From d9a8f9d8ccc0b7c1135d0ecde006a75d25f66aee Mon Sep 17 00:00:00 2001
From: Alexander Larsson <[email protected]>
Date: Mon, 10 Jan 2022 16:43:08 +0100
Subject: [PATCH] Transaction: Fail the resolve if xa.metadata invalid or
 missing

If we fail to parse xa.metadata from the summary cache or the commit
xa.metadata we fail the resolve.

If xa.metadata is missing in the commit we fail the resolve (it is
always set in the summary cache, because summary update converts
missing xa.metadata to "", so we either get that, or cache miss which
leads to resolving from the commit.

This means that op->resolved_metadata is always set during install and
updates, which means we will show the app permissions. The transaction
will also always make sure that this data actually matches what gets
deployed.

Before this change an invalid metadata in the summary cache could lead
to a NULL resolved_metadata, which means we wouldn't print the app
permissions, yet we would still deploy some metadata file that could
have permissions. (NOTE: It would fail to deploy unless the
xa.metadata in the commit matched the metadata file, but in this
corner case we would't compare the summary and commit metadata, so
they may differ.)

Conflict:NA
Reference:https://github.com/flatpak/flatpak/commit/d9a8f9d8ccc0b7c1135d0ecde006a75d25f66aee

---
 common/flatpak-transaction.c | 84 +++++++++++++++++++++++-------------
 1 file changed, 55 insertions(+), 29 deletions(-)

diff --git a/common/flatpak-transaction.c b/common/flatpak-transaction.c
index 721da14..b0908c3 100644
--- a/common/flatpak-transaction.c
+++ b/common/flatpak-transaction.c
@@ -2957,12 +2957,13 @@ emit_eol_and_maybe_skip (FlatpakTransaction          *self,
   g_signal_emit (self, signals[END_OF_LIFED_WITH_REBASE], 0, op->remote, flatpak_decomposed_get_ref (op->ref), op->eol, op->eol_rebase, previous_ids, &op->skip);
 }
 
-static void
+static gboolean
 mark_op_resolved (FlatpakTransactionOperation *op,
                   const char                  *commit,
                   GFile                       *sideload_path,
                   GBytes                      *metadata,
-                  GBytes                      *old_metadata)
+                  GBytes                      *old_metadata,
+                  GError                     **error)
 {
   g_debug ("marking op %s:%s resolved to %s", kind_to_str (op->kind), flatpak_decomposed_get_ref (op->ref), commit ? commit : "-");
 
@@ -2980,13 +2981,12 @@ mark_op_resolved (FlatpakTransactionOperation *op,
   if (metadata)
     {
       g_autoptr(GKeyFile) metakey = g_key_file_new ();
-      if (g_key_file_load_from_bytes (metakey, metadata, G_KEY_FILE_NONE, NULL))
-        {
-          op->resolved_metadata = g_bytes_ref (metadata);
-          op->resolved_metakey = g_steal_pointer (&metakey);
-        }
-      else
-        g_message ("Warning: Failed to parse metadata for %s\n", flatpak_decomposed_get_ref (op->ref));
+      if (!g_key_file_load_from_bytes (metakey, metadata, G_KEY_FILE_NONE, NULL))
+        return flatpak_fail_error (error, FLATPAK_ERROR_INVALID_DATA,
+                                   "Metadata for %s is invalid", flatpak_decomposed_get_ref (op->ref));
+
+      op->resolved_metadata = g_bytes_ref (metadata);
+      op->resolved_metakey = g_steal_pointer (&metakey);
     }
   if (old_metadata)
     {
@@ -2997,31 +2997,40 @@ mark_op_resolved (FlatpakTransactionOperation *op,
           op->resolved_old_metakey = g_steal_pointer (&metakey);
         }
       else
-        g_message ("Warning: Failed to parse old metadata for %s\n", flatpak_decomposed_get_ref (op->ref));
+         {
+          /* This shouldn't happen, but a NULL old metadata is safe (all permisssions are considered new) */
+          g_message ("Warning: Failed to parse old metadata for %s\n", flatpak_decomposed_get_ref (op->ref));
+        }
     }
+
+  return TRUE;
 }
 
-static void
+static gboolean
 resolve_op_end (FlatpakTransaction *self,
                 FlatpakTransactionOperation *op,
                 const char *checksum,
                 GFile *sideload_path,
-                GBytes *metadata_bytes)
+                GBytes *metadata_bytes,
+                GError **error)
 {
   g_autoptr(GBytes) old_metadata_bytes = NULL;
 
   old_metadata_bytes = load_deployed_metadata (self, op->ref, NULL, NULL);
-  mark_op_resolved (op, checksum, sideload_path, metadata_bytes, old_metadata_bytes);
+  if (!mark_op_resolved (op, checksum, sideload_path, metadata_bytes, old_metadata_bytes, error))
+    return FALSE;
   emit_eol_and_maybe_skip (self, op);
+  return TRUE;
  }
 
