Use the stack RNG everywhere

...except in tests.

Note this replaces some uses of a cryptographic RNG with a plain RNG.

PiperOrigin-RevId: 376070666

16 files changed, 82 insertions, 99 deletions

diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go
index f42d73178..e1c4b06fc 100644
--- a/pkg/sentry/socket/netfilter/netfilter.go
+++ b/pkg/sentry/socket/netfilter/netfilter.go
@@ -58,8 +58,8 @@ var nameToID = map[string]stack.TableID{
 
 // DefaultLinuxTables returns the rules of stack.DefaultTables() wrapped for
 // compatibility with netfilter extensions.
-func DefaultLinuxTables() *stack.IPTables {
-	tables := stack.DefaultTables()
+func DefaultLinuxTables(seed uint32) *stack.IPTables {
+	tables := stack.DefaultTables(seed)
 	tables.VisitTargets(func(oldTarget stack.Target) stack.Target {
 		switch val := oldTarget.(type) {
 		case *stack.AcceptTarget:
diff --git a/pkg/tcpip/network/ipv6/mld_test.go b/pkg/tcpip/network/ipv6/mld_test.go
index 71d1c3e28..bc9cf6999 100644
--- a/pkg/tcpip/network/ipv6/mld_test.go
+++ b/pkg/tcpip/network/ipv6/mld_test.go
@@ -16,6 +16,7 @@ package ipv6_test
 
 import (
 	"bytes"
+	"math/rand"
 	"testing"
 	"time"
 
@@ -138,7 +139,8 @@ func TestSendQueuedMLDReports(t *testing.T) {
 			var secureRNG bytes.Reader
 			secureRNG.Reset(secureRNGBytes[:])
 			s := stack.New(stack.Options{
-				SecureRNG: &secureRNG,
+				SecureRNG:  &secureRNG,
+				RandSource: rand.NewSource(time.Now().UnixNano()),
 				NetworkProtocols: []stack.NetworkProtocolFactory{ipv6.NewProtocolWithOptions(ipv6.Options{
 					DADConfigs: stack.DADConfigurations{
 						DupAddrDetectTransmits: test.dadTransmits,
diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go
index b300ed894..0f24500e7 100644
--- a/pkg/tcpip/network/ipv6/ndp_test.go
+++ b/pkg/tcpip/network/ipv6/ndp_test.go
@@ -17,6 +17,7 @@ package ipv6
 import (
 	"bytes"
 	"context"
+	"math/rand"
 	"strings"
 	"testing"
 	"time"
@@ -1240,8 +1241,9 @@ func TestCheckDuplicateAddress(t *testing.T) {
 	var secureRNG bytes.Reader
 	secureRNG.Reset(secureRNGBytes[:])
 	s := stack.New(stack.Options{
-		SecureRNG: &secureRNG,
-		Clock:     clock,
+		Clock:      clock,
+		RandSource: rand.NewSource(time.Now().UnixNano()),
+		SecureRNG:  &secureRNG,
 		NetworkProtocols: []stack.NetworkProtocolFactory{NewProtocolWithOptions(Options{
 			DADConfigs: dadConfigs,
 		})},
diff --git a/pkg/tcpip/ports/ports.go b/pkg/tcpip/ports/ports.go
index b5b013b64..854d6a6ba 100644
--- a/pkg/tcpip/ports/ports.go
+++ b/pkg/tcpip/ports/ports.go
@@ -101,7 +101,7 @@ func (dc destToCounter) intersectionFlags(res Reservation) (BitFlags, int) {
 		// Wildcard destinations affect all destinations for TupleOnly.
 		if dest.addr == anyIPAddress || res.Dest.Addr == anyIPAddress {
 			// Only bitwise and the TupleOnlyFlag.
-			intersection &= ((^TupleOnlyFlag) | counter.SharedFlags())
+			intersection &= (^TupleOnlyFlag) | counter.SharedFlags()
 			count++
 		}
 	}
@@ -238,13 +238,13 @@ type PortTester func(port uint16) (good bool, err tcpip.Error)
 // possible ephemeral ports, allowing the caller to decide whether a given port
 // is suitable for its needs, and stopping when a port is found or an error
 // occurs.
-func (pm *PortManager) PickEphemeralPort(testPort PortTester) (port uint16, err tcpip.Error) {
+func (pm *PortManager) PickEphemeralPort(rng *rand.Rand, testPort PortTester) (port uint16, err tcpip.Error) {
 	pm.ephemeralMu.RLock()
 	firstEphemeral := pm.firstEphemeral
 	numEphemeral := pm.numEphemeral
 	pm.ephemeralMu.RUnlock()
 
