In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
usb: usbfs: fix use-after-free of usb_device in usbdev_release()<\/p>\n
usbdev_release() drops its reference to the struct usb_device before
\ndraining the list of completed async URBs, but that drain path reads back
\nthrough the same object: free_async() calls dec_usb_memory_use_count()
\nfor any URB whose buffer came from the usbfs mmap() region, and its first
\nstatement is bus_to_hcd(ps->dev->bus).<\/p>\n
After a disconnect the usbfs reference can be the last one, in which case
\nusb_put_dev() frees the device and the subsequent loop reads offset 80 of
\nfreed memory and uses the result as a struct usb_hcd *, which
\nhcd_buffer_free_pages() then dereferences.<\/p>\n
This is reachable by an unprivileged process that has read\/write access to
\na \/dev\/bus\/usb node: mmap() the fd, submit one URB with a buffer inside the
\nmapping, wait for the device to be unplugged, then munmap() and close().
\nIt reproduces on every attempt rather than being a race, because a live
\nMAP_SHARED vma holds a reference on the struct file, so usbdev_release()
\ncannot run until the last vma is gone and the freeing branch of
\ndec_usb_memory_use_count() is always taken.<\/p>\n
BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae\/0x410
\n Read of size 8 at addr ffff8880122ee050 by task poc\/769
\n CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G B 6.12.94 #3<\/p>\n
Call Trace:
\n dec_usb_memory_use_count+0x3ae\/0x410
\n free_async+0x2aa\/0x4f0
\n usbdev_release+0x375\/0x460
\n __fput+0x3ea\/0xb50
\n __x64_sys_close+0x86\/0x100<\/p>\n
Allocated by task 11:
\n usb_alloc_dev+0x55\/0xd90
\n hub_event+0x2524\/0x43d0<\/p>\n
Freed by task 769:
\n kfree+0x121\/0x360
\n device_release+0xd2\/0x280
\n usb_put_dev+0x23\/0x30
\n usbdev_release+0x2d8\/0x460<\/p>\n
Release the device reference after the drain loop instead. Nothing between
\nthe two points requires it to have been dropped.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
usb: usbfs: fix use-after-free of usb_device in usbdev_release()<\/p>\n
usbdev_release() drops its reference to the struct usb_device bef<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-17328","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/17328","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17328"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17328"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17328"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}