OSX/sec/securityd/asynchttp.c

   1 /*
   2  * Copyright (c) 2009-2010,2012-2015 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * asynchttp.c - asynchronous http get/post engine.
  26  */
  27
  28 #include "asynchttp.h"
  29
  30 #include <CoreFoundation/CFNumber.h>
  31 #include <CoreFoundation/CFStream.h>
  32 #include <CFNetwork/CFProxySupport.h>     /* CFNetworkCopySystemProxySettings */
  33 #include <CFNetwork/CFSocketStreamPriv.h> /* kCFStreamPropertySourceApplication */
  34 #include <Security/SecInternal.h>
  35 #include "SecBase64.h"
  36 #include <AssertMacros.h>
  37 #include <utilities/debugging.h>
  38 #include <utilities/SecDispatchRelease.h>
  39 #include <asl.h>
  40 #include <string.h>
  41
  42 #include <inttypes.h>
  43
  44 #if __LP64__
  45 #define PRIstatus "d"
  46 #else
  47 #define PRIstatus "ld"
  48 #endif
  49
  50 /* POST method has Content-Type header line equal to
  51    "application/ocsp-request" */
  52 static CFStringRef kContentType         = CFSTR("Content-Type");
  53 static CFStringRef kAppOcspRequest      = CFSTR("application/ocsp-request");
  54
  55 /* SPI to specify timeout on CFReadStream */
  56 #define _kCFStreamPropertyReadTimeout   CFSTR("_kCFStreamPropertyReadTimeout")
  57 #define _kCFStreamPropertyWriteTimeout   CFSTR("_kCFStreamPropertyWriteTimeout")
  58
  59 /* The timeout we set - 7 seconds */
  60 #define STREAM_TIMEOUT          (7 * NSEC_PER_SEC)
  61
  62 #define POST_BUFSIZE   2048
  63
  64 /* There has got to be an easier way to do this.  For now we based this code
  65    on CFNetwork/Connection/URLResponse.cpp. */
  66 static CFStringRef copyParseMaxAge(CFStringRef cacheControlHeader) {
  67     /* The format of the cache control header is a comma-separated list, but
  68        each list element could be a key-value pair, with the value quoted and
  69        possibly containing a comma. */
  70     CFStringInlineBuffer inlineBuf = {};
  71     CFRange componentRange;
  72     CFIndex length = CFStringGetLength(cacheControlHeader);
  73     bool done = false;
  74     CFCharacterSetRef whitespaceSet = CFCharacterSetGetPredefined(kCFCharacterSetWhitespace);
  75     CFStringRef maxAgeValue = NULL;
  76
  77     CFStringInitInlineBuffer(cacheControlHeader, &inlineBuf, CFRangeMake(0, length));
  78     componentRange.location = 0;
  79
  80     while (!done) {
  81         bool inQuotes = false;
  82         bool foundComponentStart = false;
  83         CFIndex charIndex = componentRange.location;
  84         CFIndex componentEnd = -1;
  85         CFRange maxAgeRg;
  86         componentRange.length = 0;
  87
  88         while (charIndex < length) {
  89             UniChar ch = CFStringGetCharacterFromInlineBuffer(&inlineBuf, charIndex);
  90             if (!inQuotes && ch == ',') {
  91                 componentRange.length = charIndex - componentRange.location;
  92                 break;
  93             }
  94             if (!CFCharacterSetIsCharacterMember(whitespaceSet, ch)) {
  95                 if (!foundComponentStart) {
  96                     foundComponentStart = true;
  97                     componentRange.location = charIndex;
  98                 } else {
  99                     componentEnd = charIndex;
 100                 }
 101                 if (ch == '\"') {
 102                     inQuotes = (inQuotes == false);
 103                 }
 104             }
 105             charIndex ++;
 106         }
 107
 108         if (componentEnd == -1) {
 109             componentRange.length = charIndex - componentRange.location;
 110         } else {
 111             componentRange.length = componentEnd - componentRange.location + 1;
 112         }
 113
 114         if (charIndex == length) {
 115             /* Fell off the end; this is the last component. */
 116             done = true;
 117         }
 118
 119         /* componentRange should now contain the range of the current
 120            component; trimmed of any whitespace. */
 121
 122         /* We want to look for a max-age value. */
 123         if (!maxAgeValue && CFStringFindWithOptions(cacheControlHeader, CFSTR("max-age"), componentRange, kCFCompareCaseInsensitive | kCFCompareAnchored, &maxAgeRg)) {
 124             CFIndex equalIdx;
 125             CFIndex maxCompRg = componentRange.location + componentRange.length;
