From: Alan Stern stern@rowland.harvard.edu

stable inclusion from stable-v5.10.195 commit 3cef18d13f37c80160dc7302cdd25e8749821a2d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I819LJ CVE: CVE-2023-37453

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

--------------------------------

commit 85d07c55621676d47d873d2749b88f783cd4d5a1 upstream.

In preparation for reworking the usb_get_device_descriptor() routine, it is desirable to unite the two different code paths responsible for initially determining endpoint 0's maximum packet size in a newly discovered USB device. Making this determination presents a chicken-and-egg sort of problem, in that the only way to learn the maxpacket value is to get it from the device descriptor retrieved from the device, but communicating with the device to retrieve a descriptor requires us to know beforehand the ep0 maxpacket size.

In practice this problem is solved in two different ways, referred to in hub.c as the "old scheme" and the "new scheme". The old scheme (which is the approach recommended by the USB-2 spec) involves asking the device to send just the first eight bytes of its device descriptor. Such a transfer uses packets containing no more than eight bytes each, and every USB device must have an ep0 maxpacket size

= 8, so this should succeed. Since the bMaxPacketSize0 field of the

device descriptor lies within the first eight bytes, this is all we need.

The new scheme is an imitation of the technique used in an early Windows USB implementation, giving it the happy advantage of working with a wide variety of devices (some of them at the time would not work with the old scheme, although that's probably less true now). It involves making an initial guess of the ep0 maxpacket size, asking the device to send up to 64 bytes worth of its device descriptor (which is only 18 bytes long), and then resetting the device to clear any error condition that might have resulted from the guess being wrong. The initial guess is determined by the connection speed; it should be correct in all cases other than full speed, for which the allowed values are 8, 16, 32, and 64 (in this case the initial guess is 64).

The reason for this patch is that the old- and new-scheme parts of hub_port_init() use different code paths, one involving usb_get_device_descriptor() and one not, for their initial reads of the device descriptor. Since these reads have essentially the same purpose and are made under essentially the same circumstances, this is illogical. It makes more sense to have both of them use a common subroutine.

This subroutine does basically what the new scheme's code did, because that approach is more general than the one used by the old scheme. It only needs to know how many bytes to transfer and whether or not it is being called for the first iteration of a retry loop (in case of certain time-out errors). There are two main differences from the former code:

We initialize the bDescriptorType field of the transfer buffer to 0 before performing the transfer, to avoid possibly accessing an uninitialized value afterward.

We read the device descriptor into a temporary buffer rather than storing it directly into udev->descriptor, which the old scheme implementation used to do.

Since the whole point of this first read of the device descriptor is to determine the bMaxPacketSize0 value, that is what the new routine returns (or an error code). The value is stored in a local variable rather than in udev->descriptor. As a side effect, this necessitates moving a section of code that checks the bcdUSB field for SuperSpeed devices until after the full device descriptor has been retrieved.

Signed-off-by: Alan Stern stern@rowland.harvard.edu Cc: Oliver Neukum oneukum@suse.com Link: https://lore.kernel.org/r/495cb5d4-f956-4f4a-a875-1e67e9489510@rowland.harva... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Lin Yujun linyujun809@huawei.com --- drivers/usb/core/hub.c | 173 ++++++++++++++++++++++------------------- 1 file changed, 94 insertions(+), 79 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 7af2def631a2..098e92c65348 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4594,6 +4594,67 @@ static int hub_enable_device(struct usb_device *udev) return hcd->driver->enable_device(hcd, udev); }