-	offset := uint32(rand.Int31n(int32(numEphemeral)))
+	offset := uint32(rng.Int31n(int32(numEphemeral)))
 	return pickEphemeralPort(offset, firstEphemeral, numEphemeral, testPort)
 }
 
@@ -303,7 +303,7 @@ func pickEphemeralPort(offset uint32, first, count uint16, testPort PortTester)
 // An optional PortTester can be passed in which if provided will be used to
 // test if the picked port can be used. The function should return true if the
 // port is safe to use, false otherwise.
-func (pm *PortManager) ReservePort(res Reservation, testPort PortTester) (reservedPort uint16, err tcpip.Error) {
+func (pm *PortManager) ReservePort(rng *rand.Rand, res Reservation, testPort PortTester) (reservedPort uint16, err tcpip.Error) {
 	pm.mu.Lock()
 	defer pm.mu.Unlock()
 
@@ -328,7 +328,7 @@ func (pm *PortManager) ReservePort(res Reservation, testPort PortTester) (reserv
 	}
 
 	// A port wasn't specified, so try to find one.
-	return pm.PickEphemeralPort(func(p uint16) (bool, tcpip.Error) {
+	return pm.PickEphemeralPort(rng, func(p uint16) (bool, tcpip.Error) {
 		res.Port = p
 		if !pm.reserveSpecificPortLocked(res) {
 			return false, nil
diff --git a/pkg/tcpip/ports/ports_test.go b/pkg/tcpip/ports/ports_test.go
index 6c4fb8c68..a91b130df 100644
--- a/pkg/tcpip/ports/ports_test.go
+++ b/pkg/tcpip/ports/ports_test.go
@@ -18,6 +18,7 @@ import (
 	"math"
 	"math/rand"
 	"testing"
+	"time"
 
 	"github.com/google/go-cmp/cmp"
 	"gvisor.dev/gvisor/pkg/tcpip"
@@ -331,6 +332,7 @@ func TestPortReservation(t *testing.T) {
 		t.Run(test.tname, func(t *testing.T) {
 			pm := NewPortManager()
 			net := []tcpip.NetworkProtocolNumber{fakeNetworkNumber}
+			rng := rand.New(rand.NewSource(time.Now().UnixNano()))
 
 			for _, test := range test.actions {
 				first, _ := pm.PortRange()
@@ -356,7 +358,7 @@ func TestPortReservation(t *testing.T) {
 					BindToDevice: test.device,
 					Dest:         test.dest,
 				}
-				gotPort, err := pm.ReservePort(portRes, nil /* testPort */)
+				gotPort, err := pm.ReservePort(rng, portRes, nil /* testPort */)
 				if diff := cmp.Diff(test.want, err); diff != "" {
 					t.Fatalf("unexpected error from ReservePort(%+v, _), (-want, +got):\n%s", portRes, diff)
 				}
@@ -417,10 +419,11 @@ func TestPickEphemeralPort(t *testing.T) {
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			pm := NewPortManager()
+			rng := rand.New(rand.NewSource(time.Now().UnixNano()))
 			if err := pm.SetPortRange(firstEphemeral, firstEphemeral+numEphemeralPorts); err != nil {
 				t.Fatalf("failed to set ephemeral port range: %s", err)
 			}
-			port, err := pm.PickEphemeralPort(test.f)
+			port, err := pm.PickEphemeralPort(rng, test.f)
 			if diff := cmp.Diff(test.wantErr, err); diff != "" {
 				t.Fatalf("unexpected error from PickEphemeralPort(..), (-want, +got):\n%s", diff)
 			}
diff --git a/pkg/tcpip/stack/iptables.go b/pkg/tcpip/stack/iptables.go
index d2f666c09..0a26f6dd8 100644
--- a/pkg/tcpip/stack/iptables.go
+++ b/pkg/tcpip/stack/iptables.go
@@ -42,7 +42,7 @@ const reaperDelay = 5 * time.Second
 
