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authorAlan Stern <stern@rowland.harvard.edu>2017-06-13 15:23:42 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-26 07:13:10 +0200
commitf5dc61753d0e27705ff79813f0f0714fd5bd37bb (patch)
treec0663291ccdb6ba0e8c096c32bff5b4d78af3829
parent89c15994a06d996f4917c3c122a4e8446a205422 (diff)
USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks
commit f16443a034c7aa359ddf6f0f9bc40d01ca31faea upstream. Using the syzkaller kernel fuzzer, Andrey Konovalov generated the following error in gadgetfs: > BUG: KASAN: use-after-free in __lock_acquire+0x3069/0x3690 > kernel/locking/lockdep.c:3246 > Read of size 8 at addr ffff88003a2bdaf8 by task kworker/3:1/903 > > CPU: 3 PID: 903 Comm: kworker/3:1 Not tainted 4.12.0-rc4+ #35 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Workqueue: usb_hub_wq hub_event > Call Trace: > __dump_stack lib/dump_stack.c:16 [inline] > dump_stack+0x292/0x395 lib/dump_stack.c:52 > print_address_description+0x78/0x280 mm/kasan/report.c:252 > kasan_report_error mm/kasan/report.c:351 [inline] > kasan_report+0x230/0x340 mm/kasan/report.c:408 > __asan_report_load8_noabort+0x19/0x20 mm/kasan/report.c:429 > __lock_acquire+0x3069/0x3690 kernel/locking/lockdep.c:3246 > lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855 > __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > spin_lock include/linux/spinlock.h:299 [inline] > gadgetfs_suspend+0x89/0x130 drivers/usb/gadget/legacy/inode.c:1682 > set_link_state+0x88e/0xae0 drivers/usb/gadget/udc/dummy_hcd.c:455 > dummy_hub_control+0xd7e/0x1fb0 drivers/usb/gadget/udc/dummy_hcd.c:2074 > rh_call_control drivers/usb/core/hcd.c:689 [inline] > rh_urb_enqueue drivers/usb/core/hcd.c:846 [inline] > usb_hcd_submit_urb+0x92f/0x20b0 drivers/usb/core/hcd.c:1650 > usb_submit_urb+0x8b2/0x12c0 drivers/usb/core/urb.c:542 > usb_start_wait_urb+0x148/0x5b0 drivers/usb/core/message.c:56 > usb_internal_control_msg drivers/usb/core/message.c:100 [inline] > usb_control_msg+0x341/0x4d0 drivers/usb/core/message.c:151 > usb_clear_port_feature+0x74/0xa0 drivers/usb/core/hub.c:412 > hub_port_disable+0x123/0x510 drivers/usb/core/hub.c:4177 > hub_port_init+0x1ed/0x2940 drivers/usb/core/hub.c:4648 > hub_port_connect drivers/usb/core/hub.c:4826 [inline] > hub_port_connect_change drivers/usb/core/hub.c:4999 [inline] > port_event drivers/usb/core/hub.c:5105 [inline] > hub_event+0x1ae1/0x3d40 drivers/usb/core/hub.c:5185 > process_one_work+0xc08/0x1bd0 kernel/workqueue.c:2097 > process_scheduled_works kernel/workqueue.c:2157 [inline] > worker_thread+0xb2b/0x1860 kernel/workqueue.c:2233 > kthread+0x363/0x440 kernel/kthread.c:231 > ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:424 > > Allocated by task 9958: > save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59 > save_stack+0x43/0xd0 mm/kasan/kasan.c:513 > set_track mm/kasan/kasan.c:525 [inline] > kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:617 > kmem_cache_alloc_trace+0x87/0x280 mm/slub.c:2745 > kmalloc include/linux/slab.h:492 [inline] > kzalloc include/linux/slab.h:665 [inline] > dev_new drivers/usb/gadget/legacy/inode.c:170 [inline] > gadgetfs_fill_super+0x24f/0x540 drivers/usb/gadget/legacy/inode.c:1993 > mount_single+0xf6/0x160 fs/super.c:1192 > gadgetfs_mount+0x31/0x40 drivers/usb/gadget/legacy/inode.c:2019 > mount_fs+0x9c/0x2d0 fs/super.c:1223 > vfs_kern_mount.part.25+0xcb/0x490 fs/namespace.c:976 > vfs_kern_mount fs/namespace.c:2509 [inline] > do_new_mount fs/namespace.c:2512 [inline] > do_mount+0x41b/0x2d90 fs/namespace.c:2834 > SYSC_mount fs/namespace.c:3050 [inline] > SyS_mount+0xb0/0x120 fs/namespace.c:3027 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > Freed by task 9960: > save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59 > save_stack+0x43/0xd0 mm/kasan/kasan.c:513 > set_track mm/kasan/kasan.c:525 [inline] > kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:590 > slab_free_hook mm/slub.c:1357 [inline] > slab_free_freelist_hook