| 1 | package clamd |
| 2 | |
| 3 | import ( |
| 4 | "bufio" |
| 5 | "bytes" |
| 6 | "context" |
| 7 | "encoding/binary" |
| 8 | "io" |
| 9 | "net" |
| 10 | "strings" |
| 11 | "testing" |
| 12 | "time" |
| 13 | ) |
| 14 | |
| 15 | // fakeDeadline bounds the fake clamd's side of every pipe, so a protocol bug |
| 16 | // surfaces as a failing test rather than a hung one. |
| 17 | const fakeDeadline = 5 * time.Second |
| 18 | |
| 19 | // frameReader decodes the INSTREAM framing off the wire: an optional |
| 20 | // NUL-terminated command, then 4-byte big-endian length + payload chunks, |
| 21 | // ending at the zero-length chunk. It exists so the tests assert the bytes we |
| 22 | // actually put on the socket rather than trusting the writer to agree with |
| 23 | // itself. |
| 24 | type frameReader struct { |
| 25 | r *bufio.Reader |
| 26 | cmdRead bool |
| 27 | remain uint32 |
| 28 | done bool |
| 29 | } |
| 30 | |
| 31 | func newFrameReader(r io.Reader) *frameReader { |
| 32 | return &frameReader{r: bufio.NewReader(r)} |
| 33 | } |
| 34 | |
| 35 | func (f *frameReader) Read(p []byte) (int, error) { |
| 36 | if !f.cmdRead { |
| 37 | if _, err := f.r.ReadString(0); err != nil { |
| 38 | return 0, err |
| 39 | } |
| 40 | f.cmdRead = true |
| 41 | } |
| 42 | for f.remain == 0 { |
| 43 | if f.done { |
| 44 | return 0, io.EOF |
| 45 | } |
| 46 | var hdr [4]byte |
| 47 | if _, err := io.ReadFull(f.r, hdr[:]); err != nil { |
| 48 | return 0, err |
| 49 | } |
| 50 | f.remain = binary.BigEndian.Uint32(hdr[:]) |
| 51 | if f.remain == 0 { |
| 52 | f.done = true |
| 53 | return 0, io.EOF |
| 54 | } |
| 55 | } |
| 56 | if uint32(len(p)) > f.remain { |
| 57 | p = p[:f.remain] |
| 58 | } |
| 59 | n, err := f.r.Read(p) |
| 60 | f.remain -= uint32(n) |
| 61 | return n, err |
| 62 | } |
| 63 | |
| 64 | // fakeClamd stands a clamd on one end of a net.Pipe. It reads the command, |
| 65 | // drains any INSTREAM frames, hands back the payload, then writes reply. |
| 66 | // |
| 67 | // NOTE: over net.Pipe (unbuffered, synchronous) the server MUST finish reading |
| 68 | // before it writes, or both ends deadlock — the client is still blocked in a |
| 69 | // write nobody is reading while the server blocks in a write nobody is |
| 70 | // reading. Every helper here keeps that order. |
| 71 | func fakeClamd(t *testing.T, reply string) (*Client, <-chan []byte) { |
| 72 | t.Helper() |
| 73 | client, server := net.Pipe() |
| 74 | // A framing bug does not fail these tests, it HANGS them: a wrong length |
| 75 | // header has the fake waiting on megabytes the client will never send |
| 76 | // while the client waits on a reply. Verified by flipping the header to |
| 77 | // little-endian, which without this deadline wedges until the package |
| 78 | // test timeout ten minutes later. The deadline turns that into a clean |
| 79 | // failure in seconds. |
| 80 | _ = server.SetDeadline(time.Now().Add(fakeDeadline)) |
| 81 | got := make(chan []byte, 1) |
| 82 | go func() { |
| 83 | defer server.Close() |
| 84 | br := bufio.NewReader(server) |
| 85 | cmd, err := br.ReadString(0) |
| 86 | if err != nil { |
| 87 | got <- nil |
| 88 | return |
| 89 | } |
| 90 | var payload []byte |
| 91 | if strings.Contains(cmd, "INSTREAM") { |
| 92 | payload, _ = io.ReadAll(&frameReader{r: br, cmdRead: true}) |
| 93 | } |
| 94 | got <- payload |
| 95 | _, _ = server.Write([]byte(reply)) |
| 96 | }() |
| 97 | t.Cleanup(func() { client.Close() }) |
| 98 | return newWithConn(client), got |
| 99 | } |
| 100 | |
| 101 | func replyFixture(t *testing.T, reply string) Result { |
| 102 | t.Helper() |
| 103 | c, _ := fakeClamd(t, reply) |
| 104 | res, err := c.ScanStream(context.Background(), bytes.NewReader([]byte("payload"))) |
| 105 | if err != nil { |
| 106 | t.Fatalf("ScanStream: %v", err) |
