issue #1057 Parsing/decrypting of complex PGP messages in Kotlin

FlowCrypt/build.gradle

@@ -456,6 +456,8 @@ dependencies {
     implementation 'net.openid:appauth:0.9.1'
     implementation 'org.bitbucket.b_c:jose4j:0.7.8'
     implementation 'me.everything:overscroll-decor-android:1.1.0'
+    implementation 'com.googlecode.owasp-java-html-sanitizer:owasp-java-html-sanitizer:20200713.1'
+    implementation 'org.jsoup:jsoup:1.13.1'
 
     implementation ('org.pgpainless:pgpainless-core:0.2.3') {
         //exclude group: 'org.bouncycastle' because we will specify it manually

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/AttMeta.kt

@@ -1,13 +1,16 @@
 /*
  * © 2016-present FlowCrypt a.s. Limitations apply. Contact human@flowcrypt.com
- * Contributors: DenBond7
+ * Contributors:
+ *   DenBond7
+ *   Ivan Pizhenko
  */
 
 package com.flowcrypt.email.api.retrofit.response.model.node
 
 import android.os.Parcel
 import android.os.Parcelable
 import com.google.gson.annotations.Expose
+import org.json.JSONObject
 
 /**
  * @author Denis Bondarenko
@@ -19,14 +22,27 @@ data class AttMeta(
   @Expose val name: String?,
   @Expose var data: String?,
   @Expose val length: Long,
-  @Expose val type: String?
+  @Expose val type: String?,
+  @Expose val contentId: String?,
+  @Expose val url: String? = null
 ) : Parcelable {
 
+  constructor(source: JSONObject) : this(
+    name = if (source.has("name")) source.getString("name") else null,
+    data = if (source.has("data")) source.getString("data") else null,
+    length = if (source.has("size")) source.getLong("size") else 0L,
+    type = if (source.has("type")) source.getString("type") else null,
+    contentId = if (source.has("contentId")) source.getString("contentId") else null,
+    url = if (source.has("url")) source.getString("url") else null
+  )
+
   constructor(source: Parcel) : this(
-    source.readString(),
-    source.readString(),
-    source.readLong(),
-    source.readString()
+    name = source.readString(),
+    data =source.readString(),
+    length = source.readLong(),
+    type = source.readString(),
+    contentId = source.readString(),
+    url = source.readString()
   )
 
   override fun describeContents() = 0
@@ -36,6 +52,8 @@ data class AttMeta(
     writeString(data)
     writeLong(length)
     writeString(type)
+    writeString(contentId)
+    writeString(url)
   }
 
   companion object {

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/AttMsgBlock.kt

@@ -0,0 +1,11 @@
+/*
+ * © 2016-present FlowCrypt a.s. Limitations apply. Contact human@flowcrypt.com
+ * Contributors:
+ *   Ivan Pizhenko
+ */
+
+package com.flowcrypt.email.api.retrofit.response.model.node
+
+interface AttMsgBlock : MsgBlock {
+  val attMeta: AttMeta
+}

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/DecryptErrorMsgBlock.kt

@@ -7,6 +7,7 @@ package com.flowcrypt.email.api.retrofit.response.model.node
 
 import android.os.Parcel
 import android.os.Parcelable
+import com.flowcrypt.email.security.pgp.PgpMsg
 import com.google.gson.annotations.Expose
 import com.google.gson.annotations.SerializedName
 
@@ -19,7 +20,9 @@ import com.google.gson.annotations.SerializedName
 data class DecryptErrorMsgBlock(
   @Expose override val content: String?,
   @Expose override val complete: Boolean,
-  @SerializedName("decryptErr") @Expose val error: DecryptError?
+  @SerializedName("decryptErr") @Expose val error: DecryptError?,
+  // TODO: remove above and change name of below when finally dropping Node
+  @SerializedName("kotlinDecryptErr") @Expose val kotlinError: PgpMsg.DecryptionError? = null
 ) : MsgBlock {
 
