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Commit 86b98203 authored by Jarkko Sakkinen's avatar Jarkko Sakkinen Committed by Greg Kroah-Hartman
Browse files

tpm: tpm_vtpm_proxy: fix a race condition in /dev/vtpmx creation 



commit f4032d615f90970d6c3ac1d9c0bce3351eb4445c upstream.

/dev/vtpmx is made visible before 'workqueue' is initialized, which can
lead to a memory corruption in the worst case scenario.

Address this by initializing 'workqueue' as the very first step of the
driver initialization.

Cc: stable@vger.kernel.org
Fixes: 6f99612e ("tpm: Proxy driver for supporting multiple emulated TPMs")
Reviewed-by: default avatarStefan Berger <stefanb@linux.ibm.com>
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@tuni.fi>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 96a16069

drivers/char/tpm/tpm_vtpm_proxy.c

+7 −23
Original line number Diff line number Diff line
@@ -693,37 +693,21 @@ static struct miscdevice vtpmx_miscdev = { 
	.fops = &vtpmx_fops,

};



static int vtpmx_init(void)

{

	return misc_register(&vtpmx_miscdev);

}



static void vtpmx_cleanup(void)

{

	misc_deregister(&vtpmx_miscdev);

}



static int __init vtpm_module_init(void)

{

	int rc;



	rc = vtpmx_init();

	if (rc) {

		pr_err("couldn't create vtpmx device\n");

		return rc;

	}



	workqueue = create_workqueue("tpm-vtpm");

	if (!workqueue) {

		pr_err("couldn't create workqueue\n");

		rc = -ENOMEM;

		goto err_vtpmx_cleanup;

		return -ENOMEM;

	}



	return 0;



err_vtpmx_cleanup:

	vtpmx_cleanup();

	rc = misc_register(&vtpmx_miscdev);

	if (rc) {

		pr_err("couldn't create vtpmx device\n");

		destroy_workqueue(workqueue);

	}



	return rc;

}
@@ -731,7 +715,7 @@ static int __init vtpm_module_init(void) 
static void __exit vtpm_module_exit(void)

{

	destroy_workqueue(workqueue);

	vtpmx_cleanup();

	misc_deregister(&vtpmx_miscdev);

}



module_init(vtpm_module_init);