 // DefaultTables returns a default set of tables. Each chain is set to accept
 // all packets.
-func DefaultTables() *IPTables {
+func DefaultTables(seed uint32) *IPTables {
 	return &IPTables{
 		v4Tables: [NumTables]Table{
 			NATID: {
@@ -182,7 +182,7 @@ func DefaultTables() *IPTables {
 			Postrouting: {MangleID, NATID},
 		},
 		connections: ConnTrack{
-			seed: generateRandUint32(),
+			seed: seed,
 		},
 		reaperDone: make(chan struct{}, 1),
 	}
diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index ac2fa777e..7af5ee953 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -19,11 +19,12 @@ import (
 	"context"
 	"encoding/binary"
 	"fmt"
+	"math/rand"
 	"testing"
 	"time"
 
 	"github.com/google/go-cmp/cmp"
-	"gvisor.dev/gvisor/pkg/rand"
+	cryptorand "gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/checker"
@@ -497,8 +498,9 @@ func TestDADResolve(t *testing.T) {
 
 			clock := faketime.NewManualClock()
 			s := stack.New(stack.Options{
-				Clock:     clock,
-				SecureRNG: &secureRNG,
+				Clock:      clock,
+				RandSource: rand.NewSource(time.Now().UnixNano()),
+				SecureRNG:  &secureRNG,
 				NetworkProtocols: []stack.NetworkProtocolFactory{ipv6.NewProtocolWithOptions(ipv6.Options{
 					NDPDisp: &ndpDisp,
 					DADConfigs: stack.DADConfigurations{
@@ -1035,7 +1037,7 @@ func TestSetNDPConfigurations(t *testing.T) {
 // raBufWithOptsAndDHCPv6 returns a valid NDP Router Advertisement with options
 // and DHCPv6 configurations specified.
 func raBufWithOptsAndDHCPv6(ip tcpip.Address, rl uint16, managedAddress, otherConfigurations bool, optSer header.NDPOptionsSerializer) *stack.PacketBuffer {
-	icmpSize := header.ICMPv6HeaderSize + header.NDPRAMinimumSize + int(optSer.Length())
+	icmpSize := header.ICMPv6HeaderSize + header.NDPRAMinimumSize + optSer.Length()
 	hdr := buffer.NewPrependable(header.IPv6MinimumSize + icmpSize)
 	pkt := header.ICMPv6(hdr.Prepend(icmpSize))
 	pkt.SetType(header.ICMPv6RouterAdvert)
@@ -1048,13 +1050,13 @@ func raBufWithOptsAndDHCPv6(ip tcpip.Address, rl uint16, managedAddress, otherCo
 	if managedAddress {
 		// The Managed Addresses flag field is the 7th bit of byte #1 (0-indexing)
 		// of the RA payload.
-		raPayload[1] |= (1 << 7)
+		raPayload[1] |= 1 << 7
 	}
 	// Populate the Other Configurations flag field.
 	if otherConfigurations {
 		// The Other Configurations flag field is the 6th bit of byte #1
 		// (0-indexing) of the RA payload.
-		raPayload[1] |= (1 << 6)
+		raPayload[1] |= 1 << 6
 	}
 	opts := ra.Options()
 	opts.Serialize(optSer)
@@ -3833,12 +3835,12 @@ func TestAutoGenAddrWithOpaqueIID(t *testing.T) {
 	const nicName = "nic1"
 	var secretKeyBuf [header.OpaqueIIDSecretKeyMinBytes]byte
 	secretKey := secretKeyBuf[:]
-	n, err := rand.Read(secretKey)
+	n, err := cryptorand.Read(secretKey)
 	if err != nil {
-		t.Fatalf("rand.Read(_): %s", err)
+		t.Fatalf("cryptorand.Read(_): %s", err)
 	}
 	if n != header.OpaqueIIDSecretKeyMinBytes {
-		t.Fatalf("got rand.Read(_) = (%d, _), want = (%d, _)", n, header.OpaqueIIDSecretKeyMinBytes)
+		t.Fatalf("got cryptorand.Read(_) = (%d, _), want = (%d, _)", n, header.OpaqueIIDSecretKeyMinBytes)
 	}
 
 	prefix1, subnet1, _ := prefixSubnetAddr(0, linkAddr1)
@@ -3946,12 +3948,12 @@ func TestAutoGenAddrInResponseToDADConflicts(t *testing.T) {
 
