diff options
Diffstat (limited to 'pkg/tcpip/iptables')
| -rw-r--r-- | pkg/tcpip/iptables/BUILD | 18 | ||||
| -rw-r--r-- | pkg/tcpip/iptables/iptables.go | 314 | ||||
| -rw-r--r-- | pkg/tcpip/iptables/targets.go | 144 | ||||
| -rw-r--r-- | pkg/tcpip/iptables/types.go | 180 |
4 files changed, 0 insertions, 656 deletions
diff --git a/pkg/tcpip/iptables/BUILD b/pkg/tcpip/iptables/BUILD deleted file mode 100644 index d1b73cfdf..000000000 --- a/pkg/tcpip/iptables/BUILD +++ /dev/null @@ -1,18 +0,0 @@ -load("//tools:defs.bzl", "go_library") - -package(licenses = ["notice"]) - -go_library( - name = "iptables", - srcs = [ - "iptables.go", - "targets.go", - "types.go", - ], - visibility = ["//visibility:public"], - deps = [ - "//pkg/log", - "//pkg/tcpip", - "//pkg/tcpip/header", - ], -) diff --git a/pkg/tcpip/iptables/iptables.go b/pkg/tcpip/iptables/iptables.go deleted file mode 100644 index d30571c74..000000000 --- a/pkg/tcpip/iptables/iptables.go +++ /dev/null @@ -1,314 +0,0 @@ -// Copyright 2019 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -// Package iptables supports packet filtering and manipulation via the iptables -// tool. -package iptables - -import ( - "fmt" - - "gvisor.dev/gvisor/pkg/tcpip" - "gvisor.dev/gvisor/pkg/tcpip/header" -) - -// Table names. -const ( - TablenameNat = "nat" - TablenameMangle = "mangle" - TablenameFilter = "filter" -) - -// Chain names as defined by net/ipv4/netfilter/ip_tables.c. -const ( - ChainNamePrerouting = "PREROUTING" - ChainNameInput = "INPUT" - ChainNameForward = "FORWARD" - ChainNameOutput = "OUTPUT" - ChainNamePostrouting = "POSTROUTING" -) - -// HookUnset indicates that there is no hook set for an entrypoint or -// underflow. -const HookUnset = -1 - -// DefaultTables returns a default set of tables. Each chain is set to accept -// all packets. -func DefaultTables() IPTables { - // TODO(gvisor.dev/issue/170): We may be able to swap out some strings for - // iotas. - return IPTables{ - Tables: map[string]Table{ - TablenameNat: Table{ - Rules: []Rule{ - Rule{Target: AcceptTarget{}}, - Rule{Target: AcceptTarget{}}, - Rule{Target: AcceptTarget{}}, - Rule{Target: AcceptTarget{}}, - Rule{Target: ErrorTarget{}}, - }, - BuiltinChains: map[Hook]int{ - Prerouting: 0, - Input: 1, - Output: 2, - Postrouting: 3, - }, - Underflows: map[Hook]int{ - Prerouting: 0, - Input: 1, - Output: 2, - Postrouting: 3, - }, - UserChains: map[string]int{}, - }, - TablenameMangle: Table{ - Rules: []Rule{ - Rule{Target: AcceptTarget{}}, - Rule{Target: AcceptTarget{}}, - Rule{Target: ErrorTarget{}}, - }, - BuiltinChains: map[Hook]int{ - Prerouting: 0, - Output: 1, - }, - Underflows: map[Hook]int{ - Prerouting: 0, - Output: 1, - }, - UserChains: map[string]int{}, - }, - TablenameFilter: Table{ - Rules: []Rule{ - Rule{Target: AcceptTarget{}}, - Rule{Target: AcceptTarget{}}, - Rule{Target: AcceptTarget{}}, - Rule{Target: ErrorTarget{}}, - }, - BuiltinChains: map[Hook]int{ - Input: 0, - Forward: 1, - Output: 2, - }, - Underflows: map[Hook]int{ - Input: 0, - Forward: 1, - Output: 2, - }, - UserChains: map[string]int{}, - }, - }, - Priorities: map[Hook][]string{ - Input: []string{TablenameNat, TablenameFilter}, - Prerouting: []string{TablenameMangle, TablenameNat}, - Output: []string{TablenameMangle, TablenameNat, TablenameFilter}, - }, - } -} - -// EmptyFilterTable returns a Table with no rules and the filter table chains -// mapped to HookUnset. -func EmptyFilterTable() Table { - return Table{ - Rules: []Rule{}, - BuiltinChains: map[Hook]int{ - Input: HookUnset, - Forward: HookUnset, - Output: HookUnset, - }, - Underflows: map[Hook]int{ - Input: HookUnset, - Forward: HookUnset, - Output: HookUnset, - }, - UserChains: map[string]int{}, - } -} - -// EmptyNatTable returns a Table with no rules and the filter table chains -// mapped to HookUnset. -func EmptyNatTable() Table { - return Table{ - Rules: []Rule{}, - BuiltinChains: map[Hook]int{ - Prerouting: HookUnset, - Input: HookUnset, - Output: HookUnset, - Postrouting: HookUnset, - }, - Underflows: map[Hook]int{ - Prerouting: HookUnset, - Input: HookUnset, - Output: HookUnset, - Postrouting: HookUnset, - }, - UserChains: map[string]int{}, - } -} - -// A chainVerdict is what a table decides should be done with a packet. -type chainVerdict int - -const ( - // chainAccept indicates the packet should continue through