Hi Hans,

On Mon, Mar 06, 2023 at 11:33:58AM +0100, Hans de Goede wrote:

ucsi_init() which runs from a workqueue sets ucsi->connector and on an error will clear it again.

ucsi->connector gets dereferenced by ucsi_resume(), this checks for ucsi->connector being NULL in case ucsi_init() has not finished yet; or in case ucsi_init() has failed.

ucsi_init() setting ucsi->connector and then clearing it again on an error creates a race where the check in ucsi_resume() may pass, only to have ucsi->connector free-ed underneath it when ucsi_init() hits an error.

Fix this race by making ucsi_init() store the connector array in a local variable and only assign it to ucsi->connector on success.

Fixes: bdc62f2bae8f ("usb: typec: ucsi: Simplified registration and I/O API") Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede hdegoede@redhat.com

This does not apply anymore on top of Greg's usb-next. I think you need to rebase. While at it, I have one nit below...

---

drivers/usb/typec/ucsi/ucsi.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index 8cbbb002fefe..15a2c91581a8 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -1039,9 +1039,8 @@ static struct fwnode_handle *ucsi_find_fwnode(struct ucsi_connector *con) return NULL; } -static int ucsi_register_port(struct ucsi *ucsi, int index) +static int ucsi_register_port(struct ucsi *ucsi, int index, struct ucsi_connector *con)

If con->num was set before this function is called, you don't need "index" at all:

static int ucsi_register_port(struct ucsi *ucsi, struct ucsi_connector *con)

{

• struct ucsi_connector *con = &ucsi->connector[index]; struct typec_capability *cap = &con->typec_cap; enum typec_accessory *accessory = cap->accessory; enum usb_role u_role = USB_ROLE_NONE;

@@ -1204,7 +1203,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index) */ static int ucsi_init(struct ucsi *ucsi) {

• struct ucsi_connector *con;

• struct ucsi_connector *con, *connector; u64 command, ntfy; int ret; int i;

@@ -1235,16 +1234,15 @@ static int ucsi_init(struct ucsi *ucsi) } /* Allocate the connectors. Released in ucsi_unregister() */

• ucsi->connector = kcalloc(ucsi->cap.num_connectors + 1,

• 		  sizeof(*ucsi->connector), GFP_KERNEL);
  

• if (!ucsi->connector) {

• connector = kcalloc(ucsi->cap.num_connectors + 1, sizeof(*connector), GFP_KERNEL);
• if (!connector) { ret = -ENOMEM; goto err_reset; }

/* Register all connectors */ for (i = 0; i < ucsi->cap.num_connectors; i++) {

• ret = ucsi_register_port(ucsi, i);
  

Assign it here:

connector[i].num = i + 1;

• ret = ucsi_register_port(ucsi, i, &connector[i]);
  

  if (ret) goto err_unregister; }

@@ -1256,11 +1254,12 @@ static int ucsi_init(struct ucsi *ucsi) if (ret < 0) goto err_unregister;

• ucsi->connector = connector; ucsi->ntfy = ntfy; return 0;

err_unregister:

• for (con = ucsi->connector; con->port; con++) {

• for (con = connector; con->port; con++) { ucsi_unregister_partner(con); ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON); ucsi_unregister_port_psy(con);

@@ -1269,10 +1268,7 @@ static int ucsi_init(struct ucsi *ucsi) typec_unregister_port(con->port); con->port = NULL; }

• kfree(ucsi->connector);
• ucsi->connector = NULL;

• kfree(connector);

err_reset: memset(&ucsi->cap, 0, sizeof(ucsi->cap)); ucsi_reset_ppm(ucsi);

thanks,