 126             for (equalIdx = maxAgeRg.location + maxAgeRg.length; equalIdx < maxCompRg; equalIdx ++) {
 127                 UniChar equalCh = CFStringGetCharacterFromInlineBuffer(&inlineBuf, equalIdx);
 128                 if (equalCh == '=') {
 129                     // Parse out max-age value
 130                     equalIdx ++;
 131                     while (equalIdx < maxCompRg && CFCharacterSetIsCharacterMember(whitespaceSet, CFStringGetCharacterAtIndex(cacheControlHeader, equalIdx))) {
 132                         equalIdx ++;
 133                     }
 134                     if (equalIdx < maxCompRg) {
 135                         CFReleaseNull(maxAgeValue);
 136                         maxAgeValue = CFStringCreateWithSubstring(kCFAllocatorDefault, cacheControlHeader, CFRangeMake(equalIdx, maxCompRg-equalIdx));
 137                     }
 138                 } else if (!CFCharacterSetIsCharacterMember(whitespaceSet, equalCh)) {
 139                     // Not a valid max-age header; break out doing nothing
 140                     break;
 141                 }
 142             }
 143         }
 144
 145         if (!done && maxAgeValue) {
 146             done = true;
 147         }
 148         if (!done) {
 149             /* Advance to the next component; + 1 to get past the comma. */
 150             componentRange.location = charIndex + 1;
 151         }
 152     }
 153
 154     return maxAgeValue;
 155 }
 156
 157 static void asynchttp_complete(asynchttp_t *http) {
 158     secdebug("http", "http: %p", http);
 159     /* Shutdown streams and timer, we're about to invoke our client callback. */
 160     if (http->stream) {
 161         CFReadStreamSetClient(http->stream, kCFStreamEventNone, NULL, NULL);
 162         CFReadStreamSetDispatchQueue(http->stream, NULL);
 163         CFReadStreamClose(http->stream);
 164         CFReleaseNull(http->stream);
 165     }
 166     if (http->timer) {
 167         dispatch_source_cancel(http->timer);
 168         dispatch_release_null(http->timer);
 169     }
 170
 171     if (http->completed) {
 172         /* This should probably move to our clients. */
 173         CFTimeInterval maxAge = NULL_TIME;
 174         if (http->response) {
 175             CFStringRef cacheControl = CFHTTPMessageCopyHeaderFieldValue(
 176                 http->response, CFSTR("cache-control"));
 177             if (cacheControl) {
 178                 CFStringRef maxAgeValue = copyParseMaxAge(cacheControl);
 179                 CFRelease(cacheControl);
 180                 if (maxAgeValue) {
 181                     secdebug("http", "http header max-age: %@", maxAgeValue);
 182                     maxAge = CFStringGetDoubleValue(maxAgeValue);
 183                     CFRelease(maxAgeValue);
 184                 }
 185             }
 186         }
 187         http->completed(http, maxAge);
 188     }
 189 }
 190
 191 static void handle_server_response(CFReadStreamRef stream,
 192     CFStreamEventType type, void *info) {
 193     asynchttp_t *http = (asynchttp_t *)info;
 194     if (!http->stream) {
 195         secerror("Avoiding crash due to CFReadStream invoking us after we called CFReadStreamSetDispatchQueue(stream, NULL) on a different block on our serial queue");
 196         return;
 197     }
 198
 199     switch (type) {
 200     case kCFStreamEventHasBytesAvailable:
 201     {
 202         UInt8 buffer[POST_BUFSIZE];
 203         CFIndex length;
 204         do {
 205 #if 1
 206             length = CFReadStreamRead(stream, buffer, sizeof(buffer));
 207 #else
 208             const UInt8 *buffer = CFReadStreamGetBuffer(stream, -1, &length);
 209 #endif
 210             secdebug("http",
 211                 "stream: %@ kCFStreamEventHasBytesAvailable read: %lu bytes",
 212                 stream, length);
 213             if (length < 0) {
 214                 /* Negative length == error */
 215                 asynchttp_complete(http);
 216                 break;
 217             } else if (length > 0) {
 218                 //CFHTTPMessageAppendBytes(http->response, buffer, length);
 219                 CFDataAppendBytes(http->data, buffer, length);
 220             } else {
 221                 /* Read 0 bytes. This is a no-op, but we need to keep
 222                    reading until CFReadStreamHasBytesAvailable is false.
