994 lines
		
	
	
		
			28 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			994 lines
		
	
	
		
			28 KiB
		
	
	
	
		
			C
		
	
	
	
| /***************************************************************************
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|  *                                  _   _ ____  _
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|  *  Project                     ___| | | |  _ \| |
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|  *                             / __| | | | |_) | |
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|  *                            | (__| |_| |  _ <| |___
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|  *                             \___|\___/|_| \_\_____|
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|  *
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|  * Copyright (C) 2018 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
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|  *
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|  * This software is licensed as described in the file COPYING, which
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|  * you should have received as part of this distribution. The terms
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|  * are also available at https://curl.se/docs/copyright.html.
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|  *
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|  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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|  * copies of the Software, and permit persons to whom the Software is
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|  * furnished to do so, under the terms of the COPYING file.
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|  *
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|  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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|  * KIND, either express or implied.
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|  *
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|  ***************************************************************************/
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| 
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| #include "curl_setup.h"
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| 
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| #ifndef CURL_DISABLE_DOH
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| 
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| #include "urldata.h"
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| #include "curl_addrinfo.h"
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| #include "doh.h"
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| 
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| #include "sendf.h"
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| #include "multiif.h"
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| #include "url.h"
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| #include "share.h"
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| #include "curl_base64.h"
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| #include "connect.h"
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| #include "strdup.h"
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| #include "dynbuf.h"
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| /* The last 3 #include files should be in this order */
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| #include "curl_printf.h"
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| #include "curl_memory.h"
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| #include "memdebug.h"
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| 
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| #define DNS_CLASS_IN 0x01
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| 
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| #ifndef CURL_DISABLE_VERBOSE_STRINGS
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| static const char * const errors[]={
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|   "",
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|   "Bad label",
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|   "Out of range",
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|   "Label loop",
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|   "Too small",
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|   "Out of memory",
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|   "RDATA length",
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|   "Malformat",
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|   "Bad RCODE",
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|   "Unexpected TYPE",
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|   "Unexpected CLASS",
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|   "No content",
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|   "Bad ID",
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|   "Name too long"
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| };
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| 
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| static const char *doh_strerror(DOHcode code)
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| {
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|   if((code >= DOH_OK) && (code <= DOH_DNS_NAME_TOO_LONG))
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|     return errors[code];
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|   return "bad error code";
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| }
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| #endif
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| 
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| #ifdef DEBUGBUILD
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| #define UNITTEST
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| #else
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| #define UNITTEST static
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| #endif
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| 
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| /* @unittest 1655
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|  */
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| UNITTEST DOHcode doh_encode(const char *host,
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|                             DNStype dnstype,
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|                             unsigned char *dnsp, /* buffer */
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|                             size_t len,  /* buffer size */
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|                             size_t *olen) /* output length */
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| {
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|   const size_t hostlen = strlen(host);
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|   unsigned char *orig = dnsp;
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|   const char *hostp = host;
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| 
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|   /* The expected output length is 16 bytes more than the length of
