Improve OMNI input validation

src/audio/audio_utils.cpp

@@ -105,12 +105,18 @@ std::vector<float> readWav(const std::string_view& wavData, uint32_t targetSampl
         drwav_uninit(&wav);
         throw std::runtime_error("WAV file header claims more frames than possible from data chunk size");
     }
-    // Validate decoded buffer size before resampling (float32 mono output)
+    // Validate decoded buffer size before any large allocations.
+    const uint64_t n = wav.totalPCMFrameCount;
+    size_t decodedSamples = static_cast<size_t>(n);
+    if (decodedSamples > std::numeric_limits<size_t>::max() / sizeof(float)) {
+        drwav_uninit(&wav);
+        throw std::overflow_error("Decoded audio buffer size overflow");
+    }
     if (targetSampleRate > 0) {
-        validateAudioFileSize(wav.totalPCMFrameCount, wav.sampleRate, targetSampleRate, /*will be downmixed to mono*/ 1, sizeof(float));
+        validateAudioFileSize(n, wav.sampleRate, targetSampleRate, /*will be downmixed to mono*/ 1, sizeof(float));
+    } else {
+        validateAudioFileSizeAgainstMaxValue(decodedSamples * sizeof(float));
     }
-
-    const uint64_t n = wav.totalPCMFrameCount;
     std::vector<int16_t> pcm16;
     if (n > AUDIO_BUFFER_SIZE_LIMIT / wav.channels) {
         drwav_uninit(&wav);

src/test/audio/audio_utils_test.cpp

@@ -160,6 +160,27 @@ TEST_F(AudioUtilsSampleRateTest, wavFileAcceptedWhenAtMaxFileSizeEnv) {
     UnSetEnvironmentVar("OVMS_AUDIO_MAX_FILE_SIZE_BYTES");
 }
 
+TEST_F(AudioUtilsSampleRateTest, readWithoutResampleWavRejectedWhenExceedsMaxFileSizeEnv) {
+    const std::string wav = buildWavBuffer(/*sampleRate=*/16000, /*numSamples=*/16);
+    std::string_view view(wav);
+    size_t expectedDecodedSize = static_cast<size_t>(16 * sizeof(float));
+    SetEnvironmentVar("OVMS_AUDIO_MAX_FILE_SIZE_BYTES", std::to_string(expectedDecodedSize - 1));
+    EXPECT_THROW({ auto decoded = readWithoutResample(view, "wav"); }, std::runtime_error);
+    UnSetEnvironmentVar("OVMS_AUDIO_MAX_FILE_SIZE_BYTES");
+}
+
+TEST_F(AudioUtilsSampleRateTest, readWithoutResampleWavAcceptedWhenAtMaxFileSizeEnv) {
+    const std::string wav = buildWavBuffer(/*sampleRate=*/32000, /*numSamples=*/16);
+    std::string_view view(wav);
+    // Native-rate WAV decode keeps the full 16 float samples, or 64 bytes total.
+    size_t expectedDecodedSize = static_cast<size_t>(16 * sizeof(float));
+    SetEnvironmentVar("OVMS_AUDIO_MAX_FILE_SIZE_BYTES", std::to_string(expectedDecodedSize));
+    std::vector<float> decoded;
+    EXPECT_NO_THROW({ decoded = readWithoutResample(view, "wav"); });
+    EXPECT_EQ(decoded.size(), 16u);
+    UnSetEnvironmentVar("OVMS_AUDIO_MAX_FILE_SIZE_BYTES");
+}
+
 TEST_F(AudioUtilsSampleRateTest, mp3FileRejectedWhenExceedsMaxFileSizeEnv) {
     // Minimal valid MP3 frame (see previous test for structure)
     std::string mp3;