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-rw-r--r--pkg/sentry/fs/proc/BUILD3
-rw-r--r--pkg/sentry/fs/proc/net.go126
-rw-r--r--pkg/sentry/fs/proc/proc.go2
-rw-r--r--pkg/sentry/kernel/kernel.go58
-rw-r--r--pkg/sentry/socket/socket.go10
-rw-r--r--pkg/sentry/socket/unix/unix.go2
6 files changed, 195 insertions, 6 deletions
diff --git a/pkg/sentry/fs/proc/BUILD b/pkg/sentry/fs/proc/BUILD
index f6bc90634..666b0ab3a 100644
--- a/pkg/sentry/fs/proc/BUILD
+++ b/pkg/sentry/fs/proc/BUILD
@@ -30,6 +30,7 @@ go_library(
visibility = ["//pkg/sentry:internal"],
deps = [
"//pkg/abi/linux",
+ "//pkg/log",
"//pkg/sentry/context",
"//pkg/sentry/fs",
"//pkg/sentry/fs/fsutil",
@@ -43,6 +44,8 @@ go_library(
"//pkg/sentry/kernel/time",
"//pkg/sentry/mm",
"//pkg/sentry/socket/rpcinet",
+ "//pkg/sentry/socket/unix",
+ "//pkg/sentry/socket/unix/transport",
"//pkg/sentry/usage",
"//pkg/sentry/usermem",
"//pkg/syserror",
diff --git a/pkg/sentry/fs/proc/net.go b/pkg/sentry/fs/proc/net.go
index 219eea7f8..55a958f9e 100644
--- a/pkg/sentry/fs/proc/net.go
+++ b/pkg/sentry/fs/proc/net.go
@@ -15,19 +15,24 @@
package proc
import (
+ "bytes"
"fmt"
"time"
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+ "gvisor.googlesource.com/gvisor/pkg/log"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/proc/seqfile"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/ramfs"
"gvisor.googlesource.com/gvisor/pkg/sentry/inet"
+ "gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+ "gvisor.googlesource.com/gvisor/pkg/sentry/socket/unix"
+ "gvisor.googlesource.com/gvisor/pkg/sentry/socket/unix/transport"
)
// newNet creates a new proc net entry.
-func (p *proc) newNetDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
+func (p *proc) newNetDir(ctx context.Context, k *kernel.Kernel, msrc *fs.MountSource) *fs.Inode {
var contents map[string]*fs.Inode
if s := p.k.NetworkStack(); s != nil {
contents = map[string]*fs.Inode{
@@ -52,6 +57,8 @@ func (p *proc) newNetDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
"tcp": newStaticProcInode(ctx, msrc, []byte(" sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode")),
"udp": newStaticProcInode(ctx, msrc, []byte(" sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops")),
+
+ "unix": seqfile.NewSeqFileInode(ctx, &netUnix{k: k}, msrc),
}
if s.SupportsIPv6() {
@@ -182,3 +189,120 @@ func (n *netDev) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]se
return data, 0
}
+
+// netUnix implements seqfile.SeqSource for /proc/net/unix.
+//
+// +stateify savable
+type netUnix struct {
+ k *kernel.Kernel
+}
+
+// NeedsUpdate implements seqfile.SeqSource.NeedsUpdate.
+func (*netUnix) NeedsUpdate(generation int64) bool {
+ return true
+}
+
+// ReadSeqFileData implements seqfile.SeqSource.ReadSeqFileData.
+func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
+ if h != nil {
+ return []seqfile.SeqData{}, 0
+ }
+
+ var buf bytes.Buffer
+ // Header
+ fmt.Fprintf(&buf, "Num RefCount Protocol Flags Type St Inode Path\n")
+
+ // Entries
+ for _, sref := range n.k.ListSockets(linux.AF_UNIX) {
+ s := sref.Get()
+ if s == nil {
+ log.Debugf("Couldn't resolve weakref %v in socket table, racing with destruction?", sref)
+ continue
+ }
+ sfile := s.(*fs.File)
+ sops, ok := sfile.FileOperations.(*unix.SocketOperations)
+ if !ok {
+ panic(fmt.Sprintf("Found non-unix socket file in unix socket table: %+v", sfile))
+ }
+
+ addr, err := sops.Endpoint().GetLocalAddress()
+ if err != nil {
+ log.Warningf("Failed to retrieve socket name from %+v: %v", sfile, err)
+ addr.Addr = "<unknown>"
+ }
+
+ sockFlags := 0
+ if ce, ok := sops.Endpoint().(transport.ConnectingEndpoint); ok {
+ if ce.Listening() {
+ // For unix domain sockets, linux reports a single flag
+ // value if the socket is listening, of __SO_ACCEPTCON.
