linux-kernel - Re: [tpmdd-devel] [PATCH RFC v3 5/5] tpm2: expose resource manager via a device link /dev/tpms<n>

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Message-ID: <1484751663.2717.10.camel@HansenPartnership.com>
Date:   Wed, 18 Jan 2017 10:01:03 -0500
From:   James Bottomley <James.Bottomley@...senPartnership.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        tpmdd-devel@...ts.sourceforge.net
Cc:     open list <linux-kernel@...r.kernel.org>,
        linux-security-module@...r.kernel.org
Subject: Re: [tpmdd-devel] [PATCH RFC v3 5/5] tpm2: expose resource manager
 via    a device link /dev/tpms<n>

On Mon, 2017-01-16 at 15:12 +0200, Jarkko Sakkinen wrote:
> From: James Bottomley <James.Bottomley@...senPartnership.com>
> 
> Currently the Resource Manager (RM) is not exposed to userspace. 
>  Make
> this exposure via a separate device, which can now be opened multiple
> times because each read/write transaction goes separately via the RM.
> 
> Concurrency is protected by the chip->tpm_mutex for each read/write
> transaction separately.  The TPM is cleared of all transient objects
> by the time the mutex is dropped, so there should be no interference
> between the kernel and userspace.

There's actually a missing kfree of context_buf on the tpms_release
path as well.  This patch fixes it up.

James

---

commit 778425973c532a0c1ec2b5b2ccd7ff995e2cc9db
Author: James Bottomley <James.Bottomley@...senPartnership.com>
Date:   Wed Jan 18 09:58:23 2017 -0500

    add missing kfree to tpms_release

diff --git a/drivers/char/tpm/tpms-dev.c b/drivers/char/tpm/tpms-dev.c
index c10b308..6bb687f 100644
--- a/drivers/char/tpm/tpms-dev.c
+++ b/drivers/char/tpm/tpms-dev.c
@@ -37,6 +37,7 @@ static int tpms_release(struct inode *inode, struct file *file)
 	struct tpms_priv *priv = container_of(fpriv, struct tpms_priv, priv);
 
 	tpm_common_release(file, fpriv);
+	kfree(priv->space.context_buf);
 	kfree(priv);
 
 	return 0;