From: Todd Kjos tkjos@google.com
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: 44d8047f1d87 ("binder: use standard functions to allocate fds") Cc: stable stable@vger.kernel.org Acked-by: Christian Brauner christian.brauner@ubuntu.com Signed-off-by: Todd Kjos tkjos@google.com Link: https://lore.kernel.org/r/20211015233811.3532235-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/android/binder.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
--- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -1870,7 +1870,7 @@ static void binder_transaction_buffer_re 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)) { @@ -1956,9 +1956,8 @@ static void binder_transaction_buffer_re 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. */ @@ -3176,6 +3175,7 @@ err_invalid_target_handle: * 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. @@ -3185,7 +3185,7 @@ err_invalid_target_handle: 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) { @@ -3213,7 +3213,7 @@ 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); }
@@ -3415,7 +3415,7 @@ static int binder_thread_write(struct bi 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; }
@@ -4108,7 +4108,7 @@ retry: 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,