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| author | Carlos Llamas <cmllamas@google.com> | 2023-09-22 17:51:37 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-10-05 12:48:08 +0200 |
| commit | 1aa3aaf8953c84bad398adf6c3cabc9d6685bf7d (patch) | |
| tree | fec28eedc5e526e0c1f42aeb7416a60fbfe911a9 | |
| parent | 53604854c6f00ce1db4393499125aff94e3d9bbd (diff) | |
| download | lwn-1aa3aaf8953c84bad398adf6c3cabc9d6685bf7d.tar.gz lwn-1aa3aaf8953c84bad398adf6c3cabc9d6685bf7d.zip | |
binder: fix memory leaks of spam and pending work
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: stable@vger.kernel.org
Fixes: 0567461a7a6e ("binder: return pending info for frozen async txns")
Fixes: a7dc1e6f99df ("binder: tell userspace to dump current backtrace when detected oneway spamming")
Reported-by: syzbot+7f10c1653e35933c0f1e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20230922175138.230331-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/android/binder.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 367afac5f1bf..92128aae2d06 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -4812,6 +4812,8 @@ static void binder_release_work(struct binder_proc *proc, "undelivered TRANSACTION_ERROR: %u\n", e->cmd); } break; + case BINDER_WORK_TRANSACTION_PENDING: + case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT: case BINDER_WORK_TRANSACTION_COMPLETE: { binder_debug(BINDER_DEBUG_DEAD_TRANSACTION, "undelivered TRANSACTION_COMPLETE\n"); |