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|    * the QNAME-encoding of the host name.
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|    *
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|    * A valid DNS name may not contain a zero-length label, except at
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|    * the end.  For this reason, a name beginning with a dot, or
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|    * containing a sequence of two or more consecutive dots, is invalid
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|    * and cannot be encoded as a QNAME.
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|    *
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|    * If the host name ends with a trailing dot, the corresponding
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|    * QNAME-encoding is one byte longer than the host name. If (as is
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|    * also valid) the hostname is shortened by the omission of the
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|    * trailing dot, then its QNAME-encoding will be two bytes longer
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|    * than the host name.
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|    *
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|    * Each [ label, dot ] pair is encoded as [ length, label ],
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|    * preserving overall length.  A final [ label ] without a dot is
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|    * also encoded as [ length, label ], increasing overall length
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|    * by one. The encoding is completed by appending a zero byte,
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|    * representing the zero-length root label, again increasing
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|    * the overall length by one.
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|    */
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| 
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|   size_t expected_len;
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|   DEBUGASSERT(hostlen);
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|   expected_len = 12 + 1 + hostlen + 4;
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|   if(host[hostlen-1]!='.')
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|     expected_len++;
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| 
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|   if(expected_len > (256 + 16)) /* RFCs 1034, 1035 */
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|     return DOH_DNS_NAME_TOO_LONG;
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| 
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|   if(len < expected_len)
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|     return DOH_TOO_SMALL_BUFFER;
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| 
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|   *dnsp++ = 0; /* 16 bit id */
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|   *dnsp++ = 0;
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|   *dnsp++ = 0x01; /* |QR|   Opcode  |AA|TC|RD| Set the RD bit */
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|   *dnsp++ = '\0'; /* |RA|   Z    |   RCODE   |                */
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|   *dnsp++ = '\0';
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|   *dnsp++ = 1;    /* QDCOUNT (number of entries in the question section) */
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|   *dnsp++ = '\0';
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|   *dnsp++ = '\0'; /* ANCOUNT */
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|   *dnsp++ = '\0';
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|   *dnsp++ = '\0'; /* NSCOUNT */
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|   *dnsp++ = '\0';
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|   *dnsp++ = '\0'; /* ARCOUNT */
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| 
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|   /* encode each label and store it in the QNAME */
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|   while(*hostp) {
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|     size_t labellen;
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|     char *dot = strchr(hostp, '.');
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|     if(dot)
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|       labellen = dot - hostp;
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|     else
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|       labellen = strlen(hostp);
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|     if((labellen > 63) || (!labellen)) {
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|       /* label is too long or too short, error out */
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|       *olen = 0;
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|       return DOH_DNS_BAD_LABEL;
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|     }
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|     /* label is non-empty, process it */
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|     *dnsp++ = (unsigned char)labellen;
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|     memcpy(dnsp, hostp, labellen);
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|     dnsp += labellen;
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|     hostp += labellen;
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|     /* advance past dot, but only if there is one */
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|     if(dot)
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|       hostp++;
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|   } /* next label */
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| 
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|   *dnsp++ = 0; /* append zero-length label for root */
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| 
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|   /* There are assigned TYPE codes beyond 255: use range [1..65535]  */
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|   *dnsp++ = (unsigned char)(255 & (dnstype>>8)); /* upper 8 bit TYPE */
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|   *dnsp++ = (unsigned char)(255 & dnstype);      /* lower 8 bit TYPE */
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| 
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|   *dnsp++ = '\0'; /* upper 8 bit CLASS */
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|   *dnsp++ = DNS_CLASS_IN; /* IN - "the Internet" */
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| 
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|   *olen = dnsp - orig;
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| 
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|   /* verify that our estimation of length is valid, since
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|    * this has led to buffer overflows in this function */
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|   DEBUGASSERT(*olen == expected_len);
