HID: debug: fix the ring buffer implementation
commit
13054abbaa4f1fd4e6f3b4b63439ec033b4c8035 upstream.
Ring buffer implementation in hid_debug_event() and hid_debug_events_read()
is strange allowing lost or corrupted data. After commit
717adfdaf147
("HID: debug: check length before copy_to_user()") it is possible to enter
an infinite loop in hid_debug_events_read() by providing 0 as count, this
locks up a system. Fix this by rewriting the ring buffer implementation
with kfifo and simplify the code.
This fixes CVE-2019-3819.
v2: fix an execution logic and add a comment
v3: use __set_current_state() instead of set_current_state()
Backport to v4.4: some (tree-wide) patches are missing in v4.4 so
cherry-pick relevant pieces from:
*
6396bb22151 ("treewide: kzalloc() -> kcalloc()")
*
a9a08845e9ac ("vfs: do bulk POLL* -> EPOLL* replacement")
*
92529623d242 ("HID: debug: improve hid_debug_event()")
*
174cd4b1e5fb ("sched/headers: Prepare to move signal wakeup & sigpending
methods from <linux/sched.h> into <linux/sched/signal.h>")
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1669187
Cc: stable@vger.kernel.org # v4.18+
Fixes:
cd667ce24796 ("HID: use debugfs for events/reports dumping")
Fixes:
717adfdaf147 ("HID: debug: check length before copy_to_user()")
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>