 	var secretKeyBuf [header.OpaqueIIDSecretKeyMinBytes]byte
 	secretKey := secretKeyBuf[:]
-	n, err := rand.Read(secretKey)
+	n, err := cryptorand.Read(secretKey)
 	if err != nil {
-		t.Fatalf("rand.Read(_): %s", err)
+		t.Fatalf("cryptorand.Read(_): %s", err)
 	}
 	if n != header.OpaqueIIDSecretKeyMinBytes {
-		t.Fatalf("got rand.Read(_) = (%d, _), want = (%d, _)", n, header.OpaqueIIDSecretKeyMinBytes)
+		t.Fatalf("got cryptorand.Read(_) = (%d, _), want = (%d, _)", n, header.OpaqueIIDSecretKeyMinBytes)
 	}
 
 	prefix, subnet, _ := prefixSubnetAddr(0, linkAddr1)
@@ -4311,12 +4313,12 @@ func TestAutoGenAddrContinuesLifetimesAfterRetry(t *testing.T) {
 
 	var secretKeyBuf [header.OpaqueIIDSecretKeyMinBytes]byte
 	secretKey := secretKeyBuf[:]
-	n, err := rand.Read(secretKey)
+	n, err := cryptorand.Read(secretKey)
 	if err != nil {
-		t.Fatalf("rand.Read(_): %s", err)
+		t.Fatalf("cryptorand.Read(_): %s", err)
 	}
 	if n != header.OpaqueIIDSecretKeyMinBytes {
-		t.Fatalf("got rand.Read(_) = (%d, _), want = (%d, _)", n, header.OpaqueIIDSecretKeyMinBytes)
+		t.Fatalf("got cryptorand.Read(_) = (%d, _), want = (%d, _)", n, header.OpaqueIIDSecretKeyMinBytes)
 	}
 
 	prefix, subnet, _ := prefixSubnetAddr(0, linkAddr1)
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 1ebf9670c..40d277312 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -20,7 +20,6 @@
 package stack
 
 import (
-	"bytes"
 	"encoding/binary"
 	"fmt"
 	"io"
@@ -223,10 +222,16 @@ type Options struct {
 	// RandSource must be thread-safe.
 	RandSource rand.Source
 
-	// IPTables are the initial iptables rules. If nil, iptables will allow
+	// IPTables are the initial iptables rules. If nil, DefaultIPTables will be
+	// used to construct the initial iptables rules.
 	// all traffic.
 	IPTables *IPTables
 
+	// DefaultIPTables is an optional iptables rules constructor that is called
+	// if IPTables is nil. If both fields are nil, iptables will allow all
+	// traffic.
+	DefaultIPTables func(uint32) *IPTables
+
 	// SecureRNG is a cryptographically secure random number generator.
 	SecureRNG io.Reader
 }
@@ -324,23 +329,32 @@ func New(opts Options) *Stack {
 		opts.UniqueID = new(uniqueIDGenerator)
 	}
 
+	if opts.SecureRNG == nil {
+		opts.SecureRNG = cryptorand.Reader
+	}
+
 	randSrc := opts.RandSource
 	if randSrc == nil {
+		var v int64
+		if err := binary.Read(opts.SecureRNG, binary.LittleEndian, &v); err != nil {
+			panic(err)
+		}
 		// Source provided by rand.NewSource is not thread-safe so
 		// we wrap it in a simple thread-safe version.
-		randSrc = &lockedRandomSource{src: rand.NewSource(generateRandInt64())}
+		randSrc = &lockedRandomSource{src: rand.NewSource(v)}
 	}
+	randomGenerator := rand.New(randSrc)
 
+	seed := randomGenerator.Uint32()
 	if opts.IPTables == nil {
-		opts.IPTables = DefaultTables()
+		if opts.DefaultIPTables == nil {
+			opts.DefaultIPTables = DefaultTables
+		}
+		opts.IPTables = opts.DefaultIPTables(seed)
 	}
 
 	opts.NUDConfigs.resetInvalidFields()
 
