/security/ima/ascii_runtime_measurements of the files I am
> accessing.
> Please let me know if I am doing anything incorrectly.
>
> 10 4612bce355b2dbc45ecd95e17001636be8832c7f ima-ng
> sha1:fddd9a28c2b15acf3b0fc9ec0cf187cb2153d7f2
> /lib/firmware/vk-boot1-bcm958401m2.ecdsa.bin
> 10 4c0eb0fc30eb7ac3a30a27f05c1d2a8d28d6a9ec ima-ng
> sha1:b16d343dd63352d10309690c71b110762a9444c3
> /lib/firmware/vk-boot2-bcm958401m2_a72.ecdsn
>
> The sha1 sum matches:
> root@genericx86-64:/sys/kernel/security/ima# sha1sum
> /lib/firmware/vk-boot1-bcm958401m2.ecdsa.bin
> fddd9a28c2b15acf3b0fc9ec0cf187cb2153d7f2
> /lib/firmware/vk-boot1-bcm958401m2.ecdsa.bin
>
> root@genericx86-64:/sys/kernel/security/ima# sha1sum
> /lib/firmware/vk-boot2-bcm958401m2_a72.ecdsa.bin
> b16d343dd63352d10309690c71b110762a9444c3
> /lib/firmware/vk-boot2-bcm958401m2_a72.ecdsa.bin
Looks good!
(FYI, a larger hash algorithm can be specified in the Kconfig or
"ima_hash=" on the boot command line.)
Mimi
prev parent reply other threads:[~2020-06-05 23:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-05 22:59 [PATCH v6 0/8] firmware: add partial read support in request_firmware_into_buf Scott Branden
2020-06-05 22:59 ` [PATCH v6 1/8] fs: introduce kernel_pread_file* support Scott Branden
2020-06-06 3:20 ` Matthew Wilcox
2020-06-06 4:56 ` Scott Branden
2020-06-05 22:59 ` [PATCH v6 2/8] firmware: add offset to request_firmware_into_buf Scott Branden
2020-06-06 1:34 ` kernel test robot
2020-06-05 22:59 ` [PATCH v6 3/8] test_firmware: add partial read support for request_firmware_into_buf Scott Branden
2020-06-05 22:59 ` [PATCH v6 4/8] firmware: test partial file reads of request_firmware_into_buf Scott Branden
2020-06-05 22:59 ` [PATCH v6 5/8] bcm-vk: add bcm_vk UAPI Scott Branden
2020-06-05 22:59 ` [PATCH v6 6/8] misc: bcm-vk: add Broadcom VK driver Scott Branden
2020-06-05 22:59 ` [PATCH v6 7/8] MAINTAINERS: bcm-vk: add maintainer for Broadcom VK Driver Scott Branden
2020-06-05 22:59 ` [PATCH v6 8/8] ima: add FIRMWARE_PARTIAL_READ support Scott Branden
2020-06-05 23:19 ` Mimi Zohar
2020-06-05 23:31 ` Scott Branden
2020-06-05 23:48 ` Mimi Zohar [this message]
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