mm/slub.c:1379 [inline] > slab_free mm/slub.c:2961 [inline] > kfree+0xed/0x2b0 mm/slub.c:3882 > put_dev+0x124/0x160 drivers/usb/gadget/legacy/inode.c:163 > gadgetfs_kill_sb+0x33/0x60 drivers/usb/gadget/legacy/inode.c:2027 > deactivate_locked_super+0x8d/0xd0 fs/super.c:309 > deactivate_super+0x21e/0x310 fs/super.c:340 > cleanup_mnt+0xb7/0x150 fs/namespace.c:1112 > __cleanup_mnt+0x1b/0x20 fs/namespace.c:1119 > task_work_run+0x1a0/0x280 kernel/task_work.c:116 > exit_task_work include/linux/task_work.h:21 [inline] > do_exit+0x18a8/0x2820 kernel/exit.c:878 > do_group_exit+0x14e/0x420 kernel/exit.c:982 > get_signal+0x784/0x1780 kernel/signal.c:2318 > do_signal+0xd7/0x2130 arch/x86/kernel/signal.c:808 > exit_to_usermode_loop+0x1ac/0x240 arch/x86/entry/common.c:157 > prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] > syscall_return_slowpath+0x3ba/0x410 arch/x86/entry/common.c:263 > entry_SYSCALL_64_fastpath+0xbc/0xbe > > The buggy address belongs to the object at ffff88003a2bdae0 > which belongs to the cache kmalloc-1024 of size 1024 > The buggy address is located 24 bytes inside of > 1024-byte region [ffff88003a2bdae0, ffff88003a2bdee0) > The buggy address belongs to the page: > page:ffffea0000e8ae00 count:1 mapcount:0 mapping: (null) > index:0x0 compound_mapcount: 0 > flags: 0x100000000008100(slab|head) > raw: 0100000000008100 0000000000000000 0000000000000000 0000000100170017 > raw: ffffea0000ed3020 ffffea0000f5f820 ffff88003e80efc0 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff88003a2bd980: fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff88003a2bda00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > >ffff88003a2bda80: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fb > ^ > ffff88003a2bdb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88003a2bdb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== What this means is that the gadgetfs_suspend() routine was trying to access dev->lock after it had been deallocated. The root cause is a race in the dummy_hcd driver; the dummy_udc_stop() routine can race with the rest of the driver because it contains no locking. And even when proper locking is added, it can still race with the set_link_state() function because that function incorrectly drops the private spinlock before invoking any gadget driver callbacks. The result of this race, as seen above, is that set_link_state() can invoke a callback in gadgetfs even after gadgetfs has been unbound from dummy_hcd's UDC and its private data structures have been deallocated. include/linux/usb/gadget.h documents that the ->reset, ->disconnect, ->suspend, and ->resume callbacks may be invoked in interrupt context. In general this is necessary, to prevent races with gadget driver removal. This patch fixes dummy_hcd to retain the spinlock across these calls, and it adds a spinlock acquisition to dummy_udc_stop() to prevent the race. The net2280 driver makes the same mistake of dropping the private spinlock for its ->disconnect and ->reset callback invocations. The patch fixes it too. Lastly, since gadgetfs_suspend() may be invoked in interrupt context, it cannot assume that interrupts are enabled when it runs. It must use spin_lock_irqsave() instead of spin_lock_irq(). The patch fixes that bug as well. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/gadget/legacy/inode.c5
-rw-r--r--drivers/usb/gadget/udc/dummy_hcd.c13
-rw-r--r--drivers/usb/gadget/udc/net2280.c9
3 files changed, 8 insertions, 19 deletions
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index de014436fb22..43ce2cfcdb4d 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1676,9 +1676,10 @@ static void
gadgetfs_suspend (struct usb_gadget *gadget)
{
struct dev_data *dev = get_gadget_data (gadget);
+ unsigned long flags;
INFO (dev, "suspended from state %d\n", dev->state);
- spin_lock (&dev->lock);
+ spin_lock_irqsave(&dev->lock, flags);
switch (dev->state) {
case STATE_DEV_SETUP: // VERY odd... host died??
