owasp-modsecurity / owasp-modsecurity/ModSecurity-nginx

Possible dereference of Null

Open Beginner friendly
#359 3 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

:1st_place_medal: good first issue enhancement
Dominant language
Perl
Stars
1.9k
Forks
312
PR merge metrics
No merged PRs in 30d

Description

In result of static analyse of nginx source code (including ngx_http_modsecurity_module) with Svace static analyzer I found error of cathegory "DEREFERENCE OF NULL" (checker finds situations where possible value equal to null can be dereferenced) in ngx_http_modsecurity_module.c

Initialization with possible null returned value here: https://github.com/owasp-modsecurity/ModSecurity-nginx/blob/fd28e6ae3bc9e3e33e5ab177afce5c24af41a6ed/src/ngx_http_modsecurity_module.c#L202

And dereference of location->key field here:
https://github.com/owasp-modsecurity/ModSecurity-nginx/blob/fd28e6ae3bc9e3e33e5ab177afce5c24af41a6ed/src/ngx_http_modsecurity_module.c#L203


Found by Linux Verification Center with SVACE

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start in src/ngx_http_modsecurity_module.c at the linked lines 202–203 and inspect how the possible null return is handled before location->key is dereferenced. Re-run the relevant Svace analysis or equivalent checks and confirm the reported DEREFERENCE OF NULL warning is resolved without changing valid request handling.

Written by the indexing model from the issue text.

Assessment

Tech stack
c, nginx
Domain
backend, security
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Active
Clarity
Clearly specified
Newbie friendliness
76/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.