vfs_shadow_copy2: Preserve all open flags assuming ROFS

Instead of replacing open flags with just O_RDONLY, filter out all those
flags unrelated to a Read Only File System

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14573

Signed-off-by: Anoop C S <anoopcs@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Thu Nov 12 17:23:19 UTC 2020 on sn-devel-184

diff --git a/source3/modules/vfs_shadow_copy2.c b/source3/modules/vfs_shadow_copy2.c
index e5413b75128bb0e6cc17c3b54053e617859a38eb..665080060d233c3d168ccc02dcb02a7dab8938e2 100644 (file)
--- a/source3/modules/vfs_shadow_copy2.c
+++ b/source3/modules/vfs_shadow_copy2.c
@@ -1351,7 +1351,7 @@ static int shadow_copy2_openat(vfs_handle_struct *handle,
                         * EINVAL which we carefully map to EROFS. In sum, this
                         * matches Windows behaviour.
                         */
-                       flags = O_RDONLY;
+                       flags &= ~(O_WRONLY | O_RDWR | O_CREAT);
                }
                return SMB_VFS_NEXT_OPENAT(handle,
                                           dirfsp,
@@ -1385,7 +1385,7 @@ static int shadow_copy2_openat(vfs_handle_struct *handle,
         * pwrite() syscall with EINVAL which we carefully map to EROFS. In sum,
         * this matches Windows behaviour.
         */
-       flags = O_RDONLY;
+       flags &= ~(O_WRONLY | O_RDWR | O_CREAT);
 
        ret = SMB_VFS_NEXT_OPENAT(handle,
                                  dirfsp,