/* * drivers/usb/core/file.c * * (C) Copyright Linus Torvalds 1999 * (C) Copyright Johannes Erdfelt 1999-2001 * (C) Copyright Andreas Gal 1999 * (C) Copyright Gregory P. Smith 1999 * (C) Copyright Deti Fliegl 1999 (new USB architecture) * (C) Copyright Randy Dunlap 2000 * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id, * more docs, etc) * (C) Copyright Yggdrasil Computing, Inc. 2000 * (usb_device_id matching changes by Adam J. Richter) * (C) Copyright Greg Kroah-Hartman 2002-2003 * * Released under the GPLv2 only. * SPDX-License-Identifier: GPL-2.0 */ #include #include #include #include #include #include #include "usb.h" #define MAX_USB_MINORS 256 static const struct file_operations *usb_minors[MAX_USB_MINORS]; static DECLARE_RWSEM(minor_rwsem); static int usb_open(struct inode *inode, struct file *file) { int err = -ENODEV; const struct file_operations *new_fops; down_read(&minor_rwsem); new_fops = fops_get(usb_minors[iminor(inode)]); if (!new_fops) goto done; replace_fops(file, new_fops); /* Curiouser and curiouser... NULL ->open() as "no device" ? */ if (file->f_op->open) err = file->f_op->open(inode, file); done: up_read(&minor_rwsem); return err; } static const struct file_operations usb_fops = { .owner = THIS_MODULE, .open = usb_open, .llseek = noop_llseek, }; static struct usb_class { struct kref kref; struct class *class; } *usb_class; static char *usb_devnode(struct device *dev, umode_t *mode) { struct usb_class_driver *drv; drv = dev_get_drvdata(dev); if (!drv || !drv->devnode) return NULL; return drv->devnode(dev, mode); } static int init_usb_class(void) { int result = 0; if (usb_class != NULL) { kref_get(&usb_class->kref); goto exit; } usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL); if (!usb_class) { result = -ENOMEM; goto exit; } kref_init(&usb_class->kref); usb_class->class = class_create(THIS_MODULE, "usbmisc"); if (IS_ERR(usb_class->class)) { result = PTR_ERR(usb_class->class); printk(KERN_ERR "class_create failed for usb devices\n"); kfree(usb_class); usb_class = NULL; goto exit; } usb_class->class->devnode = usb_devnode; exit: return result; } static void release_usb_class(struct kref *kref) { /* Ok, we cheat as we know we only have one usb_class */ class_destroy(usb_class->class); kfree(usb_class); usb_class = NULL; } static void destroy_usb_class(void) { if (usb_class) kref_put(&usb_class->kref, release_usb_class); } int usb_major_init(void) { int error; error = register_chrdev(USB_MAJOR, "usb", &usb_fops); if (error) printk(KERN_ERR "Unable to get major %d for usb devices\n", USB_MAJOR); return error; } void usb_major_cleanup(void) { unregister_chrdev(USB_MAJOR, "usb"); } /** * usb_register_dev - register a USB device, and ask for a minor number * @intf: pointer to the usb_interface that is being registered * @class_driver: pointer to the usb_class_driver for this device * * This should be called by all USB drivers that use the USB major number. * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be * dynamically allocated out of the list of available ones. If it is not * enabled, the minor number will be based on the next available free minor, * starting at the class_driver->minor_base. * * This function also creates a usb class device in the sysfs tree. * * usb_deregister_dev() must be called when the driver is done with * the minor numbers given out by this function. * * Return: -EINVAL if something bad happens with trying to register a * device, and 0 on success. */ int usb_register_dev(struct usb_interface *intf, struct usb_class_driver *class_driver) { int retval; int minor_base = class_driver->minor_base; int minor; char name[20]; #ifdef CONFIG_USB_DYNAMIC_MINORS /* * We don't care what the device tries to start at, we want to start * at zero to pack the devices into