This is a note to let you know that I've just added the patch titled
usb: gadget: f_ncm: Fix UAF ncm object at re-bind after usb ep transport error
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-f_ncm-fix-uaf-ncm-object-at-re-bind-after-usb-ep-transport-error.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6334b8e4553cc69f51e383c9de545082213d785e Mon Sep 17 00:00:00 2001
From: Norihiko Hama <Norihiko.Hama@xxxxxxxxxxxxxx>
Date: Wed, 27 Mar 2024 11:35:50 +0900
Subject: usb: gadget: f_ncm: Fix UAF ncm object at re-bind after usb ep transport error
From: Norihiko Hama <Norihiko.Hama@xxxxxxxxxxxxxx>
commit 6334b8e4553cc69f51e383c9de545082213d785e upstream.
When ncm function is working and then stop usb0 interface for link down,
eth_stop() is called. At this piont, accidentally if usb transport error
should happen in usb_ep_enable(), 'in_ep' and/or 'out_ep' may not be enabled.
After that, ncm_disable() is called to disable for ncm unbind
but gether_disconnect() is never called since 'in_ep' is not enabled.
As the result, ncm object is released in ncm unbind
but 'dev->port_usb' associated to 'ncm->port' is not NULL.
And when ncm bind again to recover netdev, ncm object is reallocated
but usb0 interface is already associated to previous released ncm object.
Therefore, once usb0 interface is up and eth_start_xmit() is called,
released ncm object is dereferrenced and it might cause use-after-free memory.
[function unlink via configfs]
usb0: eth_stop dev->port_usb=ffffff9b179c3200
--> error happens in usb_ep_enable().
NCM: ncm_disable: ncm=ffffff9b179c3200
--> no gether_disconnect() since ncm->port.in_ep->enabled is false.
NCM: ncm_unbind: ncm unbind ncm=ffffff9b179c3200
NCM: ncm_free: ncm free ncm=ffffff9b179c3200 <-- released ncm
[function link via configfs]
NCM: ncm_alloc: ncm alloc ncm=ffffff9ac4f8a000
NCM: ncm_bind: ncm bind ncm=ffffff9ac4f8a000
NCM: ncm_set_alt: ncm=ffffff9ac4f8a000 alt=0
usb0: eth_open dev->port_usb=ffffff9b179c3200 <-- previous released ncm
usb0: eth_start dev->port_usb=ffffff9b179c3200 <--
eth_start_xmit()
--> dev->wrap()
Unable to handle kernel paging request at virtual address dead00000000014f
This patch addresses the issue by checking if 'ncm->netdev' is not NULL at
ncm_disable() to call gether_disconnect() to deassociate 'dev->port_usb'.
It's more reasonable to check 'ncm->netdev' to call gether_connect/disconnect
rather than check 'ncm->port.in_ep->enabled' since it might not be enabled
but the gether connection might be established.
Signed-off-by: Norihiko Hama <Norihiko.Hama@xxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240327023550.51214-1-Norihiko.Hama@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_ncm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/usb/gadget/function/f_ncm.c
+++ b/drivers/usb/gadget/function/f_ncm.c
@@ -878,7 +878,7 @@ static int ncm_set_alt(struct usb_functi
if (alt > 1)
goto fail;
- if (ncm->port.in_ep->enabled) {
+ if (ncm->netdev) {
DBG(cdev, "reset ncm\n");
ncm->netdev = NULL;
gether_disconnect(&ncm->port);
@@ -1367,7 +1367,7 @@ static void ncm_disable(struct usb_funct
DBG(cdev, "ncm deactivated\n");
- if (ncm->port.in_ep->enabled) {
+ if (ncm->netdev) {
ncm->netdev = NULL;
gether_disconnect(&ncm->port);
}
Patches currently in stable-queue which might be from Norihiko.Hama@xxxxxxxxxxxxxx are
queue-6.8/usb-gadget-f_ncm-fix-uaf-ncm-object-at-re-bind-after-usb-ep-transport-error.patch
