fix(api): bound claim wire fields end to end

admin/internal/server/task_claims.go

@@ -14,7 +14,10 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
-const maxClaimJSONBytes = 4096
+const (
+	maxClaimJSONBytes         = 4096
+	maxClaimResponseJSONBytes = 32 * 1024
+)
 
 func claimNext(options Options) gin.HandlerFunc {
 	return func(context *gin.Context) {
@@ -35,7 +38,16 @@ func claimNext(options Options) gin.HandlerFunc {
 			context.Status(http.StatusNoContent)
 			return
 		}
-		context.JSON(http.StatusOK, response)
+		if !taskclaim.ValidClaimResponse(response) {
+			context.Status(http.StatusServiceUnavailable)
+			return
+		}
+		encoded, err := json.Marshal(response)
+		if err != nil || len(encoded) > maxClaimResponseJSONBytes {
+			context.Status(http.StatusServiceUnavailable)
+			return
+		}
+		context.Data(http.StatusOK, "application/json; charset=utf-8", encoded)
 	}
 }
 

admin/internal/server/task_claims_test.go

@@ -3,6 +3,7 @@ package server_test
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"errors"
 	"io"
 	"net/http"
@@ -98,6 +99,52 @@ func TestClaimNextStrictJSONSuccessEmptyAndErrors(t *testing.T) {
 	}
 }
 
+func TestClaimResponseWorstLegalFieldsStayBelowCapAndInvalidServiceOutputFailsClosed(t *testing.T) {
+	goodsID := strings.Repeat("1", 32)
+	worst := taskclaim.ClaimResponse{
+		Task: taskclaim.ClaimedTask{
+			ID: claimTaskID, Version: 3, Title: strings.Repeat("<", 120),
+			ProductURL: "https://mobile.yangkeduo.com/goods.html?goods_id=" + goodsID,
+			GoodsID:    goodsID, SKUColor: strings.Repeat("<", 80), SKUSize: strings.Repeat("<", 80),
+			Quantity: 9_223_372_036_854_775_807, MaxTotalPrice: strings.Repeat("9", 29) + ".00",
+		},
+		Authorization: taskclaim.ClaimedAuthorization{ID: "70000000-0000-4000-8000-000000000001", TaskVersion: 2, ExpiresAt: "9999-12-31T23:59:59.999999999Z"},
+		Attempt:       taskclaim.ClaimedAttempt{ID: claimAttemptID, ClaimToken: strings.Repeat("a", 64), ClaimGeneration: 9_223_372_036_854_775_807, LeaseExpiresAt: "9999-12-31T23:59:59.999999999Z"},
+	}
+	authenticator := &fakeDeviceAuthenticator{principal: deviceauth.Principal{ID: claimDeviceID}}
+	service := &fakeTaskClaimService{claimResponse: worst, claimFound: true}
+	router, _ := newRouterWithClaimService(t, &memoryStore{}, emptyDetailStore{}, emptyEvidenceStore{}, authenticator, service)
+	request := `{"session_id":"` + claimSessionID + `","claim_request_id":"` + claimRequestID + `"}`
+	response := serveClaimJSON(router, "/api/v1/tasks/claim-next", request, "application/json")
+	if response.Code != http.StatusOK || !json.Valid(response.Body.Bytes()) || response.Body.Len() >= 32*1024 {
+		t.Fatalf("worst legal response = status %d, bytes %d, valid JSON %v", response.Code, response.Body.Len(), json.Valid(response.Body.Bytes()))
+	}
+
+	mutations := map[string]func(*taskclaim.ClaimResponse){
+		"invalid utf8 title": func(response *taskclaim.ClaimResponse) { response.Task.Title = string([]byte{0xff}) },
+		"overlong title":     func(response *taskclaim.ClaimResponse) { response.Task.Title += "<" },
+		"overlong goods id": func(response *taskclaim.ClaimResponse) {
+			response.Task.GoodsID += "1"
+			response.Task.ProductURL += "1"
+		},
+		"overlong color": func(response *taskclaim.ClaimResponse) { response.Task.SKUColor += "<" },
+		"overlong size":  func(response *taskclaim.ClaimResponse) { response.Task.SKUSize += "<" },
+		"overlong money": func(response *taskclaim.ClaimResponse) { response.Task.MaxTotalPrice = strings.Repeat("9", 30) + ".00" },
+	}
+	for name, mutate := range mutations {
+		t.Run(name, func(t *testing.T) {
+			invalid := worst
+			mutate(&invalid)
+			service := &fakeTaskClaimService{claimResponse: invalid, claimFound: true}
+			router, _ := newRouterWithClaimService(t, &memoryStore{}, emptyDetailStore{}, emptyEvidenceStore{}, authenticator, service)
+			response := serveClaimJSON(router, "/api/v1/tasks/claim-next", request, "application/json")
+			if response.Code != http.StatusServiceUnavailable || response.Body.Len() != 0 {
+				t.Fatalf("invalid service response = %d %q", response.Code, response.Body.String())
+			}
+		})
+	}
+}
+
 func TestRenewStrictBindingResponseAndFixedErrors(t *testing.T) {
 	authenticator := &fakeDeviceAuthenticator{principal: deviceauth.Principal{ID: claimDeviceID}}
 	service := &fakeTaskClaimService{renewResponse: taskclaim.RenewResponse{TaskID: claimTaskID, AttemptID: claimAttemptID, ClaimGeneration: 1, LeaseExpiresAt: "2026-08-04T01:04:00Z"}}

admin/internal/taskclaim/store.go

@@ -10,12 +10,12 @@ import (
 	"fmt"
 	"io"
 	"math"
-	"math/big"
 	"strings"
 	"sync"
 	"time"
 
 	"cmbuyer/admin/internal/deviceauth"
+	taskmodel "cmbuyer/admin/internal/tasks"
 )
 
