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usb: gadget: f_rndis: Refactor bind path to use __free()

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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: 45fe3b8e53 ("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
This commit is contained in:
Kuen-Han Tsai 2025-09-16 16:21:37 +08:00 committed by Greg Kroah-Hartman
parent 42988380ac
commit 0822894143
1 changed files with 35 additions and 50 deletions
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85
drivers/usb/gadget/function/f_rndis.c
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@ -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"
@ -662,6 +664,8 @@ 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;
@ -669,12 +673,9 @@ 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;
@ -692,16 +693,14 @@ 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;
@ -709,36 +708,30 @@ 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,
@ -747,21 +740,19 @@ 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
@ -778,7 +769,7 @@ 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;
@ -789,10 +780,19 @@ 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
* until we're activated via set_alt().
@ -802,21 +802,6 @@ 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)