From: Alan Stern stern@rowland.harvard.edu

stable inclusion from stable-v6.8.8 commit a4c99b57d43bab45225ba92d574a8683f9edc8e4 category: bugfix bugzilla: 189875 CVE: CVE-2024-26993

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit a90bca2228c0646fc29a72689d308e5fe03e6d78 upstream.

The sysfs_break_active_protection() routine has an obvious reference leak in its error path. If the call to kernfs_find_and_get() fails then kn will be NULL, so the companion sysfs_unbreak_active_protection() routine won't get called (and would only cause an access violation by trying to dereference kn->parent if it was called). As a result, the reference to kobj acquired at the start of the function will never be released.

Fix the leak by adding an explicit kobject_put() call when kn is NULL.

Signed-off-by: Alan Stern stern@rowland.harvard.edu Fixes: 2afc9166f79b ("scsi: sysfs: Introduce sysfs_{un,}break_active_protection()") Cc: Bart Van Assche bvanassche@acm.org Cc: stable@vger.kernel.org Reviewed-by: Bart Van Assche bvanassche@acm.org Acked-by: Tejun Heo tj@kernel.org Link: https://lore.kernel.org/r/8a4d3f0f-c5e3-4b70-a188-0ca433f9e6f9@rowland.harva... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/sysfs/file.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index a12ac0356c69..f21e73d10724 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -450,6 +450,8 @@ struct kernfs_node *sysfs_break_active_protection(struct kobject *kobj, kn = kernfs_find_and_get(kobj->sd, attr->name); if (kn) kernfs_break_active_protection(kn); + else + kobject_put(kobj); return kn; } EXPORT_SYMBOL_GPL(sysfs_break_active_protection);