-	if opts.SecureRNG == nil {
-		opts.SecureRNG = cryptorand.Reader
-	}
-
 	s := &Stack{
 		transportProtocols:       make(map[tcpip.TransportProtocolNumber]*transportProtocolState),
 		networkProtocols:         make(map[tcpip.NetworkProtocolNumber]NetworkProtocol),
@@ -353,11 +367,11 @@ func New(opts Options) *Stack {
 		handleLocal:              opts.HandleLocal,
 		tables:                   opts.IPTables,
 		icmpRateLimiter:          NewICMPRateLimiter(),
-		seed:                     generateRandUint32(),
+		seed:                     seed,
 		nudConfigs:               opts.NUDConfigs,
 		uniqueIDGenerator:        opts.UniqueID,
 		nudDisp:                  opts.NUDDisp,
-		randomGenerator:          rand.New(randSrc),
+		randomGenerator:          randomGenerator,
 		secureRNG:                opts.SecureRNG,
 		sendBufferSize: tcpip.SendBufferSizeOption{
 			Min:     MinBufferSize,
@@ -1822,27 +1836,6 @@ func (s *Stack) SecureRNG() io.Reader {
 	return s.secureRNG
 }
 
-func generateRandUint32() uint32 {
-	b := make([]byte, 4)
-	if _, err := cryptorand.Read(b); err != nil {
-		panic(err)
-	}
-	return binary.LittleEndian.Uint32(b)
-}
-
-func generateRandInt64() int64 {
-	b := make([]byte, 8)
-	if _, err := cryptorand.Read(b); err != nil {
-		panic(err)
-	}
-	buf := bytes.NewReader(b)
-	var v int64
-	if err := binary.Read(buf, binary.LittleEndian, &v); err != nil {
-		panic(err)
-	}
-	return v
-}
-
 // FindNICNameFromID returns the name of the NIC for the given NICID.
 func (s *Stack) FindNICNameFromID(id tcpip.NICID) string {
 	s.mu.RLock()
diff --git a/pkg/tcpip/stack/transport_demuxer.go b/pkg/tcpip/stack/transport_demuxer.go
index 80ad1a9d4..8a8454a6a 100644
--- a/pkg/tcpip/stack/transport_demuxer.go
+++ b/pkg/tcpip/stack/transport_demuxer.go
@@ -16,8 +16,6 @@ package stack
 
 import (
 	"fmt"
-	"math/rand"
-
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/hash/jenkins"
@@ -223,7 +221,7 @@ func (epsByNIC *endpointsByNIC) registerEndpoint(d *transportDemuxer, netProto t
 	return multiPortEp.singleRegisterEndpoint(t, flags)
 }
 
-func (epsByNIC *endpointsByNIC) checkEndpoint(d *transportDemuxer, netProto tcpip.NetworkProtocolNumber, transProto tcpip.TransportProtocolNumber, flags ports.Flags, bindToDevice tcpip.NICID) tcpip.Error {
+func (epsByNIC *endpointsByNIC) checkEndpoint(flags ports.Flags, bindToDevice tcpip.NICID) tcpip.Error {
 	epsByNIC.mu.RLock()
 	defer epsByNIC.mu.RUnlock()
 
@@ -475,7 +473,7 @@ func (d *transportDemuxer) singleRegisterEndpoint(netProto tcpip.NetworkProtocol
 	if !ok {
 		epsByNIC = &endpointsByNIC{
 			endpoints: make(map[tcpip.NICID]*multiPortEndpoint),
-			seed:      rand.Uint32(),
+			seed:      d.stack.Seed(),
 		}
 		eps.endpoints[id] = epsByNIC
 	}
@@ -502,7 +500,7 @@ func (d *transportDemuxer) singleCheckEndpoint(netProto tcpip.NetworkProtocolNum
 		return nil
 	}
 
-	return epsByNIC.checkEndpoint(d, netProto, protocol, flags, bindToDevice)
+	return epsByNIC.checkEndpoint(flags, bindToDevice)
 }
 
 // unregisterEndpoint unregisters the endpoint with the given id such that it
diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go
index d92b123c4..39f526023 100644
--- a/pkg/tcpip/transport/icmp/endpoint.go
+++ b/pkg/tcpip/transport/icmp/endpoint.go
@@ -616,7 +616,7 @@ func (e *endpoint) registerWithStack(_ tcpip.NICID, netProtos []tcpip.NetworkPro
 	}
 
