From: Johan Hovold johan@kernel.org
commit 47a1db8e797da01a1309bf42e0c0d771d4e4d4f3 upstream.
An initialised kobject must be freed using kobject_put() to avoid leaking associated resources (e.g. the object name).
Commit fe3c60684377 ("firmware: Fix a reference count leak.") "fixed" the leak in the first error path of the file registration helper but left the second one unchanged. This "fix" would however result in a NULL pointer dereference due to the release function also removing the never added entry from the fw_cfg_entry_cache list. This has now been addressed.
Fix the remaining kobject leak by restoring the common error path and adding the missing kobject_put().
Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device") Cc: stable@vger.kernel.org # 4.6 Cc: Gabriel Somlo somlo@cmu.edu Signed-off-by: Johan Hovold johan@kernel.org Link: https://lore.kernel.org/r/20211201132528.30025-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/firmware/qemu_fw_cfg.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
--- a/drivers/firmware/qemu_fw_cfg.c +++ b/drivers/firmware/qemu_fw_cfg.c @@ -603,15 +603,13 @@ static int fw_cfg_register_file(const st /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */ err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype, fw_cfg_sel_ko, "%d", entry->select); - if (err) { - kobject_put(&entry->kobj); - return err; - } + if (err) + goto err_put_entry;
/* add raw binary content access */ err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw); if (err) - goto err_add_raw; + goto err_del_entry;
/* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */ fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->name); @@ -620,9 +618,10 @@ static int fw_cfg_register_file(const st fw_cfg_sysfs_cache_enlist(entry); return 0;
-err_add_raw: +err_del_entry: kobject_del(&entry->kobj); - kfree(entry); +err_put_entry: + kobject_put(&entry->kobj); return err; }