libfdt: Check that the root-node name is empty

The root node is supposed to have an empty name, but at present this is
not checked. The behaviour of such a tree is not well defined. Most
software rightly assumes that the root node is at offset 0 and does not
check the name. This oddity was discovered as part of a security
investigation into U-Boot verified boot.

Add a check for this to fdt_check_full().

Signed-off-by: Simon Glass <>
Reported-by: Arie Haenel <>
Reported-by: Julien Lenoir <>
Message-Id: <>
Signed-off-by: David Gibson <>
6 files changed