   @Expose
@@ -28,7 +31,8 @@ data class DecryptErrorMsgBlock(
   constructor(source: Parcel) : this(
     source.readString(),
     1 == source.readInt(),
-    source.readParcelable<DecryptError>(DecryptError::class.java.classLoader)
+    source.readParcelable<DecryptError>(DecryptError::class.java.classLoader),
+    source.readParcelable<PgpMsg.DecryptionError>(PgpMsg.DecryptionError::class.java.classLoader)
   )
 
   override fun describeContents(): Int {
@@ -39,8 +43,9 @@ data class DecryptErrorMsgBlock(
     with(dest) {
       writeParcelable(type, flags)
       writeString(content)
-      writeInt((if (complete) 1 else 0))
+      writeInt(if (complete) 1 else 0)
       writeParcelable(error, flags)
+      writeParcelable(kotlinError, flags)
     }
 
   companion object {

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/DecryptedAttMsgBlock.kt

@@ -20,9 +20,9 @@ import com.google.gson.annotations.SerializedName
 data class DecryptedAttMsgBlock(
   @Expose override val content: String?,
   @Expose override val complete: Boolean,
-  @Expose val attMeta: AttMeta,
+  @Expose override val attMeta: AttMeta,
   @SerializedName("decryptErr") @Expose val error: DecryptError?
-) : MsgBlock {
+) : AttMsgBlock {
 
   var fileUri: Uri? = null
 

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/EncryptedAttLinkMsgBlock.kt

@@ -0,0 +1,45 @@
+/*
+ * © 2016-present FlowCrypt a.s. Limitations apply. Contact human@flowcrypt.com
+ * Contributors:
+ *   Ivan Pizhenko
+ */
+
+package com.flowcrypt.email.api.retrofit.response.model.node
+
+import android.os.Parcel
+import android.os.Parcelable
+import com.google.gson.annotations.Expose
+
+data class EncryptedAttLinkMsgBlock(
+  @Expose override val attMeta: AttMeta,
+) : AttMsgBlock {
+
+  @Expose
+  override val content: String = ""
+  @Expose
+  override val type: MsgBlock.Type = MsgBlock.Type.ENCRYPTED_ATT_LINK
+  @Expose
+  override val complete: Boolean = true
+
+  constructor(source: Parcel) : this(
+    source.readParcelable<AttMeta>(AttMeta::class.java.classLoader)!!
+  )
+
+  override fun writeToParcel(parcel: Parcel, flags: Int) {
+    parcel.writeParcelable(attMeta, flags)
+  }
+
+  override fun describeContents(): Int {
+    return 0
+  }
+
+  companion object CREATOR : Parcelable.Creator<EncryptedAttLinkMsgBlock> {
+    override fun createFromParcel(parcel: Parcel): EncryptedAttLinkMsgBlock {
+      return EncryptedAttLinkMsgBlock(parcel)
+    }
+
+    override fun newArray(size: Int): Array<EncryptedAttLinkMsgBlock?> {
+      return arrayOfNulls(size)
+    }
+  }
+}

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/EncryptedAttMsgBlock.kt

@@ -11,8 +11,10 @@ import android.os.Parcel
 import android.os.Parcelable
 import com.google.gson.annotations.Expose
 
-data class EncryptedAttMsgBlock(@Expose override val content: String?,
-                                @Expose val attMeta: AttMeta) : MsgBlock {
+data class EncryptedAttMsgBlock(
+  @Expose override val content: String?,
+  @Expose override val attMeta: AttMeta
+) : AttMsgBlock {
 
   var fileUri: Uri? = null
 

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/MsgBlock.kt

@@ -76,7 +76,10 @@ interface MsgBlock : Parcelable {
     SIGNED_TEXT,
 
     @SerializedName("signedHtml")
-    SIGNED_HTML;
+    SIGNED_HTML,
+
+    @SerializedName("verifiedMsg")
+    VERIFIED_MSG;
 
     override fun describeContents(): Int {
       return 0
@@ -86,24 +89,30 @@ interface MsgBlock : Parcelable {
       dest.writeInt(ordinal)
     }
 
+    fun isContentBlockType() : Boolean = CONTENT_BLOCK_TYPES.contains(this)
+
     companion object {
       @JvmField
       val CREATOR: Parcelable.Creator<Type> = object : Parcelable.Creator<Type> {
         override fun createFromParcel(source: Parcel): Type = values()[source.readInt()]
         override fun newArray(size: Int): Array<Type?> = arrayOfNulls(size)
       }
 
-      val keyBlockTypes = setOf(PUBLIC_KEY, PRIVATE_KEY)
+      val KEY_BLOCK_TYPES = setOf(PUBLIC_KEY, PRIVATE_KEY)
 
