In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
HID: multitouch: stop the release timer from being rearmed on remove<\/p>\n
mt_remove() quiesces the sticky-finger timer before stopping the
\nhardware:<\/p>\n
timer_delete_sync(&td->release_timer);<\/p>\n
sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
\n hid_hw_stop(hdev);<\/p>\n
timer_delete_sync() waits for a running callback and dequeues the timer,
\nbut it does not stop the timer from being armed again. The transport is
\nstill delivering reports at that point, and the report path rearms it:<\/p>\n
if (app->quirks & MT_QUIRK_STICKY_FINGERS) {
\n if (td->mt_io_flags & MT_IO_SLOTS_MASK)
\n mod_timer(&td->release_timer,
\n jiffies + msecs_to_jiffies(100));<\/p>\n
A report that arrives after timer_delete_sync() has returned therefore
\nleaves the timer queued. td is allocated with devm_kzalloc() against
\nhdev->dev, so it is freed when the driver is unbound, after mt_remove()
\nreturns. When the timer fires afterwards, mt_expired_timeout()
\ndereferences the freed td:<\/p>\n
struct mt_device *td = timer_container_of(td, t, release_timer);
\n struct hid_device *hdev = td->hdev;<\/p>\n
if (test_and_set_bit_lock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags))<\/p>\n
Simply moving the teardown after hid_hw_stop() does not fix this on its
\nown, because mt_expired_timeout() calls mt_release_contacts(), which
\nwalks hdev->inputs; the timer still has to be quiesced before
\nhid_hw_stop() tears the input devices down.<\/p>\n
Use timer_shutdown_sync() instead, which additionally makes any later
\nmod_timer() a no-op, so neither ordering constraint has to be traded off
\nagainst the other. This is the final-teardown pattern the function was
\nintroduced for, and hid-wiimote already uses it for the same reason.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
HID: multitouch: stop the release timer from being rearmed on remove<\/p>\n
mt_remove() quiesces the sticky-finger timer before stopping <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-41331","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/41331","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=41331"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41331"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41331"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}