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From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
	Prakhar Srivastava <prsriva02@gmail.com>,
	linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: mjg59@google.com, vgoyal@redhat.com
Subject: Re: Re:
Date: Fri, 24 May 2019 14:09:45 -0400	[thread overview]
Message-ID: <1558721385.3977.84.camel@linux.ibm.com> (raw)
In-Reply-To: <cb0eb785-9050-738e-c1bf-8e769fe096fa@huawei.com>

> >> As mentioned, the first patch description should include a shell
> >> command for verifying the digest in the kexec boot command line
> >> measurement list record against /proc/cmdline.  This patch description
> >> should include a shell command showing how to verify the digest based
> >> on the new field.  Should the new field in the ascii measurement list
> >> be displayed as a string, not hex?
> > 
> > We should define a new type. If the type is DATA_FMT_STRING, spaces are
> > replaced with '_'.
> 
> Or better. Leave it as hex, otherwise there would be a parsing problem
> if there are spaces in the data for a field.

After making a few changes, the measurement list contains the
following kexec-cmdline data:

10 edc32d1e3a5ba7272280a395b6fb56a5ef7c78c3 ima-buf
sha256:4f43b7db850e
88c49dfeffd4b1eb4f021d78033dfb05b07e45eec8d0b45275 
kexec-cmdline
726f6f
743d2f6465762f7364613420726f2072642e6c756b732e757569643d6c756b73
2d6637
3633643737632d653236622d343431642d613734652d62363633636334643832
656120
696d615f706f6c6963793d7463627c61707072616973655f746362

There's probably a better shell command, but the following works to
verify the digest locally against the /proc/cmdline:

$ echo -n -e `cat /proc/cmdline | sed 's/^.*root=/root=/'` | sha256sum
4f43b7db850e88c49dfeffd4b1eb4f021d78033dfb05b07e45eec8d0b4527f65  -

If we leave the "buf" field as ascii-hex, what would the shell command
look like when verifying the digest based on the "buf" field?

Mimi


  reply	other threads:[~2019-05-24 18:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-21  0:06 [PATCH v6 0/3] add new ima hook ima_kexec_cmdline to measure kexec boot cmdline args Prakhar Srivastava
2019-05-21  0:06 ` [PATCH v6 1/3] Add a new ima hook ima_kexec_cmdline to measure " Prakhar Srivastava
2019-05-24 14:56   ` Mimi Zohar
2019-05-21  0:06 ` [PATCH v6 2/3] add a new ima template field buf Prakhar Srivastava
2019-05-21  7:11   ` Roberto Sassu
2019-05-24 15:12   ` Mimi Zohar
2019-05-24 15:42     ` Roberto Sassu
2019-05-24 15:47       ` Re: Roberto Sassu
2019-05-24 18:09         ` Mimi Zohar [this message]
2019-05-24 19:00           ` Re: prakhar srivastava
2019-05-24 19:15             ` Re: Mimi Zohar
2019-05-21  0:06 ` [PATCH v6 3/3] call ima_kexec_cmdline to measure the cmdline args Prakhar Srivastava

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