Brad Arant
cd5e0a9905
IMAP (RFC 3501): LOGIN through UID, previously all stubs except CAPABILITY/LOGOUT/a partial APPEND. Multi-folder support with per-folder UID/flag indexing (new MailFolder class, backed by .uidvalidity/.uidnext/ .imapindex sidecar files), ENVELOPE support (new MessageHeaders class: header parsing, address-list parsing, IMAP quoting), and shared cursor-based argument parsing (new IMAPArgs class: sequence sets, flag lists, dates, folder-name normalization, and path-traversal protection via isValidFolderName - a bare ".." folder name would otherwise resolve into a sibling user's mailbox directory). POP3 (RFC 1939): USER through QUIT, previously only CAPA. Added UIDL. POP3 handlers use cursor-based parsing throughout rather than indexed access - ZString's copy constructor doesn't copy its `list` field, and POP3's dispatch passes the request by value, so indexed access into a copy was silently reading nothing. SMTP: DMARC evaluation added to the DATA-terminator path (DKIM verification + alignment/policy, Authentication-Results header, conditional rejection matching RFC 7489 6.3's p=reject + sampled pct=). AUTH LOGIN now handles RFC 4954's optional inline initial response (e.g. Python smtplib's "AUTH LOGIN <base64>" in one line) instead of only the exact three-line form. Outbound relay now forces IPv4 (AF_INET) instead of AF_UNSPEC - this server's IPv4 has a correct PTR record and SPF coverage, its IPv6 doesn't, and Gmail was rejecting outbound mail with 550 5.7.25 as a result. Delivery pipeline: local delivery now runs the message through SpamAssassin (new SpamAssassinFilter class, speaking spamd's PROCESS protocol directly over a raw socket - fails open/delivers unscanned if spamd is unreachable) instead of a plain hardlink, since scanning can tag/modify content. BARANTMailConfig: extracted config loading into its own class. compile: (see individual file changes - build script adjustments to match the above). Deliberately excluded from this commit: barantmail.log/ barantmail-service.log (operational logs, not source - barantmail.log in particular was the runaway 55GB/12.9GB file from a busy-loop bug fixed separately in ServerCore) and barantmail.cfg (this server's own live deployment config, matching how APIServer's equivalent config also stays untracked).
94 lines
4.0 KiB
C++
94 lines
4.0 KiB
C++
#ifndef __DMARCChecker_h__
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#define __DMARCChecker_h__
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#include "DKIMVerifier.h"
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#include "SPFChecker.h"
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#include <string>
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#include <vector>
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namespace mail {
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///
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/// DMARCChecker implements RFC 7489: a message is DMARC-authenticated
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/// if EITHER SPF or DKIM passed AND is "aligned" with the RFC 5322
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/// From: header's domain (the identity a human actually sees) - SPF
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/// alone checks the envelope sender, DKIM alone checks whatever
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/// domain signed it, and neither by itself stops a message whose
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/// From: header claims a domain that had nothing to do with either
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/// check. Requires both SPFChecker's result and DKIMVerifier's
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/// results as input, since DMARC is defined entirely in terms of
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/// those two other mechanisms' outcomes plus the alignment check.
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///
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/// Not implemented: the RFC 7489 Public Suffix List-based
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/// organizational-domain derivation for relaxed alignment - the
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/// PSL is a several-thousand-entry external data file this codebase
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/// has no copy of and no fetch mechanism for. Approximated instead
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/// by comparing the last two dot-separated labels (e.g. treating
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/// "mail.example.com" and "example.com" as aligned via
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/// "example.com"), which is correct for ordinary domains but wrong
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/// for registrations directly under a multi-label public suffix
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/// (e.g. "example.co.uk" and "other.co.uk" would incorrectly be
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/// treated as aligned via "co.uk"). Exact (strict) alignment,
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/// requested via adkim=s/aspf=s, is unaffected by this and is exact
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/// either way.
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///
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class DMARCChecker {
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public:
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enum class Result { Pass, Fail, None };
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struct Policy {
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bool found = false;
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std::string policy = "none"; // p=
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std::string subdomainPolicy; // sp= (defaults to policy if absent)
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bool strictDKIM = false; // adkim=s (default r, relaxed)
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bool strictSPF = false; // aspf=s (default r, relaxed)
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int percent = 100; // pct=
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};
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///
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/// fromDomain: the RFC 5322 From: header's domain (what a human
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/// reading the message actually sees as the sender).
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/// spfDomain/spfResult: the identity SPF was actually evaluated
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/// against (RFC 7208 2.4 - the MAIL FROM domain, or HELO's for a
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/// null reverse-path) and its result.
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/// dkimResults: every DKIM-Signature DKIMVerifier found on this
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/// message, verified or not.
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/// appliedPolicy is filled in with the policy that was actually
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/// looked up (found==false if none was published at all - the
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/// domain isn't participating in DMARC, so this always resolves
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/// to Result::None regardless of alignment).
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///
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static Result evaluate(const std::string &fromDomain, const std::string &spfDomain, SPFChecker::Result spfResult,
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const std::vector<DKIMVerifier::SignatureResult> &dkimResults, Policy &appliedPolicy);
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static std::string resultName(Result result);
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///
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/// A DMARC-aware Authentication-Results header (RFC 8601) -
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/// summarizes spf=/dkim=/dmarc= together, the modern convention
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/// downstream filtering actually looks for (Received-SPF alone,
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/// which __SMTP_MAIL.cpp already adds, predates DMARC and doesn't
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/// record dkim/dmarc results at all).
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///
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static std::string authenticationResultsHeader(SPFChecker::Result spfResult, const std::string &spfDomain,
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const std::vector<DKIMVerifier::SignatureResult> &dkimResults,
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Result dmarcResult, const std::string &fromDomain,
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const std::string &receivingHost);
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private:
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static bool lookupPolicy(const std::string &domain, Policy &policyOut);
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static std::string organizationalDomain(const std::string &domain);
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static bool aligned(const std::string &identityDomain, const std::string &fromDomain, bool strict);
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};
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}
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#endif
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