case STATE_DEV_CONNECTED:
@@ -1689,7 +1690,7 @@ gadgetfs_suspend (struct usb_gadget *gadget)
default:
break;
}
- spin_unlock (&dev->lock);
+ spin_unlock_irqrestore(&dev->lock, flags);
}
static struct usb_gadget_driver gadgetfs_driver = {
diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index 88627b2ee4ce..64f404a1a072 100644
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -442,23 +442,16 @@ static void set_link_state(struct dummy_hcd *dum_hcd)
/* Report reset and disconnect events to the driver */
if (dum->driver && (disconnect || reset)) {
stop_activity(dum);
- spin_unlock(&dum->lock);
if (reset)
usb_gadget_udc_reset(&dum->gadget, dum->driver);
else
dum->driver->disconnect(&dum->gadget);
- spin_lock(&dum->lock);
}
} else if (dum_hcd->active != dum_hcd->old_active) {
- if (dum_hcd->old_active && dum->driver->suspend) {
- spin_unlock(&dum->lock);
+ if (dum_hcd->old_active && dum->driver->suspend)
dum->driver->suspend(&dum->gadget);
- spin_lock(&dum->lock);
- } else if (!dum_hcd->old_active && dum->driver->resume) {
- spin_unlock(&dum->lock);
+ else if (!dum_hcd->old_active && dum->driver->resume)
dum->driver->resume(&dum->gadget);
- spin_lock(&dum->lock);
- }
}
dum_hcd->old_status = dum_hcd->port_status;
@@ -985,7 +978,9 @@ static int dummy_udc_stop(struct usb_gadget *g)
struct dummy_hcd *dum_hcd = gadget_to_dummy_hcd(g);
struct dummy *dum = dum_hcd->dum;
+ spin_lock_irq(&dum->lock);
dum->driver = NULL;
+ spin_unlock_irq(&dum->lock);
return 0;
}
diff --git a/drivers/usb/gadget/udc/net2280.c b/drivers/usb/gadget/udc/net2280.c
index 6706aef907f4..a47de8c31ce9 100644
--- a/drivers/usb/gadget/udc/net2280.c
+++ b/drivers/usb/gadget/udc/net2280.c
@@ -2425,11 +2425,8 @@ static void stop_activity(struct net2280 *dev, struct usb_gadget_driver *driver)
nuke(&dev->ep[i]);
/* report disconnect; the driver is already quiesced */
- if (driver) {
- spin_unlock(&dev->lock);
+ if (driver)
driver->disconnect(&dev->gadget);
- spin_lock(&dev->lock);
- }
usb_reinit(dev);
}
@@ -3275,8 +3272,6 @@ next_endpoints:
BIT(PCI_RETRY_ABORT_INTERRUPT))
static void handle_stat1_irqs(struct net2280 *dev, u32 stat)
-__releases(dev->lock)
-__acquires(dev->lock)
{
struct net2280_ep *ep;
u32 tmp, num, mask, scratch;
@@ -3317,14 +3312,12 @@ __acquires(dev->lock)
if (disconnect || reset) {
stop_activity(dev, dev->driver);
ep0_start(dev);
- spin_unlock(&dev->lock);
if (reset)
usb_gadget_udc_reset
(&dev->gadget, dev->driver);
else
(dev->driver->disconnect)
(&dev->gadget);
- spin_lock(&dev->lock);
return;
}
}