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-rw-r--r--pkg/abi/linux/netfilter.go53
-rw-r--r--pkg/sentry/socket/netfilter/BUILD4
-rw-r--r--pkg/sentry/socket/netfilter/extensions.go100
-rw-r--r--pkg/sentry/socket/netfilter/netfilter.go186
-rw-r--r--pkg/sentry/socket/netfilter/tcp_matcher.go143
-rw-r--r--pkg/sentry/socket/netfilter/udp_matcher.go (renamed from pkg/tcpip/iptables/udp_matcher.go)91
-rw-r--r--pkg/tcpip/iptables/BUILD1
-rw-r--r--pkg/tcpip/iptables/types.go3
8 files changed, 417 insertions, 164 deletions
diff --git a/pkg/abi/linux/netfilter.go b/pkg/abi/linux/netfilter.go
index 8e40bcc62..bbc4df74c 100644
--- a/pkg/abi/linux/netfilter.go
+++ b/pkg/abi/linux/netfilter.go
@@ -348,6 +348,59 @@ func goString(cstring []byte) string {
return string(cstring)
}
+// XTTCP holds data for matching TCP packets. It corresponds to struct xt_tcp
+// in include/uapi/linux/netfilter/xt_tcpudp.h.
+type XTTCP struct {
+ // SourcePortStart specifies the inclusive start of the range of source
+ // ports to which the matcher applies.
+ SourcePortStart uint16
+
+ // SourcePortEnd specifies the inclusive end of the range of source ports
+ // to which the matcher applies.
+ SourcePortEnd uint16
+
+ // DestinationPortStart specifies the start of the destination port
+ // range to which the matcher applies.
+ DestinationPortStart uint16
+
+ // DestinationPortEnd specifies the end of the destination port
+ // range to which the matcher applies.
+ DestinationPortEnd uint16
+
+ // Option specifies that a particular TCP option must be set.
+ Option uint8
+
+ // FlagMask masks TCP flags when comparing to the FlagCompare byte. It allows
+ // for specification of which flags are important to the matcher.
+ FlagMask uint8
+
+ // FlagCompare, in combination with FlagMask, is used to match only packets
+ // that have certain flags set.
+ FlagCompare uint8
+
+ // InverseFlags flips the meaning of certain fields. See the
+ // TX_TCP_INV_* flags.
+ InverseFlags uint8
+}
+
+// SizeOfXTTCP is the size of an XTTCP.
+const SizeOfXTTCP = 12
+
+// Flags in XTTCP.InverseFlags. Corresponding constants are in
+// include/uapi/linux/netfilter/xt_tcpudp.h.
+const (
+ // Invert the meaning of SourcePortStart/End.
+ XT_TCP_INV_SRCPT = 0x01
+ // Invert the meaning of DestinationPortStart/End.
+ XT_TCP_INV_DSTPT = 0x02
+ // Invert the meaning of FlagCompare.
+ XT_TCP_INV_FLAGS = 0x04
+ // Invert the meaning of Option.
+ XT_TCP_INV_OPTION = 0x08
+ // Enable all flags.
+ XT_TCP_INV_MASK = 0x0F
+)
+
// XTUDP holds data for matching UDP packets. It corresponds to struct xt_udp
// in include/uapi/linux/netfilter/xt_tcpudp.h.
type XTUDP struct {
diff --git a/pkg/sentry/socket/netfilter/BUILD b/pkg/sentry/socket/netfilter/BUILD
index fa2a2cb66..c91ec7494 100644
--- a/pkg/sentry/socket/netfilter/BUILD
+++ b/pkg/sentry/socket/netfilter/BUILD
@@ -5,7 +5,10 @@ package(licenses = ["notice"])
go_library(
name = "netfilter",
srcs = [
+ "extensions.go",
"netfilter.go",
+ "tcp_matcher.go",
+ "udp_matcher.go",
],
# This target depends on netstack and should only be used by epsocket,
# which is allowed to depend on netstack.
@@ -17,6 +20,7 @@ go_library(
"//pkg/sentry/kernel",
"//pkg/syserr",
"//pkg/tcpip",
+ "//pkg/tcpip/header",
"//pkg/tcpip/iptables",
"//pkg/tcpip/stack",
"//pkg/usermem",
diff --git a/pkg/sentry/socket/netfilter/extensions.go b/pkg/sentry/socket/netfilter/extensions.go
new file mode 100644
index 000000000..22fd0ebe7
--- /dev/null
+++ b/pkg/sentry/socket/netfilter/extensions.go
@@ -0,0 +1,100 @@
+// Copyright 2020 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 netfilter
+
+import (
+ "fmt"
+
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/binary"
+ "gvisor.dev/gvisor/pkg/tcpip/iptables"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+// TODO(gvisor.dev/issue/170): The following per-matcher params should be
+// supported:
+// - Table name
+// - Match size
+// - User size
+// - Hooks
+// - Proto
+// - Family
+
+// matchMaker knows how to (un)marshal the matcher named name().