+ sockFlags = linux.SO_ACCEPTCON
+ }
+ }
+
+ var sockState int
+ switch sops.Endpoint().Type() {
+ case linux.SOCK_DGRAM:
+ sockState = linux.SS_CONNECTING
+ // Unlike Linux, we don't have unbound connection-less sockets,
+ // so no SS_DISCONNECTING.
+
+ case linux.SOCK_SEQPACKET:
+ fallthrough
+ case linux.SOCK_STREAM:
+ // Connectioned.
+ if sops.Endpoint().(transport.ConnectingEndpoint).Connected() {
+ sockState = linux.SS_CONNECTED
+ } else {
+ sockState = linux.SS_UNCONNECTED
+ }
+ }
+
+ // In the socket entry below, the value for the 'Num' field requires
+ // some consideration. Linux prints the address to the struct
+ // unix_sock representing a socket in the kernel, but may redact the
+ // value for unprivileged users depending on the kptr_restrict
+ // sysctl.
+ //
+ // One use for this field is to allow a privileged user to
+ // introspect into the kernel memory to determine information about
+ // a socket not available through procfs, such as the socket's peer.
+ //
+ // On gvisor, returning a pointer to our internal structures would
+ // be pointless, as it wouldn't match the memory layout for struct
+ // unix_sock, making introspection difficult. We could populate a
+ // struct unix_sock with the appropriate data, but even that
+ // requires consideration for which kernel version to emulate, as
+ // the definition of this struct changes over time.
+ //
+ // For now, we always redact this pointer.
+ fmt.Fprintf(&buf, "%#016p: %08X %08X %08X %04X %02X %5d",
+ (*unix.SocketOperations)(nil), // Num, pointer to kernel socket struct.
+ sfile.ReadRefs()-1, // RefCount, don't count our own ref.
+ 0, // Protocol, always 0 for UDS.
+ sockFlags, // Flags.
+ sops.Endpoint().Type(), // Type.
+ sockState, // State.
+ sfile.InodeID(), // Inode.
+ )
+
+ // Path
+ if len(addr.Addr) != 0 {
+ if addr.Addr[0] == 0 {
+ // Abstract path.
+ fmt.Fprintf(&buf, " @%s", string(addr.Addr[1:]))
+ } else {
+ fmt.Fprintf(&buf, " %s", string(addr.Addr))
+ }
+ }
+ fmt.Fprintf(&buf, "\n")
+
+ sfile.DecRef()
+ }
+
+ data := []seqfile.SeqData{{
+ Buf: buf.Bytes(),
+ Handle: (*netUnix)(nil),
+ }}
+ return data, 0
+}
diff --git a/pkg/sentry/fs/proc/proc.go b/pkg/sentry/fs/proc/proc.go
index be04f94af..88018e707 100644
--- a/pkg/sentry/fs/proc/proc.go
+++ b/pkg/sentry/fs/proc/proc.go
@@ -85,7 +85,7 @@ func New(ctx context.Context, msrc *fs.MountSource) (*fs.Inode, error) {
if _, ok := p.k.NetworkStack().(*rpcinet.Stack); ok {
p.AddChild(ctx, "net", newRPCInetProcNet(ctx, msrc))
} else {
- p.AddChild(ctx, "net", p.newNetDir(ctx, msrc))
+ p.AddChild(ctx, "net", p.newNetDir(ctx, k, msrc))
}
return newProcInode(p, msrc, fs.SpecialDirectory, nil), nil
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index 43e9823cb..e7e5ff777 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -43,6 +43,7 @@ import (
"gvisor.googlesource.com/gvisor/pkg/cpuid"
"gvisor.googlesource.com/gvisor/pkg/eventchannel"
"gvisor.googlesource.com/gvisor/pkg/log"
+ "gvisor.googlesource.com/gvisor/pkg/refs"
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
@@ -164,7 +165,7 @@ type Kernel struct {
// nextInotifyCookie is a monotonically increasing counter used for
// generating unique inotify event cookies.
