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-rw-r--r--pkg/sentry/kernel/BUILD1
-rw-r--r--pkg/sentry/kernel/abstract_socket_namespace.go77
-rw-r--r--pkg/sentry/socket/unix/BUILD14
-rw-r--r--pkg/sentry/socket/unix/unix.go22
-rw-r--r--pkg/sentry/socket/unix/unix_vfs2.go6
5 files changed, 87 insertions, 33 deletions
diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD
index f6886a758..5416a310d 100644
--- a/pkg/sentry/kernel/BUILD
+++ b/pkg/sentry/kernel/BUILD
@@ -163,6 +163,7 @@ go_library(
"//pkg/log",
"//pkg/metric",
"//pkg/refs",
+ "//pkg/refs_vfs2",
"//pkg/safemem",
"//pkg/secio",
"//pkg/sentry/arch",
diff --git a/pkg/sentry/kernel/abstract_socket_namespace.go b/pkg/sentry/kernel/abstract_socket_namespace.go
index 52ed5cea2..1b9721534 100644
--- a/pkg/sentry/kernel/abstract_socket_namespace.go
+++ b/pkg/sentry/kernel/abstract_socket_namespace.go
@@ -15,29 +15,21 @@
package kernel
import (
+ "fmt"
"syscall"
"gvisor.dev/gvisor/pkg/context"
- "gvisor.dev/gvisor/pkg/refs"
+ "gvisor.dev/gvisor/pkg/refs_vfs2"
"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
"gvisor.dev/gvisor/pkg/sync"
)
// +stateify savable
type abstractEndpoint struct {
- ep transport.BoundEndpoint
- wr *refs.WeakRef
- name string
- ns *AbstractSocketNamespace
-}
-
-// WeakRefGone implements refs.WeakRefUser.WeakRefGone.
-func (e *abstractEndpoint) WeakRefGone(context.Context) {
- e.ns.mu.Lock()
- if e.ns.endpoints[e.name].ep == e.ep {
- delete(e.ns.endpoints, e.name)
- }
- e.ns.mu.Unlock()
+ ep transport.BoundEndpoint
+ socket refs_vfs2.RefCounter
+ name string
+ ns *AbstractSocketNamespace
}
// AbstractSocketNamespace is used to implement the Linux abstract socket functionality.
@@ -46,7 +38,11 @@ func (e *abstractEndpoint) WeakRefGone(context.Context) {
type AbstractSocketNamespace struct {
mu sync.Mutex `state:"nosave"`
- // Keeps mapping from name to endpoint.
+ // Keeps a mapping from name to endpoint. AbstractSocketNamespace does not hold
+ // any references on any sockets that it contains; when retrieving a socket,
+ // TryIncRef() must be called in case the socket is concurrently being
+ // destroyed. It is the responsibility of the socket to remove itself from the
+ // abstract socket namespace when it is destroyed.
endpoints map[string]abstractEndpoint
}
@@ -58,15 +54,15 @@ func NewAbstractSocketNamespace() *AbstractSocketNamespace {
}
// A boundEndpoint wraps a transport.BoundEndpoint to maintain a reference on
-// its backing object.
+// its backing socket.
type boundEndpoint struct {
transport.BoundEndpoint
- rc refs.RefCounter
+ socket refs_vfs2.RefCounter
}
// Release implements transport.BoundEndpoint.Release.
func (e *boundEndpoint) Release(ctx context.Context) {
- e.rc.DecRef(ctx)
+ e.socket.DecRef(ctx)
e.BoundEndpoint.Release(ctx)
}
@@ -81,32 +77,59 @@ func (a *AbstractSocketNamespace) BoundEndpoint(name string) transport.BoundEndp
return nil
}
- rc := ep.wr.Get()
- if rc == nil {
- delete(a.endpoints, name)
+ if !ep.socket.TryIncRef() {
+ // The socket has reached zero references and is being destroyed.
return nil
}
- return &boundEndpoint{ep.ep, rc}
+ return &boundEndpoint{ep.ep, ep.socket}
}
// Bind binds the given socket.
//
-// When the last reference managed by rc is dropped, ep may be removed from the
+// When the last reference managed by socket is dropped, ep may be removed from the
// namespace.
-func (a *AbstractSocketNamespace) Bind(ctx context.Context, name string, ep transport.BoundEndpoint, rc refs.RefCounter) error {
+func (a *AbstractSocketNamespace) Bind(ctx context.Context, name string, ep transport.BoundEndpoint, socket refs_vfs2.RefCounter) error {
a.mu.Lock()
defer a.mu.Unlock()
+ // Check if there is already a socket (which has not yet been destroyed) bound at name.
if ep, ok := a.endpoints[name]; ok {
- if rc := ep.wr.Get(); rc != nil {
- rc.DecRef(ctx)
+ if ep.socket.TryIncRef() {
+ ep.socket.DecRef(ctx)
return syscall.EADDRINUSE
}
}
ae := abstractEndpoint{ep: ep, name: name, ns: a}
- ae.wr = refs.NewWeakRef(rc, &ae)
+ ae.socket = socket
a.endpoints[name] = ae
return nil
}
+
+// Remove removes the specified socket at name from the abstract socket
+// namespace, if it has not yet been replaced.