+type matchMaker interface {
+ // name is the matcher name as stored in the xt_entry_match struct.
+ name() string
+
+ // marshal converts from an iptables.Matcher to an ABI struct.
+ marshal(matcher iptables.Matcher) []byte
+
+ // unmarshal converts from the ABI matcher struct to an
+ // iptables.Matcher.
+ unmarshal(buf []byte, filter iptables.IPHeaderFilter) (iptables.Matcher, error)
+}
+
+// matchMakers maps the name of supported matchers to the matchMaker that
+// marshals and unmarshals it. It is immutable after package initialization.
+var matchMakers = map[string]matchMaker{}
+
+// registermatchMaker should be called by match extensions to register them
+// with the netfilter package.
+func registerMatchMaker(mm matchMaker) {
+ if _, ok := matchMakers[mm.name()]; ok {
+ panic(fmt.Sprintf("Multiple matches registered with name %q.", mm.name()))
+ }
+ matchMakers[mm.name()] = mm
+}
+
+func marshalMatcher(matcher iptables.Matcher) []byte {
+ matchMaker, ok := matchMakers[matcher.Name()]
+ if !ok {
+ panic(fmt.Sprintf("Unknown matcher of type %T.", matcher))
+ }
+ return matchMaker.marshal(matcher)
+}
+
+// marshalEntryMatch creates a marshalled XTEntryMatch with the given name and
+// data appended at the end.
+func marshalEntryMatch(name string, data []byte) []byte {
+ nflog("marshaling matcher %q", name)
+
+ // We have to pad this struct size to a multiple of 8 bytes.
+ size := alignUp(linux.SizeOfXTEntryMatch+len(data), 8)
+ matcher := linux.KernelXTEntryMatch{
+ XTEntryMatch: linux.XTEntryMatch{
+ MatchSize: uint16(size),
+ },
+ Data: data,
+ }
+ copy(matcher.Name[:], name)
+
+ buf := make([]byte, 0, size)
+ buf = binary.Marshal(buf, usermem.ByteOrder, matcher)
+ return append(buf, make([]byte, size-len(buf))...)
+}
+
+func unmarshalMatcher(match linux.XTEntryMatch, filter iptables.IPHeaderFilter, buf []byte) (iptables.Matcher, error) {
+ matchMaker, ok := matchMakers[match.Name.String()]
+ if !ok {
+ return nil, fmt.Errorf("unsupported matcher with name %q", match.Name.String())
+ }
+ return matchMaker.unmarshal(buf, filter)
+}
+
+// alignUp rounds a length up to an alignment. align must be a power of 2.
+func alignUp(length int, align uint) int {
+ return (length + int(align) - 1) & ^(int(align) - 1)
+}
diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go
index 445d08d11..ea02627de 100644
--- a/pkg/sentry/socket/netfilter/netfilter.go
+++ b/pkg/sentry/socket/netfilter/netfilter.go
@@ -17,6 +17,7 @@
package netfilter
import (
+ "errors"
"fmt"
"gvisor.dev/gvisor/pkg/abi/linux"
@@ -34,10 +35,6 @@ import (
// shouldn't be reached - an error has occurred if we fall through to one.
const errorTargetName = "ERROR"
-const (
- matcherNameUDP = "udp"
-)
-
// Metadata is used to verify that we are correctly serializing and
// deserializing iptables into structs consumable by the iptables tool. We save
// a metadata struct when the tables are written, and when they are read out we
@@ -67,7 +64,8 @@ func GetInfo(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr) (linux.IPT
// Find the appropriate table.
table, err := findTable(stack, info.Name)
if err != nil {
- return linux.IPTGetinfo{}, err
+ nflog("%v", err)
+ return linux.IPTGetinfo{}, syserr.ErrInvalidArgument
}
// Get the hooks that apply to this table.
@@ -94,39 +92,40 @@ func GetEntries(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr, outLen
// Read in the struct and table name.
var userEntries linux.IPTGetEntries
if _, err := t.CopyIn(outPtr, &userEntries); err != nil {
- log.Warningf("netfilter: couldn't copy in entries %q", userEntries.Name)
+ nflog("couldn't copy in entries %q", userEntries.Name)
return linux.KernelIPTGetEntries{}, syserr.FromError(err)
}
// Find the appropriate table.
table, err := findTable(stack, userEntries.Name)
if err != nil {
- log.Warningf("netfilter: couldn't find table %q", userEntries.Name)
- return linux.KernelIPTGetEntries{}, err
+ nflog("%v", err)
+ return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument
}
// Convert netstack's iptables rules to something that the iptables
// tool can understand.
