From 185fe43fb7bdab9dac70fc6498de11a1ba7b286d Mon Sep 17 00:00:00 2001
From: Alexander Larsson <alexl@redhat.com>
Date: Fri, 7 Dec 2018 16:04:22 +0100
Subject: [PATCH] extra_data: In system-helper case, canonicalize uid/gid

Make sure all files produced by apply_extra are owned by root.

Closes: #2398
Approved by: matthiasclasen
---
 common/flatpak-dir.c           |  5 ++++-
 common/flatpak-utils-private.h |  2 ++
 common/flatpak-utils.c         | 24 ++++++++++++++++++++++--
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/common/flatpak-dir.c b/common/flatpak-dir.c
index 3cdc56e3..d8369b3d 100644
--- a/common/flatpak-dir.c
+++ b/common/flatpak-dir.c
@@ -6700,7 +6700,10 @@ apply_extra_data (FlatpakDir   *self,
                      error))
     return FALSE;
 
-  if (!flatpak_canonicalize_permissions (AT_FDCWD, flatpak_file_get_path_cached (extra_files), error))
+  if (!flatpak_canonicalize_permissions (AT_FDCWD, flatpak_file_get_path_cached (extra_files),
+                                         getuid() == 0 ? 0 : -1,
+                                         getuid() == 0 ? 0 : -1,
+                                         error))
     return FALSE;
 
   if (exit_status != 0)
diff --git a/common/flatpak-utils-private.h b/common/flatpak-utils-private.h
index ada6a946..0b8fff17 100644
--- a/common/flatpak-utils-private.h
+++ b/common/flatpak-utils-private.h
@@ -479,6 +479,8 @@ gboolean flatpak_rm_rf (GFile        *dir,
 
 gboolean flatpak_canonicalize_permissions (int           parent_dfd,
                                            const char   *rel_path,
+                                           int           uid,
+                                           int           gid,
                                            GError      **error);
 
 char * flatpak_readlink (const char *path,
diff --git a/common/flatpak-utils.c b/common/flatpak-utils.c
index 736919bc..861499de 100644
--- a/common/flatpak-utils.c
+++ b/common/flatpak-utils.c
@@ -1993,6 +1993,8 @@ static gboolean
 _flatpak_canonicalize_permissions (int           parent_dfd,
                                    const char   *rel_path,
                                    gboolean      toplevel,
+                                   int           uid,
+                                   int           gid,
                                    GError      **error)
 {
   struct stat stbuf;
@@ -2008,6 +2010,22 @@ _flatpak_canonicalize_permissions (int           parent_dfd,
       return FALSE;
     }
 
+  if ((uid != -1 && uid != stbuf.st_uid) || (gid != -1 && gid != stbuf.st_gid))
+    {
+      if (TEMP_FAILURE_RETRY (fchownat (parent_dfd, rel_path, uid, gid, AT_SYMLINK_NOFOLLOW)) != 0)
+        {
+          glnx_set_error_from_errno (error);
+          return FALSE;
+        }
+
+      /* Re-read st_mode for new owner */
+      if (TEMP_FAILURE_RETRY (fstatat (parent_dfd, rel_path, &stbuf, AT_SYMLINK_NOFOLLOW)) != 0)
+        {
+          glnx_set_error_from_errno (error);
+          return FALSE;
+        }
+    }
+
   if (S_ISDIR (stbuf.st_mode))
     {
       g_auto(GLnxDirFdIterator) dfd_iter = { 0, };
@@ -2031,7 +2049,7 @@ _flatpak_canonicalize_permissions (int           parent_dfd,
               if (!glnx_dirfd_iterator_next_dent (&dfd_iter, &dent, NULL, NULL) || dent == NULL)
                 break;
 
-              if (!_flatpak_canonicalize_permissions (dfd_iter.fd, dent->d_name, FALSE, error))
+              if (!_flatpak_canonicalize_permissions (dfd_iter.fd, dent->d_name, FALSE, uid, gid, error))
                 {
                   error = NULL;
                   res = FALSE;
@@ -2086,9 +2104,11 @@ _flatpak_canonicalize_permissions (int           parent_dfd,
 gboolean
 flatpak_canonicalize_permissions (int           parent_dfd,
                                   const char   *rel_path,
+                                  int           uid,
+                                  int           gid,
                                   GError      **error)
 {
-  return _flatpak_canonicalize_permissions (parent_dfd, rel_path, TRUE, error);
+  return _flatpak_canonicalize_permissions (parent_dfd, rel_path, TRUE, uid, gid, error);
 }
 
 /* Make a directory, and its parent. Don't error if it already exists.