password-reset: a confirmed e-mail, then a link to reset the password

Agreed by the owner on 2026-10-13 ("the e-mail must be confirmed");
notifications to an unconfirmed address settled on 2026-10-17: "Без
подтверждения слать". Mockups 2f5f5b2, route guard b7bbb2c, panel guard
0774da2.

Migration 0013: users.email_confirmed_at ('' for every address saved
before it) and user_links - the SHA-256 of a link's token, its user,
purpose (confirm, reset), address, created and expiry. A changed address
loses its mark (keepConfirmed, in UpdateUser and SaveUser).

internal/web/auth/links.go. A link is 256 bits from crypto/rand, mailed as
https://SELFPOST_HOSTNAME/... - never the request's Host. Confirmation:
24 h, sent when an address is saved (Account, or the global role's user
form) and by Account's Send the link again; its page /confirm/<token> has
a button (a GET changes nothing) and confirms only for a session of its
own account. Reset: /login/reset asks for a username and answers the same
for every name (the sign-in page, "If that account has a confirmed e-mail,
the link is on its way"), mailing after the answer; only a confirmed
address gets one, none within ten minutes of the last, five links an hour
per account, five requests in 15 minutes per client address;
/login/reset/<token> (30 min) sets the password with the link taken in
the same transaction that checks the address again
(store.TakeResetLink), then ends every session. Changing the e-mail on
Account asks for the current password. A password set on Account or the
user form removes the reset links; a restore removes every link; the stop
waits for links being mailed (Server.Drain); a rejected request's log line
hides a link's token (loggedPath).

Reviewed for security before the commit (2026-10-17): no high; two
medium and five low, all fixed here - confirming needs the account's
session and the mail does not name the account (a mistyped address was a
takeover); a reset request neither replaces the links already sent nor
spends the account's quota inside ten minutes; take-and-set atomic; the
confirmation mail sent after the answer; the stop waits for mail; a
restore deletes the links; the token kept out of the log.

Tests: store TestUserLinks, TestUserLinkTakenOnce, TestEmailConfirmation,
TestTakeResetLink; auth TestResetSendsALinkOnlyToAConfirmedAddress,
TestResetLinkSetsThePasswordOnce, TestResetLinkDiesWithTheAddress,
TestResetRequestsAreLimited, TestResetRequestsAreSpaced, TestConfirmLink,
TestLinkPathsWithoutAToken; handlers TestAccountEmailIsConfirmedByItsLink,
TestUserFormSendsANewAddressItsLink; web TestLoggedPathHidesTokens; the
view's pages and fixtures; e2e password_reset_by_e_mail runs it through
the sink (and checks a link from before the restore is dead). go vet +
go test (26 packages) and make e2e on the test server for this tree.

Docs: guide § Account, security.md (the bullet and what ends sessions),
architecture (routes), schema-migrations (row 13, users, user_links),
help #account (word for word with the mockup), roadmap row done,
CHANGELOG [Unreleased].

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/web/auth/auth.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/mixeme/selfpost/internal/store"
@@ -33,6 +34,16 @@ type Module struct {
 	loginLimiter    *rateLimiter
 	setupLimiter    *rateLimiter
 	passwordLimiter *rateLimiter
+	// resetLimiter counts the requests for a reset link per client address,
+	// linkLimiter the requests a link's page gets per client address, and
+	// mailLimiter the links mailed to one user's address (links.go).
+	resetLimiter *rateLimiter
+	linkLimiter  *rateLimiter
+	mailLimiter  *rateLimiter
+	mailer       Mailer
+	// mailing counts the links being mailed after their answer, so a stop
+	// waits for them (Wait) before the database closes.
+	mailing sync.WaitGroup
 
 	trustedProxies []*net.IPNet
 }
@@ -56,11 +67,20 @@ func New(st *store.Store, cfg Config, v *view.Engine, setupTokenPath string) *Mo
 		// out of signing in (audit 2026-10-12, L15), and the one guessing
 		// is whoever holds that user's session, wherever from.
 		passwordLimiter: newRateLimiter(10, 15*time.Minute),
-		trustedProxies:  cfg.TrustedProxyCIDRs,
+		resetLimiter:    newRateLimiter(5, 15*time.Minute),
+		linkLimiter:     newRateLimiter(30, 15*time.Minute),
+		// Five links an hour to one address, of either kind: three resets
+		// asked for and a couple of confirmations is ordinary use, a mailbox
+		// full of them is not.
+		mailLimiter:    newRateLimiter(5, time.Hour),
+		trustedProxies: cfg.TrustedProxyCIDRs,
 	}
 	m.setupLimiter.startSweeper()
 	m.loginLimiter.startSweeper()
 	m.passwordLimiter.startSweeper()
+	m.resetLimiter.startSweeper()
+	m.linkLimiter.startSweeper()
+	m.mailLimiter.startSweeper()
 	// Made now rather than at the first unknown name, which would otherwise
 	// pay for two bcrypt runs (review of audit stage 4).
 	go noSuchUserHash()