[PR #2791] [MERGED] Fix length limit on names #3324

New issue

Closed

opened 2026-03-16 11:37:23 +03:00 by kerem · 0 comments

kerem commented

2026-03-16 11:37:23 +03:00

Owner

📋 Pull Request Information

Original PR: https://github.com/hickory-dns/hickory-dns/pull/2791
Author: @divergentdave
Created: 2/19/2025
Status: ✅ Merged
Merged: 2/20/2025
Merged by: @divergentdave

Base: main ← Head: david/fix-name-length-limit

📝 Commits (1)

6d1cccb Fix length limit on names

📊 Changes

2 files changed (+87 additions, -10 deletions)

View changed files

📝 crates/proto/src/dnssec/nsec3.rs (+0 -6)
📝 crates/proto/src/rr/domain/name.rs (+87 -4)

📄 Description

Inspired by reading #2780, I noticed that the overall length check in Name::extend_name() is off by one in most cases. The Name::len() function gives an approximate length for the textual representation of the name, but the limit in RFC 1035 is on the total length of the wire format, "label octets and label length octets". This PR adds a new utility function to get the encoded length of a name, and changes extend_name() to use that in its length check. Tests are added to check both the correctness of encoded_len() and the edge cases for too-long names.

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/hickory-dns/hickory-dns/pull/2791 **Author:** [@divergentdave](https://github.com/divergentdave) **Created:** 2/19/2025 **Status:** ✅ Merged **Merged:** 2/20/2025 **Merged by:** [@divergentdave](https://github.com/divergentdave) **Base:** `main` ← **Head:** `david/fix-name-length-limit` --- ### 📝 Commits (1) - [`6d1cccb`](https://github.com/hickory-dns/hickory-dns/commit/6d1cccbf2f00aa164b25b7aa55c6dbe6d75d4175) Fix length limit on names ### 📊 Changes **2 files changed** (+87 additions, -10 deletions) <details> <summary>View changed files</summary> 📝 `crates/proto/src/dnssec/nsec3.rs` (+0 -6) 📝 `crates/proto/src/rr/domain/name.rs` (+87 -4) </details> ### 📄 Description Inspired by reading #2780, I noticed that the overall length check in `Name::extend_name()` is off by one in most cases. The `Name::len()` function gives an approximate length for the textual representation of the name, but the limit in RFC 1035 is on the total length of the wire format, "label octets and label length octets". This PR adds a new utility function to get the encoded length of a name, and changes `extend_name()` to use that in its length check. Tests are added to check both the correctness of `encoded_len()` and the edge cases for too-long names. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>