From: Jia Zhang <zhang.jia@linux.alibaba.com>
To: jarkko.sakkinen@linux.intel.com, peterhuewe@gmx.de, jgg@ziepe.ca,
tweek@google.com
Cc: linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
zhang.jia@linux.alibaba.com
Subject: [PATCH 1/2] tpm/eventlog/tpm1: Simplify walking over *pos measurements
Date: Sun, 6 Jan 2019 15:23:18 +0800 [thread overview]
Message-ID: <1546759399-45360-1-git-send-email-zhang.jia@linux.alibaba.com> (raw)
The sanity check would be easier, especially for the first read
of binary_bios_measurements from the beginning.
Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com>
---
drivers/char/tpm/eventlog/tpm1.c | 37 ++++++++++++++-----------------------
1 file changed, 14 insertions(+), 23 deletions(-)
diff --git a/drivers/char/tpm/eventlog/tpm1.c b/drivers/char/tpm/eventlog/tpm1.c
index 58c8478..4cf8303 100644
--- a/drivers/char/tpm/eventlog/tpm1.c
+++ b/drivers/char/tpm/eventlog/tpm1.c
@@ -74,7 +74,7 @@
/* 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;
}
--
1.8.3.1
next reply other threads:[~2019-01-06 7:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-06 7:23 Jia Zhang [this message]
2019-01-06 7:23 ` [PATCH 2/2] tpm/eventlog/tpm1: Fix off-by-1 when reading binary_bios_measurements Jia Zhang
2019-01-10 17:36 ` Jarkko Sakkinen
2019-01-10 17:32 ` [PATCH 1/2] tpm/eventlog/tpm1: Simplify walking over *pos measurements Jarkko Sakkinen
2019-01-11 8:29 ` Jia Zhang
2019-01-11 8:59 [PATCH v2 0/2] tpm/eventlog/tpm1: Small fixes Jia Zhang
2019-01-11 8:59 ` [PATCH 1/2] tpm/eventlog/tpm1: Simplify walking over *pos measurements Jia Zhang
2019-01-16 22:09 ` Jarkko Sakkinen
2019-01-17 1:32 ` Jia Zhang
2019-01-18 15:18 ` Jarkko Sakkinen
2019-01-19 7:48 ` Jia Zhang
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