diff options
| author | Johan Hovold <johan@kernel.org> | 2021-12-01 16:25:25 +0300 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2022-01-15 02:50:52 +0300 |
| commit | d3e305592d69e21e36b76d24ca3c01971a2d09be (patch) | |
| tree | e285d91bda054ceebdc6eddc25992db0fa405539 /drivers/firmware | |
| parent | 28cc408be72cebb0f3fcc37bc74ab3196d4de726 (diff) | |
| download | linux-d3e305592d69e21e36b76d24ca3c01971a2d09be.tar.xz | |
firmware: qemu_fw_cfg: fix NULL-pointer deref on duplicate entries
Commit fe3c60684377 ("firmware: Fix a reference count leak.") "fixed"
a kobject leak in the file registration helper by properly calling
kobject_put() for the entry in case registration of the object fails
(e.g. due to a name collision).
This would however result in a NULL pointer dereference when the
release function tries to remove the never added entry from the
fw_cfg_entry_cache list.
Fix this by moving the list-removal out of the release function.
Note that the offending commit was one of the benign looking umn.edu
fixes which was reviewed but not reverted. [1][2]
[1] https://lore.kernel.org/r/202105051005.49BFABCE@keescook
[2] https://lore.kernel.org/all/YIg7ZOZvS3a8LjSv@kroah.com
Fixes: fe3c60684377 ("firmware: Fix a reference count leak.")
Cc: stable@vger.kernel.org # 5.8
Cc: Qiushi Wu <wu000273@umn.edu>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211201132528.30025-2-johan@kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/qemu_fw_cfg.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c index 172c751a4f6c..a9c64ebfc49a 100644 --- a/drivers/firmware/qemu_fw_cfg.c +++ b/drivers/firmware/qemu_fw_cfg.c @@ -388,9 +388,7 @@ static void fw_cfg_sysfs_cache_cleanup(void) struct fw_cfg_sysfs_entry *entry, *next; list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) { - /* will end up invoking fw_cfg_sysfs_cache_delist() - * via each object's release() method (i.e. destructor) - */ + fw_cfg_sysfs_cache_delist(entry); kobject_put(&entry->kobj); } } @@ -448,7 +446,6 @@ static void fw_cfg_sysfs_release_entry(struct kobject *kobj) { struct fw_cfg_sysfs_entry *entry = to_entry(kobj); - fw_cfg_sysfs_cache_delist(entry); kfree(entry); } |