+/* + * Get the bMaxPacketSize0 value during initialization by reading the + * device's device descriptor. Since we don't already know this value, + * the transfer is unsafe and it ignores I/O errors, only testing for + * reasonable received values. + * + * For "old scheme" initialization, size will be 8 so we read just the + * start of the device descriptor, which should work okay regardless of + * the actual bMaxPacketSize0 value. For "new scheme" initialization, + * size will be 64 (and buf will point to a sufficiently large buffer), + * which might not be kosher according to the USB spec but it's what + * Windows does and what many devices expect. + * + * Returns: bMaxPacketSize0 or a negative error code. + */ +static int get_bMaxPacketSize0(struct usb_device *udev, + struct usb_device_descriptor *buf, int size, bool first_time) +{ + int i, rc; + + /* + * Retry on all errors; some devices are flakey. + * 255 is for WUSB devices, we actually need to use + * 512 (WUSB1.0[4.8.1]). + */ + for (i = 0; i < GET_MAXPACKET0_TRIES; ++i) { + /* Start with invalid values in case the transfer fails */ + buf->bDescriptorType = buf->bMaxPacketSize0 = 0; + rc = usb_control_msg(udev, usb_rcvaddr0pipe(), + USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, + USB_DT_DEVICE << 8, 0, + buf, size, + initial_descriptor_timeout); + switch (buf->bMaxPacketSize0) { + case 8: case 16: case 32: case 64: case 255: + if (buf->bDescriptorType == USB_DT_DEVICE) { + rc = buf->bMaxPacketSize0; + break; + } + fallthrough; + default: + if (rc >= 0) + rc = -EPROTO; + break; + } + + /* + * Some devices time out if they are powered on + * when already connected. They need a second + * reset, so return early. But only on the first + * attempt, lest we get into a time-out/reset loop. + */ + if (rc > 0 || (rc == -ETIMEDOUT && first_time && + udev->speed > USB_SPEED_FULL)) + break; + } + return rc; +} + +#define GET_DESCRIPTOR_BUFSIZE 64 + /* Reset device, (re)assign address, get device descriptor. * Device connection must be stable, no more debouncing needed. * Returns device in USB_STATE_ADDRESS, except on error. @@ -4618,6 +4679,12 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, int devnum = udev->devnum; const char *driver_name; bool do_new_scheme; + int maxp0; + struct usb_device_descriptor *buf; + + buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO); + if (!buf) + return -ENOMEM;

/* root hub ports have a slightly longer reset period * (from USB 2.0 spec, section 7.1.7.5) @@ -4732,9 +4799,6 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,

for (retries = 0; retries < GET_DESCRIPTOR_TRIES; (++retries, msleep(100))) { if (do_new_scheme) { - struct usb_device_descriptor *buf; - int r = 0; - retval = hub_enable_device(udev); if (retval < 0) { dev_err(&udev->dev, @@ -4743,52 +4807,8 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, goto fail; }

-#define GET_DESCRIPTOR_BUFSIZE 64 - buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO); - if (!buf) { - retval = -ENOMEM; - continue; - } - - /* Retry on all errors; some devices are flakey. - * 255 is for WUSB devices, we actually need to use - * 512 (WUSB1.0[4.8.1]). - */ - for (operations = 0; operations < GET_MAXPACKET0_TRIES; - ++operations) { - buf->bMaxPacketSize0 = 0; - r = usb_control_msg(udev, usb_rcvaddr0pipe(), - USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, - USB_DT_DEVICE << 8, 0, - buf, GET_DESCRIPTOR_BUFSIZE, - initial_descriptor_timeout); - switch (buf->bMaxPacketSize0) { - case 8: case 16: case 32: case 64: case 255: - if (buf->bDescriptorType == - USB_DT_DEVICE) { - r = 0; - break; - } - fallthrough; - default: - if (r == 0) - r = -EPROTO; - break; - } - /* - * Some devices time out if they are powered on - * when already connected. They need a second - * reset. But only on the first attempt, - * lest we get into a time out/reset loop - */ - if (r == 0 || (r == -ETIMEDOUT && - retries == 0 && - udev->speed > USB_SPEED_FULL)) - break; - } - udev->descriptor.bMaxPacketSize0 = - buf->bMaxPacketSize0; - kfree(buf); + maxp0 = get_bMaxPacketSize0(udev, buf, + GET_DESCRIPTOR_BUFSIZE, retries == 0);

retval = hub_port_reset(hub, port1, udev, delay, false); if (retval < 0) /* error or disconnect */ @@ -4799,14 +4819,13 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, retval = -ENODEV; goto fail; } - if (r) { - if (r != -ENODEV) + if (maxp0 < 0) { + if (maxp0 != -ENODEV) dev_err(&udev->dev, "device descriptor read/64, error %d\n", - r); - retval = -EMSGSIZE; + maxp0); + retval = maxp0; continue; } -#undef GET_DESCRIPTOR_BUFSIZE }

/* @@ -4848,19 +4867,17 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, break; }