netstack. - chainAccept chainVerdict = iota - - // chainAccept indicates the packet should be dropped. - chainDrop - - // chainReturn indicates the packet should return to the calling chain - // or the underflow rule of a builtin chain. - chainReturn -) - -// Check runs pkt through the rules for hook. It returns true when the packet -// should continue traversing the network stack and false when it should be -// dropped. -// -// Precondition: pkt.NetworkHeader is set. -func (it *IPTables) Check(hook Hook, pkt tcpip.PacketBuffer) bool { - // Go through each table containing the hook. - for _, tablename := range it.Priorities[hook] { - table := it.Tables[tablename] - ruleIdx := table.BuiltinChains[hook] - switch verdict := it.checkChain(hook, pkt, table, ruleIdx); verdict { - // If the table returns Accept, move on to the next table. - case chainAccept: - continue - // The Drop verdict is final. - case chainDrop: - return false - case chainReturn: - // Any Return from a built-in chain means we have to - // call the underflow. - underflow := table.Rules[table.Underflows[hook]] - switch v, _ := underflow.Target.Action(pkt); v { - case RuleAccept: - continue - case RuleDrop: - return false - case RuleJump, RuleReturn: - panic("Underflows should only return RuleAccept or RuleDrop.") - default: - panic(fmt.Sprintf("Unknown verdict: %d", v)) - } - - default: - panic(fmt.Sprintf("Unknown verdict %v.", verdict)) - } - } - - // Every table returned Accept. - return true -} - -// Precondition: pkt.NetworkHeader is set. -func (it *IPTables) checkChain(hook Hook, pkt tcpip.PacketBuffer, table Table, ruleIdx int) chainVerdict { - // Start from ruleIdx and walk the list of rules until a rule gives us - // a verdict. - for ruleIdx < len(table.Rules) { - switch verdict, jumpTo := it.checkRule(hook, pkt, table, ruleIdx); verdict { - case RuleAccept: - return chainAccept - - case RuleDrop: - return chainDrop - - case RuleReturn: - return chainReturn - - case RuleJump: - // "Jumping" to the next rule just means we're - // continuing on down the list. - if jumpTo == ruleIdx+1 { - ruleIdx++ - continue - } - switch verdict := it.checkChain(hook, pkt, table, jumpTo); verdict { - case chainAccept: - return chainAccept - case chainDrop: - return chainDrop - case chainReturn: - ruleIdx++ - continue - default: - panic(fmt.Sprintf("Unknown verdict: %d", verdict)) - } - - default: - panic(fmt.Sprintf("Unknown verdict: %d", verdict)) - } - - } - - // We got through the entire table without a decision. Default to DROP - // for safety. - return chainDrop -} - -// Precondition: pk.NetworkHeader is set. -func (it *IPTables) checkRule(hook Hook, pkt tcpip.PacketBuffer, table Table, ruleIdx int) (RuleVerdict, int) { - rule := table.Rules[ruleIdx] - - // If pkt.NetworkHeader hasn't been set yet, it will be contained in - // pkt.Data.First(). - if pkt.NetworkHeader == nil { - pkt.NetworkHeader = pkt.Data.First() - } - - // Check whether the packet matches the IP header filter. - if !filterMatch(rule.Filter, header.IPv4(pkt.NetworkHeader)) { - // Continue on to the next rule. - return RuleJump, ruleIdx + 1 - } - - // Go through each rule matcher. If they all match, run - // the rule target. - for _, matcher := range rule.Matchers { - matches, hotdrop := matcher.Match(hook, pkt, "") - if hotdrop { - return RuleDrop, 0 - } - if !matches { - // Continue on to the next rule. - return RuleJump, ruleIdx + 1 - } - } - - // All the matchers matched, so run the target. - return rule.Target.Action(pkt) -} - -func filterMatch(filter IPHeaderFilter, hdr header.IPv4) 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 - } - - return true -} diff --git a/pkg/tcpip/iptables/targets.go b/pkg/tcpip/iptables/targets.go deleted file mode 100644 index e457f2349..000000000 --- a/pkg/tcpip/iptables/targets.go +++ /dev/null @@ -1,144 +0,0 @@ -// Copyright 2019 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package iptables - -import ( - "gvisor.dev/gvisor/pkg/log" - "gvisor.dev/gvisor/pkg/tcpip" - "gvisor.dev/gvisor/pkg/tcpip/header" -) - -// AcceptTarget accepts packets. -type AcceptTarget struct{} - -// Action implements Target.Action. -func (AcceptTarget) Action(packet tcpip.PacketBuffer) (RuleVerdict, int) { - return RuleAccept, 0 -} - -// DropTarget drops packets. -type DropTarget struct{} - -// Action implements Target.Action. -func (DropTarget) Action(packet tcpip.PacketBuffer) (RuleVerdict, int) { - return RuleDrop, 0 -} - -// ErrorTarget logs an error and drops the packet. It represents a target that -// should be unreachable. -type ErrorTarget struct{} - -// Action implements Target.Action. -func (ErrorTarget) Action(packet tcpip.PacketBuffer) (RuleVerdict, int) { - log.Debugf("ErrorTarget triggered.") - return RuleDrop, 0 -} - -// UserChainTarget marks a rule as the beginning of a user chain. -type UserChainTarget struct { - Name string -} - -// Action implements Target.Action. -func (UserChainTarget) Action(tcpip.PacketBuffer) (RuleVerdict, int) { - panic("UserChainTarget should never be called.") -} - -// ReturnTarget returns from the current chain. If the chain is a built-in, the -// hook's underflow should be called. -type ReturnTarget struct{} - -// Action implements Target.Action. -func (ReturnTarget) Action(tcpip.PacketBuffer) (RuleVerdict, int) { - return RuleReturn, 0 -} - -// RedirectTarget redirects the packet by modifying the destination port/IP. -// Min and Max values for IP and Ports in the struct indicate the range of -// values which can be used to redirect. -type RedirectTarget struct { - // TODO(gvisor.dev/issue/170): Other flags need to be added after - // we support them. - // RangeProtoSpecified flag indicates single port is specified to - // redirect. - RangeProtoSpecified bool - - // Min address used to redirect. - MinIP tcpip.Address - - // Max address used to redirect. - MaxIP tcpip.Address - - // Min port used to redirect. - MinPort uint16 - - // Max port used to redirect. - MaxPort uint16 -} - -// Action implements Target.Action. -// TODO(gvisor.dev/issue/170): Parse headers without copying. The current -// implementation only works for PREROUTING and calls pkt.Clone(), neither -// of which should be the case. -func (rt RedirectTarget) Action(pkt tcpip.PacketBuffer) (RuleVerdict, int) { - newPkt := pkt.Clone() - - // Set network header. - headerView := newPkt.Data.First() - netHeader := header.IPv4(headerView) - newPkt.NetworkHeader = headerView[:header.IPv4MinimumSize] - - hlen := int(netHeader.HeaderLength()) - tlen := int(netHeader.TotalLength()) - newPkt.Data.TrimFront(hlen) - newPkt.Data.CapLength(tlen - hlen) - - // TODO(gvisor.dev/issue/170): Change destination address to - // loopback or interface address on which the packet was - // received. - - // TODO(gvisor.dev/issue/170): Check Flags in RedirectTarget if - // we need to change dest address (for OUTPUT chain) or ports. - switch protocol := netHeader.TransportProtocol(); protocol { - case header.UDPProtocolNumber: - var udpHeader header.UDP - if newPkt.TransportHeader != nil { - udpHeader = header.UDP(newPkt.TransportHeader) - } else { - if len(pkt.Data.First()) < header.UDPMinimumSize { - return RuleDrop, 0 - } - udpHeader = header.UDP(newPkt.Data.First()) - } - udpHeader.SetDestinationPort(rt.MinPort) - case header.TCPProtocolNumber: - var tcpHeader header.TCP - if newPkt.TransportHeader != nil { - tcpHeader = header.TCP(newPkt.TransportHeader) - } else { - if len(pkt.Data.First()) < header.TCPMinimumSize { - return RuleDrop, 0 - } - tcpHeader = header.TCP(newPkt.TransportHeader) - } - // TODO(gvisor.dev/issue/170): Need to recompute checksum - // and implement nat connection tracking to support TCP. - tcpHeader.SetDestinationPort(rt.MinPort) - default: - return RuleDrop, 0 - } - - return RuleAccept, 0 -} diff --git a/pkg/tcpip/iptables/types.go b/pkg/tcpip/iptables/types.go deleted file mode 100644 index e7fcf6bff..000000000 --- a/pkg/tcpip/iptables/types.go +++ /dev/null @@ -1,180 +0,0 @@ -// Copyright 2019 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package iptables - -import ( - "gvisor.dev/gvisor/pkg/tcpip" -) - -// A Hook specifies one of the hooks built into the network stack. -// -// Userspace app Userspace app -// ^ | -// | v -// [Input] [Output] -// ^ | -// | v -// | routing -// | | -// | v -// ----->[Prerouting]----->routing----->[Forward]---------[Postrouting]-----> -type Hook uint - -// These values correspond to values in include/uapi/linux/netfilter.h. -const ( - // Prerouting happens before a packet is routed to applications or to - // be forwarded. - Prerouting Hook = iota - - // Input happens before a packet reaches an application. - Input - - // Forward happens once it's