-
Notifications
You must be signed in to change notification settings - Fork 1.3k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
netfilter: Support multiport matching (-m multiport)
This set of changes adds:
- support for `xt_multiport_{,v1}` matchers for matching for
a range of ports and their inverse, i.e.,:
```
-m multiport [!] --[s|d]ports (PORT,...|PORT:PORT,...)
```
- support for `IP{,6}T_SO_GET_REVISION_MATCH` socket options,
which allows `iptables` to query for the highest supported
revision for a given matcher- Loading branch information
1 parent
0f8db9f
commit adbd45a
Showing
11 changed files
with
1,137 additions
and
4 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,242 @@ | ||
| // Copyright 2024 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/marshal" | ||
| "gvisor.dev/gvisor/pkg/tcpip" | ||
| "gvisor.dev/gvisor/pkg/tcpip/header" | ||
| "gvisor.dev/gvisor/pkg/tcpip/stack" | ||
| ) | ||
|
|
||
| const ( | ||
| matcherNameMultiport string = "multiport" | ||
| matcherRevMultiport uint8 = 0 | ||
| matcherPfxMultiport string = (matcherNameMultiport + ".0") | ||
| ) | ||
|
|
||
| // multiportMarshaler handles marshalling and | ||
| // unmarshalling of "xt_multiport" matchers. | ||
| type multiportMarshaler struct{} | ||
|
|
||
| // multiportMatcher represents a multiport matcher | ||
| // with source and/or destination ports. | ||
| type multiportMatcher struct { | ||
| flags uint8 // Port match flag (source/destination/either). | ||
| count uint8 // Number of ports. | ||
| ports []uint16 // List of ports to match against. | ||
| } | ||
|
|
||
| // init registers the "multiportMarshaler" with the matcher registry. | ||
| func init() { | ||
| registerMatchMaker(multiportMarshaler{}) | ||
| } | ||
|
|
||
| // name returns the name of the marshaler. | ||
| func (multiportMarshaler) name() string { | ||
| return matcherNameMultiport | ||
| } | ||
|
|
||
| // revision returns the revision number of the marshaler. | ||
| func (multiportMarshaler) revision() uint8 { | ||
| return matcherRevMultiport | ||
| } | ||
|
|
||
| // marshal converts a matcher into its binary representation. | ||
| func (multiportMarshaler) marshal(mr matcher) []byte { | ||
| m := mr.(*multiportMatcher) | ||
| var xtmp linux.XTMultiport | ||
|
|
||
| nflog("%s: marshal: XTMultiport: %+v", matcherPfxMultiport, m) | ||
|
|
||
| // Set the match criteria flag. | ||
| xtmp.Flags = m.flags | ||
|
|
||
| // Set the count of ports and populate the "Ports" slice. | ||
| xtmp.Count = uint8(len(m.ports)) | ||
|
|
||
| // Truncate the "ports" slice to the maximum allowed | ||
| // by "XT_MULTI_PORTS" to prevent out-of-bounds writes. | ||
| if xtmp.Count > linux.XT_MULTI_PORTS { | ||
| xtmp.Count = linux.XT_MULTI_PORTS | ||
| } | ||
|
|
||
| // Copy over the ports. | ||
| for i := uint8(0); i < xtmp.Count; i++ { | ||
| xtmp.Ports[i] = m.ports[i] | ||
| } | ||
|
|
||
| // Marshal the XTMultiport structure into binary format. | ||
| return marshalEntryMatch(matcherNameMultiport, marshal.Marshal(&xtmp)) | ||
| } | ||
|
|
||
| // unmarshal converts binary data into a multiportMatcher instance. | ||
| func (multiportMarshaler) unmarshal(_ IDMapper, buf []byte, filter stack.IPHeaderFilter) (stack.Matcher, error) { | ||
| var matchData linux.XTMultiport | ||
|
|
||
| nflog("%s: raw: XTMultiport: %+v", matcherPfxMultiport, buf) | ||
|
|
||
| // Check if the buffer has enough data for XTMultiport. | ||
| if len(buf) < linux.SizeOfXTMultiport { | ||
| return nil, fmt.Errorf( | ||
| "%s: insufficient data, got %d, want: >= %d", | ||
| matcherPfxMultiport, | ||
| len(buf), | ||
| linux.SizeOfXTMultiport, | ||
| ) | ||
| } | ||
|
|
||
| // Unmarshal the buffer into the XTMultiport structure. | ||
| matchData.UnmarshalUnsafe(buf) | ||
| nflog("%s: parsed XTMultiport: %+v", matcherPfxMultiport, matchData) | ||
|
|
||
| // Validate the port count. | ||
| if matchData.Count == 0 || matchData.Count > linux.XT_MULTI_PORTS { | ||
| return nil, fmt.Errorf( | ||
| "%s: invalid port count, got %d, want: [1, %d]", | ||
| matcherPfxMultiport, matchData.Count, linux.XT_MULTI_PORTS, | ||
| ) | ||
| } | ||
|
|
||
| // Extract the list of ports from the match data. | ||
| ports := make([]uint16, matchData.Count) | ||
| for i := 0; i < int(matchData.Count); i++ { | ||
| ports[i] = matchData.Ports[i] | ||
| } | ||
|
|
||
| // Initialize "multiportMatcher" with the extracted ports. | ||
| matcher := &multiportMatcher{ | ||
| flags: matchData.Flags, | ||
| count: matchData.Count, | ||
| ports: ports, | ||
| } | ||
|
|
||
| return matcher, nil | ||
| } | ||
|
|
||