entries, meta, err := convertNetstackToBinary(userEntries.Name.String(), table)
if err != nil {
- return linux.KernelIPTGetEntries{}, err
+ nflog("couldn't read entries: %v", err)
+ return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument
}
if meta != table.Metadata().(metadata) {
panic(fmt.Sprintf("Table %q metadata changed between writing and reading. Was saved as %+v, but is now %+v", userEntries.Name.String(), table.Metadata().(metadata), meta))
}
if binary.Size(entries) > uintptr(outLen) {
- log.Warningf("Insufficient GetEntries output size: %d", uintptr(outLen))
+ nflog("insufficient GetEntries output size: %d", uintptr(outLen))
return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument
}
return entries, nil
}
-func findTable(stack *stack.Stack, tablename linux.TableName) (iptables.Table, *syserr.Error) {
+func findTable(stack *stack.Stack, tablename linux.TableName) (iptables.Table, error) {
ipt := stack.IPTables()
table, ok := ipt.Tables[tablename.String()]
if !ok {
- return iptables.Table{}, syserr.ErrInvalidArgument
+ return iptables.Table{}, fmt.Errorf("couldn't find table %q", tablename)
}
return table, nil
}
@@ -154,15 +153,14 @@ func FillDefaultIPTables(stack *stack.Stack) {
// format expected by the iptables tool. Linux stores each table as a binary
// blob that can only be traversed by parsing a bit, reading some offsets,
// jumping to those offsets, parsing again, etc.
-func convertNetstackToBinary(tablename string, table iptables.Table) (linux.KernelIPTGetEntries, metadata, *syserr.Error) {
+func convertNetstackToBinary(tablename string, table iptables.Table) (linux.KernelIPTGetEntries, metadata, error) {
// Return values.
var entries linux.KernelIPTGetEntries
var meta metadata
// The table name has to fit in the struct.
if linux.XT_TABLE_MAXNAMELEN < len(tablename) {
- log.Warningf("Table name %q too long.", tablename)
- return linux.KernelIPTGetEntries{}, metadata{}, syserr.ErrInvalidArgument
+ return linux.KernelIPTGetEntries{}, metadata{}, fmt.Errorf("table name %q too long.", tablename)
}
copy(entries.Name[:], tablename)
@@ -228,46 +226,6 @@ func convertNetstackToBinary(tablename string, table iptables.Table) (linux.Kern
return entries, meta, nil
}
-func marshalMatcher(matcher iptables.Matcher) []byte {
- switch m := matcher.(type) {
- case *iptables.UDPMatcher:
- return marshalUDPMatcher(m)
- default:
- // TODO(gvisor.dev/issue/170): Support other matchers.
- panic(fmt.Errorf("unknown matcher of type %T", matcher))
- }
-}
-
-func marshalUDPMatcher(matcher *iptables.UDPMatcher) []byte {
- nflog("convert to binary: marshalling UDP matcher: %+v", matcher)
-
- // We have to pad this struct size to a multiple of 8 bytes.
- size := alignUp(linux.SizeOfXTEntryMatch+linux.SizeOfXTUDP, 8)
-
- linuxMatcher := linux.KernelXTEntryMatch{
- XTEntryMatch: linux.XTEntryMatch{
- MatchSize: uint16(size),
- },
- Data: make([]byte, 0, linux.SizeOfXTUDP),
- }
- copy(linuxMatcher.Name[:], matcherNameUDP)
-
- xtudp := linux.XTUDP{
- SourcePortStart: matcher.Data.SourcePortStart,
- SourcePortEnd: matcher.Data.SourcePortEnd,
- DestinationPortStart: matcher.Data.DestinationPortStart,
- DestinationPortEnd: matcher.Data.DestinationPortEnd,
- InverseFlags: matcher.Data.InverseFlags,
- }
- linuxMatcher.Data = binary.Marshal(linuxMatcher.Data, usermem.ByteOrder, xtudp)
-
- buf := make([]byte, 0, size)
- buf = binary.Marshal(buf, usermem.ByteOrder, linuxMatcher)
- buf = append(buf, make([]byte, size-len(buf))...)
- nflog("convert to binary: marshalled UDP matcher into %v", buf)
- return buf[:]
-}
-
func marshalTarget(target iptables.Target) []byte {
switch target.(type) {
case iptables.UnconditionalAcceptTarget:
@@ -331,7 +289,7 @@ func translateFromStandardVerdict(verdict iptables.Verdict) int32 {
// translateToStandardVerdict translates from the value in a
// linux.XTStandardTarget to an iptables.Verdict.
-func translateToStandardVerdict(val int32) (iptables.Verdict, *syserr.Error) {
+func translateToStandardVerdict(val int32) (iptables.Verdict, error) {
// TODO(gvisor.dev/issue/170): Support other verdicts.
switch val {
case -linux.NF_ACCEPT - 1:
@@ -339,13 +297,12 @@ func translateToStandardVerdict(val int32) (iptables.Verdict, *syserr.Error) {
case -linux.NF_DROP - 1:
return iptables.Drop, nil
case -linux.NF_QUEUE - 1:
- log.Warningf("Unsupported iptables verdict QUEUE.")