- retval = usb_get_device_descriptor(udev, 8); - if (retval < 8) { + /* !do_new_scheme || wusb */ + maxp0 = get_bMaxPacketSize0(udev, buf, 8, retries == 0); + if (maxp0 < 0) { + retval = maxp0; if (retval != -ENODEV) dev_err(&udev->dev, "device descriptor read/8, error %d\n", retval); - if (retval >= 0) - retval = -EMSGSIZE; } else { u32 delay;

- retval = 0; - delay = udev->parent->hub_delay; udev->hub_delay = min_t(u32, delay, USB_TP_TRANSMISSION_DELAY_MAX); @@ -4877,27 +4894,10 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, if (retval) goto fail;

- /* - * Some superspeed devices have finished the link training process - * and attached to a superspeed hub port, but the device descriptor - * got from those devices show they aren't superspeed devices. Warm - * reset the port attached by the devices can fix them. - */ - if ((udev->speed >= USB_SPEED_SUPER) && - (le16_to_cpu(udev->descriptor.bcdUSB) < 0x0300)) { - dev_err(&udev->dev, "got a wrong device descriptor, " - "warm reset device\n"); - hub_port_reset(hub, port1, udev, - HUB_BH_RESET_TIME, true); - retval = -EINVAL; - goto fail; - } - - if (udev->descriptor.bMaxPacketSize0 == 0xff || - udev->speed >= USB_SPEED_SUPER) + if (maxp0 == 0xff || udev->speed >= USB_SPEED_SUPER) i = 512; else - i = udev->descriptor.bMaxPacketSize0; + i = maxp0; if (usb_endpoint_maxp(&udev->ep0.desc) != i) { if (udev->speed == USB_SPEED_LOW || !(i == 8 || i == 16 || i == 32 || i == 64)) { @@ -4923,6 +4923,20 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, goto fail; }

+ /* + * Some superspeed devices have finished the link training process + * and attached to a superspeed hub port, but the device descriptor + * got from those devices show they aren't superspeed devices. Warm + * reset the port attached by the devices can fix them. + */ + if ((udev->speed >= USB_SPEED_SUPER) && + (le16_to_cpu(udev->descriptor.bcdUSB) < 0x0300)) { + dev_err(&udev->dev, "got a wrong device descriptor, warm reset device\n"); + hub_port_reset(hub, port1, udev, HUB_BH_RESET_TIME, true); + retval = -EINVAL; + goto fail; + } + usb_detect_quirks(udev);

if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) { @@ -4943,6 +4957,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, hub_port_disable(hub, port1, 0); update_devnum(udev, devnum); /* for disconnect processing */ } + kfree(buf); return retval; }

From: Alan Stern stern@rowland.harvard.edu

stable inclusion from stable-v5.10.195 commit 9d241c5d9a9b7ad95c90c6520272fe404d5ac88f category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I819LJ CVE: CVE-2023-37453

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

--------------------------------

commit ff33299ec8bb80cdcc073ad9c506bd79bb2ed20b upstream.

Syzbot reported an out-of-bounds read in sysfs.c:read_descriptors():

BUG: KASAN: slab-out-of-bounds in read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883 Read of size 8 at addr ffff88801e78b8c8 by task udevd/5011

CPU: 0 PID: 5011 Comm: udevd Not tainted 6.4.0-rc6-syzkaller-00195-g40f71e7cd3c6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351 print_report mm/kasan/report.c:462 [inline] kasan_report+0x11c/0x130 mm/kasan/report.c:572 read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883 ... Allocated by task 758: ... __do_kmalloc_node mm/slab_common.c:966 [inline] __kmalloc+0x5e/0x190 mm/slab_common.c:979 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:680 [inline] usb_get_configuration+0x1f7/0x5170 drivers/usb/core/config.c:887 usb_enumerate_device drivers/usb/core/hub.c:2407 [inline] usb_new_device+0x12b0/0x19d0 drivers/usb/core/hub.c:2545

As analyzed by Khazhy Kumykov, the cause of this bug is a race between read_descriptors() and hub_port_init(): The first routine uses a field in udev->descriptor, not expecting it to change, while the second overwrites it.

Prior to commit 45bf39f8df7f ("USB: core: Don't hold device lock while reading the "descriptors" sysfs file") this race couldn't occur, because the routines were mutually exclusive thanks to the device locking. Removing that locking from read_descriptors() exposed it to the race.

