Flagsmith/flagsmith

Null-terminated query parameters cause server errors in the Core SDK endpoints

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#2901 opened on Oct 30, 2023

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buggood first issue

Description

Example Sentry issue: FLAGSMITH-API-3TZ

ValueError: A string literal cannot contain NUL (0x00) characters.
(15 additional frame(s) were not displayed)
...
  File "environments/identities/views.py", line 185, in get
    .get_or_create(identifier=identifier, environment=request.environment)

This should be a problem for every view that accesses query parameters directly.

A quick search yields 8 occurences of this: https://github.com/search?q=repo%3AFlagsmith%2Fflagsmith+query_params.get&type=code

For each of those we need to assess the performance impact of using a serializer (DRF's CharField handles null chars).

Contributor guide

Tech stack
pythondjangorest api
Domain
backendapi
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
basic PythonDjango REST Framework understanding
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the impact of null bytes in query parameters across the codebase. Focus on the 8 occurrences of query params.get identified in the linked GitHub search. Test each endpoint with null characters to confirm the error. Consider replacing direct query parameter access with DRF serializers (which handle null chars) while assessing performance trade offs. The Sentry issue points to environments/identities/views.py line 185 as a starting point.