 const writeTimeout = 2 * time.Second
@@ -80,7 +80,7 @@ func (store *Store) validateStoredClaims(ctx context.Context) error {
 	rows, err := store.database.QueryContext(ctx, `SELECT claims.claimed_by_device_id, claims.task_id, claims.authorization_id,
 		claims.attempt_id, claims.claim_generation, claims.claim_nonce, typeof(claims.claim_nonce), length(claims.claim_nonce),
 		claims.claim_token_sha256, typeof(claims.claim_token_sha256), length(claims.claim_token_sha256),
-		claims.authorization_task_version, claims.goods_id, claims.sku_color, claims.sku_size,
+		claims.task_title, claims.authorization_task_version, claims.goods_id, claims.sku_color, claims.sku_size,
 		claims.quantity, claims.total_price_cap, claims.authorization_expires_at, claims.closed_at,
 		attempts.claim_generation, attempts.status, authorizations.status, tasks.status
 		FROM purchase_attempt_claims AS claims
@@ -96,21 +96,21 @@ func (store *Store) validateStoredClaims(ctx context.Context) error {
 		var deviceID, taskID, authorizationID, attemptID string
 		var generation, authorizationTaskVersion, quantity int
 		var nonce, storedHash []byte
-		var nonceType, hashType, goodsID, color, size, price, expires string
+		var nonceType, hashType, title, goodsID, color, size, price, expires string
 		var nonceLength, hashLength int
 		var closed, attemptStatus, authorizationStatus, taskStatus sql.NullString
 		var attemptGeneration sql.NullInt64
 		if err := rows.Scan(&deviceID, &taskID, &authorizationID, &attemptID, &generation,
 			&nonce, &nonceType, &nonceLength, &storedHash, &hashType, &hashLength,
-			&authorizationTaskVersion, &goodsID, &color, &size, &quantity, &price, &expires, &closed,
+			&title, &authorizationTaskVersion, &goodsID, &color, &size, &quantity, &price, &expires, &closed,
 			&attemptGeneration, &attemptStatus, &authorizationStatus, &taskStatus); err != nil {
 			return errors.New("validate stored task claims")
 		}
 		if !deviceauth.ValidDeviceID(deviceID) || !validUUID(taskID) || !validUUID(authorizationID) || !validUUID(attemptID) ||
 			generation <= 0 || nonceType != "blob" || nonceLength != sha256.Size || len(nonce) != sha256.Size ||
 			hashType != "blob" || hashLength != sha256.Size || len(storedHash) != sha256.Size ||
-			authorizationTaskVersion <= 0 || !digitsOnly(goodsID) || color == "" || size == "" || quantity <= 0 ||
-			!canonicalMoney(price) || !validCanonicalTime(expires) || (closed.Valid && !validCanonicalTime(closed.String)) ||
+			authorizationTaskVersion <= 0 || !taskmodel.ValidTaskWireFields(title, goodsID, color, size, price) || quantity <= 0 ||
+			!validCanonicalTime(expires) || (closed.Valid && !validCanonicalTime(closed.String)) ||
 			!attemptGeneration.Valid || attemptGeneration.Int64 != int64(generation) ||
 			!validAttemptStatus(attemptStatus) || !validAuthorizationStatus(authorizationStatus) || !validTaskStatus(taskStatus) {
 			return errors.New("stored task claim metadata is invalid")
@@ -577,9 +577,9 @@ func (store *Store) scanClaim(row rowScanner) (claimRecord, bool, error) {
 	if !validUUID(record.AttemptID) || !validUUID(record.TaskID) || !validUUID(record.AuthorizationID) ||
 		!deviceauth.ValidDeviceID(record.DeviceID) || !validUUID(record.SessionID) || record.Generation <= 0 ||
 		record.CurrentAttemptGeneration != record.Generation ||
-		record.TaskVersion <= 0 || record.AuthorizationTaskVersion <= 0 || strings.TrimSpace(record.TaskTitle) == "" ||
-		!digitsOnly(record.GoodsID) || record.SKUColor == "" || record.SKUSize == "" || record.Quantity <= 0 ||
-		!canonicalMoney(record.TotalPriceCap) || len(record.Nonce) != sha256.Size || len(record.TokenHash) != sha256.Size {
+		record.TaskVersion <= 0 || record.AuthorizationTaskVersion <= 0 ||
+		!taskmodel.ValidTaskWireFields(record.TaskTitle, record.GoodsID, record.SKUColor, record.SKUSize, record.TotalPriceCap) ||
+		record.Quantity <= 0 || len(record.Nonce) != sha256.Size || len(record.TokenHash) != sha256.Size {
 		return claimRecord{}, false, errors.New("stored task claim metadata is invalid")
 	}
 	record.LeaseExpiresAt, err = parseCanonicalTime(record.LeaseExpiresText)
@@ -602,7 +602,11 @@ func (store *Store) scanClaim(row rowScanner) (claimRecord, bool, error) {
 }
 
 func (record claimRecord) authorizationConsistent() bool {
-	return record.AuthorizationTaskVersion == record.CurrentAuthorizationTaskVersion &&
+	return taskmodel.ValidAuthorizationFields(record.CurrentGoodsID, record.CurrentSKUColor,
+		record.CurrentSKUSize, record.CurrentTotalPriceCap) &&
+		taskmodel.ValidTaskWireFields(record.CurrentTaskTitle, record.CurrentTaskGoodsID,
+			record.CurrentTaskSKUColor, record.CurrentTaskSKUSize, record.CurrentTaskMaxTotalPrice) &&
+		record.AuthorizationTaskVersion == record.CurrentAuthorizationTaskVersion &&
 		record.GoodsID == record.CurrentGoodsID && record.SKUColor == record.CurrentSKUColor &&
 		record.SKUSize == record.CurrentSKUSize && record.Quantity == record.CurrentQuantity &&
 		record.TotalPriceCap == record.CurrentTotalPriceCap &&
@@ -623,8 +627,12 @@ func (record claimRecord) recoverableBusinessState() bool {
 }
 
 func (store *Store) responseFor(record claimRecord, responseLease string) (ClaimResponse, error) {
-	if !validCanonicalTime(responseLease) {
-		return ClaimResponse{}, errors.New("stored claim response lease is invalid")
+	// Exact idempotent replay is allowed to ignore later source-row drift, but the
+	// immutable response snapshot itself must still satisfy the current wire bounds.
+	if !validCanonicalTime(responseLease) ||
+		!taskmodel.ValidTaskWireFields(record.TaskTitle, record.GoodsID, record.SKUColor, record.SKUSize, record.TotalPriceCap) ||
+		record.Quantity <= 0 {
+		return ClaimResponse{}, errors.New("stored claim response snapshot is invalid")
 	}
 	token := deriveToken(store.secret, record.DeviceID, record.TaskID, record.AuthorizationID, record.AttemptID, record.Generation, record.Nonce)
 	return ClaimResponse{
@@ -690,8 +698,8 @@ func findCandidate(ctx context.Context, transaction *sql.Tx, now time.Time) (can
 
 func validCandidate(item candidate) bool {
 	return validUUID(item.AuthorizationID) && validUUID(item.TaskID) && item.TaskVersion > 0 && item.TaskVersion < math.MaxInt &&
-		strings.TrimSpace(item.Title) != "" && digitsOnly(item.GoodsID) && item.SKUColor != "" && item.SKUSize != "" &&
-		item.Quantity > 0 && canonicalMoney(item.TotalPriceCap)
+		taskmodel.ValidTaskWireFields(item.Title, item.GoodsID, item.SKUColor, item.SKUSize, item.TotalPriceCap) &&
+		item.Quantity > 0
 }
 
 func validAttemptStatus(value sql.NullString) bool {
@@ -798,33 +806,6 @@ func validUUID(value string) bool {
 	return value[14] == '4' && (value[19] == '8' || value[19] == '9' || value[19] == 'a' || value[19] == 'b')
 }
 
-func digitsOnly(value string) bool {
-	if value == "" {
-		return false
-	}
-	for _, character := range value {
-		if character < '0' || character > '9' {
-			return false
-		}
-	}
-	return true
-}
-
-func canonicalMoney(value string) bool {
-	parts := strings.Split(value, ".")
-	if len(parts) != 2 || len(parts[0]) == 0 || len(parts[1]) != 2 || (len(parts[0]) > 1 && parts[0][0] == '0') {
-		return false
-	}
-	for _, part := range parts {
-		if !digitsOnly(part) {
-			return false
-		}
-	}
-	cents := new(big.Int)
-	_, ok := cents.SetString(parts[0]+parts[1], 10)
-	return ok && cents.Sign() > 0
-}
-
 func productURL(goodsID string) string {
 	return "https://mobile.yangkeduo.com/goods.html?goods_id=" + goodsID
 }

admin/internal/taskclaim/store_test.go

@@ -193,6 +193,88 @@ func TestClaimRollsBackEveryBusinessMutationOnLateFailure(t *testing.T) {
 	}
 }
 
