2006-05-26 14:43:31

by Seiji Munetoh

Subject: [PATCH 2/2] tpm: bios log parsing fixes

This patch changes the binary output format to actual ACPI TCPA log
structure since the current format does not contain all event-data
information that need to verify the PCRs in TPM.
tpm_binary_bios_measurements_show() uses get_event_name() to convert the
binary event-data to ascii format, and puts them as binary. However, to
verify the PCRs, the event-data must be a actual binary event-data used
by SHA1 calc. in BIOS.

So, I think actual ACPI TCPA log is good for this binary output format.
That way, any userland tools easily parse this data with reference to
TCG PC specification.

Signed-off-by: Seiji Munetoh <[email protected]>
---

--- linux-2.6.17-rc4/drivers/char/tpm/tpm_bios.c 2006-05-16
09:33:06.000000000 +0900
+++ linux-2.6.17-rc4-tpm/drivers/char/tpm/tpm_bios.c 2006-05-24
07:11:44.000000000 +0900
@@ -275,53 +284,13 @@ static int get_event_name(char *dest, st

static int tpm_binary_bios_measurements_show(struct seq_file *m, void
*v)
{
-
- char *eventname;
- char data[4];
- u32 help;
- int i, len;
struct tcpa_event *event = (struct tcpa_event *) v;
- unsigned char *event_entry =
- (unsigned char *) (v + sizeof(struct tcpa_event));
-
- eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL);
- if (!eventname) {
- printk(KERN_ERR "%s: ERROR - No Memory for event name\n ",
- __func__);
- return -ENOMEM;
- }
-
- /* 1st: PCR used is in little-endian format (4 bytes) */
- help = le32_to_cpu(event->pcr_index);
- memcpy(data, &help, 4);
- for (i = 0; i < 4; i++)
- seq_putc(m, data[i]);
-
- /* 2nd: SHA1 (20 bytes) */
- for (i = 0; i < 20; i++)
- seq_putc(m, event->pcr_value[i]);
+ char *data = (char *) v;
+ int i;

- /* 3rd: event type identifier (4 bytes) */
- help = le32_to_cpu(event->event_type);
- memcpy(data, &help, 4);
- for (i = 0; i < 4; i++)
+ for (i = 0;i < sizeof(struct tcpa_event) + event->event_size; i++)
seq_putc(m, data[i]);

- len = 0;
-
- len += get_event_name(eventname, event, event_entry);
-
- /* 4th: filename <= 255 + \'0' delimiter */
- if (len > TCG_EVENT_NAME_LEN_MAX)
- len = TCG_EVENT_NAME_LEN_MAX;
-
- for (i = 0; i < len; i++)
- seq_putc(m, eventname[i]);
-
- /* 5th: delimiter */
- seq_putc(m, '\0');
-
- kfree(eventname);
return 0;
}

2006-05-26 14:45:52

by Kylene Jo Hall

Subject: Re: [PATCH 2/2] tpm: bios log parsing fixes

Ack'ed-by: Kylene Hall <[email protected]>

On Fri, 2006-05-26 at 23:43 +0900, Seiji Munetoh wrote:
> This patch changes the binary output format to actual ACPI TCPA log
> structure since the current format does not contain all event-data
> information that need to verify the PCRs in TPM.
> tpm_binary_bios_measurements_show() uses get_event_name() to convert the
> binary event-data to ascii format, and puts them as binary. However, to
> verify the PCRs, the event-data must be a actual binary event-data used
> by SHA1 calc. in BIOS.
>
> So, I think actual ACPI TCPA log is good for this binary output format.
> That way, any userland tools easily parse this data with reference to
> TCG PC specification.
>
> Signed-off-by: Seiji Munetoh <[email protected]>
> ---
>
> --- linux-2.6.17-rc4/drivers/char/tpm/tpm_bios.c 2006-05-16
> 09:33:06.000000000 +0900
> +++ linux-2.6.17-rc4-tpm/drivers/char/tpm/tpm_bios.c 2006-05-24
> 07:11:44.000000000 +0900
> @@ -275,53 +284,13 @@ static int get_event_name(char *dest, st
>
> static int tpm_binary_bios_measurements_show(struct seq_file *m, void
> *v)
> {
> -
> - char *eventname;
> - char data[4];
> - u32 help;
> - int i, len;
> struct tcpa_event *event = (struct tcpa_event *) v;
> - unsigned char *event_entry =
> - (unsigned char *) (v + sizeof(struct tcpa_event));
> -
> - eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL);
> - if (!eventname) {
> - printk(KERN_ERR "%s: ERROR - No Memory for event name\n ",
> - __func__);
> - return -ENOMEM;
> - }
> -
> - /* 1st: PCR used is in little-endian format (4 bytes) */
> - help = le32_to_cpu(event->pcr_index);
> - memcpy(data, &help, 4);
> - for (i = 0; i < 4; i++)
> - seq_putc(m, data[i]);
> -
> - /* 2nd: SHA1 (20 bytes) */
> - for (i = 0; i < 20; i++)
> - seq_putc(m, event->pcr_value[i]);
> + char *data = (char *) v;
> + int i;
>
> - /* 3rd: event type identifier (4 bytes) */
> - help = le32_to_cpu(event->event_type);
> - memcpy(data, &help, 4);
> - for (i = 0; i < 4; i++)
> + for (i = 0;i < sizeof(struct tcpa_event) + event->event_size; i++)
> seq_putc(m, data[i]);
>
> - len = 0;
> -
> - len += get_event_name(eventname, event, event_entry);
> -
> - /* 4th: filename <= 255 + \'0' delimiter */
> - if (len > TCG_EVENT_NAME_LEN_MAX)
> - len = TCG_EVENT_NAME_LEN_MAX;
> -
> - for (i = 0; i < len; i++)
> - seq_putc(m, eventname[i]);
> -
> - /* 5th: delimiter */
> - seq_putc(m, '\0');
> -
> - kfree(eventname);
> return 0;
> }
>
>
>
>