+ return iptables.Invalid, errors.New("unsupported iptables verdict QUEUE")
case linux.NF_RETURN:
- log.Warningf("Unsupported iptables verdict RETURN.")
+ return iptables.Invalid, errors.New("unsupported iptables verdict RETURN")
default:
- log.Warningf("Unknown iptables verdict %d.", val)
+ return iptables.Invalid, fmt.Errorf("unknown iptables verdict %d", val)
}
- return iptables.Invalid, syserr.ErrInvalidArgument
}
// SetEntries sets iptables rules for a single table. See
@@ -353,7 +310,7 @@ func translateToStandardVerdict(val int32) (iptables.Verdict, *syserr.Error) {
func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
// Get the basic rules data (struct ipt_replace).
if len(optVal) < linux.SizeOfIPTReplace {
- log.Warningf("netfilter.SetEntries: optVal has insufficient size for replace %d", len(optVal))
+ nflog("optVal has insufficient size for replace %d", len(optVal))
return syserr.ErrInvalidArgument
}
var replace linux.IPTReplace
@@ -367,7 +324,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
case iptables.TablenameFilter:
table = iptables.EmptyFilterTable()
default:
- log.Warningf("We don't yet support writing to the %q table (gvisor.dev/issue/170)", replace.Name.String())
+ nflog("we don't yet support writing to the %q table (gvisor.dev/issue/170)", replace.Name.String())
return syserr.ErrInvalidArgument
}
@@ -381,7 +338,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
// Get the struct ipt_entry.
if len(optVal) < linux.SizeOfIPTEntry {
- log.Warningf("netfilter: optVal has insufficient size for entry %d", len(optVal))
+ nflog("optVal has insufficient size for entry %d", len(optVal))
return syserr.ErrInvalidArgument
}
var entry linux.IPTEntry
@@ -391,7 +348,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
optVal = optVal[linux.SizeOfIPTEntry:]
if entry.TargetOffset < linux.SizeOfIPTEntry {
- log.Warningf("netfilter: entry has too-small target offset %d", entry.TargetOffset)
+ nflog("entry has too-small target offset %d", entry.TargetOffset)
return syserr.ErrInvalidArgument
}
@@ -399,7 +356,8 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
// filtering fields.
filter, err := filterFromIPTIP(entry.IP)
if err != nil {
- return err
+ nflog("bad iptip: %v", err)
+ return syserr.ErrInvalidArgument
}
// TODO(gvisor.dev/issue/170): Matchers and targets can specify
@@ -407,25 +365,26 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
// Get matchers.
matchersSize := entry.TargetOffset - linux.SizeOfIPTEntry
if len(optVal) < int(matchersSize) {
- log.Warningf("netfilter: entry doesn't have enough room for its matchers (only %d bytes remain)", len(optVal))
+ nflog("entry doesn't have enough room for its matchers (only %d bytes remain)", len(optVal))
return syserr.ErrInvalidArgument
}
matchers, err := parseMatchers(filter, optVal[:matchersSize])
if err != nil {
- log.Warningf("netfilter: failed to parse matchers: %v", err)
- return err
+ nflog("failed to parse matchers: %v", err)
+ return syserr.ErrInvalidArgument
}
optVal = optVal[matchersSize:]
// Get the target of the rule.
targetSize := entry.NextOffset - entry.TargetOffset
if len(optVal) < int(targetSize) {
- log.Warningf("netfilter: entry doesn't have enough room for its target (only %d bytes remain)", len(optVal))
+ nflog("entry doesn't have enough room for its target (only %d bytes remain)", len(optVal))
return syserr.ErrInvalidArgument
}
target, err := parseTarget(optVal[:targetSize])
if err != nil {
- return err
+ nflog("failed to parse target: %v", err)
+ return syserr.ErrInvalidArgument
}
optVal = optVal[targetSize:]
@@ -438,7 +397,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
offset += uint32(entry.NextOffset)
if initialOptValLen-len(optVal) != int(entry.NextOffset) {
- log.Warningf("netfilter: entry NextOffset is %d, but entry took up %d bytes", entry.NextOffset, initialOptValLen-len(optVal))
+ nflog("entry NextOffset is %d, but entry took up %d bytes", entry.NextOffset, initialOptValLen-len(optVal))
}
}
@@ -456,11 +415,11 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
}
}
if ruleIdx := table.BuiltinChains[hk]; ruleIdx == iptables.HookUnset {
- log.Warningf("Hook %v is unset.", hk)
+ nflog("hook %v is unset.", hk)
return syserr.ErrInvalidArgument
}
if ruleIdx := table.Underflows[hk]; ruleIdx == iptables.HookUnset {
- log.Warningf("Underflow %v is unset.", hk)
+ nflog("underflow %v is unset.", hk)
return syserr.ErrInvalidArgument
}
}
@@ -472,7 +431,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
for hook, ruleIdx := range table.BuiltinChains {
if hook != iptables.Input {
if _, ok := table.Rules[ruleIdx].Target.(iptables.UnconditionalAcceptTarget); !ok {
- log.Warningf("Hook %d is unsupported.", hook)
+ nflog("hook %d is unsupported.", hook)
return syserr.ErrInvalidArgument
}
}
@@ -498,7 +457,7 @@ func SetEntries(stack *stack.Stack, optVal []byte) *syserr.Error {
// parseMatchers parses 0 or more matchers from optVal. optVal should contain
// only the matchers.