+func TestClaimRejectsOutOfBoundsCandidatesWithoutBusinessMutation(t *testing.T) {
+	mutations := map[string]func(*testing.T, *sql.DB){
+		"invalid utf8 title": func(t *testing.T, database *sql.DB) {
+			execClaimSQL(t, database, `UPDATE tasks SET title=? WHERE id=?`, string([]byte{0xff}), testTaskA)
+		},
+		"overlong title": func(t *testing.T, database *sql.DB) {
+			execClaimSQL(t, database, `UPDATE tasks SET title=? WHERE id=?`, strings.Repeat("😀", 121), testTaskA)
+		},
+		"overlong goods id": func(t *testing.T, database *sql.DB) {
+			value := strings.Repeat("1", 33)
+			execClaimSQL(t, database, `UPDATE tasks SET goods_id=? WHERE id=?`, value, testTaskA)
+			execClaimSQL(t, database, `UPDATE order_authorizations SET goods_id=? WHERE id=?`, value, testAuthA)
+		},
+		"overlong color": func(t *testing.T, database *sql.DB) {
+			value := strings.Repeat("色", 81)
+			execClaimSQL(t, database, `UPDATE tasks SET sku_color=? WHERE id=?`, value, testTaskA)
+			execClaimSQL(t, database, `UPDATE order_authorizations SET sku_color=? WHERE id=?`, value, testAuthA)
+		},
+		"overlong size": func(t *testing.T, database *sql.DB) {
+			value := strings.Repeat("码", 81)
+			execClaimSQL(t, database, `UPDATE tasks SET sku_size=? WHERE id=?`, value, testTaskA)
+			execClaimSQL(t, database, `UPDATE order_authorizations SET sku_size=? WHERE id=?`, value, testAuthA)
+		},
+		"overlong money": func(t *testing.T, database *sql.DB) {
+			value := strings.Repeat("1", 30) + ".00"
+			execClaimSQL(t, database, `UPDATE tasks SET max_total_price=? WHERE id=?`, value, testTaskA)
+			execClaimSQL(t, database, `UPDATE order_authorizations SET total_price_cap=? WHERE id=?`, value, testAuthA)
+		},
+	}
+	for name, mutate := range mutations {
+		t.Run(name, func(t *testing.T) {
+			database := openClaimTestDatabase(t)
+			insertDevice(t, database, testDeviceA, []byte("device-a"))
+			insertCandidate(t, database, testTaskA, testAuthA, testNow, testNow.Add(time.Minute), true)
+			mutate(t, database)
+			store := mustStore(t, database, bytes.Repeat([]byte{0x32}, 32), 30*time.Second)
+			store.now = func() time.Time { return testNow }
+			if _, found, err := store.ClaimNext(context.Background(), testDeviceA, ClaimCommand{SessionID: testSessionA, ClaimRequestID: testClaimRequestA}); err == nil || found {
+				t.Fatalf("ClaimNext = found %v, err %v; want closed failure", found, err)
+			}
+			assertClaimState(t, database, 0, "PENDING", "ACTIVE")
+		})
+	}
+}
+
+func TestClaimReplayRevalidatesImmutableResponseSnapshot(t *testing.T) {
+	mutations := map[string]func(*testing.T, *sql.DB){
+		"title": func(t *testing.T, database *sql.DB) {
+			execClaimSQL(t, database, `UPDATE purchase_attempt_claims SET task_title=? WHERE task_id=?`, strings.Repeat("😀", 121), testTaskA)
+		},
+		"goods id": func(t *testing.T, database *sql.DB) {
+			execClaimSQL(t, database, `UPDATE purchase_attempt_claims SET goods_id=? WHERE task_id=?`, strings.Repeat("1", 33), testTaskA)
+		},
+		"color": func(t *testing.T, database *sql.DB) {
+			execClaimSQL(t, database, `UPDATE purchase_attempt_claims SET sku_color=? WHERE task_id=?`, strings.Repeat("色", 81), testTaskA)
+		},
+		"size": func(t *testing.T, database *sql.DB) {
+			execClaimSQL(t, database, `UPDATE purchase_attempt_claims SET sku_size=? WHERE task_id=?`, strings.Repeat("码", 81), testTaskA)
+		},
+		"money": func(t *testing.T, database *sql.DB) {
+			execClaimSQL(t, database, `UPDATE purchase_attempt_claims SET total_price_cap=? WHERE task_id=?`, strings.Repeat("1", 30)+".00", testTaskA)
+		},
+	}
+	for name, mutate := range mutations {
+		t.Run(name, func(t *testing.T) {
+			database := openClaimTestDatabase(t)
+			insertDevice(t, database, testDeviceA, []byte("device-a"))
+			insertCandidate(t, database, testTaskA, testAuthA, testNow, testNow.Add(time.Minute), true)
+			store := mustStore(t, database, bytes.Repeat([]byte{0x34}, 32), 30*time.Second)
+			store.now = func() time.Time { return testNow }
+			command := ClaimCommand{SessionID: testSessionA, ClaimRequestID: testClaimRequestA}
+			if _, found, err := store.ClaimNext(context.Background(), testDeviceA, command); err != nil || !found {
+				t.Fatalf("initial ClaimNext = found %v, err %v", found, err)
+			}
+			mutate(t, database)
+			if _, found, err := store.ClaimNext(context.Background(), testDeviceA, command); err == nil || found {
+				t.Fatalf("replay = found %v, err %v; want invalid snapshot", found, err)
+			}
+		})
+	}
+}
+
 func TestClaimEligibilityStableOrderAndConcurrentUniqueness(t *testing.T) {
 	database := openClaimTestDatabase(t)
 	insertDevice(t, database, testDeviceA, []byte("device-a"))
@@ -849,6 +931,13 @@ func insertCandidate(t *testing.T, database *sql.DB, taskID, authorizationID str
 	}
 }
 
+func execClaimSQL(t *testing.T, database *sql.DB, statement string, arguments ...any) {
+	t.Helper()
+	if _, err := database.Exec(statement, arguments...); err != nil {
+		t.Fatalf("execute claim test SQL: %v", err)
+	}
+}
+
 func assertClaimState(t *testing.T, database *sql.DB, wantClaims int, wantTaskStatus, wantAuthorizationStatus string) {
 	t.Helper()
 	var count int

admin/internal/taskclaim/types.go

@@ -5,6 +5,9 @@ package taskclaim
 import (
 	"context"
 	"errors"
+	"math"
+
+	taskmodel "cmbuyer/admin/internal/tasks"
 )
 
 var (
@@ -61,6 +64,29 @@ type ClaimResponse struct {
 	Attempt       ClaimedAttempt       `json:"attempt"`
 }
 
+// ValidClaimResponse closes the service-to-HTTP boundary as well as the SQLite
+// boundary. A fake or future Service implementation cannot bypass the same field
+// limits enforced while creating and claiming the task.
+func ValidClaimResponse(response ClaimResponse) bool {
+	authorizationExpires, authorizationErr := parseCanonicalTime(response.Authorization.ExpiresAt)
+	leaseExpires, leaseErr := parseCanonicalTime(response.Attempt.LeaseExpiresAt)
+	return validUUID(response.Task.ID) && response.Task.Version > 0 &&
+		response.Authorization.TaskVersion > 0 && response.Authorization.TaskVersion < math.MaxInt &&
+		response.Task.Version == response.Authorization.TaskVersion+1 &&
+		taskmodel.ValidTaskWireFields(response.Task.Title, response.Task.GoodsID,
+			response.Task.SKUColor, response.Task.SKUSize, response.Task.MaxTotalPrice) &&
+		response.Task.ProductURL == productURL(response.Task.GoodsID) && response.Task.Quantity > 0 &&
+		validUUID(response.Authorization.ID) && authorizationErr == nil &&
+		validUUID(response.Attempt.ID) && response.Attempt.ClaimGeneration > 0 &&
+		len(response.Attempt.ClaimToken) == 64 && tokenTextValid(response.Attempt.ClaimToken) &&
+		leaseErr == nil && !leaseExpires.After(authorizationExpires)
+}
+
+func tokenTextValid(value string) bool {
+	_, ok := decodeToken(value)
+	return ok
+}
+
 type RenewResponse struct {
 	TaskID          string `json:"task_id"`
 	AttemptID       string `json:"attempt_id"`

admin/internal/tasks/authorization.go

@@ -50,7 +50,7 @@ type TaskRow struct {
 }
 
 func normalizeCents(value string) (string, *big.Int, bool) {
-	if value == "" || strings.TrimSpace(value) != value {
+	if value == "" || len(value) > MaxMoneyASCIICharacters || strings.TrimSpace(value) != value {
 		return "", nil, false
 	}
 	parts := strings.Split(value, ".")
@@ -71,6 +71,11 @@ func normalizeCents(value string) (string, *big.Int, bool) {
 	return value, cents, true
 }
 