-      val replaceableBlockTypes = setOf(
+      val REPLACEABLE_BLOCK_TYPES = setOf(
         PUBLIC_KEY, PRIVATE_KEY, SIGNED_MSG, ENCRYPTED_MSG, ENCRYPTED_MSG_LINK
       )
 
-      val wellKnownBlockTypes = setOf(
+      val WELL_KNOWN_BLOCK_TYPES = setOf(
         PUBLIC_KEY, PRIVATE_KEY, SIGNED_MSG, ENCRYPTED_MSG
       )
 
-      val signedBlocks = setOf(SIGNED_TEXT, SIGNED_HTML, SIGNED_MSG)
+      val SIGNED_BLOCK_TYPES = setOf(SIGNED_TEXT, SIGNED_HTML, SIGNED_MSG)
+
+      val CONTENT_BLOCK_TYPES = setOf(
+        PLAIN_TEXT, PLAIN_HTML, DECRYPTED_TEXT, DECRYPTED_HTML, SIGNED_MSG, VERIFIED_MSG
+      )
 
       fun ofSerializedName(serializedName: String): Type {
         for (v in values()) {

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/MsgBlockFactory.kt

@@ -6,9 +6,13 @@
 package com.flowcrypt.email.api.retrofit.response.model.node
 
 import android.os.Parcel
+import com.flowcrypt.email.extensions.java.io.toBase64EncodedString
+import com.flowcrypt.email.security.pgp.PgpKey
+import java.io.InputStream
+import java.util.Base64
+import javax.mail.internet.MimePart
 
 object MsgBlockFactory {
-  @JvmStatic
   val supportedMsgBlockTypes = listOf(
     MsgBlock.Type.PUBLIC_KEY,
     MsgBlock.Type.DECRYPT_ERROR,
@@ -18,21 +22,19 @@ object MsgBlockFactory {
     MsgBlock.Type.SIGNED_TEXT
   )
 
-  @JvmStatic
   fun fromParcel(type: MsgBlock.Type, source: Parcel): MsgBlock {
     return when (type) {
       MsgBlock.Type.PUBLIC_KEY -> PublicKeyMsgBlock(source)
       MsgBlock.Type.DECRYPT_ERROR -> DecryptErrorMsgBlock(source)
       MsgBlock.Type.DECRYPTED_ATT -> DecryptedAttMsgBlock(source)
       MsgBlock.Type.ENCRYPTED_ATT -> EncryptedAttMsgBlock(source)
       MsgBlock.Type.SIGNED_TEXT, MsgBlock.Type.SIGNED_HTML, MsgBlock.Type.SIGNED_MSG -> {
-        SignedBlock(source)
+        SignedMsgBlock(source)
       }
       else -> GenericMsgBlock(type, source)
     }
   }
 
-  @JvmStatic
   fun fromContent(
     type: MsgBlock.Type,
     content: String?,
@@ -41,20 +43,38 @@ object MsgBlockFactory {
   ): MsgBlock {
     val complete = !missingEnd
     return when (type) {
-      MsgBlock.Type.PUBLIC_KEY -> PublicKeyMsgBlock(content, complete, null)
+      MsgBlock.Type.PUBLIC_KEY -> {
+        val keyDetails = if (content != null && complete) {
+          PgpKey.parseKeys(content).toPgpKeyDetailsList().firstOrNull()
+        } else null
+        PublicKeyMsgBlock(content, complete, keyDetails)
+      }
       MsgBlock.Type.DECRYPT_ERROR -> DecryptErrorMsgBlock(content, complete, null)
       MsgBlock.Type.SIGNED_TEXT -> {
-        SignedBlock(SignedBlock.Type.SIGNED_TEXT, content, complete, signature)
+        SignedMsgBlock(SignedMsgBlock.Type.SIGNED_TEXT, content, complete, signature)
       }
       MsgBlock.Type.SIGNED_HTML -> {
-        SignedBlock(SignedBlock.Type.SIGNED_HTML, content, complete, signature)
+        SignedMsgBlock(SignedMsgBlock.Type.SIGNED_HTML, content, complete, signature)
       }
       else -> GenericMsgBlock(type, content, complete)
     }
   }
 
