alistair23-linux/drivers/usb/usbip/stub.h
Shuah Khan (Samsung OSG) 22076557b0 usbip: usbip_host: fix NULL-ptr deref and use-after-free errors
usbip_host updates device status without holding lock from stub probe,
disconnect and rebind code paths. When multiple requests to import a
device are received, these unprotected code paths step all over each
other and drive fails with NULL-ptr deref and use-after-free errors.

The driver uses a table lock to protect the busid array for adding and
deleting busids to the table. However, the probe, disconnect and rebind
paths get the busid table entry and update the status without holding
the busid table lock. Add a new finer grain lock to protect the busid
entry. This new lock will be held to search and update the busid entry
fields from get_busid_idx(), add_match_busid() and del_match_busid().

match_busid_show() does the same to access the busid entry fields.

get_busid_priv() changed to return the pointer to the busid entry holding
the busid lock. stub_probe(), stub_disconnect() and stub_device_rebind()
call put_busid_priv() to release the busid lock before returning. This
changes fixes the unprotected code paths eliminating the race conditions
in updating the busid entries.

Reported-by: Jakub Jirasek
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-15 09:52:02 +02:00

101 lines
2.2 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2003-2008 Takahiro Hirofuchi
*/
#ifndef __USBIP_STUB_H
#define __USBIP_STUB_H
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/usb.h>
#include <linux/wait.h>
#define STUB_BUSID_OTHER 0
#define STUB_BUSID_REMOV 1
#define STUB_BUSID_ADDED 2
#define STUB_BUSID_ALLOC 3
struct stub_device {
struct usb_device *udev;
struct usbip_device ud;
__u32 devid;
/*
* stub_priv preserves private data of each urb.
* It is allocated as stub_priv_cache and assigned to urb->context.
*
* stub_priv is always linked to any one of 3 lists;
* priv_init: linked to this until the comletion of a urb.
* priv_tx : linked to this after the completion of a urb.
* priv_free: linked to this after the sending of the result.
*
* Any of these list operations should be locked by priv_lock.
*/
spinlock_t priv_lock;
struct list_head priv_init;
struct list_head priv_tx;
struct list_head priv_free;
/* see comments for unlinking in stub_rx.c */
struct list_head unlink_tx;
struct list_head unlink_free;
wait_queue_head_t tx_waitq;
};
/* private data into urb->priv */
struct stub_priv {
unsigned long seqnum;
struct list_head list;
struct stub_device *sdev;
struct urb *urb;
int unlinking;
};
struct stub_unlink {
unsigned long seqnum;
struct list_head list;
__u32 status;
};
/* same as SYSFS_BUS_ID_SIZE */
#define BUSID_SIZE 32
struct bus_id_priv {
char name[BUSID_SIZE];
char status;
int interf_count;
struct stub_device *sdev;
struct usb_device *udev;
char shutdown_busid;
spinlock_t busid_lock;
};
/* stub_priv is allocated from stub_priv_cache */
extern struct kmem_cache *stub_priv_cache;
/* stub_dev.c */
extern struct usb_device_driver stub_driver;
/* stub_main.c */
struct bus_id_priv *get_busid_priv(const char *busid);
void put_busid_priv(struct bus_id_priv *bid);
int del_match_busid(char *busid);
void stub_device_cleanup_urbs(struct stub_device *sdev);
/* stub_rx.c */
int stub_rx_loop(void *data);
/* stub_tx.c */
void stub_enqueue_ret_unlink(struct stub_device *sdev, __u32 seqnum,
__u32 status);
void stub_complete(struct urb *urb);
int stub_tx_loop(void *data);
#endif /* __USBIP_STUB_H */