[4.2.y-ckt stable] Patch "TPM: Avoid reference to potentially freed memory" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    TPM: Avoid reference to potentially freed memory

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From f4d6e1977134b8b450d90822b61490f121f3461d Mon Sep 17 00:00:00 2001
From: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
Date: Thu, 22 Oct 2015 22:32:41 +0200
Subject: TPM: Avoid reference to potentially freed memory

commit eb8ed1eb9a158c460d10205eaff71fd4ac67c160 upstream.

Reference to the 'np' node is dropped before dereferencing the 'sizep' and
'basep' pointers, which could by then point to junk if the node has been
freed.

Refactor code to call 'of_node_put' later.

Fixes: c5df39262dd5 ("drivers/char/tpm: Add securityfs support for event log")
Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
Acked-by: Peter Huewe <PeterHuewe at gmx.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/char/tpm/tpm_of.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index eebe625..40f4150 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -53,17 +53,18 @@ int read_log(struct tpm_bios_log *log)
 		goto cleanup_eio;
 	}

-	of_node_put(np);
 	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
 	if (!log->bios_event_log) {
 		pr_err("%s: ERROR - Not enough memory for BIOS measurements\n",
 		       __func__);
+		of_node_put(np);
 		return -ENOMEM;
 	}

 	log->bios_event_log_end = log->bios_event_log + *sizep;

 	memcpy(log->bios_event_log, __va(be64_to_cpup(basep)), *sizep);
+	of_node_put(np);

 	return 0;

--
1.9.1