Re: [PATCH V10 2/3] IMA: Define a new template field buf

On Mon, 2019-06-24 at 19:03 -0300, Thiago Jung Bauermann wrote:

Hello Prakhar,

Prakhar Srivastava [off-list ref] writes:

quoted

diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index 00dd5a434689..a01a17e5c581 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c

@@ -26,6 +26,7 @@ static struct ima_template_desc builtin_templates[] = {
 	{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
 	{.name = "ima-ng", .fmt = "d-ng|n-ng"},
 	{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
+	{.name = "ima-buf", .fmt = "d-ng|n-ng|buf"},
 	{.name = "", .fmt = ""},	/* placeholder for a custom format */
 };

@@ -43,6 +44,8 @@ static const struct ima_template_field supported_fields[] = {
 	 .field_show = ima_show_template_string},
 	{.field_id = "sig", .field_init = ima_eventsig_init,
 	 .field_show = ima_show_template_sig},
+	{.field_id = "buf", .field_init = ima_eventbuf_init,
+	 .field_show = ima_show_template_buf},
 };
 #define MAX_TEMPLATE_NAME_LEN 15

Currently, MAX_TEMPLATE_NAME_LEN is the length of a template that
contains all valid fields. It may make sense to increase it since
there's a new field being added.

I suggest using a sizeof() to show where the number comes from (and
which can be visually shown to be correct):

#define MAX_TEMPLATE_NAME_LEN sizeof("d|n|d-ng|n-ng|sig|buf")

The sizeof() is calculated at compile time.

MAX_TEMPLATE_NAME_LEN is used when restoring measurements carried over
from a kexec.  'd' and 'd-ng' should not both be defined in the
template description, nor should 'n' and 'n-ng'.  Even without the
duplication, the MAX_TEPLATE_NAME_LEN is greater than the current 15.

Thiago, could you address this as a separate patch?

thanks!

Mimi