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-rw-r--r--pkg/sentry/fsimpl/mqfs/registry.go24
-rw-r--r--pkg/sentry/kernel/ipc_namespace.go2
-rw-r--r--pkg/sentry/kernel/mq/mq.go166
3 files changed, 167 insertions, 25 deletions
diff --git a/pkg/sentry/fsimpl/mqfs/registry.go b/pkg/sentry/fsimpl/mqfs/registry.go
index 89ffaaf04..ea1f2981c 100644
--- a/pkg/sentry/fsimpl/mqfs/registry.go
+++ b/pkg/sentry/fsimpl/mqfs/registry.go
@@ -81,7 +81,7 @@ func NewRegistryImpl(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *
}
// Get implements mq.RegistryImpl.Get.
-func (r *RegistryImpl) Get(ctx context.Context, name string, rOnly, wOnly, readWrite, block bool, flags uint32) (*vfs.FileDescription, bool, error) {
+func (r *RegistryImpl) Get(ctx context.Context, name string, access mq.AccessType, block bool, flags uint32) (*vfs.FileDescription, bool, error) {
r.mu.Lock()
defer r.mu.Unlock()
@@ -91,13 +91,13 @@ func (r *RegistryImpl) Get(ctx context.Context, name string, rOnly, wOnly, readW
}
qInode := inode.(*queueInode)
- if !qInode.queue.HasPermissions(auth.CredentialsFromContext(ctx), perm(rOnly, wOnly, readWrite)) {
+ if !qInode.queue.HasPermissions(auth.CredentialsFromContext(ctx), perm(access)) {
// "The queue exists, but the caller does not have permission to
// open it in the specified mode."
return nil, false, linuxerr.EACCES
}
- fd, err := r.newFD(qInode.queue, qInode, rOnly, wOnly, readWrite, block, flags)
+ fd, err := r.newFD(qInode.queue, qInode, access, block, flags)
if err != nil {
return nil, false, err
}
@@ -105,7 +105,7 @@ func (r *RegistryImpl) Get(ctx context.Context, name string, rOnly, wOnly, readW
}
// New implements mq.RegistryImpl.New.
-func (r *RegistryImpl) New(ctx context.Context, name string, q *mq.Queue, rOnly, wOnly, readWrite, block bool, perm linux.FileMode, flags uint32) (*vfs.FileDescription, error) {
+func (r *RegistryImpl) New(ctx context.Context, name string, q *mq.Queue, access mq.AccessType, block bool, perm linux.FileMode, flags uint32) (*vfs.FileDescription, error) {
r.mu.Lock()
defer r.mu.Unlock()
@@ -115,7 +115,7 @@ func (r *RegistryImpl) New(ctx context.Context, name string, q *mq.Queue, rOnly,
if err != nil {
return nil, err
}
- return r.newFD(q, qInode, rOnly, wOnly, readWrite, block, flags)
+ return r.newFD(q, qInode, access, block, flags)
}
// Unlink implements mq.RegistryImpl.Unlink.
@@ -154,8 +154,8 @@ func (r *RegistryImpl) lookup(ctx context.Context, name string) (kernfs.Inode, e
}
// newFD returns a new file description created using the given queue and inode.
-func (r *RegistryImpl) newFD(q *mq.Queue, inode *queueInode, rOnly, wOnly, readWrite, block bool, flags uint32) (*vfs.FileDescription, error) {
- view, err := mq.NewView(q, rOnly, wOnly, readWrite, block)
+func (r *RegistryImpl) newFD(q *mq.Queue, inode *queueInode, access mq.AccessType, block bool, flags uint32) (*vfs.FileDescription, error) {
+ view, err := mq.NewView(q, access, block)
if err != nil {
return nil, err
}
@@ -172,13 +172,13 @@ func (r *RegistryImpl) newFD(q *mq.Queue, inode *queueInode, rOnly, wOnly, readW
}
// perm returns a permission mask created using given flags.
-func perm(rOnly, wOnly, readWrite bool) fs.PermMask {
- switch {
- case readWrite:
+func perm(access mq.AccessType) fs.PermMask {
+ switch access {
+ case mq.ReadWrite:
return fs.PermMask{Read: true, Write: true}
- case wOnly:
+ case mq.WriteOnly:
return fs.PermMask{Write: true}
- case rOnly:
+ case mq.ReadOnly:
return fs.PermMask{Read: true}
default:
return fs.PermMask{} // Can't happen, see NewView.
diff --git a/pkg/sentry/kernel/ipc_namespace.go b/pkg/sentry/kernel/ipc_namespace.go
index 429a4b983..50b4e015e 100644
--- a/pkg/sentry/kernel/ipc_namespace.go
+++ b/pkg/sentry/kernel/ipc_namespace.go
@@ -87,7 +87,7 @@ func (i *IPCNamespace) InitPosixQueues(ctx context.Context, vfsObj *vfs.VirtualF
if err != nil {
return err
}
- i.posixQueues = mq.NewRegistry(impl)
+ i.posixQueues = mq.NewRegistry(i.userNS, impl)
return nil
}
diff --git a/pkg/sentry/kernel/mq/mq.go b/pkg/sentry/kernel/mq/mq.go
index 217478dca..c21cc9d47 100644
--- a/pkg/sentry/kernel/mq/mq.go
+++ b/pkg/sentry/kernel/mq/mq.go
@@ -18,6 +18,7 @@ package mq
import (
"bytes"
"fmt"
+ "strings"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
@@ -29,9 +30,31 @@ import (
"gvisor.dev/gvisor/pkg/waiter"
)
+// AccessType is the access type passed to mq_open.
