On 5/15/23 18:25, Jarkko Sakkinen wrote:

From: Jarkko Sakkinen jarkko.sakkinen@tuni.fi

/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: 6f99612e2500 ("tpm: Proxy driver for supporting multiple emulated TPMs") Signed-off-by: Jarkko Sakkinen jarkko.sakkinen@tuni.fi

---

v2:

• Replace vtpmx_cleanup() with destroy_workqueue(): https://lore.kernel.org/linux-integrity/CSLCEYDKKWWE.36POIXVT65SLE@suppilova...
• Fix typo: https://lore.kernel.org/linux-integrity/4651cf1c-423d-05c2-b4c3-9d829a2eadf4...

---

drivers/char/tpm/tpm_vtpm_proxy.c | 30 +++++++----------------------- 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c index 5c865987ba5c..30e953988cab 100644 --- a/drivers/char/tpm/tpm_vtpm_proxy.c +++ b/drivers/char/tpm/tpm_vtpm_proxy.c @@ -683,37 +683,21 @@ 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; } @@ -721,7 +705,7 @@ 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);

Reviewed-by: Stefan Berger stefanb@linux.ibm.com