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Threat Model Analysis for simd-lite/simd-json

Threat: Threat: Crafted JSON for Integer Overflow in parse_number

  • Threat: Crafted JSON for Integer Overflow in parse_number

    • Description: An attacker provides a JSON document containing extremely large or small integer values (near the limits of int64_t or uint64_t) designed to trigger integer overflow/underflow within simd-json's parse_number or related internal functions during the conversion from string to numeric types. The attacker exploits specific SIMD instructions or logic flaws in the integer parsing routines.
    • Impact: Incorrect parsing, unexpected behavior, and potentially (though less likely with careful usage) could contribute to memory corruption if the application doesn't handle the parsed values safely.
    • Affected Component: simd-json's number parsing logic, specifically functions related to integer parsing (e.g., parse_number, internal functions, SIMD-accelerated integer parsing routines).
    • Risk Severity: High (Potentially leading to incorrect parsing and, in rare cases and with improper handling in the application, could contribute to memory issues).
    • Mitigation Strategies:
      • Input Validation (Pre-Parsing): Validate numeric strings before simd-json to ensure they are within a safe range. Reject out-of-range numbers.
      • Range Checks (Post-Parsing): After parsing, check if the resulting values are within expected bounds. Treat out-of-range values as errors.
      • Fuzz Testing: Fuzz test parse_number with a wide range of integer values, including boundary conditions.
      • Safe Integer Libraries: If the application requires very large numbers, use a "safe integer" library after parsing with simd-json.

Threat: Threat: DoS via Excessive String Escapes in parse_string

  • Threat: DoS via Excessive String Escapes in parse_string

    • Description: An attacker crafts JSON with strings containing an excessive number of escape sequences (e.g., \uXXXX, \\, \"). This forces simd-json's parse_string and its escape sequence handling (including SIMD-accelerated routines) to consume excessive CPU time and potentially memory. The attacker exploits the performance characteristics of the SIMD string processing.
    • Impact: Denial of Service (DoS) due to high CPU usage and potentially memory exhaustion.
    • Affected Component: simd-json's string parsing logic, specifically parse_string and its escape sequence handling, including SIMD-accelerated string processing.
    • Risk Severity: High (DoS is a likely outcome).
    • Mitigation Strategies:
      • Input Validation (Pre-Parsing): Limit the number of escape sequences allowed within a string before simd-json.
      • String Length Limits: Enforce strict limits on string length before parsing.
      • Resource Limits: Enforce CPU time and memory limits on the parsing process.
      • Fuzz Testing: Fuzz test parse_string with various combinations and quantities of escape sequences.

Threat: Threat: Buffer Overflow in UTF-8 Validation (validate_utf8)

  • Threat: Buffer Overflow in UTF-8 Validation (validate_utf8)

    • Description: An attacker provides JSON with invalid UTF-8 sequences. A bug in simd-json's validate_utf8 (or related internal functions, including SIMD-accelerated UTF-8 processing) could lead to a buffer overflow/underflow. The attacker crafts specific byte sequences to exploit a hypothetical vulnerability in the SIMD-accelerated UTF-8 validation.
    • Impact: Potentially Remote Code Execution (RCE) if a buffer overflow can be exploited.
    • Affected Component: simd-json's UTF-8 validation logic, specifically validate_utf8 and related SIMD-accelerated UTF-8 processing routines.
    • Risk Severity: Critical (RCE is a potential, though unlikely, outcome).
    • Mitigation Strategies:
      • Regular Updates: Keep simd-json updated to the latest version.
      • Fuzz Testing: Extensively fuzz test validate_utf8 with valid and invalid UTF-8 sequences, including edge cases.
      • Memory Safety Tools: Use memory safety tools (e.g., AddressSanitizer, Valgrind) during development and testing.
      • Independent UTF-8 Validation (Pre-Parsing): Use a separate, well-vetted UTF-8 validation library before simd-json for redundancy.