In the Linux kernel, the following vulnerability has been resolved:

bonding: do not clear curr_active_slave prematurely when releasing all slaves

When releasing all slaves during bond destruction (all == true), __bond_release_one() unconditionally clears bond->curr_active_slave to NULL in every iteration.

If a backup slave is released before the active slave, bond_alb_deinit_slave() triggers rlb_teach_disabled_mac_on_primary(), which increments the active slave dev promiscuity counter and sets bond_info->primary_is_promisc = 1.

Because bond->curr_active_slave was prematurely cleared to NULL when releasing the backup slave, the subsequent iteration releasing the active slave evaluates oldcurrent as NULL, so bond_change_active_slave(bond, NULL) is skipped. Consequently, bond_alb_handle_active_change() is never called to decrement the promiscuity counter, permanently leaking promiscuous mode on the physical device after bond teardown.

When oldcurrent == slave, bond_change_active_slave(bond, NULL) already sets bond->curr_active_slave to NULL. We only need to avoid selecting a new active slave when all == true. Replace the if (all) branch with if (!all && oldcurrent == slave).

In the Linux kernel, the following vulnerability has been resolved:

bonding: do not clear curr_active_slave prematurely when releasing all slaves

When releasing all slaves during bond destruction (all == true), __bond_release_one() unconditionally clears bond->curr_active_slave to NULL in every iteration.

If a backup slave is released before the active slave, bond_alb_deinit_slave() triggers rlb_teach_disabled_mac_on_primary(), which increments the active slave dev promiscuity counter and sets bond_info->primary_is_promisc = 1.

Because bond->curr_active_slave was prematurely cleared to NULL when releasing the backup slave, the subsequent iteration releasing the active slave evaluates oldcurrent as NULL, so bond_change_active_slave(bond, NULL) is skipped. Consequently, bond_alb_handle_active_change() is never called to decrement the promiscuity counter, permanently leaking promiscuous mode on the physical device after bond teardown.

When oldcurrent == slave, bond_change_active_slave(bond, NULL) already sets bond->curr_active_slave to NULL. We only need to avoid selecting a new active slave when all == true. Replace the if (all) branch with if (!all && oldcurrent == slave).

Affected: Ubuntu:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe and 246 more

In the Linux kernel, the following vulnerability has been resolved: bonding: do not clear curr_active_slave prematurely when releasing all slaves When releasing all slaves during bond destruction (all == true), __bond_release_one() unconditionally clears bond->curr_active_slave to NULL in every iteration. If a backup slave is released before the active slave, bond_alb_deinit_slave() triggers rlb_teach_disabled_mac_on_primary(), which increments the active slave dev promiscuity counter and sets bond_info->primary_is_promisc = 1. Because bond->curr_active_slave was prematurely cleared to NULL when releasing the backup slave, the subsequent iteration releasing the active slave evaluates oldcurrent as NULL, so bond_change_active_slave(bond, NULL) is skipped. Consequently, bond_alb_handle_active_change() is never called to decrement the promiscuity counter, permanently leaking promiscuous mode on the physical device after bond teardown. When oldcurrent == slave, bond_change_active_slave(bond, NULL) already sets bond->curr_active_slave to NULL. We only need to avoid selecting a new active slave when all == true. Replace the if (all) branch with if (!all && oldcurrent == slave).

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service Zustand herbeizuführen oder nicht näher spezifizierten Angriff durchzuführen.