diff options
Diffstat (limited to 'pkg')
| -rw-r--r-- | pkg/sentry/kernel/msgqueue/msgqueue.go | 278 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/BUILD | 1 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/linux64.go | 8 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_msgqueue.go | 85 |
4 files changed, 362 insertions, 10 deletions
diff --git a/pkg/sentry/kernel/msgqueue/msgqueue.go b/pkg/sentry/kernel/msgqueue/msgqueue.go index 3ce926950..c111297d7 100644 --- a/pkg/sentry/kernel/msgqueue/msgqueue.go +++ b/pkg/sentry/kernel/msgqueue/msgqueue.go @@ -119,14 +119,21 @@ type Queue struct { type Message struct { msgEntry - // mType is an integer representing the type of the sent message. - mType int64 + // Type is an integer representing the type of the sent message. + Type int64 - // mText is an untyped block of memory. - mText []byte + // Text is an untyped block of memory. + Text []byte - // mSize is the size of mText. - mSize uint64 + // Size is the size of Text. + Size uint64 +} + +// Blocker is used for blocking Queue.Send, and Queue.Receive calls that serves +// as an abstracted version of kernel.Task. kernel.Task is not directly used to +// prevent circular dependencies. +type Blocker interface { + Block(C <-chan struct{}) error } // FindOrCreate creates a new message queue or returns an existing one. See @@ -186,6 +193,265 @@ func (r *Registry) Remove(id ipc.ID, creds *auth.Credentials) error { return nil } +// FindByID returns the queue with the specified ID and an error if the ID +// doesn't exist. +func (r *Registry) FindByID(id ipc.ID) (*Queue, error) { + r.mu.Lock() + defer r.mu.Unlock() + + mech := r.reg.FindByID(id) + if mech == nil { + return nil, linuxerr.EINVAL + } + return mech.(*Queue), nil +} + +// Send appends a message to the message queue, and returns an error if sending +// fails. See msgsnd(2). +func (q *Queue) Send(ctx context.Context, m Message, b Blocker, wait bool, pid int32) (err error) { + // Try to perform a non-blocking send using queue.append. If EWOULDBLOCK + // is returned, start the blocking procedure. Otherwise, return normally. + creds := auth.CredentialsFromContext(ctx) + if err := q.append(ctx, m, creds, pid); err != linuxerr.EWOULDBLOCK { + return err + } + + if !wait { + return linuxerr.EAGAIN + } + + e, ch := waiter.NewChannelEntry(nil) + q.senders.EventRegister(&e, waiter.EventOut) + + for { + if err = q.append(ctx, m, creds, pid); err != linuxerr.EWOULDBLOCK { + break + } + b.Block(ch) + } + + q.senders.EventUnregister(&e) + return err +} + +// append appends a message to the queue's message list and notifies waiting +// receivers that a message has been inserted. It returns an error if adding +// the message would cause the queue to exceed its maximum capacity, which can +// be used as a signal to block the task. Other errors should be returned as is. +func (q *Queue) append(ctx context.Context, m Message, creds *auth.Credentials, pid int32) error { + if m.Type <= 0 { + return linuxerr.EINVAL + } + + q.mu.Lock() + defer q.mu.Unlock() + + if !q.obj.CheckPermissions(creds, fs.PermMask{Write: true}) { + // The calling process does not have write permission on the message + // queue, and does not have the CAP_IPC_OWNER capability in the user + // namespace that governs its IPC namespace. + return linuxerr.EACCES + } + + // Queue was removed while the process was waiting. + if q.dead { + return linuxerr.EIDRM + } + + // Check if sufficient space is available (the queue isn't full.) From + // the man pages: + // + // "A message queue