Re: [Linux-ima-devel] [PATCH v6 03/10] ima: permit duplicate measurement list entries

From: Dmitry Kasatkin
Date: Tue Nov 08 2016 - 14:47:53 EST


On Fri, Oct 21, 2016 at 5:44 AM, Thiago Jung Bauermann
<bauerman@xxxxxxxxxxxxxxxxxx> wrote:
> From: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
>
> Measurements carried across kexec need to be added to the IMA
> measurement list, but should not prevent measurements of the newly
> booted kernel from being added to the measurement list. This patch
> adds support for allowing duplicate measurements.
>
> The "boot_aggregate" measurement entry is the delimiter between soft
> boots.
>
> Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
> ---
> security/integrity/ima/ima_queue.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
> index 4b1bb7787839..12d1b040bca9 100644
> --- a/security/integrity/ima/ima_queue.c
> +++ b/security/integrity/ima/ima_queue.c
> @@ -65,11 +65,12 @@ static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value,
> }
>
> /* ima_add_template_entry helper function:
> - * - Add template entry to measurement list and hash table.
> + * - Add template entry to the measurement list and hash table, for
> + * all entries except those carried across kexec.
> *
> * (Called with ima_extend_list_mutex held.)
> */
> -static int ima_add_digest_entry(struct ima_template_entry *entry)
> +static int ima_add_digest_entry(struct ima_template_entry *entry, int flags)
> {
> struct ima_queue_entry *qe;
> unsigned int key;
> @@ -85,8 +86,10 @@ static int ima_add_digest_entry(struct ima_template_entry *entry)
> list_add_tail_rcu(&qe->later, &ima_measurements);
>
> atomic_long_inc(&ima_htable.len);
> - key = ima_hash_key(entry->digest);
> - hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
> + if (flags) {

It looks lile "bool", not flags in fact.


> + key = ima_hash_key(entry->digest);
> + hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]);
> + }
> return 0;
> }
>
> @@ -126,7 +129,7 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,
> }
> }
>
> - result = ima_add_digest_entry(entry);
> + result = ima_add_digest_entry(entry, 1);
> if (result < 0) {
> audit_cause = "ENOMEM";
> audit_info = 0;
> @@ -155,7 +158,7 @@ int ima_restore_measurement_entry(struct ima_template_entry *entry)
> int result = 0;
>
> mutex_lock(&ima_extend_list_mutex);
> - result = ima_add_digest_entry(entry);
> + result = ima_add_digest_entry(entry, 0);
> mutex_unlock(&ima_extend_list_mutex);
> return result;
> }
> --
> 2.7.4
>
>
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--
Thanks,
Dmitry