decided that a packet should be forwarded - // to another host. - Forward - - // Output happens after a packet is written by an application to be - // sent out. - Output - - // Postrouting happens just before a packet goes out on the wire. - Postrouting - - // The total number of hooks. - NumHooks -) - -// A RuleVerdict is what a rule decides should be done with a packet. -type RuleVerdict int - -const ( - // RuleAccept indicates the packet should continue through netstack. - RuleAccept RuleVerdict = iota - - // RuleDrop indicates the packet should be dropped. - RuleDrop - - // RuleJump indicates the packet should jump to another chain. - RuleJump - - // RuleReturn indicates the packet should return to the previous chain. - RuleReturn -) - -// IPTables holds all the tables for a netstack. -type IPTables struct { - // Tables maps table names to tables. User tables have arbitrary names. - Tables map[string]Table - - // Priorities maps each hook to a list of table names. The order of the - // list is the order in which each table should be visited for that - // hook. - Priorities map[Hook][]string -} - -// A Table defines a set of chains and hooks into the network stack. It is -// really just a list of rules with some metadata for entrypoints and such. -type Table struct { - // Rules holds the rules that make up the table. - Rules []Rule - - // BuiltinChains maps builtin chains to their entrypoint rule in Rules. - BuiltinChains map[Hook]int - - // Underflows maps builtin chains to their underflow rule in Rules - // (i.e. the rule to execute if the chain returns without a verdict). - Underflows map[Hook]int - - // UserChains holds user-defined chains for the keyed by name. Users - // can give their chains arbitrary names. - UserChains map[string]int - - // Metadata holds information about the Table that is useful to users - // of IPTables, but not to the netstack IPTables code itself. - metadata interface{} -} - -// ValidHooks returns a bitmap of the builtin hooks for the given table. -func (table *Table) ValidHooks() uint32 { - hooks := uint32(0) - for hook := range table.BuiltinChains { - hooks |= 1 << hook - } - return hooks -} - -// Metadata returns the metadata object stored in table. -func (table *Table) Metadata() interface{} { - return table.metadata -} - -// SetMetadata sets the metadata object stored in table. -func (table *Table) SetMetadata(metadata interface{}) { - table.metadata = metadata -} - -// A Rule is a packet processing rule. It consists of two pieces. First it -// contains zero or more matchers, each of which is a specification of which -// packets this rule applies to. If there are no matchers in the rule, it -// applies to any packet. -type Rule struct { - // Filter holds basic IP filtering fields common to every rule. - Filter IPHeaderFilter - - // Matchers is the list of matchers for this rule. - Matchers []Matcher - - // Target is the action to invoke if all the matchers match the packet. - Target Target -} - -// IPHeaderFilter holds basic IP filtering data common to every rule. -type IPHeaderFilter struct { - // Protocol matches the transport protocol. - Protocol tcpip.TransportProtocolNumber - - // Dst matches the destination IP address. - Dst tcpip.Address - - // DstMask masks bits of the destination IP address when comparing with - // Dst. - DstMask tcpip.Address - - // DstInvert inverts the meaning of the destination IP check, i.e. when - // true the filter will match packets that fail the destination - // comparison. - DstInvert bool -} - -// A Matcher is the interface for matching packets. -type Matcher interface { - // Name returns the name of the Matcher. - Name() string - - // Match returns whether the packet matches and whether the packet - // should be "hotdropped", i.e. dropped immediately. This is usually - // used for suspicious packets. - // - // Precondition: packet.NetworkHeader is set. - Match(hook Hook, packet tcpip.PacketBuffer, interfaceName string) (matches bool, hotdrop bool) -} - -// A Target is the interface for taking an action for a packet. -type Target interface { - // Action takes an action on the packet and returns a verdict on how - // traversal should (or should not) continue. If the return value is - // Jump, it also returns the index of the rule to jump to. - Action(packet tcpip.PacketBuffer) (RuleVerdict, int) -} |