 223                  */
 224             }
 225         } while (CFReadStreamHasBytesAvailable(stream));
 226         break;
 227     }
 228     case kCFStreamEventErrorOccurred:
 229     {
 230         CFStreamError error = CFReadStreamGetError(stream);
 231
 232         secdebug("http",
 233             "stream: %@ kCFStreamEventErrorOccurred domain: %ld error: %ld",
 234             stream, error.domain, (long) error.error);
 235
 236         if (error.domain == kCFStreamErrorDomainPOSIX) {
 237             secerror("CFReadStream posix: %s", strerror(error.error));
 238         } else if (error.domain == kCFStreamErrorDomainMacOSStatus) {
 239             secerror("CFReadStream osstatus: %"PRIstatus, error.error);
 240         } else {
 241             secerror("CFReadStream domain: %ld error: %"PRIstatus,
 242                 error.domain, error.error);
 243         }
 244         asynchttp_complete(http);
 245         break;
 246     }
 247     case kCFStreamEventEndEncountered:
 248     {
 249         http->response = (CFHTTPMessageRef)CFReadStreamCopyProperty(
 250             stream, kCFStreamPropertyHTTPResponseHeader);
 251         secdebug("http", "stream: %@ kCFStreamEventEndEncountered hdr: %@",
 252             stream, http->response);
 253         CFHTTPMessageSetBody(http->response, http->data);
 254         asynchttp_complete(http);
 255         break;
 256     }
 257     default:
 258         secerror("handle_server_response unexpected event type: %lu",
 259             type);
 260         break;
 261     }
 262 }
 263
 264 /* Create a URI suitable for use in an http GET request, will return NULL if
 265    the length would exceed 255 bytes. */
 266 static CFURLRef createGetURL(CFURLRef responder, CFDataRef request) {
 267     CFURLRef getURL = NULL;
 268     CFMutableDataRef base64Request = NULL;
 269     CFStringRef base64RequestString = NULL;
 270     CFStringRef peRequest = NULL;
 271     CFIndex base64Len;
 272
 273     base64Len = SecBase64Encode(NULL, CFDataGetLength(request), NULL, 0);
 274     /* Don't bother doing all the work below if we know the end result will
 275        exceed 255 bytes (minus one for the '/' separator makes 254). */
 276     if (base64Len + CFURLGetBytes(responder, NULL, 0) > 254)
 277         return NULL;
 278
 279     require(base64Request = CFDataCreateMutable(kCFAllocatorDefault,
 280         base64Len), errOut);
 281     CFDataSetLength(base64Request, base64Len);
 282     SecBase64Encode(CFDataGetBytePtr(request), CFDataGetLength(request),
 283         (char *)CFDataGetMutableBytePtr(base64Request), base64Len);
 284     require(base64RequestString = CFStringCreateWithBytes(kCFAllocatorDefault,
 285         CFDataGetBytePtr(base64Request), base64Len, kCFStringEncodingUTF8,
 286         false), errOut);
 287     /* percent-encode all reserved characters from RFC 3986 [2.2] */
 288     require(peRequest = CFURLCreateStringByAddingPercentEscapes(
 289         kCFAllocatorDefault, base64RequestString, NULL,
 290         CFSTR(":/?#[]@!$&'()*+,;="), kCFStringEncodingUTF8), errOut);
 291 #if 1
 292     CFStringRef urlString = CFURLGetString(responder);
 293     CFStringRef fullURL;
 294     if (CFStringHasSuffix(urlString, CFSTR("/"))) {
 295         fullURL = CFStringCreateWithFormat(kCFAllocatorDefault, NULL,
 296             CFSTR("%@%@"), urlString, peRequest);
 297     } else {
 298         fullURL = CFStringCreateWithFormat(kCFAllocatorDefault, NULL,