+func ValidCanonicalMoney(value string) bool {
+	canonical, _, ok := normalizeCents(value)
+	return ok && canonical == value
+}
+
 func startItems(command StartCommand) ([]StartItem, error) {
 	if !validUUID(command.StartKey) || len(command.Tasks) == 0 || len(command.Tasks) > maxStartItems {
 		return nil, ErrInvalidStart

admin/internal/tasks/start_purchases_store_test.go

@@ -8,6 +8,7 @@ import (
 	"math"
 	"reflect"
 	"sort"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -164,12 +165,27 @@ func TestStartPurchasesRejectsEveryTaskConflictWithoutAuthorization(t *testing.T
 		"nondigit goods id": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
 			execTestSQL(t, store.database, `UPDATE tasks SET goods_id='937x' WHERE id=?`, id)
 		},
+		"overlong goods id": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
+			execTestSQL(t, store.database, `UPDATE tasks SET goods_id=? WHERE id=?`, strings.Repeat("1", MaxGoodsIDCharacters+1), id)
+		},
+		"invalid utf8 title": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
+			execTestSQL(t, store.database, `UPDATE tasks SET title=? WHERE id=?`, string([]byte{0xff}), id)
+		},
+		"overlong title": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
+			execTestSQL(t, store.database, `UPDATE tasks SET title=? WHERE id=?`, strings.Repeat("😀", MaxTitleCodePoints+1), id)
+		},
 		"empty color": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
 			execTestSQL(t, store.database, `UPDATE tasks SET sku_color='' WHERE id=?`, id)
 		},
+		"overlong color": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
+			execTestSQL(t, store.database, `UPDATE tasks SET sku_color=? WHERE id=?`, strings.Repeat("色", MaxSKUTextCodePoints+1), id)
+		},
 		"empty size": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
 			execTestSQL(t, store.database, `UPDATE tasks SET sku_size='' WHERE id=?`, id)
 		},
+		"overlong size": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
+			execTestSQL(t, store.database, `UPDATE tasks SET sku_size=? WHERE id=?`, strings.Repeat("码", MaxSKUTextCodePoints+1), id)
+		},
 		"quantity over policy": func(_ *testing.T, store *SQLiteStore, _ string, _ *StartItem) {
 			store.policy.MaxQuantity = 1
 		},
@@ -179,6 +195,9 @@ func TestStartPurchasesRejectsEveryTaskConflictWithoutAuthorization(t *testing.T
 		"noncanonical leading zero": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
 			execTestSQL(t, store.database, `UPDATE tasks SET max_total_price='012.80' WHERE id=?`, id)
 		},
+		"overlong canonical price": func(t *testing.T, store *SQLiteStore, id string, _ *StartItem) {
+			execTestSQL(t, store.database, `UPDATE tasks SET max_total_price=? WHERE id=?`, strings.Repeat("1", MaxMoneyASCIICharacters-2)+".00", id)
+		},
 		"price over policy": func(_ *testing.T, store *SQLiteStore, _ string, _ *StartItem) {
 			store.policy.MaxTotalPrice = "12.79"
 		},
@@ -199,6 +218,43 @@ func TestStartPurchasesRejectsEveryTaskConflictWithoutAuthorization(t *testing.T
 	}
 }
 
+func TestStartPurchasesReplayRejectsMalformedAuthorizationOrTaskSnapshot(t *testing.T) {
+	mutations := map[string]func(*testing.T, *sql.DB, string){
+		"authorization goods id": func(t *testing.T, database *sql.DB, id string) {
+			execTestSQL(t, database, `UPDATE order_authorizations SET goods_id=? WHERE task_id=?`, strings.Repeat("1", MaxGoodsIDCharacters+1), id)
+		},
+		"authorization color": func(t *testing.T, database *sql.DB, id string) {
+			execTestSQL(t, database, `UPDATE order_authorizations SET sku_color=? WHERE task_id=?`, strings.Repeat("色", MaxSKUTextCodePoints+1), id)
+		},
+		"authorization size": func(t *testing.T, database *sql.DB, id string) {
+			execTestSQL(t, database, `UPDATE order_authorizations SET sku_size=? WHERE task_id=?`, strings.Repeat("码", MaxSKUTextCodePoints+1), id)
+		},
+		"authorization money": func(t *testing.T, database *sql.DB, id string) {
+			execTestSQL(t, database, `UPDATE order_authorizations SET total_price_cap=? WHERE task_id=?`, strings.Repeat("1", MaxMoneyASCIICharacters-2)+".00", id)
+		},
+		"task title": func(t *testing.T, database *sql.DB, id string) {
+			execTestSQL(t, database, `UPDATE tasks SET title=? WHERE id=?`, strings.Repeat("😀", MaxTitleCodePoints+1), id)
+		},
+	}
+	for name, mutate := range mutations {
+		t.Run(name, func(t *testing.T) {
+			database := migratedDatabase(t)
+			store := configuredStartStore(t, database)
+			id := startTestUUID(1)
+			createStartDraft(t, store, id)
+			command := StartCommand{StartKey: startTestUUID(1001), Tasks: []StartItem{{TaskID: id, ExpectedTaskVersion: 1}}}
+			if _, err := store.StartPurchases(context.Background(), command, "admin"); err != nil {
+				t.Fatal(err)
+			}
+			mutate(t, database, id)
+			if _, err := store.StartPurchases(context.Background(), command, "admin"); !errors.Is(err, ErrStartConflict) {
+				t.Fatalf("replay error = %v, want ErrStartConflict", err)
+			}
+			assertAuthorizationCount(t, database, 1)
+		})
+	}
+}
+
 func TestStartPurchasesRollsBackWholeBatchForLateConflictAndSQLFailure(t *testing.T) {
 	for _, test := range []struct {
 		name       string

admin/internal/tasks/start_store.go

@@ -142,7 +142,9 @@ func (store *SQLiteStore) StartPurchases(ctx context.Context, command StartComma
 			}
 			return StartResult{}, err
 		}
-		if status != "DRAFT" || version != item.ExpectedTaskVersion || !goodsIDValid(goods) || color == "" || size == "" || quantity < 1 || quantity > store.policy.MaxQuantity {
+		if status != "DRAFT" || version != item.ExpectedTaskVersion ||
+			!ValidTaskWireFields(title, goods, color, size, price) ||
+			quantity < 1 || quantity > store.policy.MaxQuantity {
 			return StartResult{}, ErrStartConflict
 		}
 		canonical, cents, ok := normalizeCents(price)
@@ -179,20 +181,15 @@ func (store *SQLiteStore) StartPurchases(ctx context.Context, command StartComma
 	return result, nil
 }
 
