[PATCH] tpm: Fix expected number of response bytes of TPM1.2 PCR Extend

Stefan Berger
2017-02-15T16:56:36Z

The TPM1.2 PCR Extend operation only returns 20 bytes in the body,
which is the size of the PCR state.

This fixes a problem where IMA gets errors with every PCR Extend.

Fixes: c659af78eb7b ("tpm: Check size of response before accessing data")
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
---
drivers/char/tpm/tpm-interface.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 6e368ee..bd2128e 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -767,7 +767,7 @@ EXPORT_SYMBOL_GPL(tpm_pcr_read);

#define TPM_ORD_PCR_EXTEND cpu_to_be32(20)
#define EXTEND_PCR_RESULT_SIZE 34
-#define EXTEND_PCR_RESULT_BODY_SIZE 24
+#define EXTEND_PCR_RESULT_BODY_SIZE 20
static const struct tpm_input_header pcrextend_header = {
.tag = TPM_TAG_RQU_COMMAND,
.length = cpu_to_be32(34),
--
2.4.3