FROMLIST: binder: fix memory leaks of spam and pending work

commit 1aa3aaf8953c84bad398adf6c3cabc9d6685bf7d upstream

A transaction complete work is allocated and queued for each
transaction. Under certain conditions the work->type might be marked as
BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT to notify userspace about
potential spamming threads or as BINDER_WORK_TRANSACTION_PENDING when
the target is currently frozen.

However, these work types are not being handled in binder_release_work()
so they will leak during a cleanup. This was reported by syzkaller with
the following kmemleak dump:

BUG: memory leak
unreferenced object 0xffff88810e2d6de0 (size 32):
  comm "syz-executor338", pid 5046, jiffies 4294968230 (age 13.590s)
  hex dump (first 32 bytes):
    e0 6d 2d 0e 81 88 ff ff e0 6d 2d 0e 81 88 ff ff  .m-......m-.....
    04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff81573b75>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1114
    [<ffffffff83d41873>] kmalloc include/linux/slab.h:599 [inline]
    [<ffffffff83d41873>] kzalloc include/linux/slab.h:720 [inline]
    [<ffffffff83d41873>] binder_transaction+0x573/0x4050 drivers/android/binder.c:3152
    [<ffffffff83d45a05>] binder_thread_write+0x6b5/0x1860 drivers/android/binder.c:4010
    [<ffffffff83d486dc>] binder_ioctl_write_read drivers/android/binder.c:5066 [inline]
    [<ffffffff83d486dc>] binder_ioctl+0x1b2c/0x3cf0 drivers/android/binder.c:5352
    [<ffffffff816b25f2>] vfs_ioctl fs/ioctl.c:51 [inline]
    [<ffffffff816b25f2>] __do_sys_ioctl fs/ioctl.c:871 [inline]
    [<ffffffff816b25f2>] __se_sys_ioctl fs/ioctl.c:857 [inline]
    [<ffffffff816b25f2>] __x64_sys_ioctl+0xf2/0x140 fs/ioctl.c:857
    [<ffffffff84b30008>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff84b30008>] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fix the leaks by kfreeing these work types in binder_release_work() and
handle them as a BINDER_WORK_TRANSACTION_COMPLETE cleanup.

Cc: [email protected]
Fixes: a7dc1e6f99df ("binder: tell userspace to dump current backtrace when detected oneway spamming")
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e
Suggested-by: Alice Ryhl <[email protected]>
Signed-off-by: Carlos Llamas <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Acked-by: Todd Kjos <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
[cmllamas: backport to v5.15 by dropping BINDER_WORK_TRANSACTION_PENDING
 as commit 0567461a7a6e is not present. Remove fixes tag accordingly.]
Signed-off-by: Carlos Llamas <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Link: https://lore.kernel.org/all/[email protected]/
Change-Id: I8e1ee7af87ef5706544e4f320e9498b8f4855a6b
[cmllamas: also backport to v5.10 to fix OOT 0493c72d6d0c]
Signed-off-by: Carlos Llamas <[email protected]>
Signed-off-by: onettboots <[email protected]>

drivers/android/binder.c

@@ -4617,6 +4617,7 @@ static void binder_release_work(struct binder_proc *proc,
 				"undelivered TRANSACTION_ERROR: %u\n",
 				e->cmd);
 		} break;
+		case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT:
 		case BINDER_WORK_TRANSACTION_COMPLETE: {
 			binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
 				"undelivered TRANSACTION_COMPLETE\n");