* [PATCH v2] char: tpm: vtpm_proxy: Fix race in init
@ 2021-07-08 9:52 Saubhik Mukherjee
2021-07-09 17:37 ` Jarkko Sakkinen
2021-07-09 18:18 ` Stefan Berger
0 siblings, 2 replies; 3+ messages in thread
From: Saubhik Mukherjee @ 2021-07-08 9:52 UTC (permalink / raw)
To: peterhuewe, jarkko, jgg
Cc: Saubhik Mukherjee, linux-integrity, linux-kernel, ldv-project, andrianov
vtpm_module_init calls vtpmx_init which calls misc_register. The file
operations callbacks are registered. So, vtpmx_fops_ioctl can execute in
parallel with rest of vtpm_module_init. vtpmx_fops_ioctl calls
vtpmx_ioc_new_dev, which calls vtpm_proxy_create_device, which calls
vtpm_proxy_work_start, which could read uninitialized workqueue.
To avoid this, create workqueue before vtpmx init.
Found by Linux Driver Verification project (linuxtesting.org).
Fixes: 6f99612e2500 ("tpm: Proxy driver for supporting multiple emulated TPMs")
Signed-off-by: Saubhik Mukherjee <saubhik.mukherjee@gmail.com>
---
Changes since v1 ([0]):
- Add Fixes tag to commit message, as requested by Jarkko in [1].
[0]: https://lkml.org/lkml/2021/6/23/572
[1]: https://lkml.org/lkml/2021/6/29/695
drivers/char/tpm/tpm_vtpm_proxy.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
index 91c772e38bb5..225dfa026a8f 100644
--- a/drivers/char/tpm/tpm_vtpm_proxy.c
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -697,23 +697,22 @@ 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;
+ }
+
+ rc = vtpmx_init();
+ if (rc) {
+ pr_err("couldn't create vtpmx device\n");
+ goto err_destroy_workqueue;
}
return 0;
-err_vtpmx_cleanup:
- vtpmx_cleanup();
+err_destroy_workqueue:
+ destroy_workqueue(workqueue);
return rc;
}
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] char: tpm: vtpm_proxy: Fix race in init
2021-07-08 9:52 [PATCH v2] char: tpm: vtpm_proxy: Fix race in init Saubhik Mukherjee
@ 2021-07-09 17:37 ` Jarkko Sakkinen
2021-07-09 18:18 ` Stefan Berger
1 sibling, 0 replies; 3+ messages in thread
From: Jarkko Sakkinen @ 2021-07-09 17:37 UTC (permalink / raw)
To: Saubhik Mukherjee
Cc: peterhuewe, jgg, linux-integrity, linux-kernel, ldv-project, andrianov
On Thu, Jul 08, 2021 at 03:22:59PM +0530, Saubhik Mukherjee wrote:
> vtpm_module_init calls vtpmx_init which calls misc_register. The file
> operations callbacks are registered. So, vtpmx_fops_ioctl can execute in
> parallel with rest of vtpm_module_init. vtpmx_fops_ioctl calls
> vtpmx_ioc_new_dev, which calls vtpm_proxy_create_device, which calls
> vtpm_proxy_work_start, which could read uninitialized workqueue.
>
> To avoid this, create workqueue before vtpmx init.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Fixes: 6f99612e2500 ("tpm: Proxy driver for supporting multiple emulated TPMs")
> Signed-off-by: Saubhik Mukherjee <saubhik.mukherjee@gmail.com>
> ---
>
> Changes since v1 ([0]):
> - Add Fixes tag to commit message, as requested by Jarkko in [1].
>
> [0]: https://lkml.org/lkml/2021/6/23/572
> [1]: https://lkml.org/lkml/2021/6/29/695
>
> drivers/char/tpm/tpm_vtpm_proxy.c | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
> index 91c772e38bb5..225dfa026a8f 100644
> --- a/drivers/char/tpm/tpm_vtpm_proxy.c
> +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
> @@ -697,23 +697,22 @@ 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;
> + }
> +
> + rc = vtpmx_init();
> + if (rc) {
> + pr_err("couldn't create vtpmx device\n");
> + goto err_destroy_workqueue;
> }
>
> return 0;
>
> -err_vtpmx_cleanup:
> - vtpmx_cleanup();
> +err_destroy_workqueue:
> + destroy_workqueue(workqueue);
>
> return rc;
> }
> --
> 2.30.2
>
>
Thanks, I applied this.
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
/Jarkko
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] char: tpm: vtpm_proxy: Fix race in init
2021-07-08 9:52 [PATCH v2] char: tpm: vtpm_proxy: Fix race in init Saubhik Mukherjee
2021-07-09 17:37 ` Jarkko Sakkinen
@ 2021-07-09 18:18 ` Stefan Berger
1 sibling, 0 replies; 3+ messages in thread
From: Stefan Berger @ 2021-07-09 18:18 UTC (permalink / raw)
To: Saubhik Mukherjee, peterhuewe, jarkko, jgg
Cc: linux-integrity, linux-kernel, ldv-project, andrianov
On 7/8/21 5:52 AM, Saubhik Mukherjee wrote:
> vtpm_module_init calls vtpmx_init which calls misc_register. The file
> operations callbacks are registered. So, vtpmx_fops_ioctl can execute in
> parallel with rest of vtpm_module_init. vtpmx_fops_ioctl calls
> vtpmx_ioc_new_dev, which calls vtpm_proxy_create_device, which calls
> vtpm_proxy_work_start, which could read uninitialized workqueue.
>
> To avoid this, create workqueue before vtpmx init.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Fixes: 6f99612e2500 ("tpm: Proxy driver for supporting multiple emulated TPMs")
> Signed-off-by: Saubhik Mukherjee <saubhik.mukherjee@gmail.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-07-09 18:19 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-07-08 9:52 [PATCH v2] char: tpm: vtpm_proxy: Fix race in init Saubhik Mukherjee
2021-07-09 17:37 ` Jarkko Sakkinen
2021-07-09 18:18 ` Stefan Berger
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