-func parseMatchers(filter iptables.IPHeaderFilter, optVal []byte) ([]iptables.Matcher, *syserr.Error) {
+func parseMatchers(filter iptables.IPHeaderFilter, optVal []byte) ([]iptables.Matcher, error) {
nflog("set entries: parsing matchers of size %d", len(optVal))
var matchers []iptables.Matcher
for len(optVal) > 0 {
@@ -506,8 +465,7 @@ func parseMatchers(filter iptables.IPHeaderFilter, optVal []byte) ([]iptables.Ma
// Get the XTEntryMatch.
if len(optVal) < linux.SizeOfXTEntryMatch {
- log.Warningf("netfilter: optVal has insufficient size for entry match: %d", len(optVal))
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("optVal has insufficient size for entry match: %d", len(optVal))
}
var match linux.XTEntryMatch
buf := optVal[:linux.SizeOfXTEntryMatch]
@@ -516,45 +474,18 @@ func parseMatchers(filter iptables.IPHeaderFilter, optVal []byte) ([]iptables.Ma
// Check some invariants.
if match.MatchSize < linux.SizeOfXTEntryMatch {
- log.Warningf("netfilter: match size is too small, must be at least %d", linux.SizeOfXTEntryMatch)
- return nil, syserr.ErrInvalidArgument
+
+ return nil, fmt.Errorf("match size is too small, must be at least %d", linux.SizeOfXTEntryMatch)
}
if len(optVal) < int(match.MatchSize) {
- log.Warningf("netfilter: optVal has insufficient size for match: %d", len(optVal))
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("optVal has insufficient size for match: %d", len(optVal))
}
- buf = optVal[linux.SizeOfXTEntryMatch:match.MatchSize]
- var matcher iptables.Matcher
- var err error
- switch match.Name.String() {
- case matcherNameUDP:
- if len(buf) < linux.SizeOfXTUDP {
- log.Warningf("netfilter: optVal has insufficient size for UDP match: %d", len(optVal))
- return nil, syserr.ErrInvalidArgument
- }
- // For alignment reasons, the match's total size may
- // exceed what's strictly necessary to hold matchData.
- var matchData linux.XTUDP
- binary.Unmarshal(buf[:linux.SizeOfXTUDP], usermem.ByteOrder, &matchData)
- log.Infof("parseMatchers: parsed XTUDP: %+v", matchData)
- matcher, err = iptables.NewUDPMatcher(filter, iptables.UDPMatcherParams{
- SourcePortStart: matchData.SourcePortStart,
- SourcePortEnd: matchData.SourcePortEnd,
- DestinationPortStart: matchData.DestinationPortStart,
- DestinationPortEnd: matchData.DestinationPortEnd,
- InverseFlags: matchData.InverseFlags,
- })
- if err != nil {
- log.Warningf("netfilter: failed to create UDP matcher: %v", err)
- return nil, syserr.ErrInvalidArgument
- }
-
- default:
- log.Warningf("netfilter: unsupported matcher with name %q", match.Name.String())
- return nil, syserr.ErrInvalidArgument
+ // Parse the specific matcher.
+ matcher, err := unmarshalMatcher(match, filter, optVal[linux.SizeOfXTEntryMatch:match.MatchSize])
+ if err != nil {
+ return nil, fmt.Errorf("failed to create matcher: %v", err)
}
-
matchers = append(matchers, matcher)
// TODO(gvisor.dev/issue/170): Check the revision field.
@@ -562,8 +493,7 @@ func parseMatchers(filter iptables.IPHeaderFilter, optVal []byte) ([]iptables.Ma
}
if len(optVal) != 0 {
- log.Warningf("netfilter: optVal should be exhausted after parsing matchers")
- return nil, syserr.ErrInvalidArgument
+ return nil, errors.New("optVal should be exhausted after parsing matchers")
}
return matchers, nil
@@ -571,11 +501,10 @@ func parseMatchers(filter iptables.IPHeaderFilter, optVal []byte) ([]iptables.Ma
// parseTarget parses a target from optVal. optVal should contain only the
// target.
