src/acl/Checklist.cc

   1 /*
   2  * $Id$
   3  *
   4  * DEBUG: section 28    Access Control
   5  * AUTHOR: Duane Wessels
   6  *
   7  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   8  * ----------------------------------------------------------
   9  *
  10  *  Squid is the result of efforts by numerous individuals from
  11  *  the Internet community; see the CONTRIBUTORS file for full
  12  *  details.   Many organizations have provided support for Squid's
  13  *  development; see the SPONSORS file for full details.  Squid is
  14  *  Copyrighted (C) 2001 by the Regents of the University of
  15  *  California; see the COPYRIGHT file for full details.  Squid
  16  *  incorporates software developed and/or copyrighted by other
  17  *  sources; see the CREDITS file for full details.
  18  *
  19  *  This program is free software; you can redistribute it and/or modify
  20  *  it under the terms of the GNU General Public License as published by
  21  *  the Free Software Foundation; either version 2 of the License, or
  22  *  (at your option) any later version.
  23  *
  24  *  This program is distributed in the hope that it will be useful,
  25  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  *  GNU General Public License for more details.
  28  *
  29  *  You should have received a copy of the GNU General Public License
  30  *  along with this program; if not, write to the Free Software
  31  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  32  *
  33  * Copyright (c) 2003, Robert Collins <robertc@squid-cache.org>
  34  */
  35
  36 #include "squid.h"
  37 #include "acl/Checklist.h"
  38
  39 allow_t const &
  40 ACLChecklist::currentAnswer() const
  41 {
  42     return allow_;
  43 }
  44
  45 void
  46 ACLChecklist::currentAnswer(allow_t const newAnswer)
  47 {
  48     allow_ = newAnswer;
  49 }
  50
  51 void
  52 ACLChecklist::check()
  53 {
  54     if (checking())
  55         return;
  56
  57     /** Deny if no rules present. */
  58     currentAnswer(ACCESS_DENIED);
  59
  60     if (callerGone()) {
  61         checkCallback(currentAnswer());
  62         return;
  63     }
  64
  65     /** The ACL List should NEVER be NULL when calling this method.
  66      * Always caller should check for NULL and handle appropriate to its needs first.
  67      * We cannot select a sensible default for all callers here. */
  68     if (accessList == NULL) {
  69         debugs(28, DBG_CRITICAL, "SECURITY ERROR: ACL " << this << " checked with nothing to match against!!");
  70         currentAnswer(ACCESS_DENIED);
  71         checkCallback(currentAnswer());
  72         return;
  73     }
  74
  75     /* NOTE: This holds a cbdata reference to the current access_list
  76      * entry, not the whole list.
  77      */
  78     while (accessList != NULL) {
  79         /** \par
  80          * If the _acl_access is no longer valid (i.e. its been
  81          * freed because of a reconfigure), then bail on this
  82          * access check.  For now, return ACCESS_DENIED.
  83          */
  84
  85         if (!cbdataReferenceValid(accessList)) {
  86             cbdataReferenceDone(accessList);
  87             debugs(28, 4, "ACLChecklist::check: " << this << " accessList is invalid");
  88             continue;
  89         }
  90
  91         checking (true);
  92         checkAccessList();
  93         checking (false);
  94
  95         if (asyncInProgress()) {
  96             return;
  97         }
  98
  99         if (finished()) {
 100             /** \par
 101              * Either the request is allowed, denied, requires authentication.
