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-rw-r--r--pkg/sentry/socket/netfilter/netfilter.go21
-rw-r--r--pkg/tcpip/stack/iptables.go47
-rw-r--r--pkg/tcpip/stack/iptables_types.go62
-rw-r--r--test/iptables/filter_input.go60
-rw-r--r--test/iptables/iptables_test.go8
5 files changed, 147 insertions, 51 deletions
diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go
index 789bb94c8..47ff48c00 100644
--- a/pkg/sentry/socket/netfilter/netfilter.go
+++ b/pkg/sentry/socket/netfilter/netfilter.go
@@ -64,6 +64,8 @@ const enableLogging = false
var emptyFilter = stack.IPHeaderFilter{
Dst: "\x00\x00\x00\x00",
DstMask: "\x00\x00\x00\x00",
+ Src: "\x00\x00\x00\x00",
+ SrcMask: "\x00\x00\x00\x00",
}
// nflog logs messages related to the writing and reading of iptables.
@@ -214,11 +216,16 @@ func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelI
}
copy(entry.IPTEntry.IP.Dst[:], rule.Filter.Dst)
copy(entry.IPTEntry.IP.DstMask[:], rule.Filter.DstMask)
+ copy(entry.IPTEntry.IP.Src[:], rule.Filter.Src)
+ copy(entry.IPTEntry.IP.SrcMask[:], rule.Filter.SrcMask)
copy(entry.IPTEntry.IP.OutputInterface[:], rule.Filter.OutputInterface)
copy(entry.IPTEntry.IP.OutputInterfaceMask[:], rule.Filter.OutputInterfaceMask)
if rule.Filter.DstInvert {
entry.IPTEntry.IP.InverseFlags |= linux.IPT_INV_DSTIP
}
+ if rule.Filter.SrcInvert {
+ entry.IPTEntry.IP.InverseFlags |= linux.IPT_INV_SRCIP
+ }
if rule.Filter.OutputInterfaceInvert {
entry.IPTEntry.IP.InverseFlags |= linux.IPT_INV_VIA_OUT
}
@@ -737,6 +744,9 @@ func filterFromIPTIP(iptip linux.IPTIP) (stack.IPHeaderFilter, error) {
if len(iptip.Dst) != header.IPv4AddressSize || len(iptip.DstMask) != header.IPv4AddressSize {
return stack.IPHeaderFilter{}, fmt.Errorf("incorrect length of destination (%d) and/or destination mask (%d) fields", len(iptip.Dst), len(iptip.DstMask))
}
+ if len(iptip.Src) != header.IPv4AddressSize || len(iptip.SrcMask) != header.IPv4AddressSize {
+ return stack.IPHeaderFilter{}, fmt.Errorf("incorrect length of source (%d) and/or source mask (%d) fields", len(iptip.Src), len(iptip.SrcMask))
+ }
n := bytes.IndexByte([]byte(iptip.OutputInterface[:]), 0)
if n == -1 {
@@ -755,6 +765,9 @@ func filterFromIPTIP(iptip linux.IPTIP) (stack.IPHeaderFilter, error) {
Dst: tcpip.Address(iptip.Dst[:]),
DstMask: tcpip.Address(iptip.DstMask[:]),
DstInvert: iptip.InverseFlags&linux.IPT_INV_DSTIP != 0,
+ Src: tcpip.Address(iptip.Src[:]),
+ SrcMask: tcpip.Address(iptip.SrcMask[:]),
+ SrcInvert: iptip.InverseFlags&linux.IPT_INV_SRCIP != 0,
OutputInterface: ifname,
OutputInterfaceMask: ifnameMask,
OutputInterfaceInvert: iptip.InverseFlags&linux.IPT_INV_VIA_OUT != 0,
@@ -765,15 +778,13 @@ func containsUnsupportedFields(iptip linux.IPTIP) bool {
// The following features are supported:
// - Protocol
// - Dst and DstMask
+ // - Src and SrcMask
// - The inverse destination IP check flag
// - OutputInterface, OutputInterfaceMask and its inverse.
- var emptyInetAddr = linux.InetAddr{}
var emptyInterface = [linux.IFNAMSIZ]byte{}
// Disable any supported inverse flags.