The best way to fix the bug is to keep hub_port_init() from changing udev->descriptor once udev has been initialized and registered. Drivers expect the descriptors stored in the kernel to be immutable; we should not undermine this expectation. In fact, this change should have been made long ago.

So now hub_port_init() will take an additional argument, specifying a buffer in which to store the device descriptor it reads. (If udev has not yet been initialized, the buffer pointer will be NULL and then hub_port_init() will store the device descriptor in udev as before.) This eliminates the data race responsible for the out-of-bounds read.

The changes to hub_port_init() appear more extensive than they really are, because of indentation changes resulting from an attempt to avoid writing to other parts of the usb_device structure after it has been initialized. Similar changes should be made to the code that reads the BOS descriptor, but that can be handled in a separate patch later on. This patch is sufficient to fix the bug found by syzbot.

Reported-and-tested-by: syzbot+18996170f8096c6174d0@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-usb/000000000000c0ffe505fe86c9ca@google.com/#r Signed-off-by: Alan Stern stern@rowland.harvard.edu Cc: Khazhy Kumykov khazhy@google.com Fixes: 45bf39f8df7f ("USB: core: Don't hold device lock while reading the "descriptors" sysfs file") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/b958b47a-9a46-4c22-a9f9-e42e42c31251@rowland.harva... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Lin Yujun linyujun809@huawei.com --- drivers/usb/core/hub.c | 114 +++++++++++++++++++++++++---------------- 1 file changed, 70 insertions(+), 44 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 0945cd21669e..3ce428503e58 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4669,10 +4669,17 @@ static int get_bMaxPacketSize0(struct usb_device *udev, * the port lock. For a newly detected device that is not accessible * through any global pointers, it's not necessary to lock the device, * but it is still necessary to lock the port. + * + * For a newly detected device, @dev_descr must be NULL. The device + * descriptor retrieved from the device will then be stored in + * @udev->descriptor. For an already existing device, @dev_descr + * must be non-NULL. The device descriptor will be stored there, + * not in @udev->descriptor, because descriptors for registered + * devices are meant to be immutable. */ static int hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, - int retry_counter) + int retry_counter, struct usb_device_descriptor *dev_descr) { struct usb_device *hdev = hub->hdev; struct usb_hcd *hcd = bus_to_hcd(hdev->bus); @@ -4684,6 +4691,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, int devnum = udev->devnum; const char *driver_name; bool do_new_scheme; + const bool initial = !dev_descr; int maxp0; struct usb_device_descriptor *buf, *descr;

@@ -4722,32 +4730,34 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, } oldspeed = udev->speed;

- /* USB 2.0 section 5.5.3 talks about ep0 maxpacket ... - * it's fixed size except for full speed devices. - * For Wireless USB devices, ep0 max packet is always 512 (tho - * reported as 0xff in the device descriptor). WUSB1.0[4.8.1]. - */ - switch (udev->speed) { - case USB_SPEED_SUPER_PLUS: - case USB_SPEED_SUPER: - case USB_SPEED_WIRELESS: /* fixed at 512 */ - udev->ep0.desc.wMaxPacketSize = cpu_to_le16(512); - break; - case USB_SPEED_HIGH: /* fixed at 64 */ - udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64); - break; - case USB_SPEED_FULL: /* 8, 16, 32, or 64 */ - /* to determine the ep0 maxpacket size, try to read - * the device descriptor to get bMaxPacketSize0 and - * then correct our initial guess. + if (initial) { + /* USB 2.0 section 5.5.3 talks about ep0 maxpacket ... + * it's fixed size except for full speed devices. + * For Wireless USB devices, ep0 max packet is always 512 (tho + * reported as 0xff in the device descriptor). WUSB1.0[4.8.1]. */ - udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64); - break; - case USB_SPEED_LOW: /* fixed at 8 */ - udev->ep0.desc.wMaxPacketSize = cpu_to_le16(8); - break; - default: - goto fail; + switch (udev->speed) { + case USB_SPEED_SUPER_PLUS: + case USB_SPEED_SUPER: + case USB_SPEED_WIRELESS: /* fixed at 512 */ + udev->ep0.desc.wMaxPacketSize = cpu_to_le16(512); + break; + case USB_SPEED_HIGH: /* fixed at 64 */ + udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64); + break; + case USB_SPEED_FULL: /* 8, 16, 32, or 64 */ + /* to determine the ep0 maxpacket size, try to read + * the device descriptor to get bMaxPacketSize0 and + * then correct our initial guess. + */ + udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64); + break; + case USB_SPEED_LOW: /* fixed at 8 */ + udev->ep0.desc.wMaxPacketSize = cpu_to_le16(8); + break; + default: + goto fail; + } }