 102              */
 103             debugs(28, 3, "ACLChecklist::check: " << this << " match found, calling back with " << currentAnswer());
 104             cbdataReferenceDone(accessList); /* A */
 105             checkCallback(currentAnswer());
 106             /* From here on in, this may be invalid */
 107             return;
 108         }
 109
 110         /*
 111          * Reference the next access entry
 112          */
 113         const acl_access *A = accessList;
 114
 115         assert (A);
 116
 117         accessList = cbdataReference(A->next);
 118
 119         cbdataReferenceDone(A);
 120     }
 121
 122     /** If dropped off the end of the list return inversion of last line allow/deny action. */
 123     debugs(28, 3, HERE << this << " NO match found, returning " <<
 124            (currentAnswer() != ACCESS_DENIED ? ACCESS_DENIED : ACCESS_ALLOWED));
 125
 126     checkCallback(currentAnswer() != ACCESS_DENIED ? ACCESS_DENIED : ACCESS_ALLOWED);
 127 }
 128
 129 bool
 130 ACLChecklist::asyncInProgress() const
 131 {
 132     return async_;
 133 }
 134
 135 void
 136 ACLChecklist::asyncInProgress(bool const newAsync)
 137 {
 138     assert (!finished() && !(asyncInProgress() && newAsync));
 139     async_ = newAsync;
 140     debugs(28, 3, "ACLChecklist::asyncInProgress: " << this <<
 141            " async set to " << async_);
 142 }
 143
 144 bool
 145 ACLChecklist::finished() const
 146 {
 147     return finished_;
 148 }
 149
 150 void
 151 ACLChecklist::markFinished()
 152 {
 153     assert (!finished() && !asyncInProgress());
 154     finished_ = true;
 155     debugs(28, 3, "ACLChecklist::markFinished: " << this <<
 156            " checklist processing finished");
 157 }
 158
 159 void
 160 ACLChecklist::preCheck()
 161 {
 162     debugs(28, 3, "ACLChecklist::preCheck: " << this << " checking '" << accessList->cfgline << "'");
 163     /* what is our result on a match? */
 164     currentAnswer(accessList->allow);
 165 }
 166
 167 void
 168 ACLChecklist::checkAccessList()
 169 {
 170     preCheck();
 171     /* does the current AND clause match */
 172     matchAclListSlow(accessList->aclList);
 173 }
 174
 175 void
 176 ACLChecklist::checkForAsync()
 177 {
 178     asyncState()->checkForAsync(this);
 179 }
 180
 181 // ACLFilledChecklist overwrites this to unclock something before we
 182 // "delete this"
 183 void
 184 ACLChecklist::checkCallback(allow_t answer)
 185 {
 186     PF *callback_;
 187     void *cbdata_;
 188     debugs(28, 3, "ACLChecklist::checkCallback: " << this << " answer=" << answer);
 189
 190     callback_ = callback;
 191     callback = NULL;
 192
 193     if (cbdataReferenceValidDone(callback_data, &cbdata_))
 194         callback_(answer, cbdata_);
 195
 196     delete this;
 197 }
 198
 199 void
 200 ACLChecklist::matchAclListSlow(const ACLList * list)
 201 {
 202     matchAclList(list, false);
 203 }
 204
 205 void
 206 ACLChecklist::matchAclList(const ACLList * head, bool const fast)
 207 {
 208     PROF_start(aclMatchAclList);
 209     const ACLList *node = head;
 210
 211     finished_ = false;
 212
 213     while (node) {
 214         bool nodeMatched = node->matches(this);
 215
 216         if (fast)
 217             changeState(NullState::Instance());
 218
 219         if (finished()) {
 220             PROF_stop(aclMatchAclList);
 221             return;
 222         }
 223
 224         if (!nodeMatched || state_ != NullState::Instance()) {
 225             debugs(28, 3, "aclmatchAclList: " << this << " returning false (AND list entry failed to match)");
 226
 227             bool async = state_ != NullState::Instance();
 228
 229             checkForAsync();
 230
 231             bool async_in_progress = asyncInProgress();
 232             debugs(28, 3, "aclmatchAclList: async=" << (async ? 1 : 0) <<
 233                    " nodeMatched=" << (nodeMatched ? 1 : 0) <<
 234                    " async_in_progress=" << (async_in_progress ? 1 : 0) <<
 235                    " lastACLResult() = " << (lastACLResult() ? 1 : 0) <<
 236                    " finished() = " << finished());
