recipetool: pypi: do not clobber SRC_URI checksums

The pypi change:
"85a2a6f68af recipetool: create_buildsys_python: add pypi support"
deleted all the SRC_URI variables, including the SRC_URI checksums.
These are not generated by the pypi.bbclass (how could they be trusted?)

Without the checksum(s), we are vulnerable to a man-in-the-middle attack
and zero checks on the validity of the downloaded tarball from pypi.org.

Fix by only setting S and SRC_URI to None.

Signed-off-by: Tim Orling <[email protected]>
Signed-off-by: Richard Purdie <[email protected]>

Author: moto-timo

scripts/lib/recipetool/create_buildsys_python.py

@@ -167,16 +167,11 @@ def process_url(self, args, classes, handled, extravalues):
                 if pypi_package_ext != "tar.gz":
                     extravalues["PYPI_PACKAGE_EXT"] = pypi_package_ext
 
-            # Pypi class will handle S and SRC_URIxxx variables, so remove them
+            # Pypi class will handle S and SRC_URI variables, so remove them
             # TODO: allow oe.recipeutils.patch_recipe_lines() to accept regexp so we can simplify the following to:
             # extravalues['SRC_URI(?:\[.*?\])?'] = None
             extravalues['S'] = None
             extravalues['SRC_URI'] = None
-            extravalues['SRC_URI[md5sum]'] = None
-            extravalues['SRC_URI[sha1sum]'] = None
-            extravalues['SRC_URI[sha256sum]'] = None
-            extravalues['SRC_URI[sha384sum]'] = None
-            extravalues['SRC_URI[sha512sum]'] = None
 
             classes.append('pypi')