if (udev->speed == USB_SPEED_WIRELESS) @@ -4770,22 +4780,24 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, if (udev->speed < USB_SPEED_SUPER) dev_info(&udev->dev, "%s %s USB device number %d using %s\n", - (udev->config) ? "reset" : "new", speed, + (initial ? "new" : "reset"), speed, devnum, driver_name);

- /* Set up TT records, if needed */ - if (hdev->tt) { - udev->tt = hdev->tt; - udev->ttport = hdev->ttport; - } else if (udev->speed != USB_SPEED_HIGH - && hdev->speed == USB_SPEED_HIGH) { - if (!hub->tt.hub) { - dev_err(&udev->dev, "parent hub has no TT\n"); - retval = -EINVAL; - goto fail; + if (initial) { + /* Set up TT records, if needed */ + if (hdev->tt) { + udev->tt = hdev->tt; + udev->ttport = hdev->ttport; + } else if (udev->speed != USB_SPEED_HIGH + && hdev->speed == USB_SPEED_HIGH) { + if (!hub->tt.hub) { + dev_err(&udev->dev, "parent hub has no TT\n"); + retval = -EINVAL; + goto fail; + } + udev->tt = &hub->tt; + udev->ttport = port1; } - udev->tt = &hub->tt; - udev->ttport = port1; }

/* Why interleave GET_DESCRIPTOR and SET_ADDRESS this way? @@ -4814,6 +4826,12 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,

maxp0 = get_bMaxPacketSize0(udev, buf, GET_DESCRIPTOR_BUFSIZE, retries == 0); + if (maxp0 > 0 && !initial && + maxp0 != udev->descriptor.bMaxPacketSize0) { + dev_err(&udev->dev, "device reset changed ep0 maxpacket size!\n"); + retval = -ENODEV; + goto fail; + }

retval = hub_port_reset(hub, port1, udev, delay, false); if (retval < 0) /* error or disconnect */ @@ -4883,6 +4901,12 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, } else { u32 delay;

+ if (!initial && maxp0 != udev->descriptor.bMaxPacketSize0) { + dev_err(&udev->dev, "device reset changed ep0 maxpacket size!\n"); + retval = -ENODEV; + goto fail; + } + delay = udev->parent->hub_delay; udev->hub_delay = min_t(u32, delay, USB_TP_TRANSMISSION_DELAY_MAX); @@ -4926,7 +4950,10 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, retval); goto fail; } - udev->descriptor = *descr; + if (initial) + udev->descriptor = *descr; + else + *dev_descr = *descr; kfree(descr);

/* @@ -5229,7 +5256,7 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, }

/* reset (non-USB 3.0 devices) and get descriptor */ - status = hub_port_init(hub, udev, port1, i); + status = hub_port_init(hub, udev, port1, i, NULL); if (status < 0) goto loop;

@@ -5845,7 +5872,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev) struct usb_device *parent_hdev = udev->parent; struct usb_hub *parent_hub; struct usb_hcd *hcd = bus_to_hcd(udev->bus); - struct usb_device_descriptor descriptor = udev->descriptor; + struct usb_device_descriptor descriptor; struct usb_host_bos *bos; int i, j, ret = 0; int port1 = udev->portnum; @@ -5887,7 +5914,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev) /* ep0 maxpacket size may change; let the HCD know about it. * Other endpoints will be handled by re-enumeration. */ usb_ep0_reinit(udev); - ret = hub_port_init(parent_hub, udev, port1, i); + ret = hub_port_init(parent_hub, udev, port1, i, &descriptor); if (ret >= 0 || ret == -ENOTCONN || ret == -ENODEV) break; } @@ -5899,7 +5926,6 @@ static int usb_reset_and_verify_device(struct usb_device *udev) /* Device might have changed firmware (DFU or similar) */ if (descriptors_changed(udev, &descriptor, bos)) { dev_info(&udev->dev, "device firmware changed\n"); - udev->descriptor = descriptor; /* for disconnect() calls */ goto re_enumerate; }