usb: typec: ucsi: Clear PPM capability data in ucsi_init() error path

BugLink: https://bugs.launchpad.net/bugs/1934012
commit f247f0a82a4f8c3bfed178d8fd9e069d1424ee4e upstream.

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
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Link: https://lore.kernel.org/r/20210609073535.5094-1-jackp@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 2a383aaa3970b58452c98abaa79269c8b6d65f53..3bfa8005ae65d59b22a15ba207e66c892a0f67bc 100644 (file)
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1203,6 +1203,7 @@ err_unregister:
        }
 
 err_reset:
+       memset(&ucsi->cap, 0, sizeof(ucsi->cap));
        ucsi_reset_ppm(ucsi);
 err:
        return ret;