| // name returns the name of the matcher. | ||
| func (multiportMatcher) name() string { | ||
| return matcherNameMultiport | ||
| } | ||
|
|
||
| // revision returns the revision number of the matcher. | ||
| func (multiportMatcher) revision() uint8 { | ||
| return matcherRevMultiport | ||
| } | ||
|
|
||
| // Match determines if the packet matches any of the specified ports | ||
| // and returns true if a match is found. The second boolean returned | ||
| // indicates whether the packet should be "hot" dropped, or processed | ||
| // with other matchers. | ||
| func (m *multiportMatcher) Match(hook stack.Hook, pkt *stack.PacketBuffer, _, _ string) (bool, bool) { | ||
| // Extract source and destination ports from the packet. | ||
| srcPort, dstPort, ok := extractPorts(pkt) | ||
| // The packet does not contain valid transport | ||
| // headers or uses an unsupported protocol. | ||
| if !ok { | ||
| return false, true | ||
| } | ||
|
|
||
| // Iterate through the list of ports to check for a match based on | ||
| // the specified match criteria: source, destination or either. | ||
| for i := uint8(0); i < m.count; i++ { | ||
| if exactPortMatch(m.flags, srcPort, dstPort, m.ports[i]) { | ||
| return true, false | ||
| } | ||
| } | ||
|
|
||
| // No match. | ||
| return false, false | ||
| } | ||
|
|
||
| // extractTransportHeaderPorts is a helper routine that extracts | ||
| // the source and destination ports from the provided transport | ||
| // header based on the specified transport protocol. It supports | ||
| // TCP and UDP protocols and returns the source port, destination | ||
| // port, and a boolean indicating whether the extraction was | ||
| // successful. If the protocol is unsupported or the transport | ||
| // header is too short, it returns (0, 0, false). | ||
| func extractTransportHeaderPorts(hdr []byte, prot tcpip.TransportProtocolNumber) (uint16, uint16, bool) { | ||
| switch prot { | ||
| case header.TCPProtocolNumber: | ||
| // Ensure the TCP header has the minimum required length. | ||
| if len(hdr) < header.TCPMinimumSize { | ||
| return 0, 0, false | ||
| } | ||
| // Extract and return the source and destination ports. | ||
| tcpHdr := header.TCP(hdr) | ||
| return tcpHdr.SourcePort(), tcpHdr.DestinationPort(), true | ||
|
|
||
| case header.UDPProtocolNumber: | ||
| // Similar to TCP. | ||
| if len(hdr) < header.UDPMinimumSize { | ||
| return 0, 0, false | ||
| } | ||
| udpHdr := header.UDP(hdr) | ||
| return udpHdr.SourcePort(), udpHdr.DestinationPort(), true | ||
|
|
||
| default: | ||
| // Unsupported transport protocol; cannot extract ports. | ||
| return 0, 0, false | ||
| } | ||
| } | ||
|
|
||
| // extractPorts extracts the source and destination ports from the given | ||
| // packet buffer. It supports both IPv4 and IPv6 packets and handles TCP | ||
| // and UDP transport protocols. It returns the source port, destination | ||
| // port, and a boolean indicating success. If the packet does not contain | ||
| // enough data or uses an unsupported protocol, it returns (0, 0, false). | ||
| func extractPorts(pkt *stack.PacketBuffer) (uint16, uint16, bool) { | ||
| // Retrieve the transport header (TCP/UDP) from the packet buffer. | ||
| transportHdr := pkt.TransportHeader().Slice() | ||
|
|
||
| // Determine the network protocol. | ||
| switch pkt.NetworkProtocolNumber { | ||
| case header.IPv4ProtocolNumber: | ||
| // Extract the IPv4 header from the network header | ||
| // slice, then the transport protocol from it. | ||
| ipv4 := header.IPv4(pkt.NetworkHeader().Slice()) | ||
| prot := ipv4.TransportProtocol() | ||
| return extractTransportHeaderPorts(transportHdr, prot) | ||
|
|
||
| case header.IPv6ProtocolNumber: | ||
| // Similar to IPv4. | ||
| ipv6 := header.IPv6(pkt.NetworkHeader().Slice()) | ||
| prot := ipv6.TransportProtocol() | ||
| return extractTransportHeaderPorts(transportHdr, prot) | ||
|
|
||
| default: | ||
| // Unsupported network protocol; cannot extract ports. | ||
| return 0, 0, false | ||
| } | ||
| } | ||
|
|
||
| // exactPortMatch return true if "srcPort" or "dstPort" are the | ||
| // same as "matchPort" depending on the matching criteria specified | ||
| // in "flags". | ||
| func exactPortMatch(flags uint8, srcPort, dstPort, matchPort uint16) bool { | ||
| switch flags { | ||
| case linux.XT_MULTIPORT_SOURCE: | ||
| return srcPort == matchPort | ||
| case linux.XT_MULTIPORT_DESTINATION: | ||
| return dstPort == matchPort | ||
| case linux.XT_MULTIPORT_EITHER: | ||
| return (srcPort == matchPort) || (dstPort == matchPort) | ||
| } | ||
| return false | ||
| } |
Oops, something went wrong.