-func parseTarget(optVal []byte) (iptables.Target, *syserr.Error) {
+func parseTarget(optVal []byte) (iptables.Target, error) {
nflog("set entries: parsing target of size %d", len(optVal))
if len(optVal) < linux.SizeOfXTEntryTarget {
- log.Warningf("netfilter: optVal has insufficient size for entry target %d", len(optVal))
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("optVal has insufficient size for entry target %d", len(optVal))
}
var target linux.XTEntryTarget
buf := optVal[:linux.SizeOfXTEntryTarget]
@@ -584,8 +513,7 @@ func parseTarget(optVal []byte) (iptables.Target, *syserr.Error) {
case "":
// Standard target.
if len(optVal) != linux.SizeOfXTStandardTarget {
- log.Warningf("netfilter.SetEntries: optVal has wrong size for standard target %d", len(optVal))
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("optVal has wrong size for standard target %d", len(optVal))
}
var standardTarget linux.XTStandardTarget
buf = optVal[:linux.SizeOfXTStandardTarget]
@@ -601,15 +529,13 @@ func parseTarget(optVal []byte) (iptables.Target, *syserr.Error) {
case iptables.Drop:
return iptables.UnconditionalDropTarget{}, nil
default:
- log.Warningf("Unknown verdict: %v", verdict)
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("Unknown verdict: %v", verdict)
}
case errorTargetName:
// Error target.
if len(optVal) != linux.SizeOfXTErrorTarget {
- log.Infof("netfilter.SetEntries: optVal has insufficient size for error target %d", len(optVal))
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("optVal has insufficient size for error target %d", len(optVal))
}
var errorTarget linux.XTErrorTarget
buf = optVal[:linux.SizeOfXTErrorTarget]
@@ -626,20 +552,17 @@ func parseTarget(optVal []byte) (iptables.Target, *syserr.Error) {
case errorTargetName:
return iptables.ErrorTarget{}, nil
default:
- log.Infof("Unknown error target %q doesn't exist or isn't supported yet.", errorTarget.Name.String())
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("unknown error target %q doesn't exist or isn't supported yet.", errorTarget.Name.String())
}
}
// Unknown target.
- log.Infof("Unknown target %q doesn't exist or isn't supported yet.", target.Name.String())
- return nil, syserr.ErrInvalidArgument
+ return nil, fmt.Errorf("unknown target %q doesn't exist or isn't supported yet.", target.Name.String())
}
-func filterFromIPTIP(iptip linux.IPTIP) (iptables.IPHeaderFilter, *syserr.Error) {
+func filterFromIPTIP(iptip linux.IPTIP) (iptables.IPHeaderFilter, error) {
if containsUnsupportedFields(iptip) {
- log.Warningf("netfilter: unsupported fields in struct iptip: %+v", iptip)
- return iptables.IPHeaderFilter{}, syserr.ErrInvalidArgument
+ return iptables.IPHeaderFilter{}, fmt.Errorf("unsupported fields in struct iptip: %+v", iptip)
}
return iptables.IPHeaderFilter{
Protocol: tcpip.TransportProtocolNumber(iptip.Protocol),
@@ -677,8 +600,3 @@ func hookFromLinux(hook int) iptables.Hook {
}
panic(fmt.Sprintf("Unknown hook %d does not correspond to a builtin chain", hook))
}
-
-// alignUp rounds a length up to an alignment. align must be a power of 2.
-func alignUp(length int, align uint) int {
- return (length + int(align) - 1) & ^(int(align) - 1)
-}
diff --git a/pkg/sentry/socket/netfilter/tcp_matcher.go b/pkg/sentry/socket/netfilter/tcp_matcher.go
new file mode 100644
index 000000000..f9945e214
--- /dev/null
+++ b/pkg/sentry/socket/netfilter/tcp_matcher.go
@@ -0,0 +1,143 @@
+// Copyright 2020 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 netfilter
+
+import (
+ "fmt"
+
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/binary"
+ "gvisor.dev/gvisor/pkg/tcpip"
+ "gvisor.dev/gvisor/pkg/tcpip/header"
+ "gvisor.dev/gvisor/pkg/tcpip/iptables"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+const matcherNameTCP = "tcp"
+
+func init() {
+ registerMatchMaker(tcpMarshaler{})
+}
+
+// tcpMarshaler implements matchMaker for TCP matching.
+type tcpMarshaler struct{}
+
+// name implements matchMaker.name.
+func (tcpMarshaler) name() string {
+ return matcherNameTCP
+}
+
+// marshal implements matchMaker.marshal.
+func (tcpMarshaler) marshal(mr iptables.Matcher) []byte {
+ matcher := mr.(*TCPMatcher)
+ xttcp := linux.XTTCP{
+ SourcePortStart: matcher.sourcePortStart,
+ SourcePortEnd: matcher.sourcePortEnd,
+ DestinationPortStart: matcher.destinationPortStart,
+ DestinationPortEnd: matcher.destinationPortEnd,
+ }
+ buf := make([]byte, 0, linux.SizeOfXTTCP)
+ return marshalEntryMatch(matcherNameTCP, binary.Marshal(buf, usermem.ByteOrder, xttcp))
+}
+
+// unmarshal implements matchMaker.unmarshal.