-  @JvmStatic
-  fun fromAttachment(type: MsgBlock.Type, content: String?, attMeta: AttMeta): MsgBlock {
+  fun fromAttachment(type: MsgBlock.Type, attachment: MimePart): MsgBlock {
+    val attContent = attachment.content
+    val data: String? = when (attContent) {
+      is String -> Base64.getEncoder().encodeToString(attachment.inputStream.readBytes())
+      is InputStream -> attContent.toBase64EncodedString()
+      else -> null
+    }
+    val attMeta = AttMeta(
+      name = attachment.fileName,
+      data = data,
+      length = attachment.size.toLong(),
+      type = attachment.contentType,
+      contentId = attachment.contentID
+    )
+    val content = if (attContent is String) attachment.content as String else null
     return when (type) {
       MsgBlock.Type.DECRYPTED_ATT -> DecryptedAttMsgBlock(content, true, attMeta, null)
       MsgBlock.Type.ENCRYPTED_ATT -> EncryptedAttMsgBlock(content, attMeta)

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/PlainAttMsgBlock.kt

@@ -13,8 +13,8 @@ import com.google.gson.annotations.Expose
 
 data class PlainAttMsgBlock(
   @Expose override val content: String?,
-  @Expose val attMeta: AttMeta
-) : MsgBlock {
+  @Expose override val attMeta: AttMeta
+) : AttMsgBlock {
 
   var fileUri: Uri? = null
 

FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/SignedBlock.kt → FlowCrypt/src/main/java/com/flowcrypt/email/api/retrofit/response/model/node/SignedMsgBlock.kt

@@ -13,7 +13,7 @@ import com.google.gson.annotations.Expose
 /**
  * Message block which represents content with a signature.
  */
-data class SignedBlock(
+data class SignedMsgBlock(
   @Expose val signedType: Type,
   @Expose override val content: String?,
   @Expose override val complete: Boolean,

FlowCrypt/src/main/java/com/flowcrypt/email/core/msg/MimeUtils.kt

@@ -0,0 +1,52 @@
+/*
+ * © 2016-present FlowCrypt a.s. Limitations apply. Contact human@flowcrypt.com
+ * Contributors:
+ *   Ivan Pizhenko
+ */
+
+package com.flowcrypt.email.core.msg
+
+import com.flowcrypt.email.api.retrofit.response.model.node.MsgBlock
+import com.flowcrypt.email.api.retrofit.response.model.node.PlainAttMsgBlock
+import com.flowcrypt.email.extensions.kotlin.toInputStream
+import java.nio.charset.StandardCharsets
+import java.util.Locale
+import java.util.Properties
+import javax.mail.Session
+import javax.mail.internet.MimeMessage
+
+object MimeUtils {
+  fun resemblesMsg(msg: ByteArray?): Boolean {
+    if (msg == null) return false
+    val firstChars = msg.copyOfRange(0, msg.size.coerceAtMost(1000))
+      .toString(StandardCharsets.US_ASCII)
+      .toLowerCase(Locale.ROOT)
+    val contentType = CONTENT_TYPE_REGEX.find(firstChars) ?: return false
+    return CONTENT_TRANSFER_ENCODING_REGEX.containsMatchIn(firstChars)
+      || CONTENT_DISPOSITION_REGEX.containsMatchIn(firstChars)
+      || firstChars.contains(BOUNDARY_1)
+      || firstChars.contains(CHARSET)
+      || (contentType.range.first == 0 && firstChars.contains(BOUNDARY_2))
+  }
+
+  fun isPlainImgAtt(block: MsgBlock): Boolean {
+    return (block is PlainAttMsgBlock)
+        && block.attMeta.type != null
+        && imageContentTypes.contains(block.attMeta.type)
+  }
+
+  fun mimeTextToMimeMessage(mimeText: String) : MimeMessage {
+    return MimeMessage(Session.getInstance(Properties()), mimeText.toInputStream())
+  }
+
+  private val imageContentTypes = setOf(
+    "image/jpeg", "image/jpg", "image/bmp", "image/png", "image/svg+xml"
+  )
+
+  private val CONTENT_TYPE_REGEX = Regex("content-type: +[0-9a-z\\-/]+")
+  private val CONTENT_TRANSFER_ENCODING_REGEX = Regex("content-transfer-encoding: +[0-9a-z\\-/]+")
+  private val CONTENT_DISPOSITION_REGEX = Regex("content-disposition: +[0-9a-z\\-/]+")
+  private const val BOUNDARY_1 = "; boundary="
+  private const val BOUNDARY_2 = "boundary="
+  private const val CHARSET = "; charset="
+}