From c01c348ecdc66085e44912c97368809612231520 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Mon, 15 Apr 2019 11:51:38 -0400 Subject: [PATCH 1/6] USB: core: Fix unterminated string returned by usb_string() Some drivers (such as the vub300 MMC driver) expect usb_string() to return a properly NUL-terminated string, even when an error occurs. (In fact, vub300's probe routine doesn't bother to check the return code from usb_string().) When the driver goes on to use an unterminated string, it leads to kernel errors such as stack-out-of-bounds, as found by the syzkaller USB fuzzer. An out-of-range string index argument is not at all unlikely, given that some devices don't provide string descriptors and therefore list 0 as the value for their string indexes. This patch makes usb_string() return a properly terminated empty string along with the -EINVAL error code when an out-of-range index is encountered. And since a USB string index is a single-byte value, indexes >= 256 are just as invalid as values of 0 or below. Signed-off-by: Alan Stern Reported-by: syzbot+b75b85111c10b8d680f1@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/message.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 82239f27c4ccf..e844bb7b5676a 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -820,9 +820,11 @@ int usb_string(struct usb_device *dev, int index, char *buf, size_t size) if (dev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; - if (size <= 0 || !buf || !index) + if (size <= 0 || !buf) return -EINVAL; buf[0] = 0; + if (index <= 0 || index >= 256) + return -EINVAL; tbuf = kmalloc(256, GFP_NOIO); if (!tbuf) return -ENOMEM; From fc834e607ae3d18e1a20bca3f9a2d7f52ea7a2be Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 18 Apr 2019 13:12:07 -0400 Subject: [PATCH 2/6] USB: dummy-hcd: Fix failure to give back unlinked URBs The syzkaller USB fuzzer identified a failure mode in which dummy-hcd would never give back an unlinked URB. This causes usb_kill_urb() to hang, leading to WARNINGs and unkillable threads. In dummy-hcd, all URBs are given back by the dummy_timer() routine as it scans through the list of pending URBS. Failure to give back URBs can be caused by failure to start or early exit from the scanning loop. The code currently has two such pathways: One is triggered when an unsupported bus transfer speed is encountered, and the other by exhausting the simulated bandwidth for USB transfers during a frame. This patch removes those two paths, thereby allowing all unlinked URBs to be given back in a timely manner. It adds a check for the bus speed when the gadget first starts running, so that dummy_timer() will never thereafter encounter an unsupported speed. And it prevents the loop from exiting as soon as the total bandwidth has been used up (the scanning loop continues, giving back unlinked URBs as they are found, but not transferring any more data). Thanks to Andrey Konovalov for manually running the syzkaller fuzzer to help track down the source of the bug. Signed-off-by: Alan Stern Reported-and-tested-by: syzbot+d919b0f29d7b5a4994b9@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/udc/dummy_hcd.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c index baf72f95f0f1c..213b52508621e 100644 --- a/drivers/usb/gadget/udc/dummy_hcd.c +++ b/drivers/usb/gadget/udc/dummy_hcd.c @@ -979,8 +979,18 @@ static int dummy_udc_start(struct usb_gadget *g, struct dummy_hcd *dum_hcd = gadget_to_dummy_hcd(g); struct dummy *dum = dum_hcd->dum; - if (driver->max_speed == USB_SPEED_UNKNOWN) + switch (g->speed) { + /* All the speeds we support */ + case USB_SPEED_LOW: + case USB_SPEED_FULL: + case USB_SPEED_HIGH: + case USB_SPEED_SUPER: + break; + default: + dev_err(dummy_dev(dum_hcd), "Unsupported driver max speed %d\n", + driver->max_speed); return -EINVAL; + } /* * SLAVE side init ... the layer above hardware, which @@ -1784,9 +1794,10 @@ static void dummy_timer(struct timer_list *t) /* Bus speed is 500000 bytes/ms, so use a little less */ total = 490000; break; - default: + default: /* Can't happen */ dev_err(dummy_dev(dum_hcd), "bogus device speed\n"); - return; + total = 0; + break; } /* FIXME if HZ != 1000 this will probably misbehave ... */ @@ -1828,7 +1839,7 @@ static void dummy_timer(struct timer_list *t) /* Used up this frame's bandwidth? */ if (total <= 0) - break; + continue; /* find the gadget's ep for this request (if configured) */ address = usb_pipeendpoint (urb->pipe); From c2b71462d294cf517a0bc6e4fd6424d7cee5596f Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 19 Apr 2019 13:52:38 -0400 Subject: [PATCH 3/6] USB: core: Fix bug caused by duplicate interface PM usage counter The syzkaller fuzzer reported a bug in the USB hub driver which turned out to be caused by a negative runtime-PM usage counter. This allowed a hub to be runtime suspended at a time when the driver did not expect it. The symptom is a WARNING issued because the hub's status URB is submitted while it is already active: URB 0000000031fb463e submitted while active WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363 The negative runtime-PM usage count was caused by an unfortunate design decision made when runtime PM was first implemented for USB. At that time, USB class drivers were allowed to unbind from their interfaces without balancing the usage counter (i.e., leaving it with a positive count). The core code would take care of setting the counter back to 0 before allowing another driver to bind to the interface. Later on when runtime PM was implemented for the entire kernel, the opposite decision was made: Drivers were required to balance their runtime-PM get and put calls. In order to maintain backward compatibility, however, the USB subsystem adapted to the new implementation by keeping an independent usage counter for each interface and using it to automatically adjust the normal usage counter back to 0 whenever a driver was unbound. This approach involves duplicating information, but what is worse, it doesn't work properly in cases where a USB class driver delays decrementing the usage counter until after the driver's disconnect() routine has returned and the counter has been adjusted back to 0. Doing so would cause the usage counter to become negative. There's even a warning about this in the USB power management documentation! As it happens, this is exactly what the hub driver does. The kick_hub_wq() routine increments the runtime-PM usage counter, and the corresponding decrement is carried out by hub_event() in the context of the hub_wq work-queue thread. This work routine may sometimes run after the driver has been unbound from its interface, and when it does it causes the usage counter to go negative. It is not possible for hub_disconnect() to wait for a pending hub_event() call to finish, because hub_disconnect() is called with the device lock held and hub_event() acquires that lock. The only feasible fix is to reverse the original design decision: remove the duplicate interface-specific usage counter and require USB drivers to balance their runtime PM gets and puts. As far as I know, all existing drivers currently do this. Signed-off-by: Alan Stern Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- Documentation/driver-api/usb/power-management.rst | 14 +++++++++----- drivers/usb/core/driver.c | 13 ------------- drivers/usb/storage/realtek_cr.c | 13 +++++-------- include/linux/usb.h | 2 -- 4 files changed, 14 insertions(+), 28 deletions(-) diff --git a/Documentation/driver-api/usb/power-management.rst b/Documentation/driver-api/usb/power-management.rst index 79beb807996b7..4a74cf6f27972 100644 --- a/Documentation/driver-api/usb/power-management.rst +++ b/Documentation/driver-api/usb/power-management.rst @@ -370,11 +370,15 @@ autosuspend the interface's device. When the usage counter is = 0 then the interface is considered to be idle, and the kernel may autosuspend the device. -Drivers need not be concerned about balancing changes to the usage -counter; the USB core will undo any remaining "get"s when a driver -is unbound from its interface. As a corollary, drivers must not call -any of