Merge pull request #2130 from profanity-im/fix/omemo-false-cannot-decrypt-msg

Fix incorrect omemo decryption error for Key Transport Messages

src/omemo/omemo.c

@@ -1145,6 +1145,12 @@ omemo_on_message_recv(const char* const from_jid, uint32_t sid,
         return NULL;
     }
 
+    if (payload == NULL) {
+        signal_buffer_free(plaintext_key);
+        *error = OMEMO_ERR_KEY_TRANSPORT;
+        return NULL;
+    }
+
     size_t plaintext_len = payload_len;
     plaintext = malloc(plaintext_len + 1);
     res = aes128gcm_decrypt(plaintext, &plaintext_len, payload, payload_len, iv,

src/xmpp/message.c

@@ -1089,23 +1089,7 @@ _handle_groupchat(xmpp_stanza_t* const stanza)
     if (message->omemo_err != OMEMO_ERR_NONE) {
         message->enc = PROF_MSG_ENC_OMEMO;
         if (message->plain == NULL) {
-            switch (message->omemo_err) {
+            message->plain = omemo_error_to_string(message->omemo_err);
-            case OMEMO_ERR_NO_KEY:
-                message->plain = g_strdup("OMEMO message received but no key for this device found.");
-                break;
-            case OMEMO_ERR_NOT_TRUSTED:
-                message->plain = g_strdup("OMEMO message received but sender identity is untrusted.");
-                break;
-            case OMEMO_ERR_NO_SESSION:
-                message->plain = g_strdup("OMEMO message received but no session found. Try '/omemo start'.");
-                break;
-            case OMEMO_ERR_DECRYPT_FAILED:
-                message->plain = g_strdup("OMEMO message received but decryption failed.");
-                break;
-            default:
-                message->plain = g_strdup("OMEMO message received but could not be decrypted.");
-                break;
-            }
         }
     } else if (message->plain != NULL) {
         message->enc = PROF_MSG_ENC_OMEMO;
@@ -1270,23 +1254,7 @@ _handle_muc_private_message(xmpp_stanza_t* const stanza)
     if (message->omemo_err != OMEMO_ERR_NONE) {
         message->enc = PROF_MSG_ENC_OMEMO;
         if (message->plain == NULL) {
-            switch (message->omemo_err) {
+            message->plain = omemo_error_to_string(message->omemo_err);
-            case OMEMO_ERR_NO_KEY:
-                message->plain = g_strdup("OMEMO message received but no key for this device found.");
-                break;
-            case OMEMO_ERR_NOT_TRUSTED:
-                message->plain = g_strdup("OMEMO message received but sender identity is untrusted.");
-                break;
-            case OMEMO_ERR_NO_SESSION:
-                message->plain = g_strdup("OMEMO message received but no session found. Try '/omemo start'.");
-                break;
-            case OMEMO_ERR_DECRYPT_FAILED:
-                message->plain = g_strdup("OMEMO message received but decryption failed.");
-                break;
-            default:
-                message->plain = g_strdup("OMEMO message received but could not be decrypted.");
-                break;
-            }
         }
     } else if (message->plain != NULL) {
         message->enc = PROF_MSG_ENC_OMEMO;
@@ -1458,23 +1426,7 @@ _handle_chat(xmpp_stanza_t* const stanza, gboolean is_mam, gboolean is_carbon, c
     if (message->omemo_err != OMEMO_ERR_NONE) {
         message->enc = PROF_MSG_ENC_OMEMO;
         if (message->plain == NULL) {
-            switch (message->omemo_err) {
+            message->plain = omemo_error_to_string(message->omemo_err);
-            case OMEMO_ERR_NO_KEY:
-                message->plain = g_strdup("OMEMO message received but no key for this device found.");
-                break;
-            case OMEMO_ERR_NOT_TRUSTED:
-                message->plain = g_strdup("OMEMO message received but sender identity is untrusted.");
-                break;
-            case OMEMO_ERR_NO_SESSION:
-                message->plain = g_strdup("OMEMO message received but no session found. Try '/omemo start'.");
-                break;
-            case OMEMO_ERR_DECRYPT_FAILED:
-                message->plain = g_strdup("OMEMO message received but decryption failed.");
-                break;
-            default:
-                message->plain = g_strdup("OMEMO message received but could not be decrypted.");
-                break;
-            }
         }
     } else if (message->plain != NULL) {
         message->enc = PROF_MSG_ENC_OMEMO;

