Re: [PATCH v3 5/6] IMA: add hook to measure critical data from kernel components

From: Mimi Zohar
Date: Mon Aug 31 2020 - 14:24:12 EST


> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 52cbbc1f7ea2..a889bf40cb7e 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -869,6 +869,30 @@ void ima_kexec_cmdline(int kernel_fd, const void *buf, int size)
> fdput(f);
> }
>
> +/**
> + * ima_measure_critical_data - measure critical data
> + * @event_name: name for the given data
> + * @event_data_source: name of the event data source
> + * @buf: pointer to buffer containing data to measure
> + * @buf_len: length of buffer(in bytes)
> + * @measure_buf_hash: if set to true - will measure hash of the buf,
> + * instead of buf
> + *
> + * Buffers can only be measured, not appraised.
> + */
> +int ima_measure_critical_data(const char *event_name,
> + const char *event_data_source,
> + const void *buf, int buf_len,
> + bool measure_buf_hash)
> +{
> + if (!event_name || !event_data_source || !buf || !buf_len)
> + return -EINVAL;
> +
> + return process_buffer_measurement(NULL, buf, buf_len, event_name,
> + CRITICAL_DATA, 0, event_data_source,
> + measure_buf_hash);

This is exactly what I'm concerned about. Failure to measure data may
be audited, but should never fail.

Mimi

> +}