 299             CFSTR("%@/%@"), urlString, peRequest);
 300     }
 301     getURL = CFURLCreateWithString(kCFAllocatorDefault, fullURL, NULL);
 302     CFRelease(fullURL);
 303 #else
 304     getURL = CFURLCreateWithString(kCFAllocatorDefault, peRequest, responder);
 305 #endif
 306
 307 errOut:
 308     CFReleaseSafe(base64Request);
 309     CFReleaseSafe(base64RequestString);
 310     CFReleaseSafe(peRequest);
 311
 312     return getURL;
 313 }
 314
 315 bool asyncHttpPost(CFURLRef responder, CFDataRef requestData /* , bool force_nocache */ ,
 316     uint64_t timeout, asynchttp_t *http) {
 317     bool result = true; /* True, we didn't schedule any work. */
 318         /* resources to release on exit */
 319     CFURLRef getURL = NULL;
 320
 321 /* Interesting tidbit from rfc5019
 322    When sending requests that are less than or equal to 255 bytes in
 323    total (after encoding) including the scheme and delimiters (http://),
 324    server name and base64-encoded OCSPRequest structure, clients MUST
 325    use the GET method (to enable OCSP response caching).  OCSP requests
 326    larger than 255 bytes SHOULD be submitted using the POST method.
 327
 328    Interesting tidbit from rfc2616:
 329    Note: Servers ought to be cautious about depending on URI lengths
 330    above 255 bytes, because some older client or proxy
 331    implementations might not properly support these lengths.
 332
 333    Given the second note I'm assuming that the note in rfc5019 is about the
 334    length of the URI, not the length of the entire HTTP request.
 335
 336    If we need to consider the entire request we need to have 17 bytes less, or
 337    17 + 25 = 42 if we are appending a "Cache-Control: no-cache CRLF" header
 338    field.
 339
 340    The 17 and 42 above are based on the request encoding from rfc2616
 341    Method SP Request-URI SP HTTP-Version CRLF (header CRLF)* CRLF
 342    so in our case it's:
 343    GET SP URI SP HTTP/1.1 CRLF CRLF
 344    17 + len(URI) bytes
 345    or
 346    GET SP URI SP HTTP/1.1 CRLF Cache-Control: SP no-cache CRLF CRLF
 347    42 + len(URI) bytes
 348  */
 349
 350     /* First let's try creating a GET request. */
 351     getURL = createGetURL(responder, requestData);
 352     if (getURL && CFURLGetBytes(getURL, NULL, 0) < 256) {
 353         /* Get URI is less than 256 bytes encoded, making it safe even for
 354            older proxy or caching servers, so let's use HTTP GET. */
 355         secdebug("http", "GET[%ld] %@", CFURLGetBytes(getURL, NULL, 0), getURL);
 356         require_quiet(http->request = CFHTTPMessageCreateRequest(kCFAllocatorDefault,
 357             CFSTR("GET"), getURL, kCFHTTPVersion1_1), errOut);
 358     } else {
 359         /* GET Request too big to ensure error free transmission, let's
 360            create a HTTP POST http->request instead. */
 361         secdebug("http", "POST %@ CRLF body", responder);
 362         require_quiet(http->request = CFHTTPMessageCreateRequest(kCFAllocatorDefault,
 363             CFSTR("POST"), responder, kCFHTTPVersion1_1), errOut);
 364         /* Set the body and required header fields. */
 365         CFHTTPMessageSetBody(http->request, requestData);
 366         CFHTTPMessageSetHeaderFieldValue(http->request, kContentType,
 367             kAppOcspRequest);
 368     }
 369
 370 #if 0
 371     if (force_nocache) {
 372         CFHTTPMessageSetHeaderFieldValue(http->request, CFSTR("Cache-Control"),
