diff mbox series

[net,v5,3/4] ax25: Fix reference count leak issues of net_device

Message ID c1d18fcf1bf6ef65264ba992172ea1636dbf5431.1715065005.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State Superseded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

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 926 this patch: 926
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 937 this patch: 937
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 937 this patch: 937
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 16 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest fail net-next-2024-05-07--21-00 (tests: 1010)

Commit Message

Duoming Zhou May 7, 2024, 7:03 a.m. UTC
The ax25_dev_device_down() exists reference count leak issues of
the object "net_device". When the ax25 device is shutting down.
The ax25_dev_device_down() drops the reference count of net_device
one or zero times depending on if we goto unlock_put or not, which
will cause memory leak.

In order to solve the above issue, decrease the reference count of
net_device after dev->ax25_ptr is set to null.

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 | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

Comments

Markus Elfring May 7, 2024, 9:25 a.m. UTC | #1
> The ax25_dev_device_down() exists reference count leak issues of
> the object "net_device". When the ax25 device is shutting down.

* Please improve this wording for the final commit.

* Do you refer to a single issue here?

Regards,
Markus
diff mbox series

Patch

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 66aa381af0e..c6ab9b0f0be 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -121,15 +121,9 @@  void ax25_dev_device_down(struct net_device *dev)
 	list_for_each_entry(s, &ax25_dev_list, list) {
 		if (s == ax25_dev) {
 			list_del(&s->list);
-			goto unlock_put;
+			break;
 		}
 	}
-	dev->ax25_ptr = NULL;
-	spin_unlock_bh(&ax25_dev_lock);
-	ax25_dev_put(ax25_dev);
-	return;
-
-unlock_put:
 	dev->ax25_ptr = NULL;
 	spin_unlock_bh(&ax25_dev_lock);
 	netdev_put(dev, &ax25_dev->dev_tracker);