-func goodsIDValid(value string) bool {
-	if value == "" {
-		return false
-	}
-	for _, ch := range value {
-		if ch < '0' || ch > '9' {
-			return false
-		}
-	}
-	return true
-}
-
 func replayStart(ctx context.Context, tx *sql.Tx, startKey string, items []StartItem) (StartResult, bool, error) {
-	rows, err := tx.QueryContext(ctx, "SELECT id,task_id,task_version,expires_at FROM order_authorizations WHERE start_key=? ORDER BY task_id", startKey)
+	rows, err := tx.QueryContext(ctx, `SELECT authorizations.id,authorizations.task_id,
+		authorizations.task_version,authorizations.expires_at,authorizations.goods_id,
+		authorizations.sku_color,authorizations.sku_size,authorizations.quantity,
+		authorizations.total_price_cap,tasks.title,tasks.goods_id,tasks.sku_color,
+		tasks.sku_size,tasks.quantity,tasks.max_total_price
+		FROM order_authorizations AS authorizations
+		JOIN tasks ON tasks.id = authorizations.task_id
+		WHERE authorizations.start_key=? ORDER BY authorizations.task_id`, startKey)
 	if err != nil {
 		return StartResult{}, false, err
 	}
@@ -201,9 +198,22 @@ func replayStart(ctx context.Context, tx *sql.Tx, startKey string, items []Start
 	for rows.Next() {
 		var item AuthorizedTask
 		var expires string
-		if err := rows.Scan(&item.AuthorizationID, &item.TaskID, &item.TaskVersion, &expires); err != nil {
+		var authorizationGoodsID, authorizationColor, authorizationSize, authorizationPrice string
+		var taskTitle, taskGoodsID, taskColor, taskSize, taskPrice string
+		var authorizationQuantity, taskQuantity int
+		if err := rows.Scan(&item.AuthorizationID, &item.TaskID, &item.TaskVersion, &expires,
+			&authorizationGoodsID, &authorizationColor, &authorizationSize, &authorizationQuantity,
+			&authorizationPrice, &taskTitle, &taskGoodsID, &taskColor, &taskSize, &taskQuantity,
+			&taskPrice); err != nil {
 			return StartResult{}, false, err
 		}
+		if !ValidAuthorizationFields(authorizationGoodsID, authorizationColor, authorizationSize, authorizationPrice) ||
+			authorizationQuantity <= 0 ||
+			!ValidTaskWireFields(taskTitle, taskGoodsID, taskColor, taskSize, taskPrice) || taskQuantity <= 0 ||
+			authorizationGoodsID != taskGoodsID || authorizationColor != taskColor ||
+			authorizationSize != taskSize || authorizationQuantity != taskQuantity || authorizationPrice != taskPrice {
+			return StartResult{}, false, ErrStartConflict
+		}
 		item.ExpiresAt, err = time.Parse(time.RFC3339Nano, expires)
 		if err != nil {
 			return StartResult{}, false, err

admin/internal/tasks/store.go

@@ -37,6 +37,11 @@ func NewSQLiteStore(database *sql.DB) (*SQLiteStore, error) {
 }
 
 func (store *SQLiteStore) CreateDraft(ctx context.Context, draft Draft) (Draft, error) {
+	// Validate again at the persistence boundary. HTTP form validation is not the only
+	// caller, and a malformed row here would later make an authorized claim unencodable.
+	if !validUUID(draft.ID) || !ValidTaskWireFields(draft.Title, draft.GoodsID, draft.SKUColor, draft.SKUSize, draft.MaxTotalPrice) || draft.Quantity <= 0 {
+		return Draft{}, ErrInvalidDraft
+	}
 	writeContext, cancel := context.WithTimeout(ctx, sqliteWriteTimeout)
 	defer cancel()
 	// SQLite permits one writer at a time. Serializing this store's short create

admin/internal/tasks/tasks.go

@@ -9,14 +9,21 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode/utf8"
 )
 
 const (
-	maxTitleLength = 120
-	maxSKUText     = 80
+	MaxTitleCodePoints      = 120
+	MaxSKUTextCodePoints    = 80
+	MaxGoodsIDCharacters    = 32
+	MaxMoneyASCIICharacters = 32
+	maxSKUText              = MaxSKUTextCodePoints
 )
 
-var ErrCreateKeyConflict = errors.New("create key conflicts with a different task")
+var (
+	ErrCreateKeyConflict = errors.New("create key conflicts with a different task")
+	ErrInvalidDraft      = errors.New("invalid draft")
+)
 
 type Draft struct {
 	ID            string
@@ -41,13 +48,13 @@ func Validate(form Form) (Draft, Errors) {
 	if !validUUID(draft.ID) {
 		errors["create_key"] = "创建请求已过期，请重新打开表单。"
 	}
-	if draft.Title == "" || len([]rune(draft.Title)) > maxTitleLength {
+	if !validBoundedText(draft.Title, MaxTitleCodePoints) {
 		errors["title"] = "任务名称不能为空，且不能超过 120 个字符。"
 	}
-	if draft.SKUColor == "" || len([]rune(draft.SKUColor)) > maxSKUText {
+	if !validBoundedText(draft.SKUColor, MaxSKUTextCodePoints) {
 		errors["sku_color"] = "颜色分类不能为空，且不能超过 80 个字符。"
 	}
-	if draft.SKUSize == "" || len([]rune(draft.SKUSize)) > maxSKUText {
+	if !validBoundedText(draft.SKUSize, MaxSKUTextCodePoints) {
 		errors["sku_size"] = "尺码不能为空，且不能超过 80 个字符。"
 	}
 	goodsID, ok := CanonicalGoodsID(strings.TrimSpace(form.ProductURL))
@@ -93,6 +100,9 @@ func CanonicalGoodsID(value string) (string, bool) {
 			return "", false
 		}
 	}
+	if !ValidGoodsID(goodsIDs[0]) {
+		return "", false
+	}
 	return goodsIDs[0], true
 }
 
@@ -155,5 +165,43 @@ func normalizeMoney(value string) (string, bool) {
 	if whole == "0" && strings.Trim(fraction, "0") == "" {
 		return "", false
 	}
-	return whole + "." + (fraction + "00")[:2], true
+	canonical := whole + "." + (fraction + "00")[:2]
+	if len(canonical) > MaxMoneyASCIICharacters {
+		return "", false
+	}
+	return canonical, true
+}
+
+// ValidTaskWireFields is shared by creation, authorization and claim. Keeping one
+// bounded domain prevents a database row from being valid in one stage but impossible
+// to encode inside the fixed claim response budget in another stage.
+func ValidTaskWireFields(title, goodsID, skuColor, skuSize, maxTotalPrice string) bool {
+	return validBoundedText(title, MaxTitleCodePoints) &&
+		ValidAuthorizationFields(goodsID, skuColor, skuSize, maxTotalPrice)
+}
+
+func ValidAuthorizationFields(goodsID, skuColor, skuSize, totalPriceCap string) bool {
+	return ValidGoodsID(goodsID) &&
+		validBoundedText(skuColor, MaxSKUTextCodePoints) &&
+		validBoundedText(skuSize, MaxSKUTextCodePoints) &&
+		ValidCanonicalMoney(totalPriceCap)
+}
+
+func ValidGoodsID(value string) bool {
+	if value == "" || len(value) > MaxGoodsIDCharacters {
+		return false
+	}
+	for index := 0; index < len(value); index++ {
+		if value[index] < '0' || value[index] > '9' {
+			return false
+		}
+	}
+	return true
+}
+
+func validBoundedText(value string, maximum int) bool {
+	// RuneCountInString replaces malformed byte sequences with RuneError. Validate first
+	// so corrupt SQLite text cannot consume the code-point budget as if it were legitimate.
+	return utf8.ValidString(value) && value != "" && strings.TrimSpace(value) == value &&
+		utf8.RuneCountInString(value) <= maximum
 }

