vendor.sh: set random MAC address *by default*

MAC addresses are generic, inside Libreboot images where
an Intel GbE region is specified.

We commonly get users flashing multiple systems for their
own use, and sometimes they complain that they networking
broke, because they don't know that the MAC address is
identical on each machine.

This still doesn't work around the case where the same machine
is used, e.g. multiple T440p thinkpads, but if they have one
of each model, it can work nicely, because we do in fact
change it for various platforms.

This change will also reduce the number of people at conferences
in the future, where there are multiple Libreboot users, having
MAC address conflicts.

Changing the MAC address is a good practise, so we enforce good
practise. The user can still retain the old behaviour by
using this command:

./mk inject libreboot-YYYYMMDD_boardname.tar.xz setmac keep

The "keep" argument clears new_mac, which will then skip
changing the MAC address. They can also still set an arbitrary
MAC address as an argument for setmac, e.g.:

./mk inject libreboot-YYYYMMDD_boardname.tar.xz setmac 00:de:ad:c0:ff:ee

This change will be covered in the documentation.

Signed-off-by: Leah Rowe <leah@libreboot.org>

1 files changed, 22 insertions, 3 deletions

diff --git a/include/vendor.sh b/include/vendor.sh
index 525d04ad..b7a54caf 100644
--- a/include/vendor.sh
+++ b/include/vendor.sh
@@ -349,15 +349,34 @@ vendor_inject()
 	set +u +e; [ $# -lt 1 ] && $err "No options specified. - $dontflash"
 	eval "`setvars "" nukemode new_mac xchanged`"
 
+	# randomise the MAC address by default
+	# TODO: support setting CBFS MAC address for GA-G41M-ES2L
+	new_mac="??:??:??:??:??:??"
+
 	archive="$1";
 	[ $# -gt 1 ] && case "$2" in
-	nuke) nukemode="nuke" ;;
+	nuke)
+		new_mac=""
+		nukemode="nuke" ;;
 	setmac)
-		new_mac="??:??:??:??:??:??"
-		[ $# -gt 2 ] && new_mac="$3" ;;
+		[ $# -gt 2 ] && new_mac="$3" && \
+		    [ -z "$new_mac" ] && $err \
+		    "You set an empty MAC address string" ;;
 	*) $err "Unrecognised inject mode: '$2'"
 	esac
 
+	# allow the user to skip setting MAC addresses.
+	# if new_mac is empty, this script skips running nvmutil
+	[ "$new_mac" = "keep" ] && new_mac=""
+
+	# we don't allow the *user* to clear new_mac, in the setmac
+	# command, in case the build system is being integrated with
+	# another, where setmac is relied upon and is being set
+	# explicitly. this is a preventative error handle, as a courtes
+	# to that hypothetical user e.g. Linux distro package maintainer
+	# integrating this build system into their distro. if they used
+	# a variable for that, and they forgot to initialise it, they'll know.
+
 	check_release "$archive" || \
 	    $err "You must run this script on a release archive. - $dontflash"