From 4e69c7ba1b5a0c565b2d2ad2a634695d6a895f20 Mon Sep 17 00:00:00 2001
From: Maurizio D'Addona <mauritiusdadd@gmail.com>
Date: Thu, 24 Dec 2015 10:44:01 +0100
Subject: [PATCH] Add universal extraction script for both OS X and Windows
 drivers

---
 firmware/extract-firmware.sh | 164 +++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100755 firmware/extract-firmware.sh

diff --git a/firmware/extract-firmware.sh b/firmware/extract-firmware.sh
new file mode 100755
index 0000000..3931cec
--- /dev/null
+++ b/firmware/extract-firmware.sh
@@ -0,0 +1,164 @@
+#!/bin/bash
+
+# Known driver and firmware hashes
+
+# NOTE: use sha256 checksums as they are more robust that md5 against collisions
+hash_drv_wnd_105='6ec37d48c0764ed059dd49f472456a4f70150297d6397b7cc7965034cf78627e'
+hash_drv_wnd_138='7044344593bfc08ab9b41ab691213bca568c8d924d0e05136b537f66b3c46f31'
+hash_drv_osx_143='4667e6828f6bfc690a39cf9d561369a525f44394f48d0a98d750931b2f3f278b'
+
+hash_fw_wnd_105='dabb8cf8e874451ebc85c51ef524bd83ddfa237c9ba2e191f8532b896594e50e'
+hash_fw_wnd_138='ed75dc37b1a0e19949e9e046a629cb55deb6eec0f13ba8fd8dd49b5ccd5a800e'
+hash_fw_osx_143='e3e6034a67dfdaa27672dd547698bbc5b33f47f1fc7f5572a2fb68ea09d32d3d'
+
+# Driver names
+declare -A known_hashes=(
+  ["$hash_drv_wnd_105"]='Windows Boot Camp 5.1.5722'
+  ["$hash_drv_wnd_138"]='Windows Boot Camp Update Jul 29, 2015'
+  ["$hash_drv_osx_143"]='OS X, El Capitan'
+)
+
+# Offset in bytes of the firmware inside the driver
+declare -A firmw_offsets=(
+  ["$hash_drv_wnd_105"]=78208
+  ["$hash_drv_wnd_138"]=85296
+  ["$hash_drv_osx_143"]=81920
+)
+
+# Size in bytes of the firmware inside the driver 
+declare -A firmw_sizes=(
+  ["$hash_drv_wnd_105"]=1523716
+  ["$hash_drv_wnd_138"]=1421316
+  ["$hash_drv_osx_143"]=603715
+)
+
+# Compression method used to store the firmware inside the driver
+declare -A compression=(
+  ["$hash_drv_wnd_105"]='cat'
+  ["$hash_drv_wnd_138"]='cat'
+  ["$hash_drv_osx_143"]='gzip'
+)
+
+declare -A firmw_hashes=(
+  ["$hash_fw_wnd_105"]='1.05'
+  ["$hash_fw_wnd_138"]='1.38'
+  ["$hash_fw_osx_143"]='1.43'
+)
+
+printHelp()
+{
+  cat <<HELP_DOC
+Usage: extract-firmware [OPTIONS] FILE
+
+OPTION:
+
+  -h  --help          Print this help message and exit.
+
+FILE:
+
+  The url of the file containing the driver. At the moment only two drivers
+  are currently available:
+
+   - AppleCameraInterface: this is the OS X native driver, it can be found
+     in a OS X installation under the following system directory
+     /System/Library/Extensions/AppleCameraInterface.kext/Contents/MacOS/
+
+   - AppleCamera.sys: this comes within the bootcamp windows driver package.
+     You can download it from http://support.apple.com/downloads/DL1831/"
+
+HELP_DOC
+}
+
+getCheckSum()
+{
+  sha256sum $1 | awk '{ print $1 }'
+}
+
+checkDriverHash()
+{
+  # computing the hash for the input file
+  driver_hash="$(getCheckSum $1)"
+
+  # checking if it is among the known hashes
+  for cur_hash in "${!known_hashes[@]}"; do
+    if [[ "$driver_hash" == "$cur_hash" ]]; then
+      echo "Found matching hash from ${known_hashes[$cur_hash]}"
+      return
+    fi
+  done
+
+  echo "Mismatching driver hash for $1"
+  echo "The uknown hash is ${driver_hash}"
+	echo "No firmware extracted!"
+  exit 1
+}
+
+checkFirmwareHash()
+{
+  # computing the hash for the input file
+  fw_hash="$(getCheckSum $1)"
+
+  # checking if it is among the known hashes
+  for cur_hash in "${!firmw_hashes[@]}"; do
+    if [[ "$fw_hash" == "$cur_hash" ]]; then
+      echo "Extracted firmware version ${firmw_hashes[$cur_hash]}"
+      return 0
+    fi
+  done
+
+  echo "Mismatching firmware hash ${firm_hash}"
+	echo "No firmware extracted!"
+  return 1
+}
+
+extractFirmware()
+{
+  echo "Extracting firmware..."
+  dd bs=1 skip=$3 count=$4 if=$1 of="$2.tmp" &> /dev/null
+
+  echo "Decompressing the firmware using $5..."
+  case "$5" in
+    "gzip")
+      zcat "$2.tmp" > "$2"
+      ;;
+    "cat")
+      cat "$2.tmp" > "$2"
+      ;;
+  esac
+
+  echo "Deleting temporary files..."
+  rm "$2.tmp"
+}
+
+main()
+{
+  echo ""
+  if [[ -z "$1" ]]; then
+    echo "No input file specified!"
+    printHelp
+    exit 1
+  elif [[ "$1" == "--help" ]] || [[ "$1" == "-h" ]]; then
+    printHelp
+    exit 0
+  elif [[ ! -f "$1" ]]; then
+    echo "'$1' is not a file or it does not exist!"
+    exit 1
+  fi
+
+  outf="firmware.bin"
+
+  checkDriverHash "$1"
+
+  offset="${firmw_offsets[$driver_hash]}"
+  size="${firmw_sizes[$driver_hash]}"
+  comp_method="${compression[$driver_hash]}"
+
+  extractFirmware "$1" "$outf" "$offset" "$size" "$comp_method"
+
+  checkFirmwareHash "$outf"
+
+  echo ""
+  exit 0
+}
+
+main "$@"