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usb: ucsi: Fix ucsi->connector race

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commit 0482c34ec6f8557e06cd0f8e2d0e20e8ede6a22c upstream.

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
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230308154244.722337-3-hdegoede@redhat.com
Signed-off-by: Joakim Tjernlund <joakim.tjernlund@infinera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hans de Goede 2023-03-08 16:42:43 +01:00 committed by Greg Kroah-Hartman
parent e5c5cb47a9
commit fbfe493874
1 changed files with 9 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/usb/typec/ucsi/ucsi.c
View File

@ -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, 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;
@ -1062,7 +1061,6 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
init_completion(&con->complete);
mutex_init(&con->lock);
INIT_LIST_HEAD(&con->partner_tasks);
con->num = index + 1;
con->ucsi = ucsi;
cap->fwnode = ucsi_find_fwnode(con);
@ -1204,7 +1202,7 @@ out_unlock:
*/
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 +1233,16 @@ 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);
connector[i].num = i + 1;
ret = ucsi_register_port(ucsi, &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 @@ err_unregister:
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);