+func (tcpMarshaler) unmarshal(buf []byte, filter iptables.IPHeaderFilter) (iptables.Matcher, error) {
+ if len(buf) < linux.SizeOfXTTCP {
+ return nil, fmt.Errorf("buf has insufficient size for TCP match: %d", len(buf))
+ }
+
+ // For alignment reasons, the match's total size may
+ // exceed what's strictly necessary to hold matchData.
+ var matchData linux.XTTCP
+ binary.Unmarshal(buf[:linux.SizeOfXTTCP], usermem.ByteOrder, &matchData)
+ nflog("parseMatchers: parsed XTTCP: %+v", matchData)
+
+ if matchData.Option != 0 ||
+ matchData.FlagMask != 0 ||
+ matchData.FlagCompare != 0 ||
+ matchData.InverseFlags != 0 {
+ return nil, fmt.Errorf("unsupported TCP matcher flags set")
+ }
+
+ if filter.Protocol != header.TCPProtocolNumber {
+ return nil, fmt.Errorf("TCP matching is only valid for protocol %d.", header.TCPProtocolNumber)
+ }
+
+ return &TCPMatcher{
+ sourcePortStart: matchData.SourcePortStart,
+ sourcePortEnd: matchData.SourcePortEnd,
+ destinationPortStart: matchData.DestinationPortStart,
+ destinationPortEnd: matchData.DestinationPortEnd,
+ }, nil
+}
+
+// TCPMatcher matches TCP packets and their headers. It implements Matcher.
+type TCPMatcher struct {
+ sourcePortStart uint16
+ sourcePortEnd uint16
+ destinationPortStart uint16
+ destinationPortEnd uint16
+}
+
+// Name implements Matcher.Name.
+func (*TCPMatcher) Name() string {
+ return matcherNameTCP
+}
+
+// Match implements Matcher.Match.
+func (tm *TCPMatcher) Match(hook iptables.Hook, pkt tcpip.PacketBuffer, interfaceName string) (bool, bool) {
+ netHeader := header.IPv4(pkt.NetworkHeader)
+
+ if netHeader.TransportProtocol() != header.TCPProtocolNumber {
+ return false, false
+ }
+
+ // We dont't match fragments.
+ if frag := netHeader.FragmentOffset(); frag != 0 {
+ if frag == 1 {
+ return false, true
+ }
+ return false, false
+ }
+
+ // Now we need the transport header. However, this may not have been set
+ // yet.
+ // TODO(gvisor.dev/issue/170): Parsing the transport header should
+ // ultimately be moved into the iptables.Check codepath as matchers are
+ // added.
+ var tcpHeader header.TCP
+ if pkt.TransportHeader != nil {
+ tcpHeader = header.TCP(pkt.TransportHeader)
+ } else {
+ // The TCP header hasn't been parsed yet. We have to do it here.
+ if len(pkt.Data.First()) < header.TCPMinimumSize {
+ // There's no valid TCP header here, so we hotdrop the
+ // packet.
+ return false, true
+ }
+ tcpHeader = header.TCP(pkt.Data.First())
+ }
+
+ // Check whether the source and destination ports are within the
+ // matching range.
+ if sourcePort := tcpHeader.SourcePort(); sourcePort < tm.sourcePortStart || tm.sourcePortEnd < sourcePort {
+ return false, false
+ }
+ if destinationPort := tcpHeader.DestinationPort(); destinationPort < tm.destinationPortStart || tm.destinationPortEnd < destinationPort {
+ return false, false
+ }
+
+ return true, false
+}
diff --git a/pkg/tcpip/iptables/udp_matcher.go b/pkg/sentry/socket/netfilter/udp_matcher.go
index 496931d7a..86aa11696 100644
--- a/pkg/tcpip/iptables/udp_matcher.go
+++ b/pkg/sentry/socket/netfilter/udp_matcher.go
@@ -12,56 +12,89 @@
// See the License for the specific language governing permissions and
// limitations under the License.
-package iptables
+package netfilter
import (
"fmt"
- "gvisor.dev/gvisor/pkg/log"
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/binary"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
+ "gvisor.dev/gvisor/pkg/tcpip/iptables"
+ "gvisor.dev/gvisor/pkg/usermem"
)
-// TODO(gvisor.dev/issue/170): The following per-matcher params should be
-// supported:
-// - Table name
-// - Match size
-// - User size
-// - Hooks
-// - Proto
-// - Family
+const matcherNameUDP = "udp"
-// UDPMatcher matches UDP packets and their headers. It implements Matcher.
-type UDPMatcher struct {
- Data UDPMatcherParams
+func init() {
+ registerMatchMaker(udpMarshaler{})
}
-// UDPMatcherParams are the parameters used to create a UDPMatcher.
-type UDPMatcherParams struct {
- SourcePortStart uint16
- SourcePortEnd uint16
- DestinationPortStart uint16
- DestinationPortEnd uint16
- InverseFlags uint8
+// udpMarshaler implements matchMaker for UDP matching.
+type udpMarshaler struct{}
+
+// name implements matchMaker.name.
+func (udpMarshaler) name() string {
+ return matcherNameUDP
}
-// NewUDPMatcher returns a new instance of UDPMatcher.
