ngx_http_hmac_secure_link_module v2.0.0

RFC 7231 timestamps, OpenSSL 3.x, 14 bug fixes, full test suite

Add RFC 7231/IMF-fixdate and ISO 8601 'Z' suffix timestamp parsing, port HMAC computation to the OpenSSL 3.0 EVP_MAC API, fix 14 correctness and safety bugs found during code review, and add a full Perl test suite with CI.

Timestamp Parsing

• ISO 8601 Support: Added UTC 'Z' suffix support ("YYYY-MM-DDThh:mm:ssZ"). Previously, these strings fell through to the Unix branch and were silently misread.
• RFC 7231 / IMF-fixdate: Added support for "Day, DD Mon YYYY hh:mm:ss GMT", including case-insensitive month-name lookup (per RFC 7231 §7.1.1.1).
• Comma Parsing Fix: Resolved an internal-comma bug where the comma in "Sun, 06 Nov …" was mistaken for a field separator. It is now correctly skipped during boundary detection.
• Validation Logic:
  • Extracted ngx_http_secure_link_gauss() to perform calendar-field range checks (Year ≥ 1970, Month 1–12, Day 1–31, etc.).
  • Centralized logic in ngx_http_secure_link_parse_ts(), which returns (time_t)-1 on any failure.

Security & Correctness

• Y2038 Overflow Fix: Changed 365 * year (int calculation) to (time_t)year * 365. This promotes arithmetic to the wider type, preventing overflows on large dates.
• Strict Unix Validation: Replaced sscanf "%llu" with a digit-only byte scan followed by ngx_atotm(). This prevents fragments like "2025" from being accepted as valid timestamps.
• Type Mismatch Fix: Resolved a size_t vs unsigned int mismatch. Passing (u_int*)&hmac.len to HMAC() caused memory corruption on LP64 and Big-Endian systems. Now uses a local unsigned int hmac_len.
• Variable Handling: Fixed $secure_link_hmac_expires incorrectly returning token bytes by ensuring ctx->expires points to the actual expiry-period substring.
• OpenSSL Error Handling: Added checks for EVP_MD_size(). OpenSSL 3.0 returns -1 on error; previously, an unchecked cast produced a huge length passed to CRYPTO_memcmp.
• Sign Logic: Refactored GMT-offset sign detection using if/else if/else to ensure unexpected characters cannot bypass the offset application.

OpenSSL Compatibility

• API Migration: Wrapped HMAC computation in ngx_http_secure_link_hmac_compute().
  • Uses EVP_MAC on OpenSSL >= 3.0 to avoid deprecation warnings.
  • Falls back to HMAC() on OpenSSL 1.x.
• Macro Wrappers: NGX_HMAC_MD_SIZE now abstracts EVP_MD_size (1.x) and EVP_MD_get_size (3.x).
• Guard Rails: Added key.len overflow guards before narrowing size_t to int.

Code Quality

• Portable sscanf: Removed incorrect (ngx_tm_t*) casts; used plain int* for %d compatibility across platforms.
• Format String Fix: Changed %02d to %2d in sscanf. The 0 flag is a printf feature and is ignored by scanf.
• Debug Logging: Fixed timestamp width in logs; it now uses the actual substring length (int)(ts_end - ts_start) instead of a hardcoded 25 bytes.
• Static Analysis: Resolved all cppcheck --enable=all warnings by narrowing variable scopes and marking const pointers.

Documentation & Examples

• Changelog: Replaced the verbose "BUGS FIXED" block with a concise summary; full rationale lives in CHANGELOG.md.
• Separator Rules:
  • secure_link_hmac: Separator is always a comma (hardcoded).
  • secure_link_hmac_message: Separator is operator-defined (pipe, colon, slash, none, …).
• Variable Docs: Detailed documentation for $secure_link_hmac, $secure_link_hmac_expires, and $secure_link_hmac_token regarding evaluation ordering.
• Client Implementation Examples:
  • PHP: gmdate()
  • Node.js: toUTCString()
  • Python: isoformat() with 'Z' suffix.

ngx_http_hmac_secure_link_module v0.3

• Added support for Unix Timestamp (#9)
• Fixed format specifiers iso8601

ngx_http_hmac_secure_link_module v0.2

• Compatibility with ngx_http_secure_link_module
• Bugfix compilation on the latest gcc

ngx_http_hmac_secure_link_module v0.1

Update ngx_http_hmac_secure_link_module.c