| Message ID | 20230306103359.6591-3-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: ucsi: 3 bug fixes | expand |
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,
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) { - 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); + 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);
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> --- drivers/usb/typec/ucsi/ucsi.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-)