admin/internal/tasks/tasks_test.go

@@ -7,6 +7,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"runtime"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -38,13 +39,16 @@ func TestValidateNormalizesManualDraft(t *testing.T) {
 func TestValidateRejectsInvalidFieldsAndURLs(t *testing.T) {
 	base := Form{CreateKey: testKey, Title: "title", ProductURL: "https://mobile.yangkeduo.com/goods.html?goods_id=1", SKUColor: "black", SKUSize: "M", Quantity: "1", MaxTotalPrice: "1"}
 	for name, update := range map[string]func(*Form){
-		"empty title":       func(form *Form) { form.Title = "  " },
-		"long color":        func(form *Form) { form.SKUColor = string(make([]rune, maxSKUText+1)) },
-		"fraction quantity": func(form *Form) { form.Quantity = "1.5" },
-		"zero quantity":     func(form *Form) { form.Quantity = "0" },
-		"too many decimals": func(form *Form) { form.MaxTotalPrice = "1.234" },
-		"trailing decimal":  func(form *Form) { form.MaxTotalPrice = "1." },
-		"zero money":        func(form *Form) { form.MaxTotalPrice = "0.00" },
+		"empty title":        func(form *Form) { form.Title = "  " },
+		"invalid utf8 title": func(form *Form) { form.Title = string([]byte{0xff}) },
+		"long title":         func(form *Form) { form.Title = strings.Repeat("😀", MaxTitleCodePoints+1) },
+		"long color":         func(form *Form) { form.SKUColor = string(make([]rune, maxSKUText+1)) },
+		"invalid utf8 size":  func(form *Form) { form.SKUSize = string([]byte{0xff}) },
+		"fraction quantity":  func(form *Form) { form.Quantity = "1.5" },
+		"zero quantity":      func(form *Form) { form.Quantity = "0" },
+		"too many decimals":  func(form *Form) { form.MaxTotalPrice = "1.234" },
+		"trailing decimal":   func(form *Form) { form.MaxTotalPrice = "1." },
+		"zero money":         func(form *Form) { form.MaxTotalPrice = "0.00" },
 	} {
 		t.Run(name, func(t *testing.T) {
 			form := base
@@ -67,6 +71,7 @@ func TestValidateRejectsInvalidFieldsAndURLs(t *testing.T) {
 		"https://mobile.yangkeduo.com/goods.html?goods_id=1%26goods_id%3D2",
 		"https://mobile.yangkeduo.com/goods.html?goods_id=1;uin=bad",
 		"https://mobile.yangkeduo.com/other.html?goods_id=1",
+		"https://mobile.yangkeduo.com/goods.html?goods_id=" + strings.Repeat("1", MaxGoodsIDCharacters+1),
 	} {
 		if _, ok := CanonicalGoodsID(value); ok {
 			t.Fatalf("CanonicalGoodsID accepted %q", value)
@@ -75,19 +80,33 @@ func TestValidateRejectsInvalidFieldsAndURLs(t *testing.T) {
 }
 
 func TestNormalizeMoneyBoundaries(t *testing.T) {
-	for value, want := range map[string]string{"1": "1.00", "1.2": "1.20", "000.01": "0.01", "999999999999999999": "999999999999999999.00"} {
+	maximum := strings.Repeat("9", MaxMoneyASCIICharacters-3) + ".00"
+	for value, want := range map[string]string{"1": "1.00", "1.2": "1.20", "000.01": "0.01", "999999999999999999": "999999999999999999.00", maximum: maximum} {
 		got, ok := normalizeMoney(value)
 		if !ok || got != want {
 			t.Fatalf("normalizeMoney(%q) = (%q, %t), want (%q, true)", value, got, ok, want)
 		}
 	}
-	for _, value := range []string{"0", "0.0", "0.00", "1.", ".1", "1.000", "-1", "1e2", " 1"} {
+	for _, value := range []string{"0", "0.0", "0.00", "1.", ".1", "1.000", "-1", "1e2", " 1", strings.Repeat("9", MaxMoneyASCIICharacters-2) + ".00"} {
 		if got, ok := normalizeMoney(value); ok {
 			t.Fatalf("normalizeMoney(%q) = %q, want rejection", value, got)
 		}
 	}
 }
 
+func TestValidateAcceptsWorstLegalUnicodeFieldBounds(t *testing.T) {
+	goodsID := strings.Repeat("1", MaxGoodsIDCharacters)
+	draft, validation := Validate(Form{
+		CreateKey: testKey, Title: strings.Repeat("😀", MaxTitleCodePoints),
+		ProductURL: CanonicalURL(goodsID), SKUColor: strings.Repeat("色", MaxSKUTextCodePoints),
+		SKUSize: strings.Repeat("码", MaxSKUTextCodePoints), Quantity: "1",
+		MaxTotalPrice: strings.Repeat("9", MaxMoneyASCIICharacters-3) + ".00",
+	})
+	if !validation.Valid() || !ValidTaskWireFields(draft.Title, draft.GoodsID, draft.SKUColor, draft.SKUSize, draft.MaxTotalPrice) {
+		t.Fatalf("worst legal draft = %#v, validation = %#v", draft, validation)
+	}
+}
+
 func TestNewCreateKeyIsUUIDv4(t *testing.T) {
 	key, err := NewCreateKey()
 	if err != nil {
@@ -157,6 +176,36 @@ func TestSQLiteStoreCreatesListsAndHandlesIdempotency(t *testing.T) {
 	}
 }
 
+func TestSQLiteStoreRejectsInvalidDraftAtPersistenceBoundary(t *testing.T) {
+	mutations := map[string]func(*Draft){
+		"untrimmed title":    func(draft *Draft) { draft.Title = " title" },
+		"invalid utf8 title": func(draft *Draft) { draft.Title = string([]byte{0xff}) },
+		"long title":         func(draft *Draft) { draft.Title = strings.Repeat("😀", MaxTitleCodePoints+1) },
+		"long color":         func(draft *Draft) { draft.SKUColor = strings.Repeat("色", MaxSKUTextCodePoints+1) },
+		"long size":          func(draft *Draft) { draft.SKUSize = strings.Repeat("码", MaxSKUTextCodePoints+1) },
+		"long goods id":      func(draft *Draft) { draft.GoodsID = strings.Repeat("1", MaxGoodsIDCharacters+1) },
+		"long money":         func(draft *Draft) { draft.MaxTotalPrice = strings.Repeat("1", MaxMoneyASCIICharacters-2) + ".00" },
+	}
+	for name, mutate := range mutations {
+		t.Run(name, func(t *testing.T) {
+			database := migratedDatabase(t)
+			store, err := NewSQLiteStore(database)
+			if err != nil {
+				t.Fatal(err)
+			}
+			draft := testDraft(testKey, "title")
+			mutate(&draft)
+			if _, err := store.CreateDraft(context.Background(), draft); !errors.Is(err, ErrInvalidDraft) {
+				t.Fatalf("CreateDraft error = %v, want ErrInvalidDraft", err)
+			}
+			var count int
+			if err := database.QueryRow("SELECT COUNT(*) FROM tasks").Scan(&count); err != nil || count != 0 {
+				t.Fatalf("tasks after invalid create = %d, err %v", count, err)
+			}
+		})
+	}
+}
+
 func TestSQLiteStoreRollsBackFailedCreate(t *testing.T) {
 	database := migratedDatabase(t)
 	store, err := NewSQLiteStore(database)

