Commit 7e65f151 authored by Michal Pecio's avatar Michal Pecio Committed by Li Lingfeng
Browse files

usb: xhci: Fix NULL pointer dereference on certain command aborts 

stable inclusion
from stable-v6.6.76
commit b649f0d5bc256f691c7d234c3986685d54053de1
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPBJC
CVE: CVE-2024-57981

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b649f0d5bc256f691c7d234c3986685d54053de1

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

commit 1e0a19912adb68a4b2b74fd77001c96cd83eb073 upstream.

If a command is queued to the final usable TRB of a ring segment, the
enqueue pointer is advanced to the subsequent link TRB and no further.
If the command is later aborted, when the abort completion is handled
the dequeue pointer is advanced to the first TRB of the next segment.

If no further commands are queued, xhci_handle_stopped_cmd_ring() sees
the ring pointers unequal and assumes that there is a pending command,
so it calls xhci_mod_cmd_timer() which crashes if cur_cmd was NULL.

Don't attempt timer setup if cur_cmd is NULL. The subsequent doorbell
ring likely is unnecessary too, but it's harmless. Leave it alone.

This is probably Bug 219532, but no confirmation has been received.

The issue has been independently reproduced and confirmed fixed using
a USB MCU programmed to NAK the Status stage of SET_ADDRESS forever.
Everything continued working normally after several prevented crashes.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=219532


Fixes: c311e391 ("xhci: rework command timeout and cancellation,")
CC: stable@vger.kernel.org
Signed-off-by: default avatarMichal Pecio <michal.pecio@gmail.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20241227120142.1035206-4-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
parent 9d22d5b7

drivers/usb/host/xhci-ring.c

+2 −1
Original line number Diff line number Diff line
@@ -419,6 +419,7 @@ static void xhci_handle_stopped_cmd_ring(struct xhci_hcd *xhci, 
	if ((xhci->cmd_ring->dequeue != xhci->cmd_ring->enqueue) &&

	    !(xhci->xhc_state & XHCI_STATE_DYING)) {

		xhci->current_cmd = cur_cmd;

		if (cur_cmd)

			xhci_mod_cmd_timer(xhci);

		xhci_ring_cmd_db(xhci);

	}