From 1c06e9fce42fc9060e9628013b8297ce5c3d2ac0 Mon Sep 17 00:00:00 2001
From: Adrien Guinet <adrien@guinet.me>
Date: Sat, 26 Sep 2020 18:03:41 +0200
Subject: Resume download & show expected MD5 digest (#7)

* Ability to resume downloads

* Fetch version using TLS

* Show expected MD5 if returned by the server

Co-authored-by: Adrien Guinet <aguinet@quarkslab.com>
Co-authored-by: Nayil Mukhametshin <66028747+nlscc@users.noreply.github.com>
---
 samloader/fusclient.py    |  7 +++++--
 samloader/main.py         | 27 +++++++++++++++++++--------
 samloader/versionfetch.py |  2 +-
 3 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/samloader/fusclient.py b/samloader/fusclient.py
index 6836923..2acb165 100644
--- a/samloader/fusclient.py
+++ b/samloader/fusclient.py
@@ -24,9 +24,12 @@ class FUSClient(object):
             self.sessid = r.cookies["JSESSIONID"]
         r.raise_for_status()
         return r.text
-    def downloadfile(self, filename):
+    def downloadfile(self, filename, start=0):
         authv = 'FUS nonce="' + self.encnonce + '", signature="' + self.auth + '", nc="", type="", realm="", newauth="1"'
+        headers = {"Authorization": authv}
+        if start > 0:
+            headers["Range"] = "bytes={}-".format(start)
         r = requests.get("https://cloud-neofussvr.sslcs.cdngc.net/NF_DownloadBinaryForMass.do",
-            params={"file": filename}, headers={"Authorization": authv}, stream=True)
+            params={"file": filename}, headers=headers, stream=True)
         r.raise_for_status()
         return r
diff --git a/samloader/main.py b/samloader/main.py
index a4896bb..4d20bc9 100644
--- a/samloader/main.py
+++ b/samloader/main.py
@@ -3,6 +3,7 @@
 
 import click
 import os
+import base64
 import xml.etree.ElementTree as ET
 from clint.textui import progress
 
@@ -42,17 +43,27 @@ def checkupdate(model, region):
 def download(version, model, region, out):
     client = fusclient.FUSClient()
     path, filename = getbinaryfile(client, version, region, model)
-    print("Downloading file {} ...".format(path+filename))
     initdownload(client, filename)
-    r = client.downloadfile(path+filename)
-    length = int(r.headers["Content-Length"])
     if os.path.isdir(out):
         out = os.path.join(out, filename)
-    with open(out, "wb") as f:
-        for chunk in progress.bar(r.iter_content(chunk_size=0x10000), expected_size=(length/0x10000)+1):
-            if chunk:
-                f.write(chunk)
-                f.flush()
+    if os.path.exists(out):
+        f = open(out, "ab")
+        start = os.stat(out).st_size
+        print("Resuming {} at {}".format(path+filename, start))
+    else:
+        f = open(out, "wb")
+        start = 0
+        print("Downloading {}".format(path+filename))
+    r = client.downloadfile(path+filename, start)
+    length = int(r.headers["Content-Length"])
+    if "Content-MD5" in r.headers:
+        md5 = base64.b64decode(r.headers["Content-MD5"]).hex()
+        print("MD5: {}".format(md5))
+    for chunk in progress.bar(r.iter_content(chunk_size=0x10000), expected_size=(length/0x10000)+1):
+        if chunk:
+            f.write(chunk)
+            f.flush()
+    f.close()
     print("Done!")
 
 @cli.command(help="Decrypt enc4 files.")
diff --git a/samloader/versionfetch.py b/samloader/versionfetch.py
index 800a297..9ef1595 100644
--- a/samloader/versionfetch.py
+++ b/samloader/versionfetch.py
@@ -7,7 +7,7 @@ import xml.etree.ElementTree as ET
 import requests
 
 def getlatestver(region, model):
-    r = requests.get("http://fota-cloud-dn.ospserver.net/firmware/" + region + "/" + model + "/version.xml")
+    r = requests.get("https://fota-cloud-dn.ospserver.net/firmware/" + region + "/" + model + "/version.xml")
     r.raise_for_status()
     root = ET.fromstring(r.text)
     vercode = root.find("./firmware/version/latest").text
-- 
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