queue-6.8/fs-sysfs-fix-reference-leak-in-sysfs_break_active_protection.patch

   1 From a90bca2228c0646fc29a72689d308e5fe03e6d78 Mon Sep 17 00:00:00 2001
   2 From: Alan Stern <stern@rowland.harvard.edu>
   3 Date: Wed, 13 Mar 2024 17:43:41 -0400
   4 Subject: fs: sysfs: Fix reference leak in sysfs_break_active_protection()
   5
   6 From: Alan Stern <stern@rowland.harvard.edu>
   7
   8 commit a90bca2228c0646fc29a72689d308e5fe03e6d78 upstream.
   9
  10 The sysfs_break_active_protection() routine has an obvious reference
  11 leak in its error path.  If the call to kernfs_find_and_get() fails then
  12 kn will be NULL, so the companion sysfs_unbreak_active_protection()
  13 routine won't get called (and would only cause an access violation by
  14 trying to dereference kn->parent if it was called).  As a result, the
  15 reference to kobj acquired at the start of the function will never be
  16 released.
  17
  18 Fix the leak by adding an explicit kobject_put() call when kn is NULL.
  19
  20 Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
  21 Fixes: 2afc9166f79b ("scsi: sysfs: Introduce sysfs_{un,}break_active_protection()")
  22 Cc: Bart Van Assche <bvanassche@acm.org>
  23 Cc: stable@vger.kernel.org
  24 Reviewed-by: Bart Van Assche <bvanassche@acm.org>
  25 Acked-by: Tejun Heo <tj@kernel.org>
  26 Link: https://lore.kernel.org/r/8a4d3f0f-c5e3-4b70-a188-0ca433f9e6f9@rowland.harvard.edu
  27 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  28 ---
  29  fs/sysfs/file.c |    2 ++
  30  1 file changed, 2 insertions(+)
  31
  32 --- a/fs/sysfs/file.c
  33 +++ b/fs/sysfs/file.c
  34 @@ -463,6 +463,8 @@ struct kernfs_node *sysfs_break_active_p
  35         kn = kernfs_find_and_get(kobj->sd, attr->name);
  36         if (kn)
  37                 kernfs_break_active_protection(kn);
  38 +       else
  39 +               kobject_put(kobj);
  40         return kn;
  41  }
  42  EXPORT_SYMBOL_GPL(sysfs_break_active_protection);