Michael Brown fb4ce72e64 [pxe] Warn about PXE NBPs that may be EFI executables
A relatively common user mistake is to attempt to boot an EFI
executable (such as grub.efi) using a BIOS version of iPXE.

Unfortunately there are no signature checks that we can use to
unambiguously identify a PXE NBP, since a PXE NBP is just raw machine
code.  We therefore have to accept anything sufficiently small to fit
into base memory as a valid PXE NBP.

We can detect that a file might be an EFI executable by checking for
the initial "MZ" signature bytes.  This does not necessarily preclude
the file from also being a PXE NBP (since it would be possible to
create a hybrid binary which acts as both an EFI executable and a PXE
NBP, similar to the way in which wimboot and the Linux kernel are
hybrid binaries which act as both an EFI executable and a bzImage).

If the initial "MZ" signature bytes are present, then attempt to warn
the user by setting the image type to "PXE-NBP (may be EFI?)".  We
can't (sensibly) prevent the user from accidentally running an EFI
executable as a PXE NBP, but we can at least make it easier for the
user to identify their mistake.

Inspired-by: Robin Smidsrød <robin@smidsrod.no>
Inspired-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2015-08-21 15:13:19 +01:00
2015-02-26 17:59:53 +00:00
2010-05-28 00:03:47 +01:00

iPXE README File

Quick start guide:

   cd src
   make

For any more detailed instructions, see http://ipxe.org
Description
iPXE network bootloader
Readme 119 MiB
Languages
C 97.3%
Assembly 1.5%
Perl 0.6%
Makefile 0.3%
Python 0.2%