- inverseMask := uint8(linux.IPT_INV_DSTIP) | uint8(linux.IPT_INV_VIA_OUT)
- return iptip.Src != emptyInetAddr ||
- iptip.SrcMask != emptyInetAddr ||
- iptip.InputInterface != emptyInterface ||
+ inverseMask := uint8(linux.IPT_INV_DSTIP) | uint8(linux.IPT_INV_SRCIP) | uint8(linux.IPT_INV_VIA_OUT)
+ return iptip.InputInterface != emptyInterface ||
iptip.InputInterfaceMask != emptyInterface ||
iptip.Flags != 0 ||
iptip.InverseFlags&^inverseMask != 0
diff --git a/pkg/tcpip/stack/iptables.go b/pkg/tcpip/stack/iptables.go
index 443423b3c..709ede3fa 100644
--- a/pkg/tcpip/stack/iptables.go
+++ b/pkg/tcpip/stack/iptables.go
@@ -16,7 +16,6 @@ package stack
import (
"fmt"
- "strings"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
@@ -314,7 +313,7 @@ func (it *IPTables) checkRule(hook Hook, pkt *PacketBuffer, table Table, ruleIdx
}
// Check whether the packet matches the IP header filter.
- if !filterMatch(rule.Filter, header.IPv4(pkt.NetworkHeader), hook, nicName) {
+ if !rule.Filter.match(header.IPv4(pkt.NetworkHeader), hook, nicName) {
// Continue on to the next rule.
return RuleJump, ruleIdx + 1
}
@@ -335,47 +334,3 @@ func (it *IPTables) checkRule(hook Hook, pkt *PacketBuffer, table Table, ruleIdx
// All the matchers matched, so run the target.
return rule.Target.Action(pkt, &it.connections, hook, gso, r, address)
}
-
-func filterMatch(filter IPHeaderFilter, hdr header.IPv4, hook Hook, nicName string) bool {
- // TODO(gvisor.dev/issue/170): Support other fields of the filter.
- // Check the transport protocol.
- if filter.Protocol != 0 && filter.Protocol != hdr.TransportProtocol() {
- return false
- }
-
- // Check the destination IP.
- dest := hdr.DestinationAddress()
- matches := true
- for i := range filter.Dst {
- if dest[i]&filter.DstMask[i] != filter.Dst[i] {
- matches = false
- break
- }
- }
- if matches == filter.DstInvert {
- return false
- }
-
- // Check the output interface.
- // TODO(gvisor.dev/issue/170): Add the check for FORWARD and POSTROUTING
- // hooks after supported.
- if hook == Output {
- n := len(filter.OutputInterface)
- if n == 0 {
- return true
- }
-
- // If the interface name ends with '+', any interface which begins
- // with the name should be matched.
- ifName := filter.OutputInterface
- matches = true
- if strings.HasSuffix(ifName, "+") {
- matches = strings.HasPrefix(nicName, ifName[:n-1])
- } else {
- matches = nicName == ifName
- }
- return filter.OutputInterfaceInvert != matches
- }
-
- return true
-}
diff --git a/pkg/tcpip/stack/iptables_types.go b/pkg/tcpip/stack/iptables_types.go
index fe06007ae..a3bd3e700 100644
--- a/pkg/tcpip/stack/iptables_types.go
+++ b/pkg/tcpip/stack/iptables_types.go
@@ -15,7 +15,10 @@
package stack
import (
+ "strings"
+
"gvisor.dev/gvisor/pkg/tcpip"
+ "gvisor.dev/gvisor/pkg/tcpip/header"
)
// A Hook specifies one of the hooks built into the network stack.
@@ -159,6 +162,16 @@ type IPHeaderFilter struct {
// comparison.
DstInvert bool
+ // Src matches the source IP address.
+ Src tcpip.Address
+
+ // SrcMask masks bits of the source IP address when comparing with Src.
+ SrcMask tcpip.Address
+
+ // SrcInvert inverts the meaning of the source IP check, i.e. when true the
+ // filter will match packets that fail the source comparison.
+ SrcInvert bool
+
// OutputInterface matches the name of the outgoing interface for the
// packet.
OutputInterface string
@@ -173,6 +186,55 @@ type IPHeaderFilter struct {
OutputInterfaceInvert bool
}
+// match returns whether hdr matches the filter.
+func (fl IPHeaderFilter) match(hdr header.IPv4, hook Hook, nicName string) bool {
+ // TODO(gvisor.dev/issue/170): Support other fields of the filter.
+ // Check the transport protocol.
+ if fl.Protocol != 0 && fl.Protocol != hdr.TransportProtocol() {
+ return false
+ }
+
+ // Check the source and destination IPs.
+ if !filterAddress(hdr.DestinationAddress(), fl.DstMask, fl.Dst, fl.DstInvert) || !filterAddress(hdr.SourceAddress(), fl.SrcMask, fl.Src, fl.SrcInvert) {
+ return false
+ }
+
+ // Check the output interface.
+ // TODO(gvisor.dev/issue/170): Add the check for FORWARD and POSTROUTING
+ // hooks after supported.
