| 1 | package calls |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "context" |
| 6 | "fmt" |
| 7 | "log/slog" |
| 8 | "strings" |
| 9 | "testing" |
| 10 | |
| 11 | "amadan.net/rastrillo/rastrillo/mail" |
| 12 | ) |
| 13 | |
| 14 | type failingSender struct{ err error } |
| 15 | |
| 16 | func (f failingSender) Send(ctx context.Context, to, subject, body string) error { return f.err } |
| 17 | |
| 18 | // smtpish is a distinct type so the log line's "type" field is worth |
| 19 | // something: it names what failed without naming who it failed for. |
| 20 | type smtpish struct{ msg string } |
| 21 | |
| 22 | func (e smtpish) Error() string { return e.msg } |
| 23 | |
| 24 | func capture() (*slog.Logger, *bytes.Buffer) { |
| 25 | var buf bytes.Buffer |
| 26 | return slog.New(slog.NewTextHandler(&buf, nil)), &buf |
| 27 | } |
| 28 | |
| 29 | func TestMailErrorsCarryNoAddress(t *testing.T) { |
| 30 | const address = "Guest@Example.com" |
| 31 | inner := failingSender{err: fmt.Errorf("rastrillo/mail: send to %s: %w", |
| 32 | address, smtpish{msg: "550 no mailbox for guest@example.com"})} |
| 33 | logger, buf := capture() |
| 34 | |
| 35 | err := RedactMailErrors(inner, logger).Send(context.Background(), address, "s", "b") |
| 36 | if err == nil { |
| 37 | t.Fatal("a failed send answered nil") |
| 38 | } |
| 39 | if err.Error() != "calls: mail delivery failed" { |
| 40 | t.Fatalf("returned error is %q; it must be derived from nothing", err) |
| 41 | } |
| 42 | if strings.Contains(strings.ToLower(err.Error()), "guest") { |
| 43 | t.Fatalf("the returned error carries the address: %q", err) |
| 44 | } |
| 45 | log := buf.String() |
| 46 | if strings.Contains(strings.ToLower(log), "guest") { |
| 47 | t.Fatalf("the log line carries the address:\n%s", log) |
| 48 | } |
| 49 | if !strings.Contains(log, "calls.smtpish") { |
| 50 | t.Fatalf("the log line does not name the error's type:\n%s", log) |
| 51 | } |
| 52 | if !strings.Contains(log, "address_seen=true") { |
| 53 | t.Fatalf("the log line does not say the address was in the message:\n%s", log) |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | // The rune trap the first version of this file walked into (codex round |
| 58 | // 2, C2-1): it replaced the address in the message with "[address]" by |
| 59 | // finding an offset in a strings.ToLower copy and slicing the original |
| 60 | // at that offset. strings.ToLower can change a string's byte length — |
| 61 | // KELVIN SIGN (U+212A, three bytes) folds to one-byte "k"; capital |
| 62 | // dotted I (U+0130, two bytes) folds to two-byte "i̇" — so an offset |
| 63 | // found in the lowered copy does not address the same bytes in the |
| 64 | // original, and applying it could leave a suffix of the address in the |
| 65 | // "redacted" text or cut a rune in half. |
| 66 | // |
| 67 | // This version logs nothing derived from the message — only a bool, via |
| 68 | // strings.Contains over two independently-lowered strings, no slicing — |
| 69 | // so there is nothing left to desynchronise. This test is the guard |
| 70 | // that keeps it that way: two addresses carrying both trap runes, inside |
| 71 | // one error message that also contains a run of ordinary ASCII "KKK"s |
| 72 | // (an SMTP server rejecting a batch tends to shout), asserting the log |
| 73 | // holds no "@" and no fragment of either address. |
| 74 | func TestNoFragmentOfAnAddressReachesTheLog(t *testing.T) { |
| 75 | const ( |
| 76 | kelvin = "Kelvin@example.com" // ordinary ASCII K — not the Kelvin sign |
| 77 | ines = "\u0130nes@example.com" // LATIN CAPITAL LETTER I WITH DOT ABOVE |
| 78 | ) |
| 79 | inner := failingSender{err: fmt.Errorf("rastrillo/mail: send to %s: %w", kelvin, |
| 80 | smtpish{msg: "550 KKKKKKKKK unknown recipients " + kelvin + ", " + ines})} |
| 81 | logger, buf := capture() |
| 82 | |
| 83 | err := RedactMailErrors(inner, logger).Send(context.Background(), kelvin, "s", "b") |
| 84 | if err == nil { |
| 85 | t.Fatal("a failed send answered nil") |
| 86 | } |
| 87 | if err.Error() != "calls: mail delivery failed" { |
| 88 | t.Fatalf("returned error is %q, want exactly the fixed sentence", err) |
| 89 | } |
| 90 | |
| 91 | log := buf.String() |
| 92 | if strings.Contains(log, "@") { |
| 93 | t.Fatalf("the log contains an @:\n%s", log) |
