In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix one memleak in __inet_del_ifa()
I got the below warning when do fuzzing test: unregister_netdevice: waiting for bond0 to become free. Usage count = 2
It can be repoduced via:
ip link add bond0 type bond sysctl -w net.ipv4.conf.bond0.promote_secondaries=1 ip addr add 4.117.174.103/0 scope 0x40 dev bond0 ip addr add 192.168.100.111/255.255.255.254 scope 0 dev bond0 ip addr add 0.0.0.4/0 scope 0x40 secondary dev bond0 ip addr del 4.117.174.103/0 scope 0x40 dev bond0 ip link delete bond0 type bond
In this reproduction test case, an incorrect last_prim is found in __inet_del_ifa(), as a result, the secondary address(0.0.0.4/0 scope 0x40) is lost. The memory of the secondary address is leaked and the reference of in_device and net_device is leaked.
Fix this problem: Look for last_prim starting at location of the deleted IP and inserting the promoted IP into the location of last_prim.