[OE-core][PATCH] cve-update-nvd2-native: add workaround for json5 style list

[Peter Marko <peter.marko@siemens.com>]

From: Peter Marko <peter.marko@siemens.com>

NVD responses changed to an invalid json between:
* April 5, 2025 at 3:03:44 AM GMT+2
* April 5, 2025 at 4:19:48 AM GMT+2

The last response is since then in format
{
  "resultsPerPage": 625,
  "startIndex": 288000,
  "totalResults": 288625,
  "format": "NVD_CVE",
  "version": "2.0",
  "timestamp": "2025-04-07T07:17:17.534",
  "vulnerabilities": [
    {...},
    ...
    {...},
  ]
}

Json does not allow trailing , in responses, that is json5 format.
So cve-update-nvd2-native do_Fetch task fails with log backtrace ending:

...
File: '/builds/ccp/meta-siemens/projects/ccp/../../poky/meta/recipes-core/meta/cve-update-nvd2-native.bb', lineno: 234, function: update_db_file
     0230:            if raw_data is None:
     0231:                # We haven't managed to download data
     0232:                return False
     0233:
 *** 0234:            data = json.loads(raw_data)
     0235:
     0236:            index = data["startIndex"]
     0237:            total = data["totalResults"]
     0238:            per_page = data["resultsPerPage"]
...
File: '/usr/lib/python3.11/json/decoder.py', lineno: 355, function: raw_decode
     0351:        """
     0352:        try:
     0353:            obj, end = self.scan_once(s, idx)
     0354:        except StopIteration as err:
 *** 0355:            raise JSONDecodeError("Expecting value", s, err.value) from None
     0356:        return obj, end
Exception: json.decoder.JSONDecodeError: Expecting value: line 1 column 1442633 (char 1442632)
...

There was no announcement about json format of API v2.0 by nvd.
Also this happens only if whole database is queried (database update is
fine, even when multiple pages as queried).
And lastly it's only the cve list, all other lists inside are fine.
So this looks like a bug in NVD 2.0 introduced with some update.

Patch this with simple character deletion for now and let's monitor the
situation and possibly switch to json5 in the future.
Note that there is no native json5 support in python, we'd have to use
one of external libraries for it.

Signed-off-by: Peter Marko <peter.marko@siemens.com>
---
 meta/recipes-core/meta/cve-update-nvd2-native.bb | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/meta/recipes-core/meta/cve-update-nvd2-native.bb b/meta/recipes-core/meta/cve-update-nvd2-native.bb
index b9c18bf6b6..32a14a932b 100644
--- a/meta/recipes-core/meta/cve-update-nvd2-native.bb
+++ b/meta/recipes-core/meta/cve-update-nvd2-native.bb
@@ -229,6 +229,11 @@ def update_db_file(db_tmp_file, d, database_time):
                 # We haven't managed to download data
                 return False
 
+            # hack for json5 style responses
+            if raw_data[-3:] == ',]}':
+                bb.note("Removing trailing ',' from nvd response")
+                raw_data = raw_data[:-3] + ']}'
+
             data = json.loads(raw_data)
 
             index = data["startIndex"]