lkml.org 
[lkml]   [2006]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/2] tpm: bios log parsing fixes
2006/5/19, Alexey Dobriyan <adobriyan@gmail.com>:
> On Fri, May 19, 2006 at 08:29:07AM +0900, Seiji Munetoh wrote:
> > This patch fixes the BINARY output format to actual ACPI TCPA log
> > structure for any userland tool easily parse the binary data with
> > reference to TCG PC specification.
> Do you realize that you break backward compatibility? What was wrong
> with old format?

Yes I do, The problem is the binary output use get_event_name() to convert the
eventdata to ascii format. and the get_event_name() does not support all
eventdata types.Thus userspace application could not get the eventdata which
required to verify the PCRs in TPM.

I think actual ACPI log data is good for the binary output rather than current
unique binary format. It seems we are doing unnecessary transformation.

>
> > --- linux-2.6.17-rc4/drivers/char/tpm/tpm_bios.c
> > +++ linux-2.6.17-rc4-tpm/drivers/char/tpm/tpm_bios.c
> > @@ -275,53 +285,13 @@ 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;
> > }
>
>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-05-22 02:29    [W:0.042 / U:0.244 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site