Re: [PATCH 2/5] tpm: Change calc_tpm2_event_size signature

[Jarkko Sakkinen]

On Mon, Feb 11, 2019 at 03:30:49PM +0100, b...@semihalf.com wrote:
> From: Bartosz Szczepanek 
> 
> Pass tcg_efi_specid_event as an argument instead of tcg_pcr_event, as the
> former is what is actually needed to compute event size. tcg_pcr_event
> structure describes TPM event log header (even though its name), from where
> efispecid can be extracted -- it seems cleaner and less misleading to do it
> out of calc_tpm2_event_size function.
> 
> Also, use ssize_t instead of int for event log size.
> 
> Signed-off-by: Bartosz Szczepanek 

Unreviewable without call sites. NAK.

/Jarkko

[PATCH 2/5] tpm: Change calc_tpm2_event_size signature

[bsz]

From: Bartosz Szczepanek 

Pass tcg_efi_specid_event as an argument instead of tcg_pcr_event, as the
former is what is actually needed to compute event size. tcg_pcr_event
structure describes TPM event log header (even though its name), from where
efispecid can be extracted -- it seems cleaner and less misleading to do it
out of calc_tpm2_event_size function.

Also, use ssize_t instead of int for event log size.

Signed-off-by: Bartosz Szczepanek 
---
 lib/tpm.c | 20 +---
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/lib/tpm.c b/lib/tpm.c
index aaeeafe52426..263ccfdaefa5 100644
--- a/lib/tpm.c
+++ b/lib/tpm.c
@@ -15,6 +15,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /*
  * calc_tpm2_event_size() - calculate the event size, where event
@@ -23,19 +24,18 @@
  * Family "2.0".
 
  * @event: event whose size is to be calculated.
- * @event_header: the first event in the event log.
+ * @efispecid: pointer to structure describing algorithms used.
  *
- * Returns size of the event. If it is an invalid event, returns 0.
+ * Returns size of the event. If it is an invalid event, returns -EINVAL.
  */
-int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
-struct tcg_pcr_event *event_header)
+ssize_t calc_tpm2_event_size(struct tcg_pcr_event2 *event,
+struct tcg_efi_specid_event *efispecid)
 {
-   struct tcg_efi_specid_event *efispecid;
struct tcg_event_field *event_field;
void *marker;
void *marker_start;
u32 halg_size;
-   size_t size;
+   ssize_t size;
u16 halg;
int i;
int j;
@@ -45,11 +45,9 @@ int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
+ sizeof(event->count);
 
-   efispecid = (struct tcg_efi_specid_event *)event_header->event;
-
/* Check if event is malformed. */
if (event->count > efispecid->num_algs)
-   return 0;
+   return -EINVAL;
 
for (i = 0; i < event->count; i++) {
halg_size = sizeof(event->digests[i].alg_id);
@@ -64,7 +62,7 @@ int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
}
/* Algorithm without known length. Such event is unparseable. */
if (j == efispecid->num_algs)
-   return 0;
+   return -EINVAL;
}
 
event_field = (struct tcg_event_field *)marker;
@@ -73,7 +71,7 @@ int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
size = marker - marker_start;
 
if ((event->event_type == 0) && (event_field->event_size == 0))
-   return 0;
+   return -EINVAL;
 
return size;
 }
-- 
2.14.4