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GeezerVison is showing github.com — libhttpserver/src/cookie.cpp at master · etr/libhttpserver Expand file tree/ Copy pathcookie.cppMore file actions 446 lines (397 loc) · 14.9 KB / Copy pathcookie.cppFile metadata and controls446 lines (397 loc) · 14.9 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 /* This file is part of libhttpserver Copyright (C) 2011-2026 Sebastiano Merlino This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ // Implementation of the structured cookie value type. // See src/httpserver/cookie.hpp for the public contract. #include "httpserver/cookie.hpp" #include <cstdint> #include <cstdio> #include <ctime> #include <optional> #include <stdexcept> #include <string> #include <string_view> #include <utility> #include <vector> namespace httpserver { namespace { // Forbidden control characters shared by every setter (CWE-113). constexpr std::string_view kForbiddenCtrlChars("\r\n\0", 3); // Additional reject set for cookie names: per RFC 6265 §4.1.1 a // cookie-name is a `token` (RFC 7230 §3.2.6), which forbids separators // and whitespace. We at minimum reject `;`, `=`, and ASCII whitespace, // plus the control set above. bool is_invalid_name_byte(unsigned char c) noexcept { // Control + whitespace + the two attribute-delimiter characters // that would terminate the cookie-name in a `Set-Cookie` header. return c <= 0x20 // includes CR, LF, NUL, SP, HT, ... || c == 0x7f || c == ';' || c == '='; } void validate_name(std::string_view v, std::string_view ctx = "cookie::with_name") { // RFC 6265 §4.1.1 + RFC 7230 §3.2.6 token rule (relaxed: we reject // only the bytes that would cause syntactic ambiguity in a // `Set-Cookie` header). for (unsigned char c : v) { if (is_invalid_name_byte(c)) { throw std::invalid_argument( std::string(ctx) + ": name contains forbidden character " "(CR, LF, NUL, whitespace, ';', '=', or other control)"); } } } void validate_value(std::string_view v, std::string_view ctx = "cookie::with_value") { // Reject CR/LF/NUL plus `;` (attribute injection guard). The rest // of the RFC 6265 cookie-value ABNF (DQUOTE handling, etc.) is left // to the renderer; the value field is byte-transparent otherwise. if (v.find_first_of(kForbiddenCtrlChars) != std::string_view::npos || v.find(';') != std::string_view::npos) { throw std::invalid_argument( std::string(ctx) + ": value contains forbidden character " "(CR, LF, NUL, or ';')"); } } void validate_attr_param(std::string_view setter, std::string_view v) { const std::string setter_str(setter); if (v.find_first_of(kForbiddenCtrlChars) != std::string_view::npos) { throw std::invalid_argument( setter_str + ": attribute value contains forbidden control character " "(CR, LF, or NUL)"); } // CWE-113: a semicolon in a Domain or Path attribute value would // be emitted verbatim by the renderer, injecting synthetic // attributes into the Set-Cookie header (e.g. with_path("/; Secure") // produces 'name=val; Path=/; Secure' even though the caller only // meant to set a path). if (v.find(';') != std::string_view::npos) { throw std::invalid_argument( setter_str + ": attribute value contains forbidden character (';')"); } // Defense-in-depth: HTTP/1.0 legacy parsers and some CDN edge // nodes split Set-Cookie headers on commas. A Domain or Path // value containing a comma (e.g. Domain=evil.com,other.com) can // appear as two separate directives to such parsers, creating a // header-injection opportunity. RFC 6265 §4.1 av-octet permits // commas, but we reject them here to be safe. if (v.find(',') != std::string_view::npos) { throw std::invalid_argument( setter_str + ": attribute value contains forbidden character (','); " "commas can split Set-Cookie headers in legacy HTTP/1.0 parsers"); } } // IMF-fixdate formatter (RFC 7231 §7.1.1.1): // "Sun, 06 Nov 1994 08:49:37 GMT" // Locale-independent: hand-rolls the day/month spellings rather than // going through strftime, whose abbreviations are locale-sensitive. std::string format_imf_fixdate(std::int64_t epoch_seconds) { static constexpr const char* kDayNames[7] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; static constexpr const char* kMonthNames[12] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; const std::time_t t = static_cast<std::time_t>(epoch_seconds); std::tm tm{}; #if defined(_WIN32) gmtime_s(&tm, &t); #else gmtime_r(&t, &tm); #endif // tm_wday: 0..6 (Sunday=0); tm_mon: 