CVE-2025-68340

Description

In the Linux kernel, the following vulnerability has been resolved:team: Move team device type change at the end of team_port_addAttempting to add a port device that is already up will expectedly fail,but not before modifying the team device header_ops.In the case of the syzbot reproducer the gre0 device isalready in state UP when it attempts to add it as aport device of team0, this fails but before thatheader_ops->create of team0 is changed from eth_header to ipgre_headerin the call to team_dev_type_check_change.Later when we end up in ipgre_header() struct ip_tunnel* points to nonsenseas the private data of the device still holds a struct team.Example sequence of iproute2 commands to reproduce the hang/BUG():ip link add dev team0 type teamip link add dev gre0 type greip link set dev gre0 upip link set dev gre0 master team0ip link set dev team0 upping -I team0 1.1.1.1Move team_dev_type_check_change down where all other checks have passedas it changes the dev type with no way to restore it in caseone of the checks that follow it fail.Also make sure to preserve the origial mtu assignment: - If port_dev is not the same type as dev, dev takes mtu from port_dev - If port_dev is the same type as dev, port_dev takes mtu from devThis is done by adding a conditional before the call to dev_set_mtuto prevent it from assigning port_dev->mtu = dev->mtu and insteadletting team_dev_type_check_change assign dev->mtu = port_dev->mtu.The conditional is needed because the patch moves the call toteam_dev_type_check_change past dev_set_mtu.Testing: - team device driver in-tree selftests - Add/remove various devices as slaves of team device - syzbot

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234