//
- // nextInotifyCookie is mutable, and is accesed using atomic memory
+ // nextInotifyCookie is mutable, and is accessed using atomic memory
// operations.
nextInotifyCookie uint32
@@ -177,6 +178,10 @@ type Kernel struct {
// danglingEndpoints is used to save / restore tcpip.DanglingEndpoints.
danglingEndpoints struct{} `state:".([]tcpip.Endpoint)"`
+
+ // socketTable is used to track all sockets on the system. Protected by
+ // extMu.
+ socketTable map[int]map[*refs.WeakRef]struct{}
}
// InitKernelArgs holds arguments to Init.
@@ -266,6 +271,7 @@ func (k *Kernel) Init(args InitKernelArgs) error {
k.monotonicClock = &timekeeperClock{tk: args.Timekeeper, c: sentrytime.Monotonic}
k.futexes = futex.NewManager()
k.netlinkPorts = port.New()
+ k.socketTable = make(map[int]map[*refs.WeakRef]struct{})
return nil
}
@@ -1051,6 +1057,56 @@ func (k *Kernel) EmitUnimplementedEvent(ctx context.Context) {
})
}
+// socketEntry represents a socket recorded in Kernel.socketTable. It implements
+// refs.WeakRefUser for sockets stored in the socket table.
+//
+// +stateify savable
+type socketEntry struct {
+ k *Kernel
+ sock *refs.WeakRef
+ family int
+}
+
+// WeakRefGone implements refs.WeakRefUser.WeakRefGone.
+func (s *socketEntry) WeakRefGone() {
+ s.k.extMu.Lock()
+ // k.socketTable is guaranteed to point to a valid socket table for s.family
+ // at this point, since we made sure of the fact when we created this
+ // socketEntry, and we never delete socket tables.
+ delete(s.k.socketTable[s.family], s.sock)
+ s.k.extMu.Unlock()
+}
+
+// RecordSocket adds a socket to the system-wide socket table for tracking.
+//
+// Precondition: Caller must hold a reference to sock.
+func (k *Kernel) RecordSocket(sock *fs.File, family int) {
+ k.extMu.Lock()
+ table, ok := k.socketTable[family]
+ if !ok {
+ table = make(map[*refs.WeakRef]struct{})
+ k.socketTable[family] = table
+ }
+ se := socketEntry{k: k, family: family}
+ se.sock = refs.NewWeakRef(sock, &se)
+ table[se.sock] = struct{}{}
+ k.extMu.Unlock()
+}
+
+// ListSockets returns a snapshot of all sockets of a given family.
+func (k *Kernel) ListSockets(family int) []*refs.WeakRef {
+ k.extMu.Lock()
+ socks := []*refs.WeakRef{}
+ if table, ok := k.socketTable[family]; ok {
+ socks = make([]*refs.WeakRef, 0, len(table))
+ for s, _ := range table {
+ socks = append(socks, s)
+ }
+ }
+ k.extMu.Unlock()
+ return socks
+}
+
type supervisorContext struct {
context.NoopSleeper
log.Logger
diff --git a/pkg/sentry/socket/socket.go b/pkg/sentry/socket/socket.go
index e28d2c4fa..5ab423f3c 100644
--- a/pkg/sentry/socket/socket.go
+++ b/pkg/sentry/socket/socket.go
@@ -147,6 +147,7 @@ func New(t *kernel.Task, family int, stype transport.SockType, protocol int) (*f
return nil, err
}
if s != nil {
+ t.Kernel().RecordSocket(s, family)
return s, nil
}
}
@@ -163,12 +164,15 @@ func Pair(t *kernel.Task, family int, stype transport.SockType, protocol int) (*
}
for _, p := range providers {
- s, t, err := p.Pair(t, stype, protocol)
+ s1, s2, err := p.Pair(t, stype, protocol)
if err != nil {
return nil, nil, err
}
- if s != nil && t != nil {
- return s, t, nil
+ if s1 != nil && s2 != nil {
+ k := t.Kernel()
+ k.RecordSocket(s1, family)
+ k.RecordSocket(s2, family)
+ return s1, s2, nil
}
}
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index 19258e692..c857a0f33 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -219,6 +219,8 @@ func (s *SocketOperations) Accept(t *kernel.Task, peerRequested bool, flags int,
return 0, nil, 0, syserr.FromError(e)
}
+ t.Kernel().RecordSocket(ns, linux.AF_UNIX)
+
return fd, addr, addrLen, nil
}