| 94 | } |
| 95 | for _, fragment := range []string{ |
| 96 | kelvin, ines, |
| 97 | strings.ToLower(kelvin), strings.ToLower(ines), |
| 98 | "elvin", "nes", // the local parts, minus the leading trap character |
| 99 | "example.com", |
| 100 | "\u0130", // the trap rune itself |
| 101 | } { |
| 102 | if strings.Contains(log, fragment) { |
| 103 | t.Errorf("the log carries a fragment of an address, %q:\n%s", fragment, log) |
| 104 | } |
| 105 | } |
| 106 | if !strings.Contains(log, "address_seen=true") { |
| 107 | t.Errorf("the address was in the message and the log does not say so:\n%s", log) |
| 108 | } |
| 109 | if strings.ContainsRune(log, '\uFFFD') { |
| 110 | t.Errorf("the log holds a replacement rune, so something was cut mid-rune:\n%s", log) |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | func TestASuccessfulSendIsUntouched(t *testing.T) { |
| 115 | logger, buf := capture() |
| 116 | if err := RedactMailErrors(failingSender{}, logger).Send(context.Background(), "a@b.test", "s", "b"); err != nil { |
| 117 | t.Fatal(err) |
| 118 | } |
| 119 | if buf.Len() != 0 { |
| 120 | t.Fatalf("a successful send logged:\n%s", buf.String()) |
| 121 | } |
| 122 | if RedactMailErrors(nil, logger) != nil { |
| 123 | t.Fatal("a nil mailer was wrapped into a non-nil one, which would defeat the production refusal") |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | func TestAddressSeenIsCaseInsensitiveAndNeedsNoSlicing(t *testing.T) { |
| 128 | for _, tc := range []struct { |
| 129 | msg, address string |
| 130 | want bool |
| 131 | }{ |
| 132 | {"send to a@b.test: refused", "A@B.test", true}, // the recipient, folded |
| 133 | {"send to a@b.test: refused", "c@d.test", false}, |
| 134 | {"dial tcp 10.0.0.1:25: connection refused", "a@b.test", false}, |
| 135 | {"connection reset", "", false}, |
| 136 | {"550 " + "\u212A" + "elvin@example.com not found", "\u212A" + "elvin@example.com", true}, |
| 137 | } { |
| 138 | if got := addressSeen(tc.msg, tc.address); got != tc.want { |
| 139 | t.Errorf("addressSeen(%q, %q) = %v, want %v", tc.msg, tc.address, got, tc.want) |
| 140 | } |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | // mail.IsConfigured asks a Sender whether it really delivers. The |
| 145 | // wrapper has to forward that, or wrapping a logging mailer would make |
| 146 | // it look like a relay (mail/mail.go:59). |
| 147 | func TestTheWrapperForwardsDeliversAndSendList(t *testing.T) { |
| 148 | logger, buf := capture() |
| 149 | |
| 150 | logged := RedactMailErrors(mail.Logged(logger), logger) |
| 151 | if mail.IsConfigured(logged) { |
| 152 | t.Fatal("a wrapped logging mailer claims to deliver") |
| 153 | } |
| 154 | if _, ok := logged.(mail.ListSender); !ok { |
| 155 | t.Fatal("a wrapped ListSender lost SendList") |
| 156 | } |
| 157 | if err := logged.(mail.ListSender).SendList(context.Background(), |
| 158 | mail.ListMessage{To: "a@b.test", Subject: "s", Body: "b"}); err != nil { |
| 159 | t.Fatal(err) |
| 160 | } |
| 161 | buf.Reset() |
| 162 | |
| 163 | plain := RedactMailErrors(failingSender{}, logger) |
| 164 | if !mail.IsConfigured(plain) { |
| 165 | t.Fatal("a wrapped plain Sender is assumed not to deliver") |
| 166 | } |
| 167 | if _, ok := plain.(mail.ListSender); ok { |
| 168 | t.Fatal("a wrapped plain Sender gained a SendList it cannot honour") |
| 169 | } |
| 170 | |
| 171 | // A failing SendList redacts exactly as Send does. |
| 172 | failing := RedactMailErrors(failingListSender{err: fmt.Errorf("send to a@b.test: %w", smtpish{"550"})}, logger) |
| 173 | err := failing.(mail.ListSender).SendList(context.Background(), mail.ListMessage{To: "a@b.test"}) |
| 174 | if err == nil || err.Error() != "calls: mail delivery failed" { |
| 175 | t.Fatalf("SendList returned %v", err) |
| 176 | } |
| 177 | if strings.Contains(buf.String(), "a@b.test") { |
| 178 | t.Fatalf("SendList's log line carries the address:\n%s", buf.String()) |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | type failingListSender struct{ err error } |
| 183 | |
| 184 | func (f failingListSender) Send(ctx context.Context, to, subject, body string) error { return f.err } |
| 185 | func (f failingListSender) SendList(ctx context.Context, m mail.ListMessage) error { return f.err } |
| 186 | |
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