flash-image: Validate checksum of downloaded image

This also uses the meta data provided with the image.

scripts/librem5-devkit-flash-image

@@ -2,6 +2,7 @@
 
 import argparse
 import datetime
+import hashlib
 import jenkins
 import logging
 import lzma
@@ -52,6 +53,33 @@ BLOCK_SIZE = 8192
 UNCOMPRESSED_SIZE = 3600000000
 
 
+class VerifyImageException(Exception):
+    pass
+
+
+def verify_image(image, meta):
+    m = hashlib.sha256()
+    size = int(meta['image']['size'])
+    hexdigest = meta['image']['sha256sum']
+
+    logging.info("Calculating sha256sum of {}".format(image))
+    bar = tqdm.tqdm(total=size,
+                    desc='Checking',
+                    leave=False)
+    with open(image, 'rb') as f:
+        while True:
+            data = f.read(BLOCK_SIZE)
+            if data:
+                m.update(data)
+                bar.update(n=len(data))
+            else:
+                break
+    bar.close()
+    if m.hexdigest() != hexdigest:
+        raise VerifyImageException("Checksum of image {} "
+                                   "does not match {}".format(m.hexdigest(), hexdigest))
+
+
 def download_image(url, target):
     decomp = lzma.LZMADecompressor()
     logging.info("Downloading image from {}".format(url))
@@ -66,7 +94,7 @@ def download_image(url, target):
         uncompressed_size = int(meta['image']['size'])
         logging.debug("Image size is %d", uncompressed_size)
     except requests.exceptions.HTTPError:
-        logging.warning("No meta data found, size may be incorrect")
+        logging.warning("No meta data found, skipping integrity check")
         meta = None
         uncompressed_size = UNCOMPRESSED_SIZE
 
@@ -88,6 +116,8 @@ def download_image(url, target):
             download_bar.update(n=len(data))
     download_bar.close()
     decompress_bar.close()
+    if meta:
+        verify_image(target, meta)
 
 
 def find_image(jobname, type, dist):
@@ -205,6 +235,9 @@ def main():
                        uboot_target)
         write_uuu_script(uuu_target, image_target, uboot_target)
         flash_image(uuu_target)
+    except VerifyImageException as e:
+        logging.error(e)
+        return 1
     except KeyboardInterrupt:
         logging.error("CTRL-C pressed.")
         return 1