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SubjectRe: [tpmdd-devel] [PATCH 1/3] vTPM: fixed the limit checking
On 05/05/2015 08:51 PM, Hon Ching(Vicky) Lo wrote:
> Do not skip the last entry of the event log.
>
> Signed-off-by: Hon Ching(Vicky) Lo <honclo@linux.vnet.ibm.com>
> Signed-off-by: Joy Latten <jmlatten@linux.vnet.ibm.com>
>
> Changelog:
> - remove redundant code
> ---
> drivers/char/tpm/tpm_eventlog.c | 5 +----
> 1 files changed, 1 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_eventlog.c b/drivers/char/tpm/tpm_eventlog.c
> index 3a56a13..e77d8c1 100644
> --- a/drivers/char/tpm/tpm_eventlog.c
> +++ b/drivers/char/tpm/tpm_eventlog.c
> @@ -116,11 +116,8 @@ static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
>
> event = v;
>
> - if (event->event_type == 0 && event->event_size == 0)
> - return NULL;
> -
> if ((event->event_type == 0 && event->event_size == 0) ||
> - ((v + sizeof(struct tcpa_event) + event->event_size) >= limit))
> + ((v + sizeof(struct tcpa_event) + event->event_size) > limit))
> return NULL;
>
> (*pos)++;

The limit stems from log->bios_event_log_end and is calculated as follows:

log->bios_event_log_end = log->bios_event_log + len;

The '>=' above is correct since the limit address itself is not part of
the log anymore.

The log is the following sequence of addresses:

[log->bios_event_log ... log->bios_event_log + len - 1 ]

or

[log->bios_event_log ... log->bios_event_log + len [

with ']' meaning inclusive and '[' meaning exclusive.

Stefan



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