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Replica: Make drop_table idempotent so concurrent retention runs don't crash (#3595) - #82

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Replica: Make drop_table idempotent so concurrent retention runs don't crash (#3595)#82
lucaforni wants to merge 16 commits into
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youdie006-postal-fix/drop-table-if-exists

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Questa PR replica la PR originale: postalserver#3616

Autore originale: @youdie006
Branch originale: fix/drop-table-if-exists
Repository originale: youdie006/postal


Problem

ProcessMessageRetentionScheduledTask crashes with Mysql2::Error: Unknown table when two workers run retention concurrently (postalserver#3595). The task's lock is stealable after a few minutes, so two workers can call Provisioner#drop_table for the same raw-<date> table; the second one runs a bare DROP TABLE on an already-dropped table and raises.

In lib/postal/message_db/provisioner.rb, drop_table was the one un-guarded destructive query. Its sibling create_raw_table already tolerates the same concurrent-run race with rescue Mysql2::Error ... raise unless ... already exists.

Fix

Use DROP TABLE IF EXISTS, so dropping an already-removed table is a no-op instead of an error. This mirrors the concurrent-run tolerance create_raw_table has, but at the SQL level so it doesn't swallow any unrelated Mysql2::Error.

Adds a spec asserting drop_table does not raise when the table no longer exists (it fails on the old bare DROP TABLE and passes with IF EXISTS).

Scope

This is the safe, idempotent guard for the crash itself. @willpower232 noted on the issue that the underlying lock-renewal behaviour (two workers holding the retention lock at once) may also be worth revisiting — that's a separate change, and IF EXISTS stops the crash regardless of whether the lock overlap is later tightened.


AI disclosure: prepared with AI assistance (Claude Code); the fix was traced against the code and syntax-checked with ruby -c before submitting. The message_db specs run against MySQL, so the added spec is exercised by CI.

adamcooke and others added 16 commits February 1, 2026 14:48
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
The app-wide CSP already blocks inline script execution, but the HTML
preview iframe for a stored email was same-origin and un-sandboxed, and
the html_raw response had no per-action hardening. Add a sandbox on the
iframe and tighten the CSP on html_raw to script-src 'none' with
nosniff and no-referrer so the preview has defence in depth against a
future CSP bypass or regression.

Relates to GHSA-f6g9-8555-cw28.
The /img/<server>/<message> endpoint accepted a src=<url> query
parameter and proxied the body of that URL back to the caller. Nothing
in the codebase ever produces a src= parameter — the parser only
inserts a plain tracking pixel and rewrites href links — so this branch
is dead code inherited from the original AppMail import.

Drop the src branch: requests with src now return 400. The no-src path
that serves the tracking pixel and records loads is unchanged, and a
spec covers both the pixel-serving path and the removed branch.
The endpoint and domain option helpers interpolated model attributes
straight into an HTML string before marking the whole buffer html_safe.
Wrap the interpolations in h() so untrusted attributes can't break out
of the surrounding tag.

Also stop the helpers glob in rails_helper from eagerly requiring
_spec.rb files so helper specs can live under spec/helpers/, and add a
small application helper spec covering the escape behaviour.
url_with_return_to only checked that return_to started with a forward
slash, which also allowed protocol-relative values like //host and
/\host. Rails 7.1 already refuses to follow those via redirect_to, so
the user just saw a 500. Reject the same shapes in the helper instead
so we fall back to the default URL cleanly.

Adds a sessions request spec covering the rejected shapes plus the
happy-path relative redirect.
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
…rfpg-3xr5)

The Legacy API message lookup endpoints parsed the request body as JSON and
passed the `id` parameter straight through to the message database. A JSON
object supplied for `id` arrived as a Ruby Hash and was used as a raw set of
SQL `WHERE` conditions. `hash_to_sql` interpolated each Hash key directly
inside backtick identifier quoting while escaping only the value, so a key
containing a backtick could break out of the identifier and inject arbitrary
SQL into the SELECT (blind, time-based) against the message database.

Fixes:

- Escape all identifiers (columns, tables, database names) through a new
  `escape_identifier` helper that wraps in backticks and doubles embedded
  backticks. Applied across hash_to_sql, select, insert, insert_multi,
  update and delete so no caller can inject via an identifier.
- Validate the Legacy API `id` parameter at the controller boundary: reject
  any non-scalar value before it reaches the database and coerce it to an
  integer. Internal Hash-based lookups (e.g. tracking middleware) are
  unaffected.

Adds regression tests at the unit (hash_to_sql / escape_identifier) and
request (legacy messages/deliveries) levels.
Webhook and HTTP message endpoint deliveries both flow through
Postal::HTTP, which parsed the user-supplied URL and connected to its
host with no address validation. An authenticated user could point a
webhook or endpoint at a private, loopback or link-local address (e.g.
127.0.0.1, 169.254.169.254 cloud metadata, RFC1918 hosts) and make the
server issue requests into its own internal network.

Add Postal::HTTP::AddressGuard, which resolves the destination host and
rejects private/loopback/link-local/reserved/multicast IPv4 and IPv6
addresses, then pins the connection to the validated address so it cannot
be redirected via a DNS-rebinding race. Administrators can permit specific
destinations via the new postal.allowed_request_destinations config option
(hostnames or IP/CIDR ranges).

Address selection only uses families this server can actually reach so we
do not pin to an IPv6 address on a host without IPv6 connectivity; IPv4 is
preferred for predictability. HTTPEndpoint now validates that its URL is a
well-formed HTTP(S) URL with a host.
The spec relied on the test machine having real IPv6 connectivity,
which GitHub Actions runners do not have.
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
ProcessMessageRetentionScheduledTask's lock is stealable after a few minutes, so
two workers can call Provisioner#drop_table for the same table. The bare DROP
TABLE then raises Mysql2::Error (Unknown table) on the second worker and crashes
the task (postalserver#3595). Use DROP TABLE IF EXISTS, mirroring the concurrent-run
tolerance create_raw_table already has via its rescue.

Adds a spec asserting drop_table does not raise when the table is gone.
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