MEDIUM
An issue was discovered in can_can_gw_rcv in net/can/gw.c in the Linux kernel through 4.19.13. The CAN frame modification rules allow bitwise logical operations that can be also applied to the can_dlc field. The privileged 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. Because of a missing check, the CAN drivers may write arbitrary content beyond the data registers in the CAN controller's I/O memory when processing can-gw manipulated outgoing frames.
http://www.securityfocus.com/bid/106443
https://bugzilla.suse.com/show_bug.cgi?id=1120386
https://lists.debian.org/debian-lts-announce/2019/03/msg00034.html
https://lists.debian.org/debian-lts-announce/2019/04/msg00004.html
https://lists.debian.org/debian-lts-announce/2019/05/msg00002.html
https://marc.info/?l=linux-netdev&m=154651842302479&w=2
https://marc.info/?l=linux-netdev&m=154661373531512&w=2
https://support.f5.com/csp/article/K17957133
https://usn.ubuntu.com/3932-1/
https://usn.ubuntu.com/3932-2/
Source: MITRE
Published: 2019-01-03
Updated: 2019-09-03
Type: CWE-787
Base Score: 4.9
Vector: AV:L/AC:L/Au:N/C:N/I:N/A:C
Impact Score: 6.9
Exploitability Score: 3.9
Severity: MEDIUM
Base Score: 4.4
Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 0.8
Severity: MEDIUM