+ if hook == Output {
+ n := len(fl.OutputInterface)
+ if n == 0 {
+ return true
+ }
+
+ // If the interface name ends with '+', any interface which begins
+ // with the name should be matched.
+ ifName := fl.OutputInterface
+ matches := true
+ if strings.HasSuffix(ifName, "+") {
+ matches = strings.HasPrefix(nicName, ifName[:n-1])
+ } else {
+ matches = nicName == ifName
+ }
+ return fl.OutputInterfaceInvert != matches
+ }
+
+ return true
+}
+
+// filterAddress returns whether addr matches the filter.
+func filterAddress(addr, mask, filterAddr tcpip.Address, invert bool) bool {
+ matches := true
+ for i := range filterAddr {
+ if addr[i]&mask[i] != filterAddr[i] {
+ matches = false
+ break
+ }
+ }
+ return matches != invert
+}
+
// A Matcher is the interface for matching packets.
type Matcher interface {
// Name returns the name of the Matcher.
diff --git a/test/iptables/filter_input.go b/test/iptables/filter_input.go
index 41e0cfa8d..14e385f5a 100644
--- a/test/iptables/filter_input.go
+++ b/test/iptables/filter_input.go
@@ -49,6 +49,8 @@ func init() {
RegisterTestCase(FilterInputJumpTwice{})
RegisterTestCase(FilterInputDestination{})
RegisterTestCase(FilterInputInvertDestination{})
+ RegisterTestCase(FilterInputSource{})
+ RegisterTestCase(FilterInputInvertSource{})
}
// FilterInputDropUDP tests that we can drop UDP traffic.
@@ -667,3 +669,61 @@ func (FilterInputInvertDestination) ContainerAction(ip net.IP) error {
func (FilterInputInvertDestination) LocalAction(ip net.IP) error {
return sendUDPLoop(ip, acceptPort, sendloopDuration)
}
+
+// FilterInputSource verifies that we can filter packets via `-d
+// <ipaddr>`.
+type FilterInputSource struct{}
+
+// Name implements TestCase.Name.
+func (FilterInputSource) Name() string {
+ return "FilterInputSource"
+}
+
+// ContainerAction implements TestCase.ContainerAction.
+func (FilterInputSource) ContainerAction(ip net.IP) error {
+ // Make INPUT's default action DROP, then ACCEPT all packets from this
+ // machine.
+ rules := [][]string{
+ {"-P", "INPUT", "DROP"},
+ {"-A", "INPUT", "-s", fmt.Sprintf("%v", ip), "-j", "ACCEPT"},
+ }
+ if err := filterTableRules(rules); err != nil {
+ return err
+ }
+
+ return listenUDP(acceptPort, sendloopDuration)
+}
+
+// LocalAction implements TestCase.LocalAction.
+func (FilterInputSource) LocalAction(ip net.IP) error {
+ return sendUDPLoop(ip, acceptPort, sendloopDuration)
+}
+
+// FilterInputInvertSource verifies that we can filter packets via `! -d
+// <ipaddr>`.
+type FilterInputInvertSource struct{}
+
+// Name implements TestCase.Name.
+func (FilterInputInvertSource) Name() string {
+ return "FilterInputInvertSource"
+}
+
+// ContainerAction implements TestCase.ContainerAction.
+func (FilterInputInvertSource) ContainerAction(ip net.IP) error {
+ // Make INPUT's default action DROP, then ACCEPT all packets not bound
+ // for 127.0.0.1.
+ rules := [][]string{
+ {"-P", "INPUT", "DROP"},
+ {"-A", "INPUT", "!", "-s", localIP, "-j", "ACCEPT"},
+ }
+ if err := filterTableRules(rules); err != nil {
+ return err
+ }
+
+ return listenUDP(acceptPort, sendloopDuration)
+}
+
+// LocalAction implements TestCase.LocalAction.
+func (FilterInputInvertSource) LocalAction(ip net.IP) error {
+ return sendUDPLoop(ip, acceptPort, sendloopDuration)
+}
diff --git a/test/iptables/iptables_test.go b/test/iptables/iptables_test.go
index 4fd2cb46a..172ad9e16 100644
--- a/test/iptables/iptables_test.go
+++ b/test/iptables/iptables_test.go
@@ -302,3 +302,11 @@ func TestNATPreRedirectInvert(t *testing.T) {
func TestNATRedirectRequiresProtocol(t *testing.T) {
singleTest(t, NATRedirectRequiresProtocol{})
}
+
+func TestInputSource(t *testing.T) {
+ singleTest(t, FilterInputSource{})
+}
+
+func TestInputInvertSource(t *testing.T) {
+ singleTest(t, FilterInputInvertSource{})
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 08:33:39 +0000