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     public static boolean isGroupLink(String urlString) {
  30         return getGroupUrl(urlString) != null;
  31     }
  32
  33     /**
  34      * @return null iff not a group url.
  35      * @throws InvalidGroupLinkException If group url, but cannot be parsed.
  36      */
  37     public static GroupInviteLinkUrl fromUri(String urlString) throws InvalidGroupLinkException, UnknownGroupLinkVersionException {
  38         var uri = getGroupUrl(urlString);
  39
  40         if (uri == null) {
  41             return null;
  42         }
  43
  44         try {
  45             if (!"/".equals(uri.getPath()) && uri.getPath().length() > 0) {
  46                 throw new InvalidGroupLinkException("No path was expected in uri");
  47             }
  48
  49             var encoding = uri.getFragment();
  50
  51             if (encoding == null || encoding.length() == 0) {
  52                 throw new InvalidGroupLinkException("No reference was in the uri");
  53             }
  54
  55             var bytes = Base64UrlSafe.decodePaddingAgnostic(encoding);
  56             var groupInviteLink = GroupInviteLink.parseFrom(bytes);
  57
  58             switch (groupInviteLink.getContentsCase()) {
  59                 case V1CONTENTS -> {
  60                     var groupInviteLinkContentsV1 = groupInviteLink.getV1Contents();
  61                     var groupMasterKey = new GroupMasterKey(groupInviteLinkContentsV1.getGroupMasterKey()
  62                             .toByteArray());
  63                     var password = GroupLinkPassword.fromBytes(groupInviteLinkContentsV1.getInviteLinkPassword()
  64                             .toByteArray());
  65
  66                     return new GroupInviteLinkUrl(groupMasterKey, password);
  67                 }
  68                 default -> throw new UnknownGroupLinkVersionException("Url contains no known group link content");
  69             }
  70         } catch (InvalidInputException | IOException e) {
  71             throw new InvalidGroupLinkException(e);
  72         }
  73     }
  74
  75     /**
  76      * @return {@link URI} if the host name matches.
  77      */
  78     private static URI getGroupUrl(String urlString) {
  79         try {
  80             var url = new URI(urlString);
  81
  82             if (!"https".equalsIgnoreCase(url.getScheme()) && !"sgnl".equalsIgnoreCase(url.getScheme())) {
  83                 return null;
  84             }
  85
  86             return GROUP_URL_HOST.equalsIgnoreCase(url.getHost()) ? url : null;
  87         } catch (URISyntaxException e) {
  88             return null;
  89         }
  90     }
  91
  92     private GroupInviteLinkUrl(GroupMasterKey groupMasterKey, GroupLinkPassword password) {
  93         this.groupMasterKey = groupMasterKey;
  94         this.password = password;
  95         this.url = createUrl(groupMasterKey, password);
  96     }
  97
  98     protected static String createUrl(GroupMasterKey groupMasterKey, GroupLinkPassword password) {
  99         var groupInviteLink = GroupInviteLink.newBuilder()
 100                 .setV1Contents(GroupInviteLink.GroupInviteLinkContentsV1.newBuilder()
 101                         .setGroupMasterKey(ByteString.copyFrom(groupMasterKey.serialize()))
 102                         .setInviteLinkPassword(ByteString.copyFrom(password.serialize())))
 103                 .build();
 104
 105         var encoding = Base64UrlSafe.encodeBytesWithoutPadding(groupInviteLink.toByteArray());
 106
 107         return GROUP_URL_PREFIX + encoding;
 108     }
 109
 110     public String getUrl() {
 111         return url;
 112     }
 113
 114     public GroupMasterKey getGroupMasterKey() {
 115         return groupMasterKey;
 116     }
 117
 118     public GroupLinkPassword getPassword() {
 119         return password;
 120     }
 121
 122     public final static class InvalidGroupLinkException extends Exception {
 123
 124         public InvalidGroupLinkException(String message) {
 125             super(message);
 126         }
 127
 128         public InvalidGroupLinkException(Throwable cause) {
 129             super(cause);
 130         }
 131     }
 132
 133     public final static class UnknownGroupLinkVersionException extends Exception {
 134
 135         public UnknownGroupLinkVersionException(String message) {
 136             super(message);
 137         }
 138     }
 139 }