Merge pull request #38 from codecrafters-io/unsafe-reads

Enhance string decoding error handling in RealDecoder
codecrafters-io · Dec 12, 2024 · a880f2c · a880f2c
2 parents a27c6a6 + 7c9c216
commit a880f2c
Showing 1 changed file with 22 additions and 3 deletions.
diff --git a/protocol/decoder/real_decoder.go b/protocol/decoder/real_decoder.go
@@ -256,6 +256,11 @@ func (rd *RealDecoder) GetString() (string, error) {
 		return "", err
 	}
 
+	if rd.Remaining() < n {
+		rem := rd.Remaining()
+		return "", errors.NewPacketDecodingError(fmt.Sprintf("Expected string length to be %d bytes, got %d bytes", n, rem), "STRING")
+	}
+
 	tmpStr := string(rd.raw[rd.off : rd.off+n])
 	rd.off += n
 	return tmpStr, nil
@@ -270,6 +275,11 @@ func (rd *RealDecoder) GetNullableString() (*string, error) {
 		return nil, err
 	}
 
+	if rd.Remaining() < n {
+		rem := rd.Remaining()
+		return nil, errors.NewPacketDecodingError(fmt.Sprintf("Expected string length to be %d bytes, got %d bytes", n, rem), "NULLABLE_STRING")
+	}
+
 	tmpStr := string(rd.raw[rd.off : rd.off+n])
 	rd.off += n
 	return &tmpStr, nil
@@ -288,6 +298,12 @@ func (rd *RealDecoder) GetCompactString() (string, error) {
 	if length < 0 {
 		return "", errors.NewPacketDecodingError(fmt.Sprintf("Expected COMPACT_STRING length to be > 0, got %d", length), "COMPACT_STRING")
 	}
+
+	if rd.Remaining() < length {
+		rem := rd.Remaining()
+		return "", errors.NewPacketDecodingError(fmt.Sprintf("Expected string length to be %d bytes, got %d bytes", length, rem), "COMPACT_STRING")
+	}
+
 	tmpStr := string(rd.raw[rd.off : rd.off+length])
 	rd.off += length
 	return tmpStr, nil
@@ -308,6 +324,11 @@ func (rd *RealDecoder) GetCompactNullableString() (*string, error) {
 		return nil, errors.NewPacketDecodingError(fmt.Sprintf("Expected compact nullable string length to be > 0, got %d", length), "COMPACT_NULLABLE_STRING")
 	}
 
+	if rd.Remaining() < length {
+		rem := rd.Remaining()
+		return nil, errors.NewPacketDecodingError(fmt.Sprintf("Expected string length to be %d bytes, got %d bytes", length, rem), "COMPACT_NULLABLE_STRING")
+	}
+
 	tmpStr := string(rd.raw[rd.off : rd.off+length])
 	rd.off += length
 	return &tmpStr, nil
@@ -456,9 +477,7 @@ func (rd *RealDecoder) GetRawBytesFromOffset(length int) ([]byte, error) {
 
 	if rd.off >= len(rd.raw) {
 		return nil, errors.NewPacketDecodingError(fmt.Sprintf("Expected offset to be less than length of raw bytes (%d), got %d", len(rd.raw), rd.off), "RAW_BYTES_FROM_OFFSET")
-	}
-
-	if rd.off+length > len(rd.raw) {
+	} else if rd.off+length > len(rd.raw) {
 		return nil, errors.NewPacketDecodingError(fmt.Sprintf("Expected offset to be less than length of raw bytes (%d), got %d", len(rd.raw), rd.off), "RAW_BYTES_FROM_OFFSET")
 	}