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.
Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/361bbf2a4b091e120006279ec3b382d73c4a0c17.1715247018.git.duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
CVE-2024-38602
(backported from commit b505e0319852b08a3a716b64620168eab21f4ced)
[hui: This backport deletes 2 ax25_dev_put(ax25_dev) from
ax25_dev_device_down(), that is because a commit is missing:
a968c799eb1d ("ax25: merge repeat codes in ax25_dev_device_down()"),
and the missing commit can't be cleanly cherry-picked into ubuntu
kernel too, it needs to backport more commits, to be simple and to
avoid introducing many unrelevant patches, just backport the CVE
fixing commit here.]
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Acked-by: Guoqing Jiang <guoqing.jiang@canonical.com>
Acked-by: Thibault Ferrante <thibault.ferrante@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
cffdeb0919