 	// We need to find a port for the endpoint.
-	_, err := e.stack.PickEphemeralPort(func(p uint16) (bool, tcpip.Error) {
+	_, err := e.stack.PickEphemeralPort(e.stack.Rand(), func(p uint16) (bool, tcpip.Error) {
 		id.LocalPort = p
 		err := e.stack.RegisterTransportEndpoint(netProtos, e.TransProto, id, e, ports.Flags{}, 0 /* bindtodevice */)
 		switch err.(type) {
diff --git a/pkg/tcpip/transport/tcp/accept.go b/pkg/tcpip/transport/tcp/accept.go
index db75228a1..2c65b737d 100644
--- a/pkg/tcpip/transport/tcp/accept.go
+++ b/pkg/tcpip/transport/tcp/accept.go
@@ -591,7 +591,7 @@ func (e *endpoint) handleListenSegment(ctx *listenContext, s *segment) tcpip.Err
 		synOpts := header.TCPSynOptions{
 			WS:    -1,
 			TS:    opts.TS,
-			TSVal: tcpTimeStamp(e.stack.Clock().NowMonotonic(), timeStampOffset()),
+			TSVal: tcpTimeStamp(e.stack.Clock().NowMonotonic(), timeStampOffset(e.stack.Rand())),
 			TSEcr: opts.TSVal,
 			MSS:   calculateAdvertisedMSS(e.userMSS, route),
 		}
diff --git a/pkg/tcpip/transport/tcp/connect.go b/pkg/tcpip/transport/tcp/connect.go
index 08849d0cc..570e5081c 100644
--- a/pkg/tcpip/transport/tcp/connect.go
+++ b/pkg/tcpip/transport/tcp/connect.go
@@ -19,7 +19,6 @@ import (
 	"math"
 	"time"
 
-	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/sleep"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
@@ -147,11 +146,6 @@ func FindWndScale(wnd seqnum.Size) int {
 // resetState resets the state of the handshake object such that it becomes
 // ready for a new 3-way handshake.
 func (h *handshake) resetState() {
-	b := make([]byte, 4)
-	if _, err := rand.Read(b); err != nil {
-		panic(err)
-	}
-
 	h.state = handshakeSynSent
 	h.flags = header.TCPFlagSyn
 	h.ackNum = 0
diff --git a/pkg/tcpip/transport/tcp/dispatcher.go b/pkg/tcpip/transport/tcp/dispatcher.go
index 5963a169c..dff7cb89c 100644
--- a/pkg/tcpip/transport/tcp/dispatcher.go
+++ b/pkg/tcpip/transport/tcp/dispatcher.go
@@ -16,8 +16,8 @@ package tcp
 
 import (
 	"encoding/binary"
+	"math/rand"
 
-	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/sleep"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
@@ -142,15 +142,16 @@ func (p *processor) start(wg *sync.WaitGroup) {
 // in-order.
 type dispatcher struct {
 	processors []processor
-	seed       uint32
-	wg         sync.WaitGroup
+	// seed is a random secret for a jenkins hash.
+	seed uint32
+	wg   sync.WaitGroup
 }
 
-func (d *dispatcher) init(nProcessors int) {
+func (d *dispatcher) init(rng *rand.Rand, nProcessors int) {
 	d.close()
 	d.wait()
 	d.processors = make([]processor, nProcessors)
-	d.seed = generateRandUint32()
+	d.seed = rng.Uint32()
 	for i := range d.processors {
 		p := &d.processors[i]
 		p.sleeper.AddWaker(&p.newEndpointWaker, newEndpointWaker)
@@ -212,14 +213,6 @@ func (d *dispatcher) queuePacket(stackEP stack.TransportEndpoint, id stack.Trans
 	d.selectProcessor(id).queueEndpoint(ep)
 }
 
-func generateRandUint32() uint32 {
-	b := make([]byte, 4)
-	if _, err := rand.Read(b); err != nil {
-		panic(err)
-	}
-	return binary.LittleEndian.Uint32(b)
-}
-
 func (d *dispatcher) selectProcessor(id stack.TransportEndpointID) *processor {
 	var payload [4]byte
 	binary.LittleEndian.PutUint16(payload[0:], id.LocalPort)
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go
index d44f480ab..a27e2110b 100644
--- a/pkg/tcpip/transport/tcp/endpoint.go
+++ b/pkg/tcpip/transport/tcp/endpoint.go
@@ -20,12 +20,12 @@ import (
 	"fmt"
 	"io"
 	"math"
+	"math/rand"
 	"runtime"
 	"strings"
 	"sync/atomic"
 	"time"
 
