| Message ID | 86ae9712b610b3d41ce0ce3bbe268c68de6c5914.1715065005.git.duoming@zju.edu.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | ax25: Fix issues of ax25_dev and net_device | expand |
> The ax25_addr_ax25dev() and ax25_dev_device_down() exist a reference > count leak issue of the object "ax25_dev". Please improve this wording. Suggestion: Two function implementations contained programming mistakes. Thus … > 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 so far. … * How do you think about to work with indentation in such a description for item enumeration? * Would you like to add imperative wordings for improved changelogs? https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc7#n94 Regards, Markus
diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c index 1557f879377..66aa381af0e 100644 --- a/net/ax25/ax25_dev.c +++ b/net/ax25/ax25_dev.c @@ -39,6 +39,7 @@ ax25_dev *ax25_addr_ax25dev(ax25_address *addr) if (ax25cmp(addr, (const ax25_address *)ax25_dev->dev->dev_addr) == 0) { res = ax25_dev; ax25_dev_hold(ax25_dev); + break; } spin_unlock_bh(&ax25_dev_lock); @@ -91,7 +92,6 @@ void ax25_dev_device_up(struct net_device *dev) list_add(&ax25_dev->list, &ax25_dev_list); dev->ax25_ptr = ax25_dev; spin_unlock_bh(&ax25_dev_lock); - ax25_dev_hold(ax25_dev); ax25_register_dev_sysctl(ax25_dev); } @@ -132,7 +132,6 @@ void ax25_dev_device_down(struct net_device *dev) unlock_put: dev->ax25_ptr = NULL; spin_unlock_bh(&ax25_dev_lock); - ax25_dev_put(ax25_dev); netdev_put(dev, &ax25_dev->dev_tracker); ax25_dev_put(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 so far. 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> --- net/ax25/ax25_dev.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)