| 1 | package xlsx_test |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "context" |
| 6 | "os" |
| 7 | "path/filepath" |
| 8 | "strings" |
| 9 | "testing" |
| 10 | |
| 11 | "amadan.net/rastrillo/rastrillo/blobs" |
| 12 | |
| 13 | "amadan.net/oficina/sheets/internal/sheets/xlsx" |
| 14 | ) |
| 15 | |
| 16 | // StoreSealed must never let a plaintext spreadsheet reach the |
| 17 | // underlying blob backend — spec §0 and §2.3, and the task's own |
| 18 | // constraint that an unsealed generated XLSX file in a bucket defeats |
| 19 | // the one rule through a side door. This proves it against blobs.Dir |
| 20 | // (content-addressed files on disk — the same shape blobs.S3 has, |
| 21 | // minus network credentials this test environment doesn't have), by |
| 22 | // grepping the raw stored bytes for a distinctive string only a cell in |
| 23 | // the exported workbook could contain. |
| 24 | func TestStoreSealedNeverWritesPlaintext(t *testing.T) { |
| 25 | const canary = "CANARY-XLSX-BLOB-PLAINTEXT-71ad" |
| 26 | |
| 27 | db := openTestDB(t) |
| 28 | h := newTab(t, db, testSealer(t)) |
| 29 | rowID, err := h.EnsureRow(0) |
| 30 | if err != nil { |
| 31 | t.Fatalf("EnsureRow: %v", err) |
| 32 | } |
| 33 | colID, err := h.EnsureCol(0) |
| 34 | if err != nil { |
| 35 | t.Fatalf("EnsureCol: %v", err) |
| 36 | } |
| 37 | if err := h.Set(rowID, colID, canary, 1); err != nil { |
| 38 | t.Fatalf("Set: %v", err) |
| 39 | } |
| 40 | |
| 41 | blobDir := t.TempDir() |
| 42 | underlying, err := blobs.Dir(blobDir) |
| 43 | if err != nil { |
| 44 | t.Fatalf("blobs.Dir: %v", err) |
| 45 | } |
| 46 | key := make([]byte, 32) |
| 47 | for i := range key { |
| 48 | key[i] = byte(i) |
| 49 | } |
| 50 | |
| 51 | ref, err := xlsx.StoreSealed(context.Background(), underlying, key, h) |
| 52 | if err != nil { |
| 53 | t.Fatalf("StoreSealed: %v", err) |
| 54 | } |
| 55 | if ref.ContentType != "application/octet-stream" { |
| 56 | t.Fatalf("ContentType = %q, want application/octet-stream", ref.ContentType) |
| 57 | } |
| 58 | |
| 59 | entries, err := os.ReadDir(blobDir) |
| 60 | if err != nil { |
| 61 | t.Fatalf("read blob dir: %v", err) |
| 62 | } |
| 63 | if len(entries) == 0 { |
| 64 | t.Fatal("blobs.Dir wrote nothing") |
| 65 | } |
| 66 | for _, e := range entries { |
| 67 | raw, err := os.ReadFile(filepath.Join(blobDir, e.Name())) |
| 68 | if err != nil { |
| 69 | t.Fatalf("read %s: %v", e.Name(), err) |
| 70 | } |
| 71 | if bytes.Contains(raw, []byte(canary)) { |
| 72 | t.Fatalf("plaintext %q found in stored blob %s", canary, e.Name()) |
| 73 | } |
| 74 | // Also unsealed: not even a bare, un-decrypted XLSX zip should |
| 75 | // be recoverable from the stored bytes (a sealed blob's magic |
| 76 | // bytes are AES-GCM ciphertext, never the "PK\x03\x04" zip |
| 77 | // signature every XLSX file starts with). |
| 78 | if bytes.HasPrefix(raw, []byte("PK\x03\x04")) { |
| 79 | t.Fatalf("stored blob %s starts with an unsealed XLSX zip signature", e.Name()) |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | // And the round trip itself must still work: LoadSealed recovers |
| 84 | // exactly what was stored. |
| 85 | h2 := newTab(t, db, testSealer(t)) |
| 86 | if err := xlsx.LoadSealed(context.Background(), underlying, key, ref, h2); err != nil { |
| 87 | t.Fatalf("LoadSealed: %v", err) |
| 88 | } |
| 89 | rowID2, colID2, ok := cellAt(h2, 0, 0) |
| 90 | if !ok { |
| 91 | t.Fatal("LoadSealed produced no cell at (0,0)") |
| 92 | } |
| 93 | raw2, ok := h2.RawInput(rowID2, colID2) |
| 94 | if !ok || !strings.Contains(raw2, "CANARY-XLSX-BLOB-PLAINTEXT") { |
| 95 | t.Fatalf("RawInput after LoadSealed = %q, %v, want the canary text back", raw2, ok) |
| 96 | } |
| 97 | } |
| 98 | |
amadan