client/src/cmbuyer_client/core/models.py

@@ -8,6 +8,8 @@ from pathlib import Path
 
 from .errors import ValidationError
 from .validation import (
+    MAX_SKU_TEXT_CODE_POINTS,
+    MAX_TITLE_CODE_POINTS,
     canonical_product_url,
     require_exact_fields,
     require_goods_id,
@@ -83,14 +85,18 @@ class PurchaseTask:
     def __post_init__(self) -> None:
         require_uuid4(self.id, "invalid_task_id")
         require_positive_int(self.version, "invalid_task_version")
-        require_string(self.title, "invalid_task_title", maximum=32 * 1024)
-        if not self.title.strip():
+        require_string(self.title, "invalid_task_title", maximum=MAX_TITLE_CODE_POINTS)
+        if not self.title.strip() or self.title.strip() != self.title:
             raise ValidationError("invalid_task_title")
         require_goods_id(self.goods_id)
         if self.product_url != canonical_product_url(self.goods_id):
             raise ValidationError("invalid_product_url")
-        require_string(self.sku_color, "invalid_sku_color", maximum=32 * 1024)
-        require_string(self.sku_size, "invalid_sku_size", maximum=32 * 1024)
+        require_string(self.sku_color, "invalid_sku_color", maximum=MAX_SKU_TEXT_CODE_POINTS)
+        require_string(self.sku_size, "invalid_sku_size", maximum=MAX_SKU_TEXT_CODE_POINTS)
+        if self.sku_color.strip() != self.sku_color:
+            raise ValidationError("invalid_sku_color")
+        if self.sku_size.strip() != self.sku_size:
+            raise ValidationError("invalid_sku_size")
         require_positive_int(self.quantity, "invalid_quantity")
         require_money(self.max_total_price, "invalid_max_total_price")
 

client/src/cmbuyer_client/core/validation.py

@@ -21,6 +21,10 @@ RFC3339_Z_RE = re.compile(
 )
 MONEY_RE = re.compile(r"(?:0|[1-9][0-9]*)\.[0-9]{2}")
 GOODS_ID_RE = re.compile(r"[0-9]+")
+MAX_TITLE_CODE_POINTS = 120
+MAX_SKU_TEXT_CODE_POINTS = 80
+MAX_GOODS_ID_ASCII_CHARACTERS = 32
+MAX_MONEY_ASCII_CHARACTERS = 32
 
 
 def require_string(value: object, reason: str, *, maximum: int = 4096) -> str:
@@ -92,14 +96,14 @@ def require_positive_int(value: object, reason: str = "invalid_integer") -> int:
 
 
 def require_money(value: object, reason: str = "invalid_money") -> str:
-    text = require_string(value, reason, maximum=32 * 1024)
+    text = require_string(value, reason, maximum=MAX_MONEY_ASCII_CHARACTERS)
     if MONEY_RE.fullmatch(text) is None or text == "0.00":
         raise ValidationError(reason)
     return text
 
 
 def require_goods_id(value: object) -> str:
-    text = require_string(value, "invalid_goods_id", maximum=32 * 1024)
+    text = require_string(value, "invalid_goods_id", maximum=MAX_GOODS_ID_ASCII_CHARACTERS)
     if GOODS_ID_RE.fullmatch(text) is None:
         raise ValidationError("invalid_goods_id")
     return text

client/tests/core/test_models.py

@@ -100,15 +100,9 @@ class CoreModelsTests(unittest.TestCase):
                 changed["task"]["max_total_price"] = invalid
                 ClaimedTask.from_wire(changed)
 
-        wide = claim_wire()
-        wide_goods = "1" * 33
-        wide["task"].update(
-            goods_id=wide_goods,
-            product_url="https://mobile.yangkeduo.com/goods.html?goods_id=" + wide_goods,
-            max_total_price="1" * 31 + ".00",
-            quantity=2_147_483_648,
-        )
-        self.assertEqual(ClaimedTask.from_wire(wide).task.quantity, 2_147_483_648)
+        wide_quantity = claim_wire()
+        wide_quantity["task"]["quantity"] = 2_147_483_648
+        self.assertEqual(ClaimedTask.from_wire(wide_quantity).task.quantity, 2_147_483_648)
         for invalid_goods in ("１２３", "1٢3"):
             changed = claim_wire()
             changed["task"]["goods_id"] = invalid_goods
@@ -120,6 +114,47 @@ class CoreModelsTests(unittest.TestCase):
         with self.assertRaises(ValidationError):
             ClaimedTask.from_wire(too_large)
 
+    def test_claim_fields_share_explicit_server_bounds(self) -> None:
+        legal = claim_wire()
+        legal_goods = "1" * 32
+        legal["task"].update(
+            title="😀" * 120,
+            goods_id=legal_goods,
+            product_url="https://mobile.yangkeduo.com/goods.html?goods_id=" + legal_goods,
+            sku_color="色" * 80,
+            sku_size="码" * 80,
+            max_total_price="1" * 29 + ".00",
+        )
+        claimed = ClaimedTask.from_wire(legal)
+        self.assertEqual(len(claimed.task.title), 120)
+        # Python's default ensure_ascii=True expands astral characters to surrogate
+        # escape pairs, so this is a conservative parser-budget proof as well.
+        self.assertLess(len(json.dumps(legal, separators=(",", ":")).encode()), 32 * 1024)
+
+        mutations = (
+            ("title", "😀" * 121),
+            ("title", " title"),
+            ("sku_color", "色" * 81),
+            ("sku_color", "black "),
+            ("sku_size", "码" * 81),
+            ("sku_size", " M"),
+            ("max_total_price", "1" * 30 + ".00"),
+        )
+        for field, invalid in mutations:
+            changed = claim_wire()
+            changed["task"][field] = invalid
+            with self.subTest(field=field, length=len(invalid)), self.assertRaises(ValidationError):
+                ClaimedTask.from_wire(changed)
+
+        overlong_goods = "1" * 33
+        changed = claim_wire()
+        changed["task"].update(
+            goods_id=overlong_goods,
+            product_url="https://mobile.yangkeduo.com/goods.html?goods_id=" + overlong_goods,
+        )
+        with self.assertRaises(ValidationError):
+            ClaimedTask.from_wire(changed)
+
     def test_wire_strings_reject_lone_surrogates_but_accept_valid_pair(self) -> None:
         for escaped in (r'"\ud800"', r'"\udc00"'):
             value = claim_wire()

client/tests/remote/test_task_source.py

@@ -75,6 +75,32 @@ class TaskSourceTests(unittest.TestCase):
             HttpTaskSource(redirect).claim_next(self.credentials, ClaimRequest(SESSION_ID, REQUEST_ID))
         self.assertEqual(len(redirect.calls), 1)
 
