Re:

Roberto Sassu
2019-05-24T15:42:43Z

On 5/24/2019 5:12 PM, Mimi Zohar wrote:
> On Mon, 2019-05-20 at 17:06 -0700, Prakhar Srivastava wrote:
>> A buffer(cmdline args) measured into ima cannot be appraised
>> without already being aware of the buffer contents.Since we
>> don't know what cmdline args will be passed (or need to validate
>> what was passed) it is not possible to appraise it.
>>
>> Since hashs are non reversible the raw buffer is needed to
>> recompute the hash.
>> To regenrate the hash of the buffer and appraise the same
>> the contents of the buffer need to be available.
>>
>> A new template field buf is added to the existing ima template
>> fields, which can be used to store/read the buffer itself.
>> Two new fields are added to the ima_event_data to carry the
>> buf and buf_len whenever necessary.
>>
>> Updated the process_buffer_measurement call to add the buf
>> to the ima_event_data.
>> process_buffer_measurement added in "Add a new ima hook
>> ima_kexec_cmdline to measure cmdline args"
>>
>> - Add a new template field 'buf' to be used to store/read
>> the buffer data.
>> - Added two new fields to ima_event_data to hold the buf and
>> buf_len [Suggested by Roberto]
>> -Updated process_buffer_meaurement to add the buffer to
>> ima_event_data
>
> This patch description can be written more concisely.
>
> Patch 1/3 in this series introduces measuring the kexec boot command
> line.  This patch defines a new template field for storing the kexec
> boot command line in the measurement list in order for a remote
> attestation server to verify.
>
> 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 '_'.

Roberto

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