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Diffstat (limited to 'pkg/sentry/fs/proc/net.go')
-rw-r--r--pkg/sentry/fs/proc/net.go201
1 files changed, 180 insertions, 21 deletions
diff --git a/pkg/sentry/fs/proc/net.go b/pkg/sentry/fs/proc/net.go
index 9adb23608..5e28982c5 100644
--- a/pkg/sentry/fs/proc/net.go
+++ b/pkg/sentry/fs/proc/net.go
@@ -17,10 +17,10 @@ package proc
import (
"bytes"
"fmt"
+ "io"
"time"
"gvisor.dev/gvisor/pkg/abi/linux"
- "gvisor.dev/gvisor/pkg/binary"
"gvisor.dev/gvisor/pkg/log"
"gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -28,9 +28,11 @@ import (
"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
"gvisor.dev/gvisor/pkg/sentry/inet"
"gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/socket"
"gvisor.dev/gvisor/pkg/sentry/socket/unix"
"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+ "gvisor.dev/gvisor/pkg/sentry/usermem"
)
// newNet creates a new proc net entry.
@@ -57,9 +59,8 @@ func (p *proc) newNetDir(ctx context.Context, k *kernel.Kernel, msrc *fs.MountSo
"ptype": newStaticProcInode(ctx, msrc, []byte("Type Device Function")),
"route": newStaticProcInode(ctx, msrc, []byte("Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT")),
"tcp": seqfile.NewSeqFileInode(ctx, &netTCP{k: k}, msrc),
- "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),
+ "udp": seqfile.NewSeqFileInode(ctx, &netUDP{k: k}, msrc),
+ "unix": seqfile.NewSeqFileInode(ctx, &netUnix{k: k}, msrc),
}
if s.SupportsIPv6() {
@@ -216,7 +217,7 @@ func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]s
for _, se := range n.k.ListSockets() {
s := se.Sock.Get()
if s == nil {
- log.Debugf("Couldn't resolve weakref %v in socket table, racing with destruction?", se.Sock)
+ log.Debugf("Couldn't resolve weakref with ID %v in socket table, racing with destruction?", se.ID)
continue
}
sfile := s.(*fs.File)
@@ -297,6 +298,42 @@ func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]s
return data, 0
}
+func networkToHost16(n uint16) uint16 {
+ // n is in network byte order, so is big-endian. The most-significant byte
+ // should be stored in the lower address.
+ //
+ // We manually inline binary.BigEndian.Uint16() because Go does not support
+ // non-primitive consts, so binary.BigEndian is a (mutable) var, so calls to
+ // binary.BigEndian.Uint16() require a read of binary.BigEndian and an
+ // interface method call, defeating inlining.
+ buf := [2]byte{byte(n >> 8 & 0xff), byte(n & 0xff)}
+ return usermem.ByteOrder.Uint16(buf[:])
+}
+
+func writeInetAddr(w io.Writer, a linux.SockAddrInet) {
+ // linux.SockAddrInet.Port is stored in the network byte order and is
+ // printed like a number in host byte order. Note that all numbers in host
+ // byte order are printed with the most-significant byte first when
+ // formatted with %X. See get_tcp4_sock() and udp4_format_sock() in Linux.
+ port := networkToHost16(a.Port)
+
+ // linux.SockAddrInet.Addr is stored as a byte slice in big-endian order
+ // (i.e. most-significant byte in index 0). Linux represents this as a
+ // __be32 which is a typedef for an unsigned int, and is printed with
+ // %X. This means that for a little-endian machine, Linux prints the
+ // least-significant byte of the address first. To emulate this, we first
+ // invert the byte order for the address using usermem.ByteOrder.Uint32,
+ // which makes it have the equivalent encoding to a __be32 on a little
+ // endian machine. Note that this operation is a no-op on a big endian
+ // machine. Then similar to Linux, we format it with %X, which will print
+ // the most-significant byte of the __be32 address first, which is now
+ // actually the least-significant byte of the original address in
+ // linux.SockAddrInet.Addr on little endian machines, due to the conversion.