| 107 | } |
| 108 | return res |
| 109 | } |
| 110 | |
| 111 | func versionFixture(t *testing.T, reply string) string { |
| 112 | t.Helper() |
| 113 | c, _ := fakeClamd(t, reply) |
| 114 | v, err := c.Version(context.Background()) |
| 115 | if err != nil { |
| 116 | t.Fatalf("Version: %v", err) |
| 117 | } |
| 118 | return v |
| 119 | } |
| 120 | |
| 121 | // INSTREAM framing, asserted on the wire: zINSTREAM\0, then 4-byte |
| 122 | // big-endian length + payload chunks, then a zero-length chunk. |
| 123 | func TestScanStreamWireFormat(t *testing.T) { |
| 124 | client, server := net.Pipe() |
| 125 | _ = server.SetDeadline(time.Now().Add(fakeDeadline)) |
| 126 | got := make(chan []byte, 1) |
| 127 | go func() { |
| 128 | defer server.Close() |
| 129 | buf, _ := io.ReadAll(newFrameReader(server)) // reads until the zero chunk |
| 130 | got <- buf |
| 131 | server.Write([]byte("stream: OK\x00")) |
| 132 | }() |
| 133 | |
| 134 | c := newWithConn(client) |
| 135 | res, err := c.ScanStream(context.Background(), bytes.NewReader([]byte("hello"))) |
| 136 | if err != nil { |
| 137 | t.Fatal(err) |
| 138 | } |
| 139 | if res.Status != StatusClean { |
| 140 | t.Fatalf("status = %v, want clean", res.Status) |
| 141 | } |
| 142 | if b := <-got; !bytes.Equal(b, []byte("hello")) { |
| 143 | t.Fatalf("payload on the wire = %q, want %q", b, "hello") |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | func TestScanStreamInfected(t *testing.T) { |
| 148 | res := replyFixture(t, "stream: Eicar-Signature FOUND\x00") |
| 149 | if res.Status != StatusInfected { |
| 150 | t.Fatalf("status = %v, want infected", res.Status) |
| 151 | } |
| 152 | if res.Signature != "Eicar-Signature" { |
| 153 | t.Fatalf("signature = %q", res.Signature) |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | // A size refusal is SKIPPED, not FAILED. An over-large object was not judged; |
| 158 | // calling that a failure would make the evidence lie about what happened. |
| 159 | func TestScanStreamSizeExceededIsItsOwnStatus(t *testing.T) { |
| 160 | res := replyFixture(t, "INSTREAM size limit exceeded. ERROR\x00") |
| 161 | if res.Status != StatusSizeExceeded { |
| 162 | t.Fatalf("status = %v, want size-exceeded", res.Status) |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | // Anything else ending ERROR is the engine reading the object and failing on |
| 167 | // it — a per-object fact, distinct from the engine being unreachable. |
| 168 | func TestScanStreamErrorReply(t *testing.T) { |
| 169 | res := replyFixture(t, "stream: Can't allocate memory ERROR\x00") |
| 170 | if res.Status != StatusError { |
| 171 | t.Fatalf("status = %v, want error", res.Status) |
| 172 | } |
| 173 | if !strings.Contains(res.Raw, "allocate memory") { |
| 174 | t.Fatalf("the engine's own words did not survive: %q", res.Raw) |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | func TestVersionParse(t *testing.T) { |
| 179 | // zVERSION answers engine/sig-db-version/sig-db-date. |
| 180 | v := versionFixture(t, "ClamAV 1.4.1/27500/Mon Sep 1 08:00:00 2026\x00") |
| 181 | if v != "ClamAV 1.4.1/27500/Mon Sep 1 08:00:00 2026" { |
| 182 | t.Fatalf("version = %q", v) |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | // A chunked object arrives whole and in order. One Read per chunk means an |
| 187 | // off-by-one in the framing shows up as a corrupted stream, not as a slightly |
| 188 | // wrong length — this asserts we never send a frame header we then fail to |
| 189 | // fill. |
| 190 | func TestScanStreamChunksLargeObject(t *testing.T) { |
| 191 | want := bytes.Repeat([]byte("carlos"), chunkSize) // several chunks' worth |
| 192 | c, got := fakeClamd(t, "stream: OK\x00") |
| 193 | if _, err := c.ScanStream(context.Background(), bytes.NewReader(want)); err != nil { |