 237
 238             if (finished()) {
 239                 PROF_stop(aclMatchAclList);
 240                 return;
 241             }
 242
 243             if (async && nodeMatched && !asyncInProgress() && lastACLResult()) {
 244                 // async acl, but using cached response, and it was a match
 245                 node = node->next;
 246                 continue;
 247             }
 248
 249             PROF_stop(aclMatchAclList);
 250
 251             return;
 252         }
 253
 254         node = node->next;
 255     }
 256
 257     debugs(28, 3, "aclmatchAclList: " << this << " returning true (AND list satisfied)");
 258
 259     markFinished();
 260     PROF_stop(aclMatchAclList);
 261 }
 262
 263 ACLChecklist::ACLChecklist() :
 264         accessList (NULL),
 265         callback (NULL),
 266         callback_data (NULL),
 267         async_(false),
 268         finished_(false),
 269         allow_(ACCESS_DENIED),
 270         state_(NullState::Instance()),
 271         lastACLResult_(false)
 272 {
 273 }
 274
 275 ACLChecklist::~ACLChecklist()
 276 {
 277     assert (!asyncInProgress());
 278
 279     cbdataReferenceDone(accessList);
 280
 281     debugs(28, 4, "ACLChecklist::~ACLChecklist: destroyed " << this);
 282 }
 283
 284
 285 void
 286 ACLChecklist::AsyncState::changeState (ACLChecklist *checklist, AsyncState *newState) const
 287 {
 288     checklist->changeState(newState);
 289 }
 290
 291 ACLChecklist::NullState *
 292 ACLChecklist::NullState::Instance()
 293 {
 294     return &_instance;
 295 }
 296
 297 void
 298 ACLChecklist::NullState::checkForAsync(ACLChecklist *) const
 299 {}
 300
 301 ACLChecklist::NullState ACLChecklist::NullState::_instance;
 302
 303 void
 304 ACLChecklist::changeState (AsyncState *newState)
 305 {
 306     /* only change from null to active and back again,
 307      * not active to active.
 308      * relax this once conversion to states is complete
 309      * RBC 02 2003
 310      */
 311     assert (state_ == NullState::Instance() || newState == NullState::Instance());
 312     state_ = newState;
 313 }
 314
 315 ACLChecklist::AsyncState *
 316 ACLChecklist::asyncState() const
 317 {
 318     return state_;
 319 }
 320
 321 /**
 322  * Kick off a non-blocking (slow) ACL access list test
 323  *
 324  * NP: this should probably be made Async now.
 325  */
 326 void
 327 ACLChecklist::nonBlockingCheck(PF * callback_, void *callback_data_)
 328 {
 329     callback = callback_;
 330     callback_data = cbdataReference(callback_data_);
 331     check();
 332 }
 333
 334 /* Warning: do not cbdata lock this here - it
 335  * may be static or on the stack
 336  */
 337 int
 338 ACLChecklist::fastCheck()
 339 {
 340     PROF_start(aclCheckFast);
 341     currentAnswer(ACCESS_DENIED);
 342     debugs(28, 5, "aclCheckFast: list: " << accessList);
 343
 344     while (accessList) {
 345         preCheck();
 346         matchAclListFast(accessList->aclList);
 347
 348         if (finished()) {
 349             PROF_stop(aclCheckFast);
 350             cbdataReferenceDone(accessList);
 351             return currentAnswer() == ACCESS_ALLOWED;
 352         }
 353
 354         /*
 355          * Reference the next access entry
 356          */
 357         const acl_access *A = accessList;
 358
 359         assert (A);
 360
 361         accessList = cbdataReference(A->next);
 362
 363         cbdataReferenceDone(A);
 364     }
 365
 366     debugs(28, 5, "aclCheckFast: no matches, returning: " << (currentAnswer() == ACCESS_DENIED));
 367
 368     PROF_stop(aclCheckFast);
 369     return currentAnswer() == ACCESS_DENIED;
 370 }
 371
 372
 373 bool
 374 ACLChecklist::checking() const
 375 {
 376     return checking_;
 377 }
 378
 379 void
 380 ACLChecklist::checking (bool const newValue)
 381 {
 382     checking_ = newValue;
 383 }
 384
 385 bool
 386 ACLChecklist::callerGone()
 387 {
 388     return !cbdataReferenceValid(callback_data);
 389 }
 390
 391 bool
 392 ACLChecklist::matchAclListFast(const ACLList * list)
 393 {
 394     matchAclList(list, true);
 395     return finished();
 396 }
 397
 398