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authorJia Zhang <zhang.jia@linux.alibaba.com>2019-01-11 16:59:32 +0800
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2019-02-13 09:47:00 +0200
commitbb3b6b0fc57182b568ded61c55eff8a02fcfe27b (patch)
treef05b6ecfd53614425b7bd3efc20f63f617f40e3a /drivers/char/tpm
parent442601e87a4769a8daba4976ec3afa5222ca211d (diff)
tpm: Simplify the measurements loop
The responsibility of tpm1_bios_measurements_start() is to walk over the first *pos measurements, ensuring the skipped and to-be-read measurements are not out-of-boundary. This commit simplifies the loop by employing a do-while loop with the necessary sanity check. Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com> Reviewd-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char/tpm')
-rw-r--r--drivers/char/tpm/eventlog/tpm1.c37
1 files changed, 14 insertions, 23 deletions
diff --git a/drivers/char/tpm/eventlog/tpm1.c b/drivers/char/tpm/eventlog/tpm1.c
index 58c84784ba25..4cf830333684 100644
--- a/drivers/char/tpm/eventlog/tpm1.c
+++ b/drivers/char/tpm/eventlog/tpm1.c
@@ -74,7 +74,7 @@ static const char* tcpa_pc_event_id_strings[] = {
/* returns pointer to start of pos. entry of tcg log */
static void *tpm1_bios_measurements_start(struct seq_file *m, loff_t *pos)
{
- loff_t i;
+ loff_t i = 0;
struct tpm_chip *chip = m->private;
struct tpm_bios_log *log = &chip->log;
void *addr = log->bios_event_log;
@@ -83,38 +83,29 @@ static void *tpm1_bios_measurements_start(struct seq_file *m, loff_t *pos)
u32 converted_event_size;
u32 converted_event_type;
-
/* read over *pos measurements */
- for (i = 0; i < *pos; i++) {
+ do {
event = addr;
+ /* check if current entry is valid */
+ if (addr + sizeof(struct tcpa_event) >= limit)
+ return NULL;
+
converted_event_size =
do_endian_conversion(event->event_size);
converted_event_type =
do_endian_conversion(event->event_type);
- if ((addr + sizeof(struct tcpa_event)) < limit) {
- if ((converted_event_type == 0) &&
- (converted_event_size == 0))
- return NULL;
- addr += (sizeof(struct tcpa_event) +
- converted_event_size);
- }
- }
-
- /* now check if current entry is valid */
- if ((addr + sizeof(struct tcpa_event)) >= limit)
- return NULL;
-
- event = addr;
+ if (((converted_event_type == 0) && (converted_event_size == 0))
+ || ((addr + sizeof(struct tcpa_event) + converted_event_size)
+ >= limit))
+ return NULL;
- converted_event_size = do_endian_conversion(event->event_size);
- converted_event_type = do_endian_conversion(event->event_type);
+ if (i++ == *pos)
+ break;
- if (((converted_event_type == 0) && (converted_event_size == 0))
- || ((addr + sizeof(struct tcpa_event) + converted_event_size)
- >= limit))
- return NULL;
+ addr += (sizeof(struct tcpa_event) + converted_event_size);
+ } while (1);
return addr;
}