| 194 | t.Fatal(err) |
| 195 | } |
| 196 | if b := <-got; !bytes.Equal(b, want) { |
| 197 | t.Fatalf("streamed %d bytes, want %d", len(b), len(want)) |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | // Every blocking operation carries a deadline. A clamd that accepts the stream |
| 202 | // and never answers must fail the object, not wedge the pass forever. |
| 203 | func TestReadReplyHasADeadline(t *testing.T) { |
| 204 | client, server := net.Pipe() |
| 205 | defer server.Close() |
| 206 | go func() { |
| 207 | br := bufio.NewReader(server) |
| 208 | br.ReadString(0) |
| 209 | io.ReadAll(&frameReader{r: br, cmdRead: true}) |
| 210 | // ... and then never reply. |
| 211 | select {} |
| 212 | }() |
| 213 | |
| 214 | c := newWithConn(client) |
| 215 | c.timeouts.Read = 50 * time.Millisecond |
| 216 | done := make(chan error, 1) |
| 217 | go func() { |
| 218 | _, err := c.ScanStream(context.Background(), bytes.NewReader([]byte("x"))) |
| 219 | done <- err |
| 220 | }() |
| 221 | select { |
| 222 | case err := <-done: |
| 223 | if err == nil { |
| 224 | t.Fatal("a silent clamd returned success") |
| 225 | } |
| 226 | case <-time.After(5 * time.Second): |
| 227 | t.Fatal("ScanStream blocked past its read deadline") |
| 228 | } |
| 229 | } |
| 230 | |
| 231 | // A zero Timeouts means the defaults, never "wait forever". |
| 232 | func TestZeroTimeoutsTakeDefaults(t *testing.T) { |
| 233 | c := New("/run/clamav/clamd.ctl", Timeouts{}) |
| 234 | if c.timeouts.Dial <= 0 || c.timeouts.Write <= 0 || c.timeouts.Read <= 0 { |
| 235 | t.Fatalf("zero timeouts left an infinite wait: %+v", c.timeouts) |
| 236 | } |
| 237 | } |
| 238 | |
| 239 | // The address decides the network, and a leading slash is the whole rule: a |
| 240 | // unix socket is always an absolute path and a host never is. |
| 241 | func TestNetworkForAddress(t *testing.T) { |
| 242 | for addr, want := range map[string]string{ |
| 243 | "/run/clamav/clamd.ctl": "unix", |
| 244 | "/tmp/clamd.sock": "unix", |
| 245 | "scanner.internal:3310": "tcp", |
| 246 | "127.0.0.1:3310": "tcp", |
| 247 | "[::1]:3310": "tcp", |
| 248 | } { |
| 249 | if got := networkFor(addr); got != want { |
| 250 | t.Errorf("networkFor(%q) = %q, want %q", addr, got, want) |
| 251 | } |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | // A TCP client dials TCP and speaks the same protocol. The framing, deadlines |
| 256 | // and reply parsing are transport-independent, so this asserts the dial and |
| 257 | // then the whole INSTREAM exchange over a real socket. |
| 258 | func TestScanStreamOverTCP(t *testing.T) { |
| 259 | ln, err := net.Listen("tcp", "127.0.0.1:0") |
| 260 | if err != nil { |
| 261 | t.Fatal(err) |
| 262 | } |
| 263 | defer ln.Close() |
| 264 | |
| 265 | got := make(chan []byte, 1) |
| 266 | go func() { |
| 267 | conn, err := ln.Accept() |
| 268 | if err != nil { |
| 269 | got <- nil |
| 270 | return |
| 271 | } |
| 272 | defer conn.Close() |
| 273 | _ = conn.SetDeadline(time.Now().Add(fakeDeadline)) |
| 274 | br := bufio.NewReader(conn) |
| 275 | if _, err := br.ReadString(0); err != nil { |
| 276 | got <- nil |
| 277 | return |
| 278 | } |
| 279 | payload, _ := io.ReadAll(&frameReader{r: br, cmdRead: true}) |
| 280 | got <- payload |
| 281 | _, _ = conn.Write([]byte("stream: OK\x00")) |
| 282 | }() |
| 283 | |
| 284 | c := New(ln.Addr().String(), Timeouts{}) |
| 285 | if c.network != "tcp" { |
| 286 | t.Fatalf("network = %q, want tcp", c.network) |
| 287 | } |
| 288 | res, err := c.ScanStream(context.Background(), bytes.NewReader([]byte("hello"))) |
| 289 | if err != nil { |
| 290 | t.Fatal(err) |
| 291 | } |
| 292 | if res.Status != StatusClean { |
| 293 | t.Fatalf("status = %v, want clean", res.Status) |
| 294 | } |
| 295 | if b := <-got; !bytes.Equal(b, []byte("hello")) { |