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|   return DOH_OK;
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| }
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| 
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| static size_t
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| doh_write_cb(const void *contents, size_t size, size_t nmemb, void *userp)
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| {
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|   size_t realsize = size * nmemb;
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|   struct dynbuf *mem = (struct dynbuf *)userp;
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| 
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|   if(Curl_dyn_addn(mem, contents, realsize))
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|     return 0;
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| 
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|   return realsize;
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| }
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| 
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| /* called from multi.c when this DoH transfer is complete */
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| static int doh_done(struct Curl_easy *doh, CURLcode result)
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| {
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|   struct Curl_easy *data = doh->set.dohfor;
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|   struct dohdata *dohp = data->req.doh;
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|   /* so one of the DoH request done for the 'data' transfer is now complete! */
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|   dohp->pending--;
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|   infof(data, "a DoH request is completed, %u to go", dohp->pending);
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|   if(result)
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|     infof(data, "DoH request %s", curl_easy_strerror(result));
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| 
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|   if(!dohp->pending) {
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|     /* DoH completed */
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|     curl_slist_free_all(dohp->headers);
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|     dohp->headers = NULL;
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|     Curl_expire(data, 0, EXPIRE_RUN_NOW);
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|   }
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|   return 0;
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| }
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| 
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| #define ERROR_CHECK_SETOPT(x,y) \
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| do {                                          \
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|   result = curl_easy_setopt(doh, x, y);       \
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|   if(result &&                                \
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|      result != CURLE_NOT_BUILT_IN &&          \
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|      result != CURLE_UNKNOWN_OPTION)          \
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|     goto error;                               \
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| } while(0)
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| 
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| static CURLcode dohprobe(struct Curl_easy *data,
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|                          struct dnsprobe *p, DNStype dnstype,
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|                          const char *host,
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|                          const char *url, CURLM *multi,
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|                          struct curl_slist *headers)
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| {
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|   struct Curl_easy *doh = NULL;
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|   char *nurl = NULL;
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|   CURLcode result = CURLE_OK;
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|   timediff_t timeout_ms;
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|   DOHcode d = doh_encode(host, dnstype, p->dohbuffer, sizeof(p->dohbuffer),
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|                          &p->dohlen);
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|   if(d) {
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|     failf(data, "Failed to encode DoH packet [%d]", d);
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|     return CURLE_OUT_OF_MEMORY;
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|   }
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| 
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|   p->dnstype = dnstype;
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|   Curl_dyn_init(&p->serverdoh, DYN_DOH_RESPONSE);
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| 
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|   timeout_ms = Curl_timeleft(data, NULL, TRUE);
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|   if(timeout_ms <= 0) {
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|     result = CURLE_OPERATION_TIMEDOUT;
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|     goto error;
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|   }
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|   /* Curl_open() is the internal version of curl_easy_init() */
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|   result = Curl_open(&doh);
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|   if(!result) {
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|     /* pass in the struct pointer via a local variable to please coverity and
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|        the gcc typecheck helpers */
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|     struct dynbuf *resp = &p->serverdoh;
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|     ERROR_CHECK_SETOPT(CURLOPT_URL, url);
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|     ERROR_CHECK_SETOPT(CURLOPT_WRITEFUNCTION, doh_write_cb);
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|     ERROR_CHECK_SETOPT(CURLOPT_WRITEDATA, resp);
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|     ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDS, p->dohbuffer);
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|     ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDSIZE, (long)p->dohlen);
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|     ERROR_CHECK_SETOPT(CURLOPT_HTTPHEADER, headers);
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| #ifdef USE_NGHTTP2
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|     ERROR_CHECK_SETOPT(CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2TLS);
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| #endif
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| #ifndef CURLDEBUG