-	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/sleep"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/tcpip"
@@ -882,7 +882,7 @@ func newEndpoint(s *stack.Stack, netProto tcpip.NetworkProtocolNumber, waiterQue
 	}
 
 	e.segmentQueue.ep = e
-	e.TSOffset = timeStampOffset()
+	e.TSOffset = timeStampOffset(e.stack.Rand())
 	e.acceptCond = sync.NewCond(&e.acceptMu)
 	e.keepalive.timer.init(e.stack.Clock(), &e.keepalive.waker)
 
@@ -2215,7 +2215,7 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) tcp
 				BindToDevice: bindToDevice,
 				Dest:         addr,
 			}
-			if _, err := e.stack.ReservePort(portRes, nil /* testPort */); err != nil {
+			if _, err := e.stack.ReservePort(e.stack.Rand(), portRes, nil /* testPort */); err != nil {
 				if _, ok := err.(*tcpip.ErrPortInUse); !ok || !reuse {
 					return false, nil
 				}
@@ -2262,7 +2262,7 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) tcp
 					BindToDevice: bindToDevice,
 					Dest:         addr,
 				}
-				if _, err := e.stack.ReservePort(portRes, nil /* testPort */); err != nil {
+				if _, err := e.stack.ReservePort(e.stack.Rand(), portRes, nil /* testPort */); err != nil {
 					return false, nil
 				}
 			}
@@ -2598,7 +2598,7 @@ func (e *endpoint) bindLocked(addr tcpip.FullAddress) (err tcpip.Error) {
 		BindToDevice: bindToDevice,
 		Dest:         tcpip.FullAddress{},
 	}
-	port, err := e.stack.ReservePort(portRes, func(p uint16) (bool, tcpip.Error) {
+	port, err := e.stack.ReservePort(e.stack.Rand(), portRes, func(p uint16) (bool, tcpip.Error) {
 		id := e.TransportEndpointInfo.ID
 		id.LocalPort = p
 		// CheckRegisterTransportEndpoint should only return an error if there is a
@@ -2878,11 +2878,7 @@ func tcpTimeStamp(curTime tcpip.MonotonicTime, offset uint32) uint32 {
 
 // timeStampOffset returns a randomized timestamp offset to be used when sending
 // timestamp values in a timestamp option for a TCP segment.
-func timeStampOffset() uint32 {
-	b := make([]byte, 4)
-	if _, err := rand.Read(b); err != nil {
-		panic(err)
-	}
+func timeStampOffset(rng *rand.Rand) uint32 {
 	// Initialize a random tsOffset that will be added to the recentTS
 	// everytime the timestamp is sent when the Timestamp option is enabled.
 	//
@@ -2892,7 +2888,7 @@ func timeStampOffset() uint32 {
 	// NOTE: This is not completely to spec as normally this should be
 	// initialized in a manner analogous to how sequence numbers are
 	// randomized per connection basis. But for now this is sufficient.
-	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+	return rng.Uint32()
 }
 
 // maybeEnableSACKPermitted marks the SACKPermitted option enabled for this endpoint
diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go
index 7c38ad480..2fc282e73 100644
--- a/pkg/tcpip/transport/tcp/protocol.go
+++ b/pkg/tcpip/transport/tcp/protocol.go
@@ -481,6 +481,6 @@ func NewProtocol(s *stack.Stack) stack.TransportProtocol {
 		// TODO(gvisor.dev/issue/5243): Set recovery to tcpip.TCPRACKLossDetection.
 		recovery: 0,
 	}
-	p.dispatcher.init(runtime.GOMAXPROCS(0))
+	p.dispatcher.init(s.Rand(), runtime.GOMAXPROCS(0))
 	return &p
 }
diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go
index 83b589d09..b964e446b 100644
--- a/pkg/tcpip/transport/udp/endpoint.go
+++ b/pkg/tcpip/transport/udp/endpoint.go
@@ -1077,7 +1077,7 @@ func (e *endpoint) registerWithStack(netProtos []tcpip.NetworkProtocolNumber, id
 			BindToDevice: bindToDevice,
 			Dest:         tcpip.FullAddress{},
 		}
-		port, err := e.stack.ReservePort(portRes, nil /* testPort */)
+		port, err := e.stack.ReservePort(e.stack.Rand(), portRes, nil /* testPort */)
 		if err != nil {
 			return id, bindToDevice, err
 		}