the smallest available space with * no holes in the minor range. */ minor_base = 0; #endif if (class_driver->fops == NULL) return -EINVAL; if (intf->minor >= 0) return -EADDRINUSE; retval = init_usb_class(); if (retval) return retval; dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base); down_write(&minor_rwsem); for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { if (usb_minors[minor]) continue; usb_minors[minor] = class_driver->fops; intf->minor = minor; break; } up_write(&minor_rwsem); if (intf->minor < 0) return -EXFULL; /* create a usb class device for this usb interface */ snprintf(name, sizeof(name), class_driver->name, minor - minor_base); intf->usb_dev = device_create(usb_class->class, &intf->dev, MKDEV(USB_MAJOR, minor), class_driver, "%s", kbasename(name)); if (IS_ERR(intf->usb_dev)) { down_write(&minor_rwsem); usb_minors[minor] = NULL; intf->minor = -1; up_write(&minor_rwsem); retval = PTR_ERR(intf->usb_dev); } return retval; } EXPORT_SYMBOL_GPL(usb_register_dev); /** * usb_deregister_dev - deregister a USB device's dynamic minor. * @intf: pointer to the usb_interface that is being deregistered * @class_driver: pointer to the usb_class_driver for this device * * Used in conjunction with usb_register_dev(). This function is called * when the USB driver is finished with the minor numbers gotten from a * call to usb_register_dev() (usually when the device is disconnected * from the system.) * * This function also removes the usb class device from the sysfs tree. * * This should be called by all drivers that use the USB major number. */ void usb_deregister_dev(struct usb_interface *intf, struct usb_class_driver *class_driver) { if (intf->minor == -1) return; dev_dbg(&intf->dev, "removing %d minor\n", intf->minor); down_write(&minor_rwsem); usb_minors[intf->minor] = NULL; up_write(&minor_rwsem); device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor)); intf->usb_dev = NULL; intf->minor = -1; destroy_usb_class(); } EXPORT_SYMBOL_GPL(usb_deregister_dev); db9347abb318df5 (diff)
firmware: fix NULL pointer dereference in __fw_load_abort()
Since commit 5d47ec02c37ea6 ("firmware: Correct handling of fw_state_wait() return value") fw_load_abort() could be called twice and lead us to a kernel crash. This happens only when the firmware fallback mechanism (regular or custom) is used. The fallback mechanism exposes a sysfs interface for userspace to upload a file and notify the kernel when the file is loaded and ready, or to cancel an upload by echo'ing -1 into on the loading file: echo -n "-1" > /sys/$DEVPATH/loading This will call fw_load_abort(). Some distributions actually have a udev rule in place to *always* immediately cancel all firmware fallback mechanism requests (Debian), they have: $ cat /lib/udev/rules.d/50-firmware.rules # stub for immediately telling the kernel that userspace firmware loading # failed; necessary to avoid long timeouts with CONFIG_FW_LOADER_USER_HELPER=y SUBSYSTEM=="firmware", ACTION=="add", ATTR{loading}="-1 Distributions with this udev rule would run into this crash only if the fallback mechanism is used. Since most distributions disable by default using the fallback mechanism (CONFIG_FW_LOADER_USER_HELPER_FALLBACK), this would typicaly mean only 2 drivers which *require* the fallback mechanism could typically incur a crash: drivers/firmware/dell_rbu.c and the drivers/leds/leds-lp55xx-common.c driver. Distributions enabling CONFIG_FW_LOADER_USER_HELPER_FALLBACK by default are obviously more exposed to this crash. The crash happens because after commit 5b029624948d ("firmware: do not use fw_lock for fw_state protection") and subsequent fix commit 5d47ec02c37ea6 ("firmware: Correct handling of fw_state_wait() return value") a race can happen between this cancelation