carrier/crates/mail-mcp/src
Kayos 5e1c63eeaa final-approval audit fixes: HIGH-1/2/3
Three findings from the post-cleanup approval audit, all blockers
before the rename to a real codename:

HIGH-1: ReadOutput.headers map kept LAST occurrence of duplicate
headers, not FIRST. Comment said 'keep the first occurrence' but the
code used Message::header_raw(name) which internally does
.iter().rev().find(...) — returns the last one. For load-bearing
headers like References this is usually singular so the bug was
latent, but an attacker who could inject a second References: line
would have gotten to override the first one used by mail_reply for
threading. Switched to parsed.headers_raw() which iterates in arrival
order — first-occurrence guaranteed.

HIGH-2: tokio-rustls default features pulled aws-lc-rs + aws-lc-sys
into the dep tree even though we explicitly went ring-only on rustls.
The default feature chain on tokio-rustls v0.26 enables 'aws_lc_rs'
via rustls. Pinned tokio-rustls to default-features=false and the
matching small feature set: logging, tls12, ring. Verified via
`cargo tree` — no aws-lc-* in the build, single ring v0.17.14
shared between rustls + tokio-rustls. ~9s shorter cmake step in cold
builds, smaller binary, no C-FFI crypto surface area.

HIGH-3: IntoMcpError trait was introduced in the cleanup pass but
applied at only 2 of 10 tools — the other 8 still used the manual
.map_err(|e| format!('{e:#}'))? + serde_json::to_string chain.
Maintenance trap. Applied to_mcp() at all 8 sites
(mail_inbox_list, mail_folder_list, mail_search, mail_thread,
mail_attachment_get, mail_inbox_read; mail_move and mail_mark stay
with literal {"ok":true} returns — no value to serialize). Tool
methods are now uniformly:
    imap_mod::xxx(...).await.to_mcp()
or for the few that need pre-arg work, three lines instead of seven.

Wire smoke verified — read on uid 34 returns the same 13 headers
shape, no empties, all canonical fields populated. cargo test 31/31.

Repo chain: 2240bf7 -> 4251f51 -> f4b3199 -> 6432a1f -> 54a1a6b ->
6fb63b0 -> f7e698b -> b681953 -> 7c8e246 -> this.
2026-05-21 09:22:39 -07:00
..
config.rs audit-fix round 3: LOW-1 mime cleanup, INFO-2 drop empty snippet, INFO-3 unit tests + format_imap_since tightening 2026-05-21 08:00:50 -07:00
imap.rs final-approval audit fixes: HIGH-1/2/3 2026-05-21 09:22:39 -07:00
main.rs mail-mcp v0.1 — Rust MCP server for Sulkta email 2026-05-21 06:50:25 -07:00
smtp.rs cleanup pass — 17 findings from Opus code-quality audit 2026-05-21 09:09:21 -07:00
tools.rs final-approval audit fixes: HIGH-1/2/3 2026-05-21 09:22:39 -07:00