Overview
About vulnerability
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.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 4.18.0 (+8 more)
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.