+ addr := usermem.ByteOrder.Uint32(a.Addr[:])
+
+ fmt.Fprintf(w, "%08X:%04X ", addr, port)
+}
+
// netTCP implements seqfile.SeqSource for /proc/net/tcp.
//
// +stateify savable
@@ -311,6 +348,9 @@ func (*netTCP) NeedsUpdate(generation int64) bool {
// ReadSeqFileData implements seqfile.SeqSource.ReadSeqFileData.
func (n *netTCP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
+ // t may be nil here if our caller is not part of a task goroutine. This can
+ // happen for example if we're here for "sentryctl cat". When t is nil,
+ // degrade gracefully and retrieve what we can.
t := kernel.TaskFromContext(ctx)
if h != nil {
@@ -321,7 +361,7 @@ func (n *netTCP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]se
for _, se := range n.k.ListSockets() {
s := se.Sock.Get()
if s == nil {
- log.Debugf("Couldn't resolve weakref %+v in socket table, racing with destruction?", se.Sock)
+ log.Debugf("Couldn't resolve weakref with ID %v in socket table, racing with destruction?", se.ID)
continue
}
sfile := s.(*fs.File)
@@ -343,27 +383,23 @@ func (n *netTCP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]se
// Field: sl; entry number.
fmt.Fprintf(&buf, "%4d: ", se.ID)
- portBuf := make([]byte, 2)
-
// Field: local_adddress.
var localAddr linux.SockAddrInet
- if local, _, err := sops.GetSockName(t); err == nil {
- localAddr = *local.(*linux.SockAddrInet)
+ if t != nil {
+ if local, _, err := sops.GetSockName(t); err == nil {
+ localAddr = *local.(*linux.SockAddrInet)
+ }
}
- binary.LittleEndian.PutUint16(portBuf, localAddr.Port)
- fmt.Fprintf(&buf, "%08X:%04X ",
- binary.LittleEndian.Uint32(localAddr.Addr[:]),
- portBuf)
+ writeInetAddr(&buf, localAddr)
// Field: rem_address.
var remoteAddr linux.SockAddrInet
- if remote, _, err := sops.GetPeerName(t); err == nil {
- remoteAddr = *remote.(*linux.SockAddrInet)
+ if t != nil {
+ if remote, _, err := sops.GetPeerName(t); err == nil {
+ remoteAddr = *remote.(*linux.SockAddrInet)
+ }
}
- binary.LittleEndian.PutUint16(portBuf, remoteAddr.Port)
- fmt.Fprintf(&buf, "%08X:%04X ",
- binary.LittleEndian.Uint32(remoteAddr.Addr[:]),
- portBuf)
+ writeInetAddr(&buf, remoteAddr)
// Field: state; socket state.
fmt.Fprintf(&buf, "%02X ", sops.State())
@@ -386,7 +422,8 @@ func (n *netTCP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]se
log.Warningf("Failed to retrieve unstable attr for socket file: %v", err)
fmt.Fprintf(&buf, "%5d ", 0)
} else {
- fmt.Fprintf(&buf, "%5d ", uint32(uattr.Owner.UID.In(t.UserNamespace()).OrOverflow()))
+ creds := auth.CredentialsFromContext(ctx)
+ fmt.Fprintf(&buf, "%5d ", uint32(uattr.Owner.UID.In(creds.UserNamespace).OrOverflow()))
}
// Field: timeout; number of unanswered 0-window probes.
@@ -438,3 +475,125 @@ func (n *netTCP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]se
}
return data, 0
}
+
+// netUDP implements seqfile.SeqSource for /proc/net/udp.
+//
+// +stateify savable
+type netUDP struct {
+ k *kernel.Kernel
+}
+
+// NeedsUpdate implements seqfile.SeqSource.NeedsUpdate.
+func (*netUDP) NeedsUpdate(generation int64) bool {
+ return true
+}
+
+// ReadSeqFileData implements seqfile.SeqSource.ReadSeqFileData.
+func (n *netUDP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
+ // t may be nil here if our caller is not part of a task goroutine. This can
+ // happen for example if we're here for "sentryctl cat". When t is nil,
+ // degrade gracefully and retrieve what we can.
