From: Kuen-Han Tsai khtsai@google.com
[ Upstream commit 08228941436047bdcd35a612c1aec0912a29d8cd ]
After an bind/unbind cycle, the rndis->notify_req is left stale. If a subsequent bind fails, the unified error label attempts to free this stale request, leading to a NULL pointer dereference when accessing ep->ops->free_request.
Refactor the error handling in the bind path to use the __free() automatic cleanup mechanism.
Fixes: 45fe3b8e5342 ("usb ethernet gadget: split RNDIS function") Cc: stable@kernel.org Signed-off-by: Kuen-Han Tsai khtsai@google.com Link: https://lore.kernel.org/r/20250916-ready-v1-6-4997bf277548@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Link: https://lore.kernel.org/r/20250916-ready-v1-6-4997bf277548@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/function/f_rndis.c | 85 +++++++++++---------------- 1 file changed, 35 insertions(+), 50 deletions(-)
diff --git a/drivers/usb/gadget/function/f_rndis.c b/drivers/usb/gadget/function/f_rndis.c index ee95e8f5f9d48..1dbda4e98ac43 100644 --- a/drivers/usb/gadget/function/f_rndis.c +++ b/drivers/usb/gadget/function/f_rndis.c @@ -19,6 +19,8 @@
#include <linux/atomic.h>
+#include <linux/usb/gadget.h> + #include "u_ether.h" #include "u_ether_configfs.h" #include "u_rndis.h" @@ -675,6 +677,8 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) struct usb_ep *ep;
struct f_rndis_opts *rndis_opts; + struct usb_os_desc_table *os_desc_table __free(kfree) = NULL; + struct usb_request *request __free(free_usb_request) = NULL;
if (!can_support_rndis(c)) return -EINVAL; @@ -682,12 +686,9 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
if (cdev->use_os_string) { - f->os_desc_table = kzalloc(sizeof(*f->os_desc_table), - GFP_KERNEL); - if (!f->os_desc_table) + os_desc_table = kzalloc(sizeof(*os_desc_table), GFP_KERNEL); + if (!os_desc_table) return -ENOMEM; - f->os_desc_n = 1; - f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc; }
rndis_iad_descriptor.bFunctionClass = rndis_opts->class; @@ -705,16 +706,14 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) gether_set_gadget(rndis_opts->net, cdev->gadget); status = gether_register_netdev(rndis_opts->net); if (status) - goto fail; + return status; rndis_opts->bound = true; }
us = usb_gstrings_attach(cdev, rndis_strings, ARRAY_SIZE(rndis_string_defs)); - if (IS_ERR(us)) { - status = PTR_ERR(us); - goto fail; - } + if (IS_ERR(us)) + return PTR_ERR(us); rndis_control_intf.iInterface = us[0].id; rndis_data_intf.iInterface = us[1].id; rndis_iad_descriptor.iFunction = us[2].id; @@ -722,36 +721,30 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) /* allocate instance-specific interface IDs */ status = usb_interface_id(c, f); if (status < 0) - goto fail; + return status; rndis->ctrl_id = status; rndis_iad_descriptor.bFirstInterface = status;
rndis_control_intf.bInterfaceNumber = status; rndis_union_desc.bMasterInterface0 = status;
- if (cdev->use_os_string) - f->os_desc_table[0].if_id = - rndis_iad_descriptor.bFirstInterface; - status = usb_interface_id(c, f); if (status < 0) - goto fail; + return status; rndis->data_id = status;
rndis_data_intf.bInterfaceNumber = status; rndis_union_desc.bSlaveInterface0 = status;
- status = -ENODEV; - /* allocate instance-specific endpoints */ ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc); if (!ep) - goto fail; + return -ENODEV; rndis->port.in_ep = ep;
ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc); if (!ep) - goto fail; + return -ENODEV; rndis->port.out_ep = ep;
/* NOTE: a status/notification endpoint is, strictly speaking, @@ -760,21 +753,19 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) */ ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc); if (!ep) - goto fail; + return -ENODEV; rndis->notify = ep;
- status = -ENOMEM; - /* allocate notification request and buffer */ - rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL); - if (!rndis->notify_req) - goto fail; - rndis->notify_req->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL); - if (!rndis->notify_req->buf) - goto fail; - rndis->notify_req->length = STATUS_BYTECOUNT; - rndis->notify_req->context = rndis; - rndis->notify_req->complete = rndis_response_complete; + request = usb_ep_alloc_request(ep, GFP_KERNEL); + if (!request) + return -ENOMEM; + request->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL); + if (!request->buf) + return -ENOMEM; + request->length = STATUS_BYTECOUNT; + request->context = rndis; + request->complete = rndis_response_complete;
/* support all relevant hardware speeds... we expect that when * hardware is dual speed, all bulk-capable endpoints work at @@ -791,7 +782,7 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) status = usb_assign_descriptors(f, eth_fs_function, eth_hs_function, eth_ss_function, eth_ss_function); if (status) - goto fail; + return status;
rndis->port.open = rndis_open; rndis->port.close = rndis_close; @@ -802,9 +793,18 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) if (rndis->manufacturer && rndis->vendorID && rndis_set_param_vendor(rndis->params, rndis->vendorID, rndis->manufacturer)) { - status = -EINVAL; - goto fail_free_descs; + usb_free_all_descriptors(f); + return -EINVAL; + } + + if (cdev->use_os_string) { + os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc; + os_desc_table[0].if_id = rndis_iad_descriptor.bFirstInterface; + f->os_desc_table = no_free_ptr(os_desc_table); + f->os_desc_n = 1; + } + rndis->notify_req = no_free_ptr(request);
/* NOTE: all that is done without knowing or caring about * the network link ... which is unavailable to this code @@ -817,21 +817,6 @@ rndis_bind(struct usb_configuration *c, struct usb_function *f) rndis->port.in_ep->name, rndis->port.out_ep->name, rndis->notify->name); return 0; - -fail_free_descs: - usb_free_all_descriptors(f); -fail: - kfree(f->os_desc_table); - f->os_desc_n = 0; - - if (rndis->notify_req) { - kfree(rndis->notify_req->buf); - usb_ep_free_request(rndis->notify, rndis->notify_req); - } - - ERROR(cdev, "%s: can't bind, err %d\n", f->name, status); - - return status; }
void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)