+type AccessType int
+
+// Possible access types.
+const (
+ ReadOnly AccessType = iota
+ WriteOnly
+ ReadWrite
+)
+
const (
MaxName = 255 // Maximum size for a queue name.
maxPriority = linux.MQ_PRIO_MAX - 1 // Highest possible message priority.
+
+ maxQueuesDefault = linux.DFLT_QUEUESMAX // Default max number of queues.
+
+ maxMsgDefault = linux.DFLT_MSG // Default max number of messages per queue.
+ maxMsgMin = linux.MIN_MSGMAX // Min value for max number of messages per queue.
+ maxMsgLimit = linux.DFLT_MSGMAX // Limit for max number of messages per queue.
+ maxMsgHardLimit = linux.HARD_MSGMAX // Hard limit for max number of messages per queue.
+
+ msgSizeDefault = linux.DFLT_MSGSIZE // Default max message size.
+ msgSizeMin = linux.MIN_MSGSIZEMAX // Min value for max message size.
+ msgSizeLimit = linux.DFLT_MSGSIZEMAX // Limit for max message size.
+ msgSizeHardLimit = linux.HARD_MSGSIZEMAX // Hard limit for max message size.
)
// Registry is a POSIX message queue registry.
@@ -41,6 +64,12 @@ const (
//
// +stateify savable
type Registry struct {
+ // userNS is the user namespace containing this registry. Immutable.
+ userNS *auth.UserNamespace
+
+ // mu protects all fields below.
+ mu sync.Mutex `state:"nosave"`
+
// impl is an implementation of several message queue utilities needed by
// the registry. impl should be provided by mqfs.
impl RegistryImpl
@@ -54,13 +83,13 @@ type RegistryImpl interface {
// Get searchs for a queue with the given name, if it exists, the queue is
// used to create a new FD, return it and return true. If the queue doesn't
// exist, return false and no error. An error is returned if creation fails.
- Get(ctx context.Context, name string, rOnly, wOnly, readWrite, block bool, flags uint32) (*vfs.FileDescription, bool, error)
+ Get(ctx context.Context, name string, access AccessType, block bool, flags uint32) (*vfs.FileDescription, bool, error)
// New creates a new inode and file description using the given queue,
// inserts the inode into the filesystem tree using the given name, and
// returns the file description. An error is returned if creation fails, or
// if the name already exists.
- New(ctx context.Context, name string, q *Queue, rOnly, wOnly, readWrite, block bool, perm linux.FileMode, flags uint32) (*vfs.FileDescription, error)
+ New(ctx context.Context, name string, q *Queue, access AccessType, block bool, perm linux.FileMode, flags uint32) (*vfs.FileDescription, error)
// Unlink removes the queue with given name from the registry, and returns
// an error if the name doesn't exist.
@@ -73,12 +102,128 @@ type RegistryImpl interface {
// NewRegistry returns a new, initialized message queue registry. NewRegistry
// should be called when a new message queue filesystem is created, once per
// IPCNamespace.
-func NewRegistry(impl RegistryImpl) *Registry {
+func NewRegistry(userNS *auth.UserNamespace, impl RegistryImpl) *Registry {
return &Registry{
- impl: impl,
+ userNS: userNS,
+ impl: impl,
}
}
+// OpenOpts holds the options passed to FindOrCreate.
+type OpenOpts struct {
+ Name string
+ Access AccessType
+ Create bool
+ Exclusive bool
+ Block bool
+}
+
+// FindOrCreate creates a new POSIX message queue or opens an existing queue.
+// See mq_open(2).
+func (r *Registry) FindOrCreate(ctx context.Context, opts OpenOpts, perm linux.FileMode, attr *linux.MqAttr) (*vfs.FileDescription, error) {
+ // mq_overview(7) mentions that: "Each message queue is identified by a name
+ // of the form '/somename'", but the mq_open(3) man pages mention:
+ // "The mq_open() library function is implemented on top of a system call
+ // of the same name. The library function performs the check that the
+ // name starts with a slash (/), giving the EINVAL error if it does not.
+ // The kernel system call expects name to contain no preceding slash, so
+ // the C library function passes name without the preceding slash (i.e.,
+ // name+1) to the system call."
+ // So we don't need to check it.
