Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 589ac131 authored by Todd Kjos's avatar Todd Kjos Committed by Greg Kroah-Hartman
Browse files

binder: don't detect sender/target during buffer cleanup 



commit 32e9f56a96d8d0f23cb2aeb2a3cd18d40393e787 upstream.

When freeing txn buffers, binder_transaction_buffer_release()
attempts to detect whether the current context is the target by
comparing current->group_leader to proc->tsk. This is an unreliable
test. Instead explicitly pass an 'is_failure' boolean.

Detecting the sender was being used as a way to tell if the
transaction failed to be sent.  When cleaning up after
failing to send a transaction, there is no need to close
the fds associated with a BINDER_TYPE_FDA object. Now
'is_failure' can be used to accurately detect this case.

Fixes: 44d8047f ("binder: use standard functions to allocate fds")
Cc: stable <stable@vger.kernel.org>
Acked-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: default avatarTodd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211015233811.3532235-1-tkjos@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b60e89b6

drivers/android/binder.c

+7 −7
Original line number Diff line number Diff line
@@ -2257,7 +2257,7 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, 
		binder_dec_node(buffer->target_node, 1, 0);



	off_start_offset = ALIGN(buffer->data_size, sizeof(void *));

	off_end_offset = is_failure ? failed_at :

	off_end_offset = is_failure && failed_at ? failed_at :

				off_start_offset + buffer->offsets_size;

	for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;

	     buffer_offset += sizeof(binder_size_t)) {
@@ -2343,9 +2343,8 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, 
			binder_size_t fd_buf_size;

			binder_size_t num_valid;



			if (proc->tsk != current->group_leader) {

			if (is_failure) {

				/*

				 * Nothing to do if running in sender context

				 * The fd fixups have not been applied so no

				 * fds need to be closed.

				 */
@@ -3548,6 +3547,7 @@ static void binder_transaction(struct binder_proc *proc, 
 * binder_free_buf() - free the specified buffer

 * @proc:	binder proc that owns buffer

 * @buffer:	buffer to be freed

 * @is_failure:	failed to send transaction

 *

 * If buffer for an async transaction, enqueue the next async

 * transaction from the node.
@@ -3557,7 +3557,7 @@ static void binder_transaction(struct binder_proc *proc, 
static void

binder_free_buf(struct binder_proc *proc,

		struct binder_thread *thread,

		struct binder_buffer *buffer)

		struct binder_buffer *buffer, bool is_failure)

{

	binder_inner_proc_lock(proc);

	if (buffer->transaction) {
@@ -3585,7 +3585,7 @@ binder_free_buf(struct binder_proc *proc, 
		binder_node_inner_unlock(buf_node);

	}

	trace_binder_transaction_buffer_release(buffer);

	binder_transaction_buffer_release(proc, thread, buffer, 0, false);

	binder_transaction_buffer_release(proc, thread, buffer, 0, is_failure);

	binder_alloc_free_buf(&proc->alloc, buffer);

}
@@ -3786,7 +3786,7 @@ static int binder_thread_write(struct binder_proc *proc, 
				     proc->pid, thread->pid, (u64)data_ptr,

				     buffer->debug_id,

				     buffer->transaction ? "active" : "finished");

			binder_free_buf(proc, thread, buffer);

			binder_free_buf(proc, thread, buffer, false);

			break;

		}
@@ -4474,7 +4474,7 @@ static int binder_thread_read(struct binder_proc *proc, 
			buffer->transaction = NULL;

			binder_cleanup_transaction(t, "fd fixups failed",

						   BR_FAILED_REPLY);

			binder_free_buf(proc, thread, buffer);

			binder_free_buf(proc, thread, buffer, true);

			binder_debug(BINDER_DEBUG_FAILED_TRANSACTION,

				     "%d:%d %stransaction %d fd fixups failed %d/%d, line %d\n",

				     proc->pid, thread->pid,