is considered to be full if either of the following + // conditions is true: + // + // • Adding a new message to the queue would cause the total number + // of bytes in the queue to exceed the queue's maximum size (the + // msg_qbytes field). + // + // • Adding another message to the queue would cause the total + // number of messages in the queue to exceed the queue's maximum + // size (the msg_qbytes field). This check is necessary to + // prevent an unlimited number of zero-length messages being + // placed on the queue. Although such messages contain no data, + // they nevertheless consume (locked) kernel memory." + // + // The msg_qbytes field in our implementation is q.maxBytes. + if m.Size+q.byteCount > q.maxBytes || q.messageCount+1 > q.maxBytes { + return linuxerr.EWOULDBLOCK + } + + // Copy the message into the queue. + q.messages.PushBack(&m) + + q.byteCount += m.Size + q.messageCount++ + q.sendPID = pid + q.sendTime = ktime.NowFromContext(ctx) + + // Notify receivers about the new message. + q.receivers.Notify(waiter.EventIn) + + return nil +} + +// Receive removes a message from the queue and returns it. See msgrcv(2). +func (q *Queue) Receive(ctx context.Context, b Blocker, mType int64, maxSize int64, wait, truncate, except bool, pid int32) (msg *Message, err error) { + if maxSize < 0 || maxSize > maxMessageBytes { + return nil, linuxerr.EINVAL + } + max := uint64(maxSize) + + // Try to perform a non-blocking receive using queue.pop. If EWOULDBLOCK + // is returned, start the blocking procedure. Otherwise, return normally. + creds := auth.CredentialsFromContext(ctx) + if msg, err := q.pop(ctx, creds, mType, max, truncate, except, pid); err != linuxerr.EWOULDBLOCK { + return msg, err + } + + if !wait { + return nil, linuxerr.ENOMSG + } + + e, ch := waiter.NewChannelEntry(nil) + q.receivers.EventRegister(&e, waiter.EventIn) + + for { + if msg, err = q.pop(ctx, creds, mType, max, truncate, except, pid); err != linuxerr.EWOULDBLOCK { + break + } + b.Block(ch) + } + q.receivers.EventUnregister(&e) + return msg, err +} + +// pop pops the first message from the queue that matches the given type. It +// returns an error for all the cases specified in msgrcv(2). If the queue is +// empty or no message of the specified type is available, a EWOULDBLOCK error +// is returned, which can then be used as a signal to block the process or fail. +func (q *Queue) pop(ctx context.Context, creds *auth.Credentials, mType int64, maxSize uint64, truncate, except bool, pid int32) (msg *Message, _ error) { + q.mu.Lock() + defer q.mu.Unlock() + + if !q.obj.CheckPermissions(creds, fs.PermMask{Read: true}) { + // The calling process does not have read permission on the message + // queue, and does not have the CAP_IPC_OWNER capability in the user + // namespace that governs its IPC namespace. + return nil, linuxerr.EACCES + } + + // Queue was removed while the process was waiting. + if q.dead { + return nil, linuxerr.EIDRM + } + + if q.messages.Empty() { + return nil, linuxerr.EWOULDBLOCK + } + + // Get a message from the queue. + switch { + case mType == 0: + msg = q.messages.Front() + case mType > 0: + msg = q.msgOfType(mType, except) + case mType < 0: + msg = q.msgOfTypeLessThan(-1 * mType) + } + + // If no message exists, return a blocking singal. + if msg == nil { + return nil, linuxerr.EWOULDBLOCK + } + + // Check message's size is acceptable. + if maxSize < msg.Size { + if !truncate { + return nil, linuxerr.E2BIG + } + msg.Size = maxSize + msg.Text = msg.Text[:maxSize+1] + } + + q.messages.Remove(msg) + + q.byteCount -= msg.Size + q.messageCount-- + q.receivePID = pid + q.receiveTime = ktime.NowFromContext(ctx) + + // Notify senders about available space. + q.senders.Notify(waiter.EventOut) + + return msg, nil +} + +// Copy copies a message from the queue without deleting it. If no message +// exists, an error is returned. See msgrcv(MSG_COPY). +func (q *Queue) Copy(mType int64) (*Message, error) { + q.mu.Lock() + defer q.mu.Unlock() + + if mType < 0 || q.messages.Empty() { + return nil, linuxerr.ENOMSG + } + + msg := q.msgAtIndex(mType) + if msg == nil { + return nil, linuxerr.ENOMSG + } + return msg, nil +} + +// msgOfType returns the first message with the specified type, nil if no +// message is found. If except is true, the first message of a type not equal +// to mType will be returned. +// +// Precondition: caller must hold q.mu. +func (q *Queue) msgOfType(mType int64, except bool) *Message { + if except { + for msg := q.messages.Front(); msg != nil; msg = msg.Next() { + if msg.Type != mType { + return msg + } + } + return nil + } + + for msg := q.messages.Front(); msg != nil; msg = msg.Next() { + if msg.Type == mType { + return msg + } + } + return nil +} + +// msgOfTypeLessThan return the the first message with the lowest type less +// than or equal to mType, nil if no such message exists. +// +// Precondition: caller must hold q.mu. +func (q *Queue) msgOfTypeLessThan(mType int64) (m *Message) { + min := mType + for msg := q.messages.Front(); msg != nil; msg = msg.Next() { + if msg.Type <= mType && msg.Type < min { + m = msg + min = msg.Type + } + } + return m +} + +// msgAtIndex returns a pointer to a message at given index, nil if non exits. +// +// Precondition: caller must hold q.mu. +func (q *Queue) msgAtIndex(mType int64) *Message { + msg := q.messages.Front() + for ; mType != 0 && msg != nil; mType-- { + msg = msg.Next() + } + return msg +} + // Lock implements ipc.Mechanism.Lock. func (q *Queue) Lock() { q.mu.Lock() diff --git a/pkg/sentry/syscalls/linux/BUILD b/pkg/sentry/syscalls/linux/BUILD index ccccce6a9..b5a371d9a 100644 --- a/pkg/sentry/syscalls/linux/BUILD +++ b/pkg/sentry/syscalls/linux/BUILD @@ -86,6 +86,7 @@ go_library( "//pkg/sentry/kernel/eventfd", "//pkg/sentry/kernel/fasync", "//pkg/sentry/kernel/ipc", + "//pkg/sentry/kernel/msgqueue", "//pkg/sentry/kernel/pipe", "//pkg/sentry/kernel/sched", "//pkg/sentry/kernel/shm", diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go index 6f44d767b..1ead3c7e8 100644 --- a/pkg/sentry/syscalls/linux/linux64.go +++ b/pkg/sentry/syscalls/linux/linux64.go @@ -122,8 +122,8 @@ var AMD64 = &kernel.SyscallTable{ 66: syscalls.Supported("semctl", Semctl), 67: syscalls.Supported("shmdt", Shmdt), 68: syscalls.Supported("msgget", Msgget), - 69: syscalls.ErrorWithEvent("msgsnd", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921) - 70: syscalls.ErrorWithEvent("msgrcv", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921) + 69: syscalls.Supported("msgsnd", Msgsnd), + 70: syscalls.Supported("msgrcv", Msgrcv), 71: syscalls.PartiallySupported("msgctl", Msgctl, "Only supports IPC_RMID option.", []string{"gvisor.dev/issue/135"}), 72: syscalls.PartiallySupported("fcntl", Fcntl, "Not all options are supported.", nil), 73: syscalls.PartiallySupported("flock", Flock, "Locks are held within the sandbox only.", nil), @@ -618,8 +618,8 @@ var ARM64 = &kernel.SyscallTable{ 185: syscalls.ErrorWithEvent("mq_getsetattr", syserror.ENOSYS, "", []string{"gvisor.dev/issue/136"}), // TODO(b/29354921) 186: syscalls.Supported("msgget", Msgget), 