+    def test_claim_rejects_service_field_bound_drift_as_ambiguous(self) -> None:
+        mutations = (
+            ("title", "😀" * 121),
+            ("sku_color", "色" * 81),
+            ("sku_size", "码" * 81),
+            ("max_total_price", "1" * 30 + ".00"),
+        )
+        for field, invalid in mutations:
+            value = claim_wire()
+            value["task"][field] = invalid
+            transport = FakeTransport(response(200, value))
+            with self.subTest(field=field), self.assertRaises(AmbiguousRemoteError):
+                HttpTaskSource(transport).claim_next(self.credentials, ClaimRequest(SESSION_ID, REQUEST_ID))
+            self.assertEqual(len(transport.calls), 1)
+
+        goods_id = "1" * 33
+        value = claim_wire()
+        value["task"].update(
+            goods_id=goods_id,
+            product_url="https://mobile.yangkeduo.com/goods.html?goods_id=" + goods_id,
+        )
+        with self.assertRaises(AmbiguousRemoteError):
+            HttpTaskSource(FakeTransport(response(200, value))).claim_next(
+                self.credentials, ClaimRequest(SESSION_ID, REQUEST_ID)
+            )
+
     def test_fixed_conflict_and_renew_cas(self) -> None:
         conflict = FakeTransport(response(409, {"error": "claim_requires_manual"}))
         with self.assertRaises(ManualRemoteError):

docs/api.md

@@ -96,6 +96,10 @@
 ```
 
 - 服务端解析并保存 canonical URL 与 `goods_id`；URL 非拼多多商品页、`goods_id` 缺失或含歧义则拒绝。
+- `title` 以 `TrimSpace` 后持久化值计，最多 120 个 Unicode code point；`sku_color`、`sku_size`
+  同样按持久化值计，各最多 80 个 Unicode code point。非法 UTF-8 必须先拒绝，不能把替换字符当作
+  合法 code point；超限不得截断。
+- `goods_id` 只允许 1--32 位 ASCII 数字；规范金额只允许 1--32 个 ASCII 字符。
 - `max_total_price` 是本任务允许创建待付款订单的总额上限，不是参考单价。
 - 成功只产生 `DRAFT`；不得创建授权、开放设备领取或触发真机。
 
@@ -219,7 +223,12 @@
 - 同一 `claim_request_id` 同设备、同 session 稳定重放原结果；同键异载荷返回
   `409 {"error":"idempotency_conflict"}`。没有候选返回空 `204`，且 EMPTY 也持久化稳定重放。
 - claim 持久化完整成功响应快照；领取后的 task/authorization 源行变化不得让旧 request 的标题、规格、
-  数量、金额、版本或到期时间漂移。源快照不一致时，新恢复/续租失败闭合。
+  数量、金额、版本或到期时间漂移。每次首次构造和旧 request 重放都重新校验持久化响应快照的字段
+  上限；源快照不一致时，新恢复/续租失败闭合。
+- 响应内 `title` 最多 120 个 Unicode code point，`sku_color` / `sku_size` 各最多 80 个；`goods_id`
+  为 1--32 位 ASCII 数字，`max_total_price` 为最多 32 个 ASCII 字符的规范金额。创建、授权快照、
+  candidate、持久化 claim snapshot 和 HTTP 输出共用同一合法域；既有畸形行只失败闭合，不迁移、
+  截断或改写。最坏合法字段组合编码后必须明确小于既有 32 KiB claim 响应上限。
 - 一个设备最多有一个未关闭 claim。同 session 且租约有效时重放原 attempt；同一 attempt 已按服务端
   首事件原子进入 `ORDERING` 时也只在 task version 恰好为 claim 版本 +1 时恢复。不同 session、租约
   过期或业务状态异常固定返回 `409 {"error":"claim_requires_manual"}`，不释放、不转领、不新建 attempt。
@@ -365,9 +374,11 @@ claim/renew 的格式错误固定为 `400 {"error":"invalid_request"}`，超限
 
 ### 文本和金额校验
 
-- 规格字段：Unicode 规范化后精确相等；不得包含、前缀、编辑距离或 AI 猜测。
-- `goods_id`：仅 ASCII 十进制数字，canonical URL 中唯一。
-- 金额：`0.01` 到系统配置上限，至多两位小数；规范化后再比较和持久化。
+- 标题/规格字段：输入按既有 `TrimSpace` 形成实际持久化值；title 最多 120 个 Unicode code point，
+  颜色与尺码各最多 80 个。服务端先拒绝非法 UTF-8，再计 code point；不按 UTF-8 字节或视觉 grapheme
+  计数，不截断超限值。规格比较仍为规范化后精确相等；不得包含、前缀、编辑距离或 AI 猜测。
+- `goods_id`：仅 1--32 位 ASCII 十进制数字，canonical URL 中唯一。
+- 金额：`0.01` 到系统配置上限，至多两位小数；规范化后必须是最多 32 个 ASCII 字符，再比较和持久化。
 - 数量：正整数，服务端与设备均设置合理上限；不能从字符串静默截断。
 
 ## 三、采购工具本地模块合约
@@ -389,9 +400,11 @@ events/fail/fence/result 或完整 `ResultSink`。T-304/T-306 必须通过 `Dura
 同一 device id 的 Bearer 后显式重放；网络、超时、503、截断、非法/未知 2xx 同样只保留原槽。协议/409
 终止槽但不换 key。成功响应落库失败时，重启仍用原 key 向服务端恢复事实。
 
-金额按服务端合法域接受规范 ASCII 十进制正数字符串（最低 `0.01`，恰好两位小数、无前导零）；wire
-整数为正 int64，拒绝 bool。claim 成功响应总上限 32 KiB；因此客户端不额外发明 goods/title/SKU/金额
-的单字段业务上限。RFC3339Nano 按 0--9 位小数的纳秒时间轴比较，不能用 Python 微秒精度截断。
+金额按服务端合法域接受规范 ASCII 十进制正数字符串（最低 `0.01`，恰好两位小数、无前导零，最多
+32 个 ASCII 字符）；`goods_id` 只接受 1--32 位 ASCII 数字，title 最多 120 个 Unicode code point，
+颜色与尺码各最多 80 个。客户端不得截断或修复漂移响应。wire 整数为正 int64，拒绝 bool。claim 成功
+响应总上限仍为 32 KiB，最坏合法字段组合由双端契约测试证明严格小于该值。RFC3339Nano 按 0--9 位
+小数的纳秒时间轴比较，不能用 Python 微秒精度截断。
 
 ### 本地恢复合约
 

docs/tasks/T-211.md

@@ -22,7 +22,7 @@ write_paths:
   - client/tests/remote/**
 ---
 
-<!-- BEGIN VIKUNJA EXPORT id=55 synced=2026-08-04T17:18:14Z sha256=a96dc25e291e2ce904f3f78554e2354d450342d164601740c005d240c4d33c30 -->
+<!-- BEGIN VIKUNJA EXPORT id=55 synced=2026-08-04T17:25:11Z sha256=7fd613a5a64643deb5601136241868717a00cc9e7739c6f6a5bb2295e2a9210d -->
 ## 问题 / 背景
 
 claim 成功响应受 32 KiB 总 body 上限保护，但创建、授权快照、candidate 和重放链路尚未统一约束各自由文本字段，客户端也未冻结同一单字段合法域。异常或历史超长值可能让合法业务事实变成不可传输响应。
@@ -65,6 +65,10 @@ claim 成功响应受 32 KiB 总 body 上限保护，但创建、授权快照、
 ### 2026-08-04T17:18:04Z · ila
 
 2026-08-05 实现范围收紧：HTTP handler 是 service 输出的最后边界，已获总控批准将精确文件 admin/internal/server/task_claims.go 纳入 write_paths；handler 序列化前重验 claim response 与 32 KiB 上限，不扩大到其他 server 文件。
+
+### 2026-08-04T17:25:07Z · ila
+
+2026-08-05 实现里程碑：服务端共享 validator 已覆盖创建持久化、start/authorization、candidate、claim snapshot/replay 和 handler 输出；客户端 wire 同界。最坏合法服务端 JSON 使用会被 escapeHTML 为 6 字节的 < 字符证明严格小于 32 KiB，客户端用 ensure_ascii=True 做保守预算证明。focused：Go tasks/taskclaim/server 全绿；client core 8/8、remote 15/15。
 <!-- END VIKUNJA EXPORT -->
 
 ## 边界