0..11; tm_year: years since 1900 const int wday = (tm.tm_wday >= 0 && tm.tm_wday < 7) ? tm.tm_wday : 0; const int mon = (tm.tm_mon >= 0 && tm.tm_mon < 12) ? tm.tm_mon : 0; const int year = tm.tm_year + 1900; const int mday = tm.tm_mday; const int hour = tm.tm_hour; const int minute = tm.tm_min; const int sec = tm.tm_sec; char buf[40]; std::snprintf(buf, sizeof(buf), "%s, %02d %s %04d %02d:%02d:%02d GMT", kDayNames[wday], mday, kMonthNames[mon], year, hour, minute, sec); return std::string(buf); } // Trim ASCII whitespace from both ends. std::string_view trim_ws(std::string_view sv) noexcept { while (!sv.empty() && (sv.front() == ' ' || sv.front() == '\t')) { sv.remove_prefix(1); } while (!sv.empty() && (sv.back() == ' ' || sv.back() == '\t')) { sv.remove_suffix(1); } return sv; } // Map a same_site_mode value to its serialized attribute text. // Returns an empty view for `unset` so the renderer emits no // SameSite attribute at all. std::string_view same_site_attribute_text(same_site_mode m) noexcept { switch (m) { case same_site_mode::strict: return "; SameSite=Strict"; case same_site_mode::lax: return "; SameSite=Lax"; case same_site_mode::none: return "; SameSite=None"; case same_site_mode::unset: break; } return {}; } // Parse a single `; `-delimited cookie entry into a (name, value) view // pair. Returns nullopt for entries that carry no usable cookie: empty // after trimming, missing `=`, a leading `=` (empty name), or an empty // name after trimming. Strips one pair of outer DQUOTEs from the value // and trims ASCII whitespace around the name; byte-transparent // otherwise (the wire may deliver bytes the setters would reject). // Lifted out of parse_cookie_header to keep that function below the // CCN bar. std::optional<std::pair<std::string_view, std::string_view>> parse_cookie_token(std::string_view tok) { tok = trim_ws(tok); if (tok.empty()) { return std::nullopt; } const std::size_t eq = tok.find('='); if (eq == std::string_view::npos || eq == 0) { return std::nullopt; } std::string_view name_sv = tok.substr(0, eq); std::string_view value_sv = tok.substr(eq + 1); // Strip a single pair of outer DQUOTEs from the value (RFC 6265 // §5.2 step 2 implementation detail and common browser practice). if (value_sv.size() >= 2 && value_sv.front() == '"' && value_sv.back() == '"') { value_sv = value_sv.substr(1, value_sv.size() - 2); } // Trim trailing whitespace from the name (rare, but defends // against `a =b`). name_sv = trim_ws(name_sv); if (name_sv.empty()) { return std::nullopt; } return std::make_pair(name_sv, value_sv); } } // namespace // ---------------------------------------------------------------------- // Private validating mutators. // ---------------------------------------------------------------------- void cookie::do_set_name(std::string v) { validate_name(v); name_ = std::move(v); } void cookie::do_set_value(std::string v) { validate_value(v); value_ = std::move(v); } void cookie::do_set_domain(std::string v) { validate_attr_param("cookie::with_domain", v); domain_ = std::move(v); } void cookie::do_set_path(std::string v) { validate_attr_param("cookie::with_path", v); path_ = std::move(v); } // ---------------------------------------------------------------------- // Fluent setter pairs. & / && only differ in the return statement. // ---------------------------------------------------------------------- cookie& cookie::with_name(std::string v) & { do_set_name(std::move(v)); return *this; } cookie&& cookie::with_name(std::string v) && { do_set_name(std::move(v)); return std::move(*this); } cookie& cookie::with_value(std::string v) & { do_set_value(std::move(v)); return *this; } cookie&& cookie::with_value(std::string v) && { do_set_value(std::move(v)); return std::move(*this); } cookie& cookie::with_domain(std::string v) & { do_set_domain(std::move(v)); return *this; } cookie&& cookie::with_domain(std::string v) && { do_set_domain(std::move(v)); return std::move(*this); } cookie& cookie::with_path(std::string v) & { do_set_path(std::move(v)); return *this; } cookie&& cookie::with_path(std::string v) && { do_set_path(std::move(v)); return std::move(*this); } cookie& cookie::with_expires(std::int64_t epoch_seconds) & noexcept { expires_ = epoch_seconds; return *this; } cookie&& cookie::with_expires(std::int64_t epoch_seconds) && noexcept { expires_ = epoch_seconds; return std::move(*this); } cookie& cookie::with_max_age(std::int64_t