| 296 | t.Fatalf("payload over tcp = %q", b) |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | // An empty address is refused rather than dialled, and the message says |
| 301 | // address rather than socket now that either shape is legitimate. |
| 302 | func TestDialRefusesEmptyAddress(t *testing.T) { |
| 303 | c := New("", Timeouts{}) |
| 304 | if _, err := c.Version(context.Background()); err == nil || |
| 305 | !strings.Contains(err.Error(), "no address configured") { |
| 306 | t.Fatalf("err = %v", err) |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | // With AlertExceedsMax on, clamd reports an archive it could only partly scan |
| 311 | // as a FOUND whose signature names the limit. That is not an infection and it |
| 312 | // is not clean: nothing was judged, so it is the same status as an object too |
| 313 | // large to stream. Recording it clean would sign a verdict over bytes nobody |
| 314 | // read; recording it infected would make enforce block large honest archives. |
| 315 | func TestLimitHeuristicIsSizeExceededNotInfected(t *testing.T) { |
| 316 | for _, limit := range []string{"MaxScanSize", "MaxFileSize", "MaxFiles", "MaxRecursion"} { |
| 317 | reply := "stream: Heuristics.Limits.Exceeded." + limit + " FOUND\x00" |
| 318 | res := replyFixture(t, reply) |
| 319 | if res.Status != StatusSizeExceeded { |
| 320 | t.Errorf("%s: status = %v, want size-exceeded", limit, res.Status) |
| 321 | } |
| 322 | if res.Signature != "" { |
| 323 | t.Errorf("%s: a limit is not a signature, got %q", limit, res.Signature) |
| 324 | } |
| 325 | if !strings.Contains(res.Raw, limit) { |
| 326 | t.Errorf("%s: the engine's own words did not survive: %q", limit, res.Raw) |
| 327 | } |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | // Older engines name the limit without saying which one. |
| 332 | func TestBareLimitHeuristicIsSizeExceeded(t *testing.T) { |
| 333 | res := replyFixture(t, "stream: Heuristics.Limits.Exceeded FOUND\x00") |
| 334 | if res.Status != StatusSizeExceeded { |
| 335 | t.Fatalf("status = %v, want size-exceeded", res.Status) |
| 336 | } |
| 337 | } |
| 338 | |
| 339 | // A scan that ran out of TIME depends on load, not on the bytes, so it must be |
| 340 | // retried. StatusError becomes a failed verdict, which every sweep re-issues; |
| 341 | // size-exceeded becomes skipped, which is carried forward until the object |
| 342 | // changes. Filing a timeout under skipped would exclude the object for good. |
| 343 | func TestScanTimeLimitIsAnErrorSoItIsRetried(t *testing.T) { |
| 344 | res := replyFixture(t, "stream: Heuristics.Limits.Exceeded.MaxScanTime FOUND\x00") |
| 345 | if res.Status != StatusError { |
| 346 | t.Fatalf("status = %v, want error", res.Status) |
| 347 | } |
| 348 | if !strings.Contains(res.Raw, "MaxScanTime") { |
| 349 | t.Fatalf("the engine's own words did not survive: %q", res.Raw) |
| 350 | } |
| 351 | } |
| 352 | |
| 353 | // The match is on the SIGNATURE, as a prefix. A real signature that happens to |
| 354 | // carry the phrase elsewhere in its name is still an infection, and so is one |
| 355 | // that only begins with something similar. |
| 356 | func TestLookalikeSignaturesAreStillInfected(t *testing.T) { |
| 357 | for _, sig := range []string{ |
| 358 | "Win.Heuristics.Limits.Exceeded.Fake", |
| 359 | "Heuristics.Limits.ExceededButNot", |
| 360 | "Heuristics.Phishing.Email.SpoofedDomain", |
| 361 | "Eicar-Signature", |
| 362 | } { |
| 363 | res := replyFixture(t, "stream: "+sig+" FOUND\x00") |
| 364 | if res.Status != StatusInfected { |
| 365 | t.Errorf("%s: status = %v, want infected", sig, res.Status) |
| 366 | } |
| 367 | if res.Signature != sig { |
| 368 | t.Errorf("signature = %q, want %q", res.Signature, sig) |
| 369 | } |
| 370 | } |
| 371 | } |
| 372 | |
amadan