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Commit 406b9c97 authored by Andrei Homescu's avatar Andrei Homescu Committed by Dmitriy Filchenko
Browse files

Trusty Binder: split large messages in RpcTransportTipcAndroid 

tipc_send returns -EMSGSIZE when attempting to send messages
larger than a little under a page. Fragment them manually
in the transport since the receiver reassembles them.

Bug: 415302667
Test: atest -c binderRpcToTrustyTest
Flag: EXEMPT bugfix
Change-Id: Ida0eb029eedb8b38603b7a4179d3641e34e70776
parent c4dc4b74

libs/binder/RpcTransportTipcAndroid.cpp

+26 −1
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ public: 
            const std::vector<std::variant<unique_fd, borrowed_fd>>* ancillaryFds) override {

        bool sentFds = false;

        auto writeFn = [&](iovec* iovs, size_t niovs) -> ssize_t {

            // Collect the ancillary FDs.

            trusty_shm shms[kMaxTipcHandles] = {{0}};

            ssize_t shm_count = 0;
@@ -100,9 +101,33 @@ public: 
                }

            }



            auto ret = TEMP_FAILURE_RETRY(tipc_send(mSocket.fd.get(), iovs, niovs,

            // Trusty currently has a message size limit, which will go away once we

            // switch to vsock. The message is reassembled on the receiving side.

            static const size_t maxMsgSize = VIRTIO_VSOCK_MSG_SIZE_LIMIT;

            size_t niovsMsg;

            size_t currSize = 0;

            size_t cutSize = 0;

            for (niovsMsg = 0; niovsMsg < niovs; niovsMsg++) {

                if (__builtin_add_overflow(currSize, iovs[niovsMsg].iov_len, &currSize)) {

                    ALOGE("%s: iov_len add_overflow", __FUNCTION__);

                    return NO_MEMORY;

                }

                if (currSize >= maxMsgSize) {

                    // Truncate the last iov but restore it at the end

                    // so the caller can continue where we left off.

                    cutSize = currSize - maxMsgSize;

                    iovs[niovsMsg].iov_len -= cutSize;

                    niovsMsg++;

                    break;

                }

            }



            auto ret = TEMP_FAILURE_RETRY(tipc_send(mSocket.fd.get(), iovs, niovsMsg,

                                                    (shm_count == 0) ? nullptr : shms, shm_count));

            sentFds |= ret >= 0;

            if (niovsMsg > 0) {

                iovs[niovsMsg - 1].iov_len += cutSize;

            }

            return ret;

        };

libs/binder/trusty/RpcServerTrusty.cpp

+1 −1
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ RpcServerTrusty::RpcServerTrusty(std::unique_ptr<RpcTransportCtx> ctx, std::stri 
        mPortAcl(std::move(portAcl)) {

    mTipcPort.name = mPortName.c_str();

    mTipcPort.msg_max_size = msgMaxSize;

    mTipcPort.msg_queue_len = 6; // Three each way

    mTipcPort.msg_queue_len = 16;

    mTipcPort.priv = this;



    if (mPortAcl) {