vfs_streams_xattr: restrict which fcntl's are allowed on streams

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15126
MR: https://gitlab.com/samba-team/samba/-/merge_requests/2643

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

diff --git a/source3/modules/vfs_streams_xattr.c b/source3/modules/vfs_streams_xattr.c
index 3dfb894a8004e990161e3a29d551b685dba98cc6..f3371ca9b7ed146e2b8c2b838a0c2153c6cd55c8 100644 (file)
--- a/source3/modules/vfs_streams_xattr.c
+++ b/source3/modules/vfs_streams_xattr.c
@@ -1539,6 +1539,38 @@ static bool streams_xattr_strict_lock_check(struct vfs_handle_struct *handle,
        return true;
 }
 
+static int streams_xattr_fcntl(vfs_handle_struct *handle,
+                              files_struct *fsp,
+                              int cmd,
+                              va_list cmd_arg)
+{
+       va_list dup_cmd_arg;
+       void *arg;
+       int ret;
+
+       if (fsp_is_alternate_stream(fsp)) {
+               switch (cmd) {
+               case F_GETFL:
+               case F_SETFL:
+                       break;
+               default:
+                       DBG_ERR("Unsupported fcntl() cmd [%d] on [%s]\n",
+                               cmd, fsp_str_dbg(fsp));
+                       errno = EINVAL;
+                       return -1;
+               }
+       }
+
+       va_copy(dup_cmd_arg, cmd_arg);
+       arg = va_arg(dup_cmd_arg, void *);
+
+       ret = SMB_VFS_NEXT_FCNTL(handle, fsp, cmd, arg);
+
+       va_end(dup_cmd_arg);
+
+       return ret;
+}
+
 static struct vfs_fn_pointers vfs_streams_xattr_fns = {
        .fs_capabilities_fn = streams_xattr_fs_capabilities,
        .connect_fn = streams_xattr_connect,
@@ -1567,6 +1599,7 @@ static struct vfs_fn_pointers vfs_streams_xattr_fns = {
        .filesystem_sharemode_fn = streams_xattr_filesystem_sharemode,
        .linux_setlease_fn = streams_xattr_linux_setlease,
        .strict_lock_check_fn = streams_xattr_strict_lock_check,
+       .fcntl_fn = streams_xattr_fcntl,
 
        .fchown_fn = streams_xattr_fchown,
        .fchmod_fn = streams_xattr_fchmod,