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

   1 package org.asamk.signal.manager.groups;
   2
   3 import com.google.protobuf.ByteString;
   4
   5 import org.signal.storageservice.protos.groups.GroupInviteLink;
   6 import org.signal.storageservice.protos.groups.local.DecryptedGroup;
   7 import org.signal.zkgroup.InvalidInputException;
   8 import org.signal.zkgroup.groups.GroupMasterKey;
   9 import org.whispersystems.util.Base64UrlSafe;
  10
  11 import java.io.IOException;
  12 import java.net.URI;
  13 import java.net.URISyntaxException;
  14
  15 public final class GroupInviteLinkUrl {
  16
  17     private static final String GROUP_URL_HOST = "signal.group";
  18     private static final String GROUP_URL_PREFIX = "https://" + GROUP_URL_HOST + "/#";
  19
  20     private final GroupMasterKey groupMasterKey;
  21     private final GroupLinkPassword password;
  22     private final String url;
  23
  24     public static GroupInviteLinkUrl forGroup(GroupMasterKey groupMasterKey, DecryptedGroup group) {
  25         return new GroupInviteLinkUrl(groupMasterKey,
  26                 GroupLinkPassword.fromBytes(group.getInviteLinkPassword().toByteArray()));
  27     }
  28
  29     /**
  30      * @return null iff not a group url.
  31      * @throws InvalidGroupLinkException If group url, but cannot be parsed.
  32      */
  33     public static GroupInviteLinkUrl fromUri(String urlString) throws InvalidGroupLinkException, UnknownGroupLinkVersionException {
  34         var uri = getGroupUrl(urlString);
  35
  36         if (uri == null) {
  37             return null;
  38         }
  39
  40         try {
  41             if (!"/".equals(uri.getPath()) && uri.getPath().length() > 0) {
  42                 throw new InvalidGroupLinkException("No path was expected in uri");
  43             }
  44
  45             var encoding = uri.getFragment();
  46
  47             if (encoding == null || encoding.length() == 0) {
  48                 throw new InvalidGroupLinkException("No reference was in the uri");
  49             }
  50
  51             var bytes = Base64UrlSafe.decodePaddingAgnostic(encoding);
  52             var groupInviteLink = GroupInviteLink.parseFrom(bytes);
  53
  54             switch (groupInviteLink.getContentsCase()) {
  55                 case V1CONTENTS -> {
  56                     var groupInviteLinkContentsV1 = groupInviteLink.getV1Contents();
  57                     var groupMasterKey = new GroupMasterKey(groupInviteLinkContentsV1.getGroupMasterKey()
  58                             .toByteArray());
  59                     var password = GroupLinkPassword.fromBytes(groupInviteLinkContentsV1.getInviteLinkPassword()
  60                             .toByteArray());
  61
  62                     return new GroupInviteLinkUrl(groupMasterKey, password);
  63                 }
  64                 default -> throw new UnknownGroupLinkVersionException("Url contains no known group link content");
  65             }
  66         } catch (InvalidInputException | IOException e) {
  67             throw new InvalidGroupLinkException(e);
  68         }
  69     }
  70
  71     /**
  72      * @return {@link URI} if the host name matches.
  73      */
  74     private static URI getGroupUrl(String urlString) {
  75         try {
  76             var url = new URI(urlString);
  77
  78             if (!"https".equalsIgnoreCase(url.getScheme()) && !"sgnl".equalsIgnoreCase(url.getScheme())) {
  79                 return null;
  80             }
  81
  82             return GROUP_URL_HOST.equalsIgnoreCase(url.getHost()) ? url : null;
  83         } catch (URISyntaxException e) {
  84             return null;
  85         }
  86     }
  87
  88     private GroupInviteLinkUrl(GroupMasterKey groupMasterKey, GroupLinkPassword password) {
  89         this.groupMasterKey = groupMasterKey;
  90         this.password = password;
  91         this.url = createUrl(groupMasterKey, password);
  92     }
  93
  94     private static String createUrl(GroupMasterKey groupMasterKey, GroupLinkPassword password) {
  95         var groupInviteLink = GroupInviteLink.newBuilder()
  96                 .setV1Contents(GroupInviteLink.GroupInviteLinkContentsV1.newBuilder()
  97                         .setGroupMasterKey(ByteString.copyFrom(groupMasterKey.serialize()))
  98                         .setInviteLinkPassword(ByteString.copyFrom(password.serialize())))
  99                 .build();
 100
 101         var encoding = Base64UrlSafe.encodeBytesWithoutPadding(groupInviteLink.toByteArray());
 102
 103         return GROUP_URL_PREFIX + encoding;
 104     }
 105
 106     public String getUrl() {
 107         return url;
 108     }
 109
 110     public GroupMasterKey getGroupMasterKey() {
 111         return groupMasterKey;
 112     }
 113
 114     public GroupLinkPassword getPassword() {
 115         return password;
 116     }
 117
 118     public final static class InvalidGroupLinkException extends Exception {
 119
 120         public InvalidGroupLinkException(String message) {
 121             super(message);
 122         }
 123
 124         public InvalidGroupLinkException(Throwable cause) {
 125             super(cause);
 126         }
 127     }
 128
 129     public final static class UnknownGroupLinkVersionException extends Exception {
 130
 131         public UnknownGroupLinkVersionException(String message) {
 132             super(message);
 133         }
 134     }
 135 }