+func (a *AbstractSocketNamespace) Remove(name string, socket refs_vfs2.RefCounter) {
+ a.mu.Lock()
+ defer a.mu.Unlock()
+
+ ep, ok := a.endpoints[name]
+ if !ok {
+ // We never delete a map entry apart from a socket's destructor (although the
+ // map entry may be overwritten). Therefore, a socket should exist, even if it
+ // may not be the one we expect.
+ panic(fmt.Sprintf("expected socket to exist at '%s' in abstract socket namespace", name))
+ }
+
+ // A Bind() operation may race with callers of Remove(), e.g. in the
+ // following case:
+ // socket1 reaches zero references and begins destruction
+ // a.Bind("foo", ep, socket2) replaces socket1 with socket2
+ // socket1's destructor calls a.Remove("foo", socket1)
+ //
+ // Therefore, we need to check that the socket at name is what we expect
+ // before modifying the map.
+ if ep.socket == socket {
+ delete(a.endpoints, name)
+ }
+}
diff --git a/pkg/sentry/socket/unix/BUILD b/pkg/sentry/socket/unix/BUILD
index 061a689a9..cb953e4dc 100644
--- a/pkg/sentry/socket/unix/BUILD
+++ b/pkg/sentry/socket/unix/BUILD
@@ -1,12 +1,25 @@
load("//tools:defs.bzl", "go_library")
+load("//tools/go_generics:defs.bzl", "go_template_instance")
package(licenses = ["notice"])
+go_template_instance(
+ name = "socket_refs",
+ out = "socket_refs.go",
+ package = "unix",
+ prefix = "socketOpsCommon",
+ template = "//pkg/refs_vfs2:refs_template",
+ types = {
+ "T": "socketOpsCommon",
+ },
+)
+
go_library(
name = "unix",
srcs = [
"device.go",
"io.go",
+ "socket_refs.go",
"unix.go",
"unix_vfs2.go",
],
@@ -15,6 +28,7 @@ go_library(
"//pkg/abi/linux",
"//pkg/context",
"//pkg/fspath",
+ "//pkg/log",
"//pkg/refs",
"//pkg/safemem",
"//pkg/sentry/arch",
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index 2b8454edb..b7e8e4325 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -24,7 +24,6 @@ import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/fspath"
- "gvisor.dev/gvisor/pkg/refs"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
@@ -80,7 +79,7 @@ func NewWithDirent(ctx context.Context, d *fs.Dirent, ep transport.Endpoint, sty
stype: stype,
},
}
- s.EnableLeakCheck("unix.SocketOperations")
+ s.EnableLeakCheck()
return fs.NewFile(ctx, d, flags, &s)
}
@@ -89,17 +88,26 @@ func NewWithDirent(ctx context.Context, d *fs.Dirent, ep transport.Endpoint, sty
//
// +stateify savable
type socketOpsCommon struct {
- refs.AtomicRefCount
+ socketOpsCommonRefs
socket.SendReceiveTimeout
ep transport.Endpoint
stype linux.SockType
+
+ // abstractName and abstractNamespace indicate the name and namespace of the
+ // socket if it is bound to an abstract socket namespace. Once the socket is
+ // bound, they cannot be modified.
+ abstractName string
+ abstractNamespace *kernel.AbstractSocketNamespace
}
// DecRef implements RefCounter.DecRef.
func (s *socketOpsCommon) DecRef(ctx context.Context) {
- s.DecRefWithDestructor(ctx, func(context.Context) {
+ s.socketOpsCommonRefs.DecRef(func() {
s.ep.Close(ctx)
+ if s.abstractNamespace != nil {
+ s.abstractNamespace.Remove(s.abstractName, s)
+ }
})
}
@@ -284,10 +292,14 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error {
if t.IsNetworkNamespaced() {
return syserr.ErrInvalidEndpointState
}
- if err := t.AbstractSockets().Bind(t, p[1:], bep, s); err != nil {
+ asn := t.AbstractSockets()
+ name := p[1:]
+ if err := asn.Bind(t, name, bep, s); err != nil {
// syserr.ErrPortInUse corresponds to EADDRINUSE.
return syserr.ErrPortInUse
}
+ s.abstractName = name
+ s.abstractNamespace = asn
} else {
// The parent and name.
var d *fs.Dirent
diff --git a/pkg/sentry/socket/unix/unix_vfs2.go b/pkg/sentry/socket/unix/unix_vfs2.go
index dfa25241a..d066ef8ab 100644
--- a/pkg/sentry/socket/unix/unix_vfs2.go
+++ b/pkg/sentry/socket/unix/unix_vfs2.go
@@ -183,10 +183,14 @@ func (s *SocketVFS2) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error {
if t.IsNetworkNamespaced() {
return syserr.ErrInvalidEndpointState
}
- if err := t.AbstractSockets().Bind(t, p[1:], bep, s); err != nil {
+ asn := t.AbstractSockets()
+ name := p[1:]
+ if err := asn.Bind(t, name, bep, s); err != nil {
// syserr.ErrPortInUse corresponds to EADDRINUSE.
return syserr.ErrPortInUse
}
+ s.abstractName = name
+ s.abstractNamespace = asn
} else {
path := fspath.Parse(p)
root := t.FSContext().RootDirectoryVFS2()
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 04:06:33 +0000