+ t := kernel.TaskFromContext(ctx)
+
+ if h != nil {
+ return nil, 0
+ }
+
+ var buf bytes.Buffer
+ for _, se := range n.k.ListSockets() {
+ s := se.Sock.Get()
+ if s == nil {
+ log.Debugf("Couldn't resolve weakref with ID %v in socket table, racing with destruction?", se.ID)
+ continue
+ }
+ sfile := s.(*fs.File)
+ sops, ok := sfile.FileOperations.(socket.Socket)
+ if !ok {
+ panic(fmt.Sprintf("Found non-socket file in socket table: %+v", sfile))
+ }
+ if family, stype, _ := sops.Type(); family != linux.AF_INET || stype != linux.SOCK_DGRAM {
+ s.DecRef()
+ // Not udp4 socket.
+ continue
+ }
+
+ // For Linux's implementation, see net/ipv4/udp.c:udp4_format_sock().
+
+ // Field: sl; entry number.
+ fmt.Fprintf(&buf, "%5d: ", se.ID)
+
+ // Field: local_adddress.
+ var localAddr linux.SockAddrInet
+ if t != nil {
+ if local, _, err := sops.GetSockName(t); err == nil {
+ localAddr = *local.(*linux.SockAddrInet)
+ }
+ }
+ writeInetAddr(&buf, localAddr)
+
+ // Field: rem_address.
+ var remoteAddr linux.SockAddrInet
+ if t != nil {
+ if remote, _, err := sops.GetPeerName(t); err == nil {
+ remoteAddr = *remote.(*linux.SockAddrInet)
+ }
+ }
+ writeInetAddr(&buf, remoteAddr)
+
+ // Field: state; socket state.
+ fmt.Fprintf(&buf, "%02X ", sops.State())
+
+ // Field: tx_queue, rx_queue; number of packets in the transmit and
+ // receive queue. Unimplemented.
+ fmt.Fprintf(&buf, "%08X:%08X ", 0, 0)
+
+ // Field: tr, tm->when. Always 0 for UDP.
+ fmt.Fprintf(&buf, "%02X:%08X ", 0, 0)
+
+ // Field: retrnsmt. Always 0 for UDP.
+ fmt.Fprintf(&buf, "%08X ", 0)
+
+ // Field: uid.
+ uattr, err := sfile.Dirent.Inode.UnstableAttr(ctx)
+ if err != nil {
+ log.Warningf("Failed to retrieve unstable attr for socket file: %v", err)
+ fmt.Fprintf(&buf, "%5d ", 0)
+ } else {
+ creds := auth.CredentialsFromContext(ctx)
+ fmt.Fprintf(&buf, "%5d ", uint32(uattr.Owner.UID.In(creds.UserNamespace).OrOverflow()))
+ }
+
+ // Field: timeout. Always 0 for UDP.
+ fmt.Fprintf(&buf, "%8d ", 0)
+
+ // Field: inode.
+ fmt.Fprintf(&buf, "%8d ", sfile.InodeID())
+
+ // Field: ref; reference count on the socket inode. Don't count the ref
+ // we obtain while deferencing the weakref to this socket.
+ fmt.Fprintf(&buf, "%d ", sfile.ReadRefs()-1)
+
+ // Field: Socket struct address. Redacted due to the same reason as
+ // the 'Num' field in /proc/net/unix, see netUnix.ReadSeqFileData.
+ fmt.Fprintf(&buf, "%#016p ", (*socket.Socket)(nil))
+
+ // Field: drops; number of dropped packets. Unimplemented.
+ fmt.Fprintf(&buf, "%d", 0)
+
+ fmt.Fprintf(&buf, "\n")
+
+ s.DecRef()
+ }
+
+ data := []seqfile.SeqData{
+ {
+ Buf: []byte(" sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops \n"),
+ Handle: n,
+ },
+ {
+ Buf: buf.Bytes(),
+ Handle: n,
+ },
+ }
+ return data, 0
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 22:28:42 +0000