187: syscalls.PartiallySupported("msgctl", Msgctl, "Only supports IPC_RMID option.", []string{"gvisor.dev/issue/135"}), - 188: syscalls.ErrorWithEvent("msgrcv", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921) - 189: syscalls.ErrorWithEvent("msgsnd", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921) + 188: syscalls.Supported("msgrcv", Msgrcv), + 189: syscalls.Supported("msgsnd", Msgsnd), 190: syscalls.Supported("semget", Semget), 191: syscalls.Supported("semctl", Semctl), 192: syscalls.Supported("semtimedop", Semtimedop), diff --git a/pkg/sentry/syscalls/linux/sys_msgqueue.go b/pkg/sentry/syscalls/linux/sys_msgqueue.go index 3476e218d..5259ade90 100644 --- a/pkg/sentry/syscalls/linux/sys_msgqueue.go +++ b/pkg/sentry/syscalls/linux/sys_msgqueue.go @@ -17,10 +17,12 @@ package linux import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/errors/linuxerr" + "gvisor.dev/gvisor/pkg/marshal/primitive" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/kernel/ipc" + "gvisor.dev/gvisor/pkg/sentry/kernel/msgqueue" ) // Msgget implements msgget(2). @@ -41,6 +43,89 @@ func Msgget(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal return uintptr(queue.ID()), nil, nil } +// Msgsnd implements msgsnd(2). +func Msgsnd(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + id := ipc.ID(args[0].Int()) + msgAddr := args[1].Pointer() + size := args[2].Int64() + flag := args[3].Int() + + if size < 0 || size > linux.MSGMAX { + return 0, nil, linuxerr.EINVAL + } + + wait := flag&linux.IPC_NOWAIT != linux.IPC_NOWAIT + pid := int32(t.ThreadGroup().ID()) + + buf := linux.MsgBuf{ + Text: make([]byte, size), + } + if _, err := buf.CopyIn(t, msgAddr); err != nil { + return 0, nil, err + } + + queue, err := t.IPCNamespace().MsgqueueRegistry().FindByID(id) + if err != nil { + return 0, nil, err + } + + msg := msgqueue.Message{ + Type: int64(buf.Type), + Text: buf.Text, + Size: uint64(size), + } + return 0, nil, queue.Send(t, msg, t, wait, pid) +} + +// Msgrcv implements msgrcv(2). +func Msgrcv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + id := ipc.ID(args[0].Int()) + msgAddr := args[1].Pointer() + size := args[2].Int64() + mType := args[3].Int64() + flag := args[4].Int() + + wait := flag&linux.IPC_NOWAIT != linux.IPC_NOWAIT + except := flag&linux.MSG_EXCEPT == linux.MSG_EXCEPT + truncate := flag&linux.MSG_NOERROR == linux.MSG_NOERROR + + msgCopy := flag&linux.MSG_COPY == linux.MSG_COPY + + msg, err := receive(t, id, mType, size, msgCopy, wait, truncate, except) + if err != nil { + return 0, nil, err + } + + buf := linux.MsgBuf{ + Type: primitive.Int64(msg.Type), + Text: msg.Text, + } + if _, err := buf.CopyOut(t, msgAddr); err != nil { + return 0, nil, err + } + return uintptr(msg.Size), nil, nil +} + +// receive returns a message from the queue with the given ID. If msgCopy is +// true, a message is copied from the queue without being removed. Otherwise, +// a message is removed from the queue and returned. +func receive(t *kernel.Task, id ipc.ID, mType int64, maxSize int64, msgCopy, wait, truncate, except bool) (*msgqueue.Message, error) { + pid := int32(t.ThreadGroup().ID()) + + queue, err := t.IPCNamespace().MsgqueueRegistry().FindByID(id) + if err != nil { + return nil, err + } + + if msgCopy { + if wait || except { + return nil, linuxerr.EINVAL + } + return queue.Copy(mType) + } + return queue.Receive(t, t, mType, maxSize, wait, truncate, except, pid) +} + // Msgctl implements msgctl(2). func Msgctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { id := ipc.ID(args[0].Int()) |