-func NewUDPMatcher(filter IPHeaderFilter, data UDPMatcherParams) (Matcher, error) {
- log.Infof("Adding rule with UDPMatcherParams: %+v", data)
+// marshal implements matchMaker.marshal.
+func (udpMarshaler) marshal(mr iptables.Matcher) []byte {
+ matcher := mr.(*UDPMatcher)
+ xtudp := linux.XTUDP{
+ SourcePortStart: matcher.sourcePortStart,
+ SourcePortEnd: matcher.sourcePortEnd,
+ DestinationPortStart: matcher.destinationPortStart,
+ DestinationPortEnd: matcher.destinationPortEnd,
+ }
+ buf := make([]byte, 0, linux.SizeOfXTUDP)
+ return marshalEntryMatch(matcherNameUDP, binary.Marshal(buf, usermem.ByteOrder, xtudp))
+}
+
+// unmarshal implements matchMaker.unmarshal.
+func (udpMarshaler) unmarshal(buf []byte, filter iptables.IPHeaderFilter) (iptables.Matcher, error) {
+ if len(buf) < linux.SizeOfXTUDP {
+ return nil, fmt.Errorf("buf has insufficient size for UDP match: %d", len(buf))
+ }
+
+ // For alignment reasons, the match's total size may exceed what's
+ // strictly necessary to hold matchData.
+ var matchData linux.XTUDP
+ binary.Unmarshal(buf[:linux.SizeOfXTUDP], usermem.ByteOrder, &matchData)
+ nflog("parseMatchers: parsed XTUDP: %+v", matchData)
- if data.InverseFlags != 0 {
+ if matchData.InverseFlags != 0 {
return nil, fmt.Errorf("unsupported UDP matcher inverse flags set")
}
if filter.Protocol != header.UDPProtocolNumber {
- return nil, fmt.Errorf("UDP matching is only valid for protocol %d", header.UDPProtocolNumber)
+ return nil, fmt.Errorf("UDP matching is only valid for protocol %d.", header.UDPProtocolNumber)
}
- return &UDPMatcher{Data: data}, nil
+ return &UDPMatcher{
+ sourcePortStart: matchData.SourcePortStart,
+ sourcePortEnd: matchData.SourcePortEnd,
+ destinationPortStart: matchData.DestinationPortStart,
+ destinationPortEnd: matchData.DestinationPortEnd,
+ }, nil
+}
+
+// UDPMatcher matches UDP packets and their headers. It implements Matcher.
+type UDPMatcher struct {
+ sourcePortStart uint16
+ sourcePortEnd uint16
+ destinationPortStart uint16
+ destinationPortEnd uint16
+}
+
+// Name implements Matcher.Name.
+func (*UDPMatcher) Name() string {
+ return matcherNameUDP
}
// Match implements Matcher.Match.
-func (um *UDPMatcher) Match(hook Hook, pkt tcpip.PacketBuffer, interfaceName string) (bool, bool) {
+func (um *UDPMatcher) Match(hook iptables.Hook, pkt tcpip.PacketBuffer, interfaceName string) (bool, bool) {
netHeader := header.IPv4(pkt.NetworkHeader)
// TODO(gvisor.dev/issue/170): Proto checks should ultimately be moved
@@ -98,10 +131,10 @@ func (um *UDPMatcher) Match(hook Hook, pkt tcpip.PacketBuffer, interfaceName str
// Check whether the source and destination ports are within the
// matching range.
- if sourcePort := udpHeader.SourcePort(); sourcePort < um.Data.SourcePortStart || um.Data.SourcePortEnd < sourcePort {
+ if sourcePort := udpHeader.SourcePort(); sourcePort < um.sourcePortStart || um.sourcePortEnd < sourcePort {
return false, false
}
- if destinationPort := udpHeader.DestinationPort(); destinationPort < um.Data.DestinationPortStart || um.Data.DestinationPortEnd < destinationPort {
+ if destinationPort := udpHeader.DestinationPort(); destinationPort < um.destinationPortStart || um.destinationPortEnd < destinationPort {
return false, false
}
diff --git a/pkg/tcpip/iptables/BUILD b/pkg/tcpip/iptables/BUILD
index bab26580b..d1b73cfdf 100644
--- a/pkg/tcpip/iptables/BUILD
+++ b/pkg/tcpip/iptables/BUILD
@@ -8,7 +8,6 @@ go_library(
"iptables.go",
"targets.go",
"types.go",
- "udp_matcher.go",
],
visibility = ["//visibility:public"],
deps = [
diff --git a/pkg/tcpip/iptables/types.go b/pkg/tcpip/iptables/types.go
index 2ea8994ae..7d593c35c 100644
--- a/pkg/tcpip/iptables/types.go
+++ b/pkg/tcpip/iptables/types.go
@@ -171,6 +171,9 @@ type IPHeaderFilter struct {
// 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.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 16:38:30 +0000