the ``usb_autopm_*`` functions after their ``disconnect`` -routine has returned. +Drivers must be careful to balance their overall changes to the usage +counter. Unbalanced "get"s will remain in effect when a driver is +unbound from its interface, preventing the device from going into +runtime suspend should the interface be bound to a driver again. On +the other hand, drivers are allowed to achieve this balance by calling +the ``usb_autopm_*`` functions even after their ``disconnect`` routine +has returned -- say from within a work-queue routine -- provided they +retain an active reference to the interface (via ``usb_get_intf`` and +``usb_put_intf``). Drivers using the async routines are responsible for their own synchronization and mutual exclusion. diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index 8987cec9549dd..ebcadaad89d1d 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -473,11 +473,6 @@ static int usb_unbind_interface(struct device *dev) pm_runtime_disable(dev); pm_runtime_set_suspended(dev); - /* Undo any residual pm_autopm_get_interface_* calls */ - for (r = atomic_read(&intf->pm_usage_cnt); r > 0; --r) - usb_autopm_put_interface_no_suspend(intf); - atomic_set(&intf->pm_usage_cnt, 0); - if (!error) usb_autosuspend_device(udev); @@ -1633,7 +1628,6 @@ void usb_autopm_put_interface(struct usb_interface *intf) int status; usb_mark_last_busy(udev); - atomic_dec(&intf->pm_usage_cnt); status = pm_runtime_put_sync(&intf->dev); dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n", __func__, atomic_read(&intf->dev.power.usage_count), @@ -1662,7 +1656,6 @@ void usb_autopm_put_interface_async(struct usb_interface *intf) int status; usb_mark_last_busy(udev); - atomic_dec(&intf->pm_usage_cnt); status = pm_runtime_put(&intf->dev); dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n", __func__, atomic_read(&intf->dev.power.usage_count), @@ -1684,7 +1677,6 @@ void usb_autopm_put_interface_no_suspend(struct usb_interface *intf) struct usb_device *udev = interface_to_usbdev(intf); usb_mark_last_busy(udev); - atomic_dec(&intf->pm_usage_cnt); pm_runtime_put_noidle(&intf->dev); } EXPORT_SYMBOL_GPL(usb_autopm_put_interface_no_suspend); @@ -1715,8 +1707,6 @@ int usb_autopm_get_interface(struct usb_interface *intf) status = pm_runtime_get_sync(&intf->dev); if (status < 0) pm_runtime_put_sync(&intf->dev); - else - atomic_inc(&intf->pm_usage_cnt); dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n", __func__, atomic_read(&intf->dev.power.usage_count), status); @@ -1750,8 +1740,6 @@ int usb_autopm_get_interface_async(struct usb_interface *intf) status = pm_runtime_get(&intf->dev); if (status < 0 && status != -EINPROGRESS) pm_runtime_put_noidle(&intf->dev); - else - atomic_inc(&intf->pm_usage_cnt); dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n", __func__, atomic_read(&intf->dev.power.usage_count), status); @@ -1775,7 +1763,6 @@ void usb_autopm_get_interface_no_resume(struct usb_interface *intf) struct usb_device *udev = interface_to_usbdev(intf); usb_mark_last_busy(udev); - atomic_inc(&intf->pm_usage_cnt); pm_runtime_get_noresume(&intf->dev); } EXPORT_SYMBOL_GPL(usb_autopm_get_interface_no_resume); diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c index 31b0244419387..cc794e25a0b6e 100644 --- a/drivers/usb/storage/realtek_cr.c +++ b/drivers/usb/storage/realtek_cr.c @@ -763,18 +763,16 @@ static void rts51x_suspend_timer_fn(struct timer_list *t) break; case RTS51X_STAT_IDLE: case RTS51X_STAT_SS: - usb_stor_dbg(us, "RTS51X_STAT_SS, intf->pm_usage_cnt:%d, power.usage:%d\n", - atomic_read(&us->pusb_intf->pm_usage_cnt), + usb_stor_dbg(us, "RTS51X_STAT_SS, power.usage:%d\n", atomic_read(&us->pusb_intf->dev.power.usage_count)); - if (atomic_read(&us->pusb_intf->pm_usage_cnt) > 0) { + if (atomic_read(&us->pusb_intf->dev.power.usage_count) > 0) { usb_stor_dbg(us, "Ready to enter SS state\n"); rts51x_set_stat(chip, RTS51X_STAT_SS); /* ignore mass storage interface's children */ pm_suspend_ignore_children(&us->pusb_intf->dev, true); usb_autopm_put_interface_async(us->pusb_intf); - usb_stor_dbg(us, "RTS51X_STAT_SS 