nmode's Git Repositories - signal-cli/blob - lib/src/main/java/org/asamk/signal/manager/api/GroupInviteLinkUrl.java

   1 package org.asamk.signal.manager.api;
   2
   3 import org.asamk.signal.manager.groups.GroupLinkPassword;
   4 import org.signal.libsignal.zkgroup.InvalidInputException;
   5 import org.signal.libsignal.zkgroup.groups.GroupMasterKey;
   6 import org.signal.storageservice.protos.groups.GroupInviteLink;
   7 import org.signal.storageservice.protos.groups.local.DecryptedGroup;
   8 import org.whispersystems.util.Base64UrlSafe;
   9
  10 import java.io.IOException;
  11 import java.net.URI;
  12 import java.net.URISyntaxException;
  13
  14 import okio.ByteString;
  15
  16 public final class GroupInviteLinkUrl {
  17
  18     private static final String GROUP_URL_HOST = "signal.group";
  19     private static final String GROUP_URL_PREFIX = "https://" + GROUP_URL_HOST + "/#";
  20
  21     private final GroupMasterKey groupMasterKey;
  22     private final GroupLinkPassword password;
  23     private final String url;
  24
  25     public static GroupInviteLinkUrl forGroup(GroupMasterKey groupMasterKey, DecryptedGroup group) {
  26         return new GroupInviteLinkUrl(groupMasterKey,
  27                 GroupLinkPassword.fromBytes(group.inviteLinkPassword.toByteArray()));
  28     }
  29
  30     /**
  31      * @return null iff not a group url.
  32      * @throws InvalidGroupLinkException If group url, but cannot be parsed.
  33      */
  34     public static GroupInviteLinkUrl fromUri(String urlString) throws InvalidGroupLinkException, UnknownGroupLinkVersionException {
  35         var uri = getGroupUrl(urlString);
  36
  37         if (uri == null) {
  38             return null;
  39         }
  40
  41         try {
  42             if (!"/".equals(uri.getPath()) && !uri.getPath().isEmpty()) {
  43                 throw new InvalidGroupLinkException("No path was expected in uri");
  44             }
  45
  46             var encoding = uri.getFragment();
  47
  48             if (encoding == null || encoding.isEmpty()) {
  49                 throw new InvalidGroupLinkException("No reference was in the uri");
  50             }
  51
  52             var bytes = Base64UrlSafe.decodePaddingAgnostic(encoding);
  53             GroupInviteLink groupInviteLink = GroupInviteLink.ADAPTER.decode(bytes);
  54
  55             if (groupInviteLink.v1Contents != null) {
  56                 var groupInviteLinkContentsV1 = groupInviteLink.v1Contents;
  57                 var groupMasterKey = new GroupMasterKey(groupInviteLinkContentsV1.groupMasterKey.toByteArray());
  58                 var password = GroupLinkPassword.fromBytes(groupInviteLinkContentsV1.inviteLinkPassword.toByteArray());
  59
  60                 return new GroupInviteLinkUrl(groupMasterKey, password);
  61             } else {
  62                 throw new UnknownGroupLinkVersionException("Url contains no known group link content");
  63             }
  64         } catch (InvalidInputException | IOException e) {
  65             throw new InvalidGroupLinkException(e);
  66         }
  67     }
  68
  69     /**
  70      * @return {@link URI} if the host name matches.
  71      */
  72     private static URI getGroupUrl(String urlString) {
  73         try {
  74             var url = new URI(urlString);
  75
  76             if (!"https".equalsIgnoreCase(url.getScheme()) && !"sgnl".equalsIgnoreCase(url.getScheme())) {
  77                 return null;
  78             }
  79
  80             return GROUP_URL_HOST.equalsIgnoreCase(url.getHost()) ? url : null;
  81         } catch (URISyntaxException e) {
  82             return null;
  83         }
  84     }
  85
  86     private GroupInviteLinkUrl(GroupMasterKey groupMasterKey, GroupLinkPassword password) {
  87         this.groupMasterKey = groupMasterKey;
  88         this.password = password;
  89         this.url = createUrl(groupMasterKey, password);
  90     }
  91
  92     private static String createUrl(GroupMasterKey groupMasterKey, GroupLinkPassword password) {
  93         var groupInviteLink = new GroupInviteLink.Builder().v1Contents(new GroupInviteLink.GroupInviteLinkContentsV1.Builder().groupMasterKey(
  94                         ByteString.of(groupMasterKey.serialize()))
  95                 .inviteLinkPassword(ByteString.of(password.serialize()))
  96                 .build()).build();
  97
  98         var encoding = Base64UrlSafe.encodeBytesWithoutPadding(groupInviteLink.encode());
  99
 100         return GROUP_URL_PREFIX + encoding;
 101     }
 102
 103     public String getUrl() {
 104         return url;
 105     }
 106
 107     public GroupMasterKey getGroupMasterKey() {
 108         return groupMasterKey;
 109     }
 110
 111     public GroupLinkPassword getPassword() {
 112         return password;
 113     }
 114
 115     public final static class InvalidGroupLinkException extends Exception {
 116
 117         public InvalidGroupLinkException(String message) {
 118             super(message);
 119         }
 120
 121         public InvalidGroupLinkException(Throwable cause) {
 122             super(cause);
 123         }
 124     }
 125
 126     public final static class UnknownGroupLinkVersionException extends Exception {
 127
 128         public UnknownGroupLinkVersionException(String message) {
 129             super(message);
 130         }
 131     }
 132 }