* [PATCH] usb: typec: ucsi: Clear PPM capability data in ucsi_init() error path
@ 2021-06-09 7:35 Jack Pham
2021-06-09 12:03 ` Heikki Krogerus
0 siblings, 1 reply; 2+ messages in thread
From: Jack Pham @ 2021-06-09 7:35 UTC (permalink / raw
To: Heikki Krogerus, Greg KH
Cc: Subbaraman Narayanamurthy, linux-usb, Mayank Rana, stable,
Jack Pham
From: Mayank Rana <mrana@codeaurora.org>
If ucsi_init() fails for some reason (e.g. ucsi_register_port()
fails or general communication failure to the PPM), particularly at
any point after the GET_CAPABILITY command had been issued, this
results in unwinding the initialization and returning an error.
However the ucsi structure's ucsi_capability member retains its
current value, including likely a non-zero num_connectors.
And because ucsi_init() itself is done in a workqueue a UCSI
interface driver will be unaware that it failed and may think the
ucsi_register() call was completely successful. Later, if
ucsi_unregister() is called, due to this stale ucsi->cap value it
would try to access the items in the ucsi->connector array which
might not be in a proper state or not even allocated at all and
results in NULL or invalid pointer dereference.
Fix this by clearing the ucsi->cap value to 0 during the error
path of ucsi_init() in order to prevent a later ucsi_unregister()
from entering the connector cleanup loop.
Fixes: c1b0bc2dabfa ("usb: typec: Add support for UCSI interface")
Cc: stable@vger.kernel.org
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
---
drivers/usb/typec/ucsi/ucsi.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index b433169ef6fa..b7d104c80d85 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1253,6 +1253,7 @@ static int ucsi_init(struct ucsi *ucsi)
}
err_reset:
+ memset(&ucsi->cap, 0, sizeof(ucsi->cap));
ucsi_reset_ppm(ucsi);
err:
return ret;
--
2.24.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] usb: typec: ucsi: Clear PPM capability data in ucsi_init() error path
2021-06-09 7:35 [PATCH] usb: typec: ucsi: Clear PPM capability data in ucsi_init() error path Jack Pham
@ 2021-06-09 12:03 ` Heikki Krogerus
0 siblings, 0 replies; 2+ messages in thread
From: Heikki Krogerus @ 2021-06-09 12:03 UTC (permalink / raw
To: Jack Pham
Cc: Greg KH, Subbaraman Narayanamurthy, linux-usb, Mayank Rana,
stable
On Wed, Jun 09, 2021 at 12:35:35AM -0700, Jack Pham wrote:
> From: Mayank Rana <mrana@codeaurora.org>
>
> If ucsi_init() fails for some reason (e.g. ucsi_register_port()
> fails or general communication failure to the PPM), particularly at
> any point after the GET_CAPABILITY command had been issued, this
> results in unwinding the initialization and returning an error.
> However the ucsi structure's ucsi_capability member retains its
> current value, including likely a non-zero num_connectors.
> And because ucsi_init() itself is done in a workqueue a UCSI
> interface driver will be unaware that it failed and may think the
> ucsi_register() call was completely successful. Later, if
> ucsi_unregister() is called, due to this stale ucsi->cap value it
> would try to access the items in the ucsi->connector array which
> might not be in a proper state or not even allocated at all and
> results in NULL or invalid pointer dereference.
>
> Fix this by clearing the ucsi->cap value to 0 during the error
> path of ucsi_init() in order to prevent a later ucsi_unregister()
> from entering the connector cleanup loop.
>
> Fixes: c1b0bc2dabfa ("usb: typec: Add support for UCSI interface")
> Cc: stable@vger.kernel.org
> Signed-off-by: Mayank Rana <mrana@codeaurora.org>
> Signed-off-by: Jack Pham <jackp@codeaurora.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
> drivers/usb/typec/ucsi/ucsi.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index b433169ef6fa..b7d104c80d85 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -1253,6 +1253,7 @@ static int ucsi_init(struct ucsi *ucsi)
> }
>
> err_reset:
> + memset(&ucsi->cap, 0, sizeof(ucsi->cap));
> ucsi_reset_ppm(ucsi);
> err:
> return ret;
> --
> 2.24.0
--
heikki
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2021-06-09 7:35 [PATCH] usb: typec: ucsi: Clear PPM capability data in ucsi_init() error path Jack Pham
2021-06-09 12:03 ` Heikki Krogerus
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