+
+ if len(opts.Name) == 0 {
+ return nil, linuxerr.ENOENT
+ }
+ if len(opts.Name) > MaxName {
+ return nil, linuxerr.ENAMETOOLONG
+ }
+ if strings.ContainsRune(opts.Name, '/') {
+ return nil, linuxerr.EACCES
+ }
+ if opts.Name == "." || opts.Name == ".." {
+ return nil, linuxerr.EINVAL
+ }
+
+ // Construct status flags.
+ var flags uint32
+ if opts.Block {
+ flags = linux.O_NONBLOCK
+ }
+ switch opts.Access {
+ case ReadOnly:
+ flags = flags | linux.O_RDONLY
+ case WriteOnly:
+ flags = flags | linux.O_WRONLY
+ case ReadWrite:
+ flags = flags | linux.O_RDWR
+ }
+
+ r.mu.Lock()
+ defer r.mu.Unlock()
+ fd, ok, err := r.impl.Get(ctx, opts.Name, opts.Access, opts.Block, flags)
+ if err != nil {
+ return nil, err
+ }
+
+ if ok {
+ if opts.Create && opts.Exclusive {
+ // "Both O_CREAT and O_EXCL were specified in oflag, but a queue
+ // with this name already exists."
+ return nil, linuxerr.EEXIST
+ }
+ return fd, nil
+ }
+
+ if !opts.Create {
+ // "The O_CREAT flag was not specified in oflag, and no queue with this name
+ // exists."
+ return nil, linuxerr.ENOENT
+ }
+
+ q, err := r.newQueueLocked(auth.CredentialsFromContext(ctx), fs.FileOwnerFromContext(ctx), fs.FilePermsFromMode(perm), attr)
+ if err != nil {
+ return nil, err
+ }
+ return r.impl.New(ctx, opts.Name, q, opts.Access, opts.Block, perm, flags)
+}
+
+// newQueueLocked creates a new queue using the given attributes. If attr is nil
+// return a queue with default values, otherwise use attr to create a new queue,
+// and return an error if attributes are invalid.
+func (r *Registry) newQueueLocked(creds *auth.Credentials, owner fs.FileOwner, perms fs.FilePermissions, attr *linux.MqAttr) (*Queue, error) {
+ if attr == nil {
+ return &Queue{
+ owner: owner,
+ perms: perms,
+ maxMessageCount: int64(maxMsgDefault),
+ maxMessageSize: uint64(msgSizeDefault),
+ }, nil
+ }
+
+ // "O_CREAT was specified in oflag, and attr was not NULL, but
+ // attr->mq_maxmsg or attr->mq_msqsize was invalid. Both of these fields
+ // these fields must be greater than zero. In a process that is
+ // unprivileged (does not have the CAP_SYS_RESOURCE capability),
+ // attr->mq_maxmsg must be less than or equal to the msg_max limit, and
+ // attr->mq_msgsize must be less than or equal to the msgsize_max limit.
+ // In addition, even in a privileged process, attr->mq_maxmsg cannot
+ // exceed the HARD_MAX limit." - man mq_open(3).
+ if attr.MqMaxmsg <= 0 || attr.MqMsgsize <= 0 {
+ return nil, linuxerr.EINVAL
+ }
+
+ if attr.MqMaxmsg > maxMsgHardLimit || (!creds.HasCapabilityIn(linux.CAP_SYS_RESOURCE, r.userNS) && (attr.MqMaxmsg > maxMsgLimit || attr.MqMsgsize > msgSizeLimit)) {
+ return nil, linuxerr.EINVAL
+ }
+
+ return &Queue{
+ owner: owner,
+ perms: perms,
+ maxMessageCount: attr.MqMaxmsg,
+ maxMessageSize: uint64(attr.MqMsgsize),
+ }, nil
+}
+
// Destroy destroys the registry and releases all held references.
func (r *Registry) Destroy(ctx context.Context) {
r.impl.Destroy(ctx)
@@ -117,9 +262,6 @@ type Queue struct {
// from this queue.
subscriber *Subscriber
- // nonBlock is true if this queue is non-blocking.
- nonBlock bool
-
// messageCount is the number of messages currently in the queue.
messageCount int64
@@ -171,13 +313,13 @@ type Writer struct {
}
// NewView creates a new view into a queue and returns it.
-func NewView(q *Queue, rOnly, wOnly, readWrite, block bool) (View, error) {
- switch {
- case readWrite:
+func NewView(q *Queue, access AccessType, block bool) (View, error) {
+ switch access {
+ case ReadWrite:
return ReaderWriter{Queue: q, block: block}, nil
- case wOnly:
+ case WriteOnly:
return Writer{Queue: q, block: block}, nil
- case rOnly:
+ case ReadOnly:
return Reader{Queue: q, block: block}, nil
default:
// This case can't happen, due to O_RDONLY flag being 0 and O_WRONLY
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 05:38:53 +0000