01, intf->pm_usage_cnt:%d, power.usage:%d\n", - atomic_read(&us->pusb_intf->pm_usage_cnt), + usb_stor_dbg(us, "RTS51X_STAT_SS 01, power.usage:%d\n", atomic_read(&us->pusb_intf->dev.power.usage_count)); } break; @@ -807,11 +805,10 @@ static void rts51x_invoke_transport(struct scsi_cmnd *srb, struct us_data *us) int ret; if (working_scsi(srb)) { - usb_stor_dbg(us, "working scsi, intf->pm_usage_cnt:%d, power.usage:%d\n", - atomic_read(&us->pusb_intf->pm_usage_cnt), + usb_stor_dbg(us, "working scsi, power.usage:%d\n", atomic_read(&us->pusb_intf->dev.power.usage_count)); - if (atomic_read(&us->pusb_intf->pm_usage_cnt) <= 0) { + if (atomic_read(&us->pusb_intf->dev.power.usage_count) <= 0) { ret = usb_autopm_get_interface(us->pusb_intf); usb_stor_dbg(us, "working scsi, ret=%d\n", ret); } diff --git a/include/linux/usb.h b/include/linux/usb.h index 5e49e82c43684..ff010d1fd1c78 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -200,7 +200,6 @@ usb_find_last_int_out_endpoint(struct usb_host_interface *alt, * @dev: driver model's view of this device * @usb_dev: if an interface is bound to the USB major, this will point * to the sysfs representation for that device. - * @pm_usage_cnt: PM usage counter for this interface * @reset_ws: Used for scheduling resets from atomic context. * @resetting_device: USB core reset the device, so use alt setting 0 as * current; needs bandwidth alloc after reset. @@ -257,7 +256,6 @@ struct usb_interface { struct device dev; /* interface specific device info */ struct device *usb_dev; - atomic_t pm_usage_cnt; /* usage counter for autosuspend */ struct work_struct reset_ws; /* for resets in atomic context */ }; #define to_usb_interface(d) container_of(d, struct usb_interface, dev) From c409ca3be3c6ff3a1eeb303b191184e80d412862 Mon Sep 17 00:00:00 2001 From: Malte Leip Date: Sun, 14 Apr 2019 12:00:12 +0200 Subject: [PATCH 4/6] usb: usbip: fix isoc packet num validation in get_pipe Change the validation of number_of_packets in get_pipe to compare the number of packets to a fixed maximum number of packets allowed, set to be 1024. This number was chosen due to it being used by other drivers as well, for example drivers/usb/host/uhci-q.c Background/reason: The get_pipe function in stub_rx.c validates the number of packets in isochronous mode and aborts with an error if that number is too large, in order to prevent malicious input from possibly triggering large memory allocations. This was previously done by checking whether pdu->u.cmd_submit.number_of_packets is bigger than the number of packets that would be needed for pdu->u.cmd_submit.transfer_buffer_length bytes if all except possibly the last packet had maximum length, given by usb_endpoint_maxp(epd) * usb_endpoint_maxp_mult(epd). This leads to an error if URBs with packets shorter than the maximum possible length are submitted, which is allowed according to Documentation/driver-api/usb/URB.rst and occurs for example with the snd-usb-audio driver. Fixes: c6688ef9f297 ("usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input") Signed-off-by: Malte Leip Cc: stable Acked-by: Shuah Khan Signed-off-by: Greg Kroah-Hartman --- drivers/usb/usbip/stub_rx.c | 12 +++--------- drivers/usb/usbip/usbip_common.h | 7 +++++++ 2 files changed, 10 insertions(+), 9 deletions(-) diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c index 97b09a42a10ca..dbfb2f24d71ea 100644 --- a/drivers/usb/usbip/stub_rx.c +++ b/drivers/usb/usbip/stub_rx.c @@ -361,16 +361,10 @@ static int get_pipe(struct stub_device *sdev, struct usbip_header *pdu) } if (usb_endpoint_xfer_isoc(epd)) { - /* validate packet size and number of packets */ - unsigned int maxp, packets, bytes; - - maxp = usb_endpoint_maxp(epd); - maxp *= usb_endpoint_maxp_mult(epd); - bytes = pdu->u.cmd_submit.transfer_buffer_length; - packets = DIV_ROUND_UP(bytes, maxp); - + /* validate number of packets */ if (pdu->u.cmd_submit.number_of_packets < 0 || - pdu->u.cmd_submit.number_of_packets > packets) { + pdu->u.cmd_submit.number_of_packets > + USBIP_MAX_ISO_PACKETS) { dev_err(&sdev->udev->dev, "CMD_SUBMIT: isoc invalid num packets %d\n", pdu->u.cmd_submit.number_of_packets); diff --git a/drivers/usb/usbip/usbip_common.h b/drivers/usb/usbip/usbip_common.h index bf8afe9b58838..8be857a4fa132 100644 --- a/drivers/usb/usbip/usbip_common.h +++ b/drivers/usb/usbip/usbip_common.h @@ -121,6 +121,13 @@ extern struct device_attribute dev_attr_usbip_debug; #define USBIP_DIR_OUT 0x00 #define USBIP_DIR_IN 0x01 +/* + * Arbitrary limit for the maximum number of isochronous packets in an URB, + * compare for example the uhci_submit_isochronous function in + * drivers/usb/host/uhci-q.c + */ +#define USBIP_MAX_ISO_PACKETS 1024 + /** * struct usbip_header_basic - data pertinent to every request * @command: the usbip request type From ef61eb43ada6c1d6b94668f0f514e4c268093ff3 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 23 Apr 2019 14:48:29 -0400 Subject: [PATCH 5/6] USB: yurex: Fix protection fault after device removal The syzkaller USB fuzzer found a general-protection-fault bug in the yurex driver. The fault occurs when a device has been unplugged; the driver's interrupt-URB handler logs an error message referring to the device by name, after the device has been unregistered and its name deallocated. This problem is caused by the fact that the interrupt URB isn't cancelled until the driver's private data structure is released, which can happen long after the device is gone. The cure is to make sure that the interrupt URB is killed before yurex_disconnect() returns; this is exactly the sort of thing that usb_poison_urb() was meant for. Signed-off-by: Alan Stern Reported-and-tested-by: syzbot+2eb9121678bdb36e6d57@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/misc/yurex.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/usb/misc/yurex.c b/drivers/usb/misc/yurex.c index 6d9fd5f649036..7b306aa22d258 100644 --- a/drivers/usb/misc/yurex.c +++ b/drivers/usb/misc/yurex.c @@ -314,6 +314,7 @@ static void yurex_disconnect(struct usb_interface *interface) usb_deregister_dev(interface, &yurex_class); /* prevent more I/O from starting */ + usb_poison_urb(dev->urb); mutex_lock(&dev->io_mutex); dev->interface = NULL; mutex_unlock(&dev->io_mutex); From c114944d7d67f24e71562fcfc18d550ab787e4d4 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Mon, 22 Apr 2019 11:16:04 -0400 Subject: [PATCH 6/6] USB: w1 ds2490: Fix bug caused by improper use of altsetting array The syzkaller USB fuzzer spotted a slab-out-of-bounds bug in the ds2490 driver. This bug is caused by improper use of the altsetting array in the usb_interface structure (the array's entries are not always stored in numerical order), combined with a naive assumption that all interfaces probed by the driver will have the expected number of altsettings. The bug can be fixed by replacing references to the possibly non-existent intf->altsetting[alt] entry with the guaranteed-to-exist intf->cur_altsetting entry. Signed-off-by: Alan Stern Reported-and-tested-by: syzbot+d65f673b847a1a96cdba@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- drivers/w1/masters/ds2490.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/w1/masters/ds2490.c b/drivers/w1/masters/ds2490.c index 0f4ecfcdb5497..a9fb775852723 100644 --- a/drivers/w1/masters/ds2490.c +++ b/drivers/w1/masters/ds2490.c @@ -1016,15 +1016,15 @@ static int ds_probe(struct usb_interface *intf, /* alternative 3, 1ms interrupt (greatly speeds search), 64 byte bulk */ alt = 3; err = usb_set_interface(dev->udev, - intf->altsetting[alt].desc.bInterfaceNumber, alt); + intf->cur_altsetting->desc.bInterfaceNumber, alt); if (err) { dev_err(&dev->udev->dev, "Failed to set alternative setting %d " "for %d interface: err=%d.\n", alt, - intf->altsetting[alt].desc.bInterfaceNumber, err); + intf->cur_altsetting->desc.bInterfaceNumber, err); goto err_out_clear; } - iface_desc = &intf->altsetting[alt]; + iface_desc = intf->cur_altsetting; if (iface_desc->desc.bNumEndpoints != NUM_EP-1) { pr_info("Num endpoints=%d. It is not DS9490R.\n", iface_desc->desc.bNumEndpoints);