[PATCH 3.16 095/192] tpm: fix a kernel memory leak in tpm-sysfs.c

Ben Hutchings
2017-10-09T12:46:41Z

From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

commit 13b47cfcfc60495cde216eef4c01040d76174cbe upstream.

While cleaning up sysfs callback that prints EK we discovered a kernel
memory leak. This commit fixes the issue by zeroing the buffer used for
TPM command/response.

The leak happen when we use either tpm_vtpm_proxy, tpm_ibmvtpm or
xen-tpmfront.

Fixes: 0883743825e3 ("TPM: sysfs functions consolidation")
Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/char/tpm/tpm-sysfs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -54,9 +54,10 @@ static ssize_t pubek_show(struct device
ssize_t err;
int i, rc;
char *str = buf;
-
struct tpm_chip *chip = dev_get_drvdata(dev);

+ memset(&tpm_cmd, 0, sizeof(tpm_cmd));
+
tpm_cmd.header.in = tpm_readpubek_header;
err = transmit_cmd(chip, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
"attempting to read the PUBEK");