src/xmpp/omemo.c

@@ -333,6 +333,7 @@ omemo_receive_message(xmpp_stanza_t* const stanza, gboolean* trusted, omemo_erro
     unsigned char* payload_raw = NULL;
     char* iv_text = NULL;
     char* payload_text = NULL;
+    size_t payload_len = 0;
 
     *error = OMEMO_ERR_NONE;
 
@@ -372,20 +373,15 @@ omemo_receive_message(xmpp_stanza_t* const stanza, gboolean* trusted, omemo_erro
     }
 
     xmpp_stanza_t* payload = xmpp_stanza_get_child_by_name(encrypted, "payload");
-    if (!payload) {
+    if (payload) {
-        *error = OMEMO_ERR_OTHER;
+        payload_text = xmpp_stanza_get_text(payload);
-        goto quit;
+        if (payload_text) {
-    }
+            payload_raw = g_base64_decode(payload_text, &payload_len);
-    payload_text = xmpp_stanza_get_text(payload);
+            if (!payload_raw) {
-    if (!payload_text) {
+                *error = OMEMO_ERR_OTHER;
-        *error = OMEMO_ERR_OTHER;
+                goto quit;
-        goto quit;
+            }
-    }
+        }
-    size_t payload_len;
-    payload_raw = g_base64_decode(payload_text, &payload_len);
-    if (!payload_raw) {
-        *error = OMEMO_ERR_OTHER;
-        goto quit;
     }
 
     xmpp_stanza_t* key_stanza;
@@ -707,3 +703,24 @@ _omemo_bundle_publish_configure_result(xmpp_stanza_t* const stanza, void* const
 
     return 0;
 }
+
+char*
+omemo_error_to_string(omemo_error_t error)
+{
+    switch (error) {
+    case OMEMO_ERR_NO_KEY:
+        return g_strdup("OMEMO message received but no key for this device found.");
+    case OMEMO_ERR_NOT_TRUSTED:
+        return g_strdup("OMEMO message received but sender identity is untrusted.");
+    case OMEMO_ERR_NO_SESSION:
+        return g_strdup("OMEMO message received but no session found. Try '/omemo start'.");
+    case OMEMO_ERR_DECRYPT_FAILED:
+        return g_strdup("OMEMO message received but decryption failed.");
+    case OMEMO_ERR_KEY_TRANSPORT:
+        return NULL;
+    case OMEMO_ERR_NONE:
+        return NULL;
+    default:
+        return g_strdup("OMEMO message received but could not be decrypted.");
+    }
+}

src/xmpp/omemo.h

@@ -20,3 +20,4 @@ void omemo_bundle_request(const char* const jid, uint32_t device_id, ProfIqCallb
 int omemo_start_device_session_handle_bundle(xmpp_stanza_t* const stanza, void* const userdata);
 
 char* omemo_receive_message(xmpp_stanza_t* const stanza, gboolean* trusted, omemo_error_t* error) __attribute__((nonnull(2, 3)));
+char* omemo_error_to_string(omemo_error_t error);

src/xmpp/xmpp.h

@@ -132,6 +132,7 @@ typedef enum {
     OMEMO_ERR_DECRYPT_FAILED,
     OMEMO_ERR_INVALID_JID,
     OMEMO_ERR_MUC_SENDER_NOT_FOUND,
+    OMEMO_ERR_KEY_TRANSPORT,
     OMEMO_ERR_OTHER
 } omemo_error_t;