seconds) & noexcept { max_age_ = seconds; return *this; } cookie&& cookie::with_max_age(std::int64_t seconds) && noexcept { max_age_ = seconds; return std::move(*this); } cookie& cookie::with_secure(bool v) & noexcept { secure_ = v; return *this; } cookie&& cookie::with_secure(bool v) && noexcept { secure_ = v; return std::move(*this); } cookie& cookie::with_http_only(bool v) & noexcept { http_only_ = v; return *this; } cookie&& cookie::with_http_only(bool v) && noexcept { http_only_ = v; return std::move(*this); } cookie& cookie::with_same_site(same_site_mode v) & noexcept { same_site_ = v; return *this; } cookie&& cookie::with_same_site(same_site_mode v) && noexcept { same_site_ = v; return std::move(*this); } // ---------------------------------------------------------------------- // to_set_cookie_header() -- RFC 6265 §4.1 rendering. // // Attribute order is fixed (regardless of setter call order): // name=value; Expires=...; Max-Age=...; Domain=...; Path=...; // Secure; HttpOnly; SameSite=... // // SameSite=None auto-coerces Secure to true on emit (browsers reject // SameSite=None without Secure). // ---------------------------------------------------------------------- std::string cookie::to_set_cookie_header() const { if (name_.empty()) { throw std::invalid_argument( "cookie::to_set_cookie_header: name is empty -- a cookie " "with no name is not a valid Set-Cookie"); } // Render-time injection guard (defense-in-depth, CWE-113). // Cookies created via parse_cookie_header() bypass the normal // name/value validators (see the comment in that function). If a // caller naively reflects a parsed request cookie into a Set-Cookie // response header, any forbidden byte in name_ or value_ would be // emitted verbatim. We catch both here so the injection window is // closed even when the application skips re-construction. validate_name(name_, "cookie::to_set_cookie_header"); validate_value(value_, "cookie::to_set_cookie_header"); // Reserve enough for a typical cookie. The exact growth is // irrelevant; one reserve avoids most reallocations. std::string out; out.reserve(name_.size() + value_.size() + 96); out.append(name_); out.push_back('='); out.append(value_); append_time_attributes(out); append_target_attributes(out); append_flag_attributes(out); out.append(same_site_attribute_text(same_site_)); return out; } void cookie::append_time_attributes(std::string& out) const { if (expires_.has_value()) { out.append("; Expires="); out.append(format_imf_fixdate(*expires_)); } if (max_age_.has_value()) { out.append("; Max-Age="); out.append(std::to_string(*max_age_)); } } void cookie::append_target_attributes(std::string& out) const { if (!domain_.empty()) { out.append("; Domain="); out.append(domain_); } if (!path_.empty()) { out.append("; Path="); out.append(path_); } } void cookie::append_flag_attributes(std::string& out) const { // SameSite=None auto-coerces Secure=true (browser requirement). const bool effective_secure = secure_ || (same_site_ == same_site_mode::none); if (effective_secure) { out.append("; Secure"); } if (http_only_) { out.append("; HttpOnly"); } } // ---------------------------------------------------------------------- // parse_cookie_header() -- RFC 6265 §5.4 parsing. // // Single-pass walker over the `; `-separated entries. Skips entries // without an `=`. Strips outer DQUOTE pairs around values. Trims ASCII // whitespace around each token. Byte-transparent otherwise. // ---------------------------------------------------------------------- std::vector<cookie> cookie::parse_cookie_header(std::string_view header_value) { std::vector<cookie> out; if (header_value.empty()) { return out; } std::size_t pos = 0; while (pos <= header_value.size()) { const std::size_t end = header_value.find(';', pos); const std::size_t tok_end = (end == std::string_view::npos) ? header_value.size() : end; auto parsed = parse_cookie_token(header_value.substr(pos, tok_end - pos)); if (parsed.has_value()) { cookie c; // Bypass validation: parsed input may technically contain // bytes the validator would reject (e.g. a SP inside a // quoted value). We accept what the wire delivers; the // renderer is the strict side. c.name_ = std::string(parsed->first); c.value_ = std::string(parsed->second); out.push_back(std::move(c)); } if (end == std::string_view::npos) { break; } pos = end + 1; } return out; } } // namespace httpserver |
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