Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
ax25: Fix reference count leak issues of ax25_dev
The ax25_addr_ax25dev() and ax25_dev_device_down() exist a reference count leak issue of the object “ax25_dev”.
Memory leak issue in ax25_addr_ax25dev():
The reference count of the object “ax25_dev” can be increased multiple times in ax25_addr_ax25dev(). This will cause a memory leak.
Memory leak issues in ax25_dev_device_down():
The reference count of ax25_dev is set to 1 in ax25_dev_device_up() and then increase the reference count when ax25_dev is added to ax25_dev_list. As a result, the reference count of ax25_dev is 2. But when the device is shutting down. The ax25_dev_device_down() drops the reference count once or twice depending on if we goto unlock_put or not, which will cause memory leak.
As for the issue of ax25_addr_ax25dev(), it is impossible for one pointer to be on a list twice. So add a break in ax25_addr_ax25dev(). As for the issue of ax25_dev_device_down(), increase the reference count of ax25_dev once in ax25_dev_device_up() and decrease the reference count of ax25_dev after it is removed from the ax25_dev_list.
Details
- Affected product:
- Ubuntu 16.04 ELS , Ubuntu 18.04 ELS
- Affected packages:
- linux @ 4.15.0 (+2 more)
In the Linux kernel, the following vulnerability has been resolved:
ax25: Fix reference count leak issues of ax25_dev
The ax25_addr_ax25dev() and ax25_dev_device_down() exist a reference count leak issue of the object “ax25_dev”.
Memory leak issue in ax25_addr_ax25dev():
The reference count of the object “ax25_dev” can be increased multiple times in ax25_addr_ax25dev(). This will cause a memory leak.
Memory leak issues in ax25_dev_device_down():
The reference count of ax25_dev is set to 1 in ax25_dev_device_up() and then increase the reference count when ax25_dev is added to ax25_dev_list. As a result, the reference count of ax25_dev is 2. But when the device is shutting down. The ax25_dev_device_down() drops the reference count once or twice depending on if we goto unlock_put or not, which will cause memory leak.
As for the issue of ax25_addr_ax25dev(), it is impossible for one pointer to be on a list twice. So add a break in ax25_addr_ax25dev(). As for the issue of ax25_dev_device_down(), increase the reference count of ax25_dev once in ax25_dev_device_up() and decrease the reference count of ax25_dev after it is removed from the ax25_dev_list.