CVE-2022-49926 Information

Description

In the Linux kernel the following vulnerability has been resolved:

net: dsa: Fix possible memory leaks in dsa_loop_init()

kmemleak reported memory leaks in dsa_loop_init():

kmemleak: 12 new suspected memory leaks

unreferenced object 0xffff8880138ce000 (size 2048): comm \modprobe\ pid 390 jiffies 4295040478 (age 238.976s) backtrace: [<000000006a94f1d5>] kmalloc_trace+0x26/0x60 [<00000000a9c44622>] phy_device_create+0x5d/0x970 [<00000000d0ee2afc>] get_phy_device+0xf3/0x2b0 [<00000000dca0c71f>] __fixed_phy_register.part.0+0x92/0x4e0 [<000000008a834798>] fixed_phy_register+0x84/0xb0 [<0000000055223fcb>] dsa_loop_init+0xa9/0x116 [dsa_loop] …

There are two reasons for memleak in dsa_loop_init().

First fixed_phy_register() create and register phy_device:

fixed_phy_register() get_phy_device() phy_device_create() freed by phy_device_free() phy_device_register() freed by phy_device_remove()

But fixed_phy_unregister() only calls phy_device_remove(). So the memory allocated in phy_device_create() is leaked.

Second when mdio_driver_register() fail in dsa_loop_init() it just returns and there is no cleanup for phydevs.

Fix the problems by catching the error of mdio_driver_register() in dsa_loop_init() then calling both fixed_phy_unregister() and phy_device_free() to release phydevs. Also add a function for phydevs cleanup to avoid duplacate.

Reference

https://git.kernel.org/stable/c/37a098fc9b42bd7fce66764866aa514639667b6e https://git.kernel.org/stable/c/4d2024b138d9f7b02ae13ee997fd3a71e9e46254 https://git.kernel.org/stable/c/633efc8b3dc96f56f5a57f2a49764853a2fa3f50 https://git.kernel.org/stable/c/935b4beb724946a37cebf97191592d4879d3a3a3 https://git.kernel.org/stable/c/9f555b1584fc2d5d16ee3c4d9438e93ac7c502c7 https://git.kernel.org/stable/c/bbc5d7b46a729bfcbb5544f6612b7a67dd4f4d6f https://git.kernel.org/stable/c/d593e1ede655b74c42e4e4fe285ea64aee96fb5c