kernel/linux.git/drivers/android/binder.c, branch v4.14.22

binder: replace "%p" with "%pK"

2018-02-25T10:07:52+00:00

commit 8ca86f1639ec5890d400fff9211aca22d0a392eb upstream. The format specifier "%p" can leak kernel addresses. Use "%pK" instead. There were 4 remaining cases in binder.c. Signed-off-by: Todd Kjos Cc: stable Signed-off-by: Greg Kroah-Hartman

binder: check for binder_thread allocation failure in binder_poll()

2018-02-25T10:07:52+00:00

commit f88982679f54f75daa5b8eff3da72508f1e7422f upstream. If the kzalloc() in binder_get_thread() fails, binder_poll() dereferences the resulting NULL pointer. Fix it by returning POLLERR if the memory allocation failed. This bug was found by syzkaller using fault injection. Reported-by: syzbot Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

ANDROID: binder: synchronize_rcu() when using POLLFREE.

2018-02-25T10:07:52+00:00

commit 5eeb2ca02a2f6084fc57ae5c244a38baab07033a upstream. To prevent races with ep_remove_waitqueue() removing the waitqueue at the same time. Reported-by: syzbot+a2a3c4909716e271487e@syzkaller.appspotmail.com Signed-off-by: Martijn Coenen Cc: stable # 4.14+ Signed-off-by: Greg Kroah-Hartman

ANDROID: binder: remove WARN() for redundant txn error

2018-02-25T10:07:52+00:00

commit e46a3b3ba7509cb7fda0e07bc7c63a2cd90f579b upstream. binder_send_failed_reply() is called when a synchronous transaction fails. It reports an error to the thread that is waiting for the completion. Given that the transaction is synchronous, there should never be more than 1 error response to that thread -- this was being asserted with a WARN(). However, when exercising the driver with syzbot tests, cases were observed where multiple "synchronous" requests were sent without waiting for responses, so it is possible that multiple errors would be reported to the thread. This testing was conducted with panic_on_warn set which forced the crash. This is easily reproduced by sending back-to-back "synchronous" transactions without checking for any response (eg, set read_size to 0): bwr.write_buffer = (uintptr_t)&bc1; bwr.write_size = sizeof(bc1); bwr.read_buffer = (uintptr_t)&br; bwr.read_size = 0; ioctl(fd, BINDER_WRITE_READ, &bwr); sleep(1); bwr2.write_buffer = (uintptr_t)&bc2; bwr2.write_size = sizeof(bc2); bwr2.read_buffer = (uintptr_t)&br; bwr2.read_size = 0; ioctl(fd, BINDER_WRITE_READ, &bwr2); sleep(1); The first transaction is sent to the servicemanager and the reply fails because no VMA is set up by this client. After binder_send_failed_reply() is called, the BINDER_WORK_RETURN_ERROR is sitting on the thread's todo list since the read_size was 0 and the client is not waiting for a response. The 2nd transaction is sent and the BINDER_WORK_RETURN_ERROR has not been consumed, so the thread's reply_error.cmd is still set (normally cleared when the BINDER_WORK_RETURN_ERROR is handled). Therefore when the servicemanager attempts to reply to the 2nd failed transaction, the error is already set and it triggers this warning. This is a user error since it is not waiting for the synchronous transaction to complete. If it ever does check, it will see an error. Changed the WARN() to a pr_warn(). Signed-off-by: Todd Kjos Reported-by: syzbot Cc: stable Signed-off-by: Greg Kroah-Hartman

ANDROID: binder: remove waitqueue when thread exits.

2018-02-03T16:39:22+00:00

commit f5cb779ba16334b45ba8946d6bfa6d9834d1527f upstream. binder_poll() passes the thread->wait waitqueue that can be slept on for work. When a thread that uses epoll explicitly exits using BINDER_THREAD_EXIT, the waitqueue is freed, but it is never removed from the corresponding epoll data structure. When the process subsequently exits, the epoll cleanup code tries to access the waitlist, which results in a use-after-free. Prevent this by using POLLFREE when the thread exits. Signed-off-by: Martijn Coenen Reported-by: syzbot Signed-off-by: Greg Kroah-Hartman

binder: fix proc->files use-after-free

2018-01-02T19:31:15+00:00

commit 7f3dc0088b98533f17128058fac73cd8b2752ef1 upstream. proc->files cleanup is initiated by binder_vma_close. Therefore a reference on the binder_proc is not enough to prevent the files_struct from being released while the binder_proc still has a reference. This can lead to an attempt to dereference the stale pointer obtained from proc->files prior to proc->files cleanup. This has been seen once in task_get_unused_fd_flags() when __alloc_fd() is called with a stale "files". The fix is to protect proc->files with a mutex to prevent cleanup while in use. Signed-off-by: Todd Kjos Signed-off-by: Greg Kroah-Hartman

ANDROID: binder: fix transaction leak.

2017-12-10T12:40:37+00:00

commit fb2c445277e7b0b4ffe10de8114bad4eccaca948 upstream. If a call to put_user() fails, we failed to properly free a transaction and send a failed reply (if necessary). Signed-off-by: Martijn Coenen Signed-off-by: Greg Kroah-Hartman

binder: call poll_wait() unconditionally.

2017-10-20T10:53:43+00:00

Because we're not guaranteed that subsequent calls to poll() will have a poll_table_struct parameter with _qproc set. When _qproc is not set, poll_wait() is a noop, and we won't be woken up correctly. Signed-off-by: Martijn Coenen Signed-off-by: Greg Kroah-Hartman

binder: fix use-after-free in binder_transaction()

2017-10-04T09:25:10+00:00

User-space normally keeps the node alive when creating a transaction since it has a reference to the target. The local strong ref keeps it alive if the sending process dies before the target process processes the transaction. If the source process is malicious or has a reference counting bug, this can fail. In this case, when we attempt to decrement the node in the failure path, the node has already been freed. This is fixed by taking a tmpref on the node while constructing the transaction. To avoid re-acquiring the node lock and inner proc lock to increment the proc's tmpref, a helper is used that does the ref increments on both the node and proc. Signed-off-by: Todd Kjos Cc: stable Signed-off-by: Greg Kroah-Hartman

binder: fix memory corruption in binder_transaction binder

2017-09-18T14:06:00+00:00

commit 7a4408c6bd3e ("binder: make sure accesses to proc/thread are safe") made a change to enqueue tcomplete to thread->todo before enqueuing the transaction. However, in err_dead_proc_or_thread case, the tcomplete is directly freed, without dequeued. It may cause the thread->todo list to be corrupted. So, dequeue it before freeing. Fixes: 7a4408c6bd3e ("binder: make sure accesses to proc/thread are safe") Signed-off-by: Xu YiPing Signed-off-by: Todd Kjos Signed-off-by: Greg Kroah-Hartman