linux/net/can
Oliver Hartkopp 0aaa81377c can: gw: ensure DLC boundaries after CAN frame modification
Muyu Yu provided a POC where user root with CAP_NET_ADMIN can create a CAN
frame modification rule that makes the data length code a higher value than
the available CAN frame data size. In combination with a configured checksum
calculation where the result is stored relatively to the end of the data
(e.g. cgw_csum_xor_rel) the tail of the skb (e.g. frag_list pointer in
skb_shared_info) can be rewritten which finally can cause a system crash.

Michael Kubecek suggested to drop frames that have a DLC exceeding the
available space after the modification process and provided a patch that can
handle CAN FD frames too. Within this patch we also limit the length for the
checksum calculations to the maximum of Classic CAN data length (8).

CAN frames that are dropped by these additional checks are counted with the
CGW_DELETED counter which indicates misconfigurations in can-gw rules.

This fixes CVE-2019-3701.

Reported-by: Muyu Yu <ieatmuttonchuan@gmail.com>
Reported-by: Marcus Meissner <meissner@suse.de>
Suggested-by: Michal Kubecek <mkubecek@suse.cz>
Tested-by: Muyu Yu <ieatmuttonchuan@gmail.com>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: linux-stable <stable@vger.kernel.org> # >= v3.2
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-07 05:17:51 -08:00
..
Kconfig can: migrate documentation to restructured text 2018-01-26 10:46:44 +01:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
af_can.c net: Drop pernet_operations::async 2018-03-27 13:18:09 -04:00
af_can.h can: af_can: give struct holding the CAN per device receive lists a sensible name 2018-01-05 11:12:08 +01:00
bcm.c Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL 2018-06-28 10:40:47 -07:00
gw.c can: gw: ensure DLC boundaries after CAN frame modification 2019-01-07 05:17:51 -08:00
proc.c proc: introduce proc_create_net_single 2018-05-16 07:24:30 +02:00
raw.c net: add missing SOF_TIMESTAMPING_OPT_ID support 2018-12-17 23:27:00 -08:00