 
-static void
+static gboolean
 resolve_op_from_commit (FlatpakTransaction *self,
                         FlatpakTransactionOperation *op,
                         const char *checksum,
                         GFile *sideload_path,
-                        GVariant *commit_data)
+                        GVariant *commit_data,
+                        GError **error)
 {
   g_autoptr(GBytes) metadata_bytes = NULL;
   g_autoptr(GVariant) commit_metadata = NULL;
@@ -3032,9 +3041,11 @@ resolve_op_from_commit (FlatpakTransaction *self,
   commit_metadata = g_variant_get_child_value (commit_data, 0);
   g_variant_lookup (commit_metadata, "xa.metadata", "&s", &xa_metadata);
   if (xa_metadata == NULL)
-    g_message ("Warning: No xa.metadata in local commit %s ref %s", checksum, flatpak_decomposed_get_ref (op->ref));
-  else
-    metadata_bytes = g_bytes_new (xa_metadata, strlen (xa_metadata));
+    return flatpak_fail_error (error, FLATPAK_ERROR_INVALID_DATA,
+                               "No xa.metadata in local commit %s ref %s",
+                               checksum, flatpak_decomposed_get_ref (op->ref));
+
+  metadata_bytes = g_bytes_new (xa_metadata, strlen (xa_metadata));
 
   if (g_variant_lookup (commit_metadata, "xa.download-size", "t", &download_size))
     op->download_size = GUINT64_FROM_BE (download_size);
@@ -3044,15 +3055,19 @@ resolve_op_from_commit (FlatpakTransaction *self,
   g_variant_lookup (commit_metadata, OSTREE_COMMIT_META_KEY_ENDOFLIFE, "s", &op->eol);
   g_variant_lookup (commit_metadata, OSTREE_COMMIT_META_KEY_ENDOFLIFE_REBASE, "s", &op->eol_rebase);
 
-  resolve_op_end (self, op, checksum, sideload_path, metadata_bytes);
+  return resolve_op_end (self, op, checksum, sideload_path, metadata_bytes, error);
 }
 
+/* NOTE: In case of non-available summary this returns FALSE with a
+ * NULL error, but for other error cases it will be set.
+ */
 static gboolean
 try_resolve_op_from_metadata (FlatpakTransaction *self,
                               FlatpakTransactionOperation *op,
                               const char *checksum,
                               GFile *sideload_path,
-                              FlatpakRemoteState *state)
+                              FlatpakRemoteState *state,
+                              GError **error)
 {
   g_autoptr(GBytes) metadata_bytes = NULL;
   guint64 download_size = 0;
@@ -3092,8 +3107,7 @@ try_resolve_op_from_metadata (FlatpakTransaction *self,
       op->token_type = GINT32_FROM_LE (var_metadata_lookup_int32 (sparse_cache, FLATPAK_SPARSE_CACHE_KEY_TOKEN_TYPE, op->token_type));
     }
 
-  resolve_op_end (self, op, checksum, sideload_path, metadata_bytes);
-  return TRUE;
+  return resolve_op_end (self, op, checksum, sideload_path, metadata_bytes, error);
 }
 
 static gboolean
@@ -3136,7 +3150,8 @@ resolve_ops (FlatpakTransaction *self,
            * checksum we got was the version already installed.
            */
           g_assert (op->resolved_commit != NULL);
-          mark_op_resolved (op, op->resolved_commit, NULL, NULL, NULL);
+          if (!mark_op_resolved (op, op->resolved_commit, NULL, NULL, NULL, error))
+            return FALSE;
           continue;
         }
 
@@ -3145,14 +3160,16 @@ resolve_ops (FlatpakTransaction *self,
           /* We resolve to the deployed metadata, because we need it to uninstall related ops */
 
           metadata_bytes = load_deployed_metadata (self, op->ref, &checksum, NULL);
-          mark_op_resolved (op, checksum, NULL, metadata_bytes, NULL);
+           if (!mark_op_resolved (op, checksum, NULL, metadata_bytes, NULL, error))
+            return FALSE;
           continue;
         }
 
       if (op->kind == FLATPAK_TRANSACTION_OPERATION_INSTALL_BUNDLE)
         {
           g_assert (op->commit != NULL);
-          mark_op_resolved (op, op->commit, NULL, op->external_metadata, NULL);
+          if (!mark_op_resolved (op, op->commit, NULL, op->external_metadata, NULL, error))
+            return FALSE;
           continue;
         }
 
@@ -3183,7 +3200,8 @@ resolve_ops (FlatpakTransaction *self,
           if (commit_data == NULL)
             return FALSE;
 
-          resolve_op_from_commit (self, op, checksum, NULL, commit_data);
+          if (!resolve_op_from_commit (self, op, checksum, NULL, commit_data, error))
+            return FALSE;
         }
       else
         {
@@ -3242,9 +3260,16 @@ resolve_ops (FlatpakTransaction *self,
             }
 
           /* First try to resolve via metadata (if remote is available and its metadata matches the commit version) */
-          if (!try_resolve_op_from_metadata (self, op, checksum, sideload_path, state))
+          if (!try_resolve_op_from_metadata (self, op, checksum, sideload_path, state, &local_error))
             {
-              /* Else try to load the commit object.
+               if (local_error)
+                {
+                  /* Actual error, not just missing from summary */
+                  g_propagate_error (error, g_steal_pointer (&local_error));
+                  return FALSE;
+                }
+
+              /* Missing from summary, try to load the commit object.
                * Note, we don't have a token here, so this will not work for authenticated apps.
                * We handle this by catching the 401 http status and retrying. */
               g_autoptr(GVariant) commit_data = NULL;
@@ -3280,7 +3305,8 @@ resolve_ops (FlatpakTransaction *self,
                   return FALSE;
                 }
 
-              resolve_op_from_commit (self, op, checksum, sideload_path, commit_data);
+              if (!resolve_op_from_commit (self, op, checksum, sideload_path, commit_data, error))
+                return FALSE;
             }
         }
     }
-- 
2.27.0