secure-boot/create_img.sh: moved from FAT12 to MBR and FAT32 partition

BAD_INFLUE is now created ad FAT32 partition on MBR disk image
offset-based loop device mount is performed to avoid MBR destruction
by mkfs.

Signed-off-by: Mateusz Maciejewski <mateusz.maciejewski@3mdeb.com>

secure-boot/create_img.sh

@@ -10,41 +10,59 @@ error_check() {
 
 IMAGELABEL="BAD_INFLUE"
 FILES_DIR="../hello-dasharo/dist"
-IMAGE_FILE="sb_test_BAD_INFLUE.img"
+IMAGE_FILE="sb_test_data.img"
+# 34 megabytes is minimal image size to avoid mkfs.fat complaints on FAT32 creation
+IMAGE_SIZE_MEGABYTES=34
+SECTOR_SIZE_BYTES=512
+PARTTION_OFFSET_SECTORS=2048
+
+# do the math
+IMAGE_SIZE_SECTORS=$((($IMAGE_SIZE_MEGABYTES*1024*1024)/$SECTOR_SIZE_BYTES))
+OFFSET_BYTES=$(($PARTTION_OFFSET_SECTORS * $SECTOR_SIZE_BYTES))
+echo Partition offset bytes: $OFFSET_BYTES
 
 # Step 1: Create blank image
 echo "Creating blank image..."
-dd if=/dev/zero of=$IMAGE_FILE bs=1M count=4 > /dev/null 2>&1
+rm -f $IMAGE_FILE
+dd if=/dev/zero of=$IMAGE_FILE bs=$SECTOR_SIZE_BYTES count=$IMAGE_SIZE_SECTORS > /dev/null 2>&1
 error_check "Cannot create empty image file to store created certs and EFI files"
 
-mkfs.fat -F 12 $IMAGE_FILE -n $IMAGELABEL > /dev/null 2>&1
-error_check "Cannot assign label: $IMAGELABEL"
+# Step2: Create partition table and partition entry
+parted -s $IMAGE_FILE mklabel msdos mkpart primary fat32 $((PARTTION_OFFSET_SECTORS))s $(($IMAGE_SIZE_SECTORS-1))s
 
-# Step 2: Mount it in tmp dir via losetup
-echo "Setting up loop device and mounting..."
-LOOPDEV=$(sudo losetup --find --show $IMAGE_FILE)
-error_check "Cannot set up loop device"
+# Step 3: Attach loop device to created partition
+LOOPDEV=$(sudo losetup --offset $OFFSET_BYTES --show --find $IMAGE_FILE)
+echo $LOOPDEV
+MOUNTDIR=$(mktemp -d)
 
+# Step 4: Create FAT32 and name it
+sudo mkfs.fat -F 32 -n $IMAGELABEL $LOOPDEV
+error_check "Cannot create FAT32 labeled: $IMAGELABEL"
+
+# Step 5: Mount it in tmp dir
 MOUNTDIR=$(mktemp -d)
 error_check "Cannot create temporary mount directory"
-
 sudo mount $LOOPDEV $MOUNTDIR
-error_check "Cannot mount image file"
+error_check "Cannot mount FAT32 partition"
 
-# Step 3: Copy all files under files/ directory
+# Step 6: Copy all files under FILES_DIR directory
 echo "Copying files to image..."
 if [ -d "$FILES_DIR" ]; then
-    sudo cp -r $FILES_DIR/* $MOUNTDIR
+    sudo cp -v -r $FILES_DIR/* $MOUNTDIR
     error_check "Cannot copy files to image"
     sudo sync
 else
     echo "Warning: $FILES_DIR does not exist or is not a directory"
 fi
 
-# Step 4: Unmount
+echo
+echo  $MOUNTDIR contains:
+ls -l $MOUNTDIR
+
+# Step 7: Unmount
 echo "Unmounting and cleaning up..."
 sudo umount $MOUNTDIR
-error_check "Cannot unmount image"
+error_check "Cannot unmount partition"
 
 sudo losetup -d $LOOPDEV
 error_check "Cannot detach loop device"

secure-boot/sb_test_data.img

@@ -1 +1 @@
-../.git/annex/objects/F2/7G/SHA256E-s4194304--d5772027e0fef0101bf191a1652a92651c05e8dd9202ebc44e93e1fa8bd7e1f5.img/SHA256E-s4194304--d5772027e0fef0101bf191a1652a92651c05e8dd9202ebc44e93e1fa8bd7e1f5.img
+../.git/annex/objects/ww/5W/SHA256E-s35651584--9fdc6bafdd209e2200616ad6d9336ff72f8b68df35d9ae0f57e3ef9adba99a45.img/SHA256E-s35651584--9fdc6bafdd209e2200616ad6d9336ff72f8b68df35d9ae0f57e3ef9adba99a45.img