 373             CFSTR("no-cache"));
 374     }
 375 #endif
 376
 377     result = asynchttp_request(NULL, timeout, http);
 378
 379 errOut:
 380     CFReleaseSafe(getURL);
 381
 382     return result;
 383 }
 384
 385
 386 static void asynchttp_timer_proc(asynchttp_t *http CF_CONSUMED) {
 387     CFStringRef req_meth = http->request ? CFHTTPMessageCopyRequestMethod(http->request) : NULL;
 388     CFURLRef req_url = http->request ? CFHTTPMessageCopyRequestURL(http->request) : NULL;
 389     secnotice("http", "Timeout during %@ %@.", req_meth, req_url);
 390     CFReleaseSafe(req_url);
 391     CFReleaseSafe(req_meth);
 392     asynchttp_complete(http);
 393 }
 394
 395
 396 void asynchttp_free(asynchttp_t *http) {
 397     if (http) {
 398         CFReleaseNull(http->token);
 399         CFReleaseNull(http->request);
 400         CFReleaseNull(http->response);
 401         CFReleaseNull(http->data);
 402         CFReleaseNull(http->stream);
 403         dispatch_release_null(http->timer);
 404     }
 405 }
 406
 407 /* Return true, iff we didn't schedule any work, return false if we did. */
 408 bool asynchttp_request(CFHTTPMessageRef request, uint64_t timeout, asynchttp_t *http) {
 409     secdebug("http", "request %@", request);
 410     if (request) {
 411         http->request = request;
 412         CFRetain(request);
 413     }
 414
 415     /* Create the stream for the request. */
 416     require_quiet(http->stream = CFReadStreamCreateForHTTPRequest(
 417         kCFAllocatorDefault, http->request), errOut);
 418
 419     /* Set a reasonable timeout */
 420     require_quiet(http->timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, http->queue), errOut);
 421     dispatch_source_set_event_handler(http->timer, ^{
 422         asynchttp_timer_proc(http);
 423     });
 424     // Set the timer's fire time to now + STREAM_TIMEOUT seconds with a .5 second fuzz factor.
 425     uint64_t stream_timeout = timeout;
 426     if (timeout == 0) {
 427         stream_timeout = STREAM_TIMEOUT;
 428     }
 429     dispatch_source_set_timer(http->timer, dispatch_time(DISPATCH_TIME_NOW, stream_timeout),
 430                               DISPATCH_TIME_FOREVER, (int64_t)(500 * NSEC_PER_MSEC));
 431     dispatch_resume(http->timer);
 432
 433     /* Set up possible proxy info */
 434     CFDictionaryRef proxyDict = CFNetworkCopySystemProxySettings();
 435     if (proxyDict) {
 436         CFReadStreamSetProperty(http->stream, kCFStreamPropertyHTTPProxy, proxyDict);
 437         CFRelease(proxyDict);
 438     }
 439
 440     /* Set source application property info */
 441     if (http->token) {
 442         CFReadStreamSetProperty(http->stream, kCFStreamPropertySourceApplication, http->token);
 443 }
 444
 445     http->data = CFDataCreateMutable(kCFAllocatorDefault, 0);
 446
 447     CFStreamClientContext stream_context = { .info = http };
 448     CFReadStreamSetClient(http->stream,
 449         (kCFStreamEventHasBytesAvailable
 450          | kCFStreamEventErrorOccurred
 451          | kCFStreamEventEndEncountered),
 452         handle_server_response, &stream_context);
 453     CFReadStreamSetDispatchQueue(http->stream, http->queue);
 454     CFReadStreamOpen(http->stream);
 455
 456     return false; /* false -> something was scheduled. */
 457
 458 errOut:
 459     /* Deschedule timer and free anything we might have retained so far. */
 460     asynchttp_free(http);
 461     return true;
 462 }