and the firmware fw_state_wait_timeout() being woken up after a state change with which fw_load_abort() as that calls swake_up(). Upon error fw_state_wait_timeout() will also again call fw_load_abort() and trigger a null reference. At first glance we could just fix this with a !buf check on fw_load_abort() before accessing buf->fw_st, however there is a logical issue in having a state machine used for the fallback mechanism and preventing access from it once we abort as its inside the buf (buf->fw_st). The firmware_class.c code is setting the buf to NULL to annotate an abort has occurred. Replace this mechanism by simply using the state check instead. All the other code in place already uses similar checks for aborting as well so no further changes are needed. An oops can be reproduced with the new fw_fallback.sh fallback mechanism cancellation test. Either cancelling the fallback mechanism or the custom fallback mechanism triggers a crash. mcgrof@piggy ~/linux-next/tools/testing/selftests/firmware (git::20170111-fw-fixes)$ sudo ./fw_fallback.sh ./fw_fallback.sh: timeout works ./fw_fallback.sh: firmware comparison works ./fw_fallback.sh: fallback mechanism works [ this then sits here when it is trying the cancellation test ] Kernel log: test_firmware: loading 'nope-test-firmware.bin' misc test_firmware: Direct firmware load for nope-test-firmware.bin failed with error -2 misc test_firmware: Falling back to user helper BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: _request_firmware+0xa27/0xad0 PGD 0 Oops: 0000 [#1] SMP Modules linked in: test_firmware(E) ... etc ... CPU: 1 PID: 1396 Comm: fw_fallback.sh Tainted: G W E 4.10.0-rc3-next-20170111+ #30 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014 task: ffff9740b27f4340 task.stack: ffffbb15c0bc8000 RIP: 0010:_request_firmware+0xa27/0xad0 RSP: 0018:ffffbb15c0bcbd10 EFLAGS: 00010246 RAX: 00000000fffffffe RBX: ffff9740afe5aa80 RCX: 0000000000000000 RDX: ffff9740b27f4340 RSI: 0000000000000283 RDI: 0000000000000000 RBP: ffffbb15c0bcbd90 R08: ffffbb15c0bcbcd8 R09: 0000000000000000 R10: 0000000894a0d4b1 R11: 000000000000008c R12: ffffffffc0312480 R13: 0000000000000005 R14: ffff9740b1c32400 R15: 00000000000003e8 FS: 00007f8604422700(0000) GS:ffff9740bfc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000038 CR3: 000000012164c000 CR4: 00000000000006e0 Call Trace: request_firmware+0x37/0x50 trigger_request_store+0x79/0xd0 [test_firmware] dev_attr_store+0x18/0x30 sysfs_kf_write+0x37/0x40 kernfs_fop_write+0x110/0x1a0 __vfs_write+0x37/0x160 ? _cond_resched+0x1a/0x50 vfs_write+0xb5/0x1a0 SyS_write+0x55/0xc0 ? trace_do_page_fault+0x37/0xd0 entry_SYSCALL_64_fastpath+0x1e/0xad RIP: 0033:0x7f8603f49620 RSP: 002b:00007fff6287b788 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055c307b110a0 RCX: 00007f8603f49620 RDX: 0000000000000016 RSI: 000055c3084d8a90 RDI: 0000000000000001 RBP: 0000000000000016 R08: 000000000000c0ff R09: 000055c3084d6336 R10: 000055c307b108b0 R11: 0000000000000246 R12: 000055c307b13c80 R13: 000055c3084d6320 R14: 0000000000000000 R15: 00007fff6287b950 Code: 9f 64 84 e8 9c 61 fe ff b8 f4 ff ff ff e9 6b f9 ff ff 48 c7 c7 40 6b 8d 84 89 45 a8 e8 43 84 18 00 49 8b be 00 03 00 00 8b 45 a8 <83> 7f 38 02 74 08 e8 6e ec ff ff 8b 45 a8 49 c7 86 00 03 00 00 RIP: _request_firmware+0xa27/0xad0 RSP: ffffbb15c0bcbd10 CR2: 0000000000000038 ---[ end trace 6d94ac339c133e6f ]--- Fixes: 5d47ec02c37e ("firmware: Correct handling of fw_state_wait() return value") Reported-and-Tested-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reported-and-Tested-by: Patrick Bruenn <p.bruenn@beckhoff.com> Reported-by: Chris Wilson <chris@chris-wilson.co.uk> CC: <stable@vger.kernel.org> [3.10+] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/sched/act_connmark.c')