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|     /* enforce HTTPS if not debug */
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|     ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
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| #else
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|     /* in debug mode, also allow http */
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|     ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTP|CURLPROTO_HTTPS);
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| #endif
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|     ERROR_CHECK_SETOPT(CURLOPT_TIMEOUT_MS, (long)timeout_ms);
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|     ERROR_CHECK_SETOPT(CURLOPT_SHARE, data->share);
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|     if(data->set.err && data->set.err != stderr)
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|       ERROR_CHECK_SETOPT(CURLOPT_STDERR, data->set.err);
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|     if(data->set.verbose)
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|       ERROR_CHECK_SETOPT(CURLOPT_VERBOSE, 1L);
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|     if(data->set.no_signal)
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|       ERROR_CHECK_SETOPT(CURLOPT_NOSIGNAL, 1L);
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| 
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|     ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYHOST,
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|       data->set.doh_verifyhost ? 2L : 0L);
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|     ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYPEER,
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|       data->set.doh_verifypeer ? 1L : 0L);
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|     ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYSTATUS,
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|       data->set.doh_verifystatus ? 1L : 0L);
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| 
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|     /* Inherit *some* SSL options from the user's transfer. This is a
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|        best-guess as to which options are needed for compatibility. #3661
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| 
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|        Note DoH does not inherit the user's proxy server so proxy SSL settings
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|        have no effect and are not inherited. If that changes then two new
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|        options should be added to check doh proxy insecure separately,
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|        CURLOPT_DOH_PROXY_SSL_VERIFYHOST and CURLOPT_DOH_PROXY_SSL_VERIFYPEER.
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|        */
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|     if(data->set.ssl.falsestart)
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|       ERROR_CHECK_SETOPT(CURLOPT_SSL_FALSESTART, 1L);
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|     if(data->set.str[STRING_SSL_CAFILE]) {
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|       ERROR_CHECK_SETOPT(CURLOPT_CAINFO,
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|                          data->set.str[STRING_SSL_CAFILE]);
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|     }
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|     if(data->set.blobs[BLOB_CAINFO]) {
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|       ERROR_CHECK_SETOPT(CURLOPT_CAINFO_BLOB,
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|                          data->set.blobs[BLOB_CAINFO]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_CAPATH]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_CAPATH,
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|                          data->set.str[STRING_SSL_CAPATH]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_CRLFILE]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_CRLFILE,
 | |
|                          data->set.str[STRING_SSL_CRLFILE]);
 | |
|     }
 | |
|     if(data->set.ssl.certinfo)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_CERTINFO, 1L);
 | |
|     if(data->set.str[STRING_SSL_RANDOM_FILE]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_RANDOM_FILE,
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|                          data->set.str[STRING_SSL_RANDOM_FILE]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_EGDSOCKET]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_EGDSOCKET,
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|                          data->set.str[STRING_SSL_EGDSOCKET]);
 | |
|     }
 | |
|     if(data->set.ssl.fsslctx)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_CTX_FUNCTION, data->set.ssl.fsslctx);
 | |
|     if(data->set.ssl.fsslctxp)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_CTX_DATA, data->set.ssl.fsslctxp);
 | |
|     if(data->set.str[STRING_SSL_EC_CURVES]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_EC_CURVES,
 | |
|                          data->set.str[STRING_SSL_EC_CURVES]);
 | |
|     }
 | |
| 
 | |
|     {
 | |
|       long mask =
 | |
|         (data->set.ssl.enable_beast ?
 | |
|          CURLSSLOPT_ALLOW_BEAST : 0) |
 | |
|         (data->set.ssl.no_revoke ?
 | |
|          CURLSSLOPT_NO_REVOKE : 0) |
 | |
|         (data->set.ssl.no_partialchain ?
 | |
|          CURLSSLOPT_NO_PARTIALCHAIN : 0) |
 | |
|         (data->set.ssl.revoke_best_effort ?
 | |
|          CURLSSLOPT_REVOKE_BEST_EFFORT : 0) |
 | |
|         (data->set.ssl.native_ca_store ?
 | |
|          CURLSSLOPT_NATIVE_CA : 0) |
 | |
|         (data->set.ssl.auto_client_cert ?
 | |
|          CURLSSLOPT_AUTO_CLIENT_CERT : 0);
 | |
| 
 | |
|       (void)curl_easy_setopt(doh, CURLOPT_SSL_OPTIONS, mask);
 | |
|     }
 | |
| 
 | |
|     doh->set.fmultidone = doh_done;
 | |
|     doh->set.dohfor = data; /* identify for which transfer this is done */
 | |
|     p->easy = doh;
 | |
| 
 | |
|     /* DoH private_data must be null because the user must have a way to
 | |
|        distinguish their transfer's handle from DoH handles in user
 | |
|        callbacks (ie SSL CTX callback). */
 | |
|     DEBUGASSERT(!doh->set.private_data);
 | |
| 
 | |
|     if(curl_multi_add_handle(multi, doh))
 | |
|       goto error;
 | |
|   }
 | |
|   else
 | |
|     goto error;
 | |
|   free(nurl);
 | |
|   return CURLE_OK;
 | |
| 
 | |
|   error:
 | |
|   free(nurl);
 | |
|   Curl_close(&doh);
 | |
|   return result;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * Curl_doh() resolves a name using DoH. It resolves a name and returns a
 | |
|  * 'Curl_addrinfo *' with the address information.
 | |
|  */
 | |
| 
 | |
| struct Curl_addrinfo *Curl_doh(struct Curl_easy *data,
 | |
|                                const char *hostname,
 | |
|                                int port,
 | |
|                                int *waitp)
 | |
| {
 | |
|   CURLcode result = CURLE_OK;
 | |
|   int slot;
 | |
|   struct dohdata *dohp;
 | |
|   struct connectdata *conn = data->conn;
 | |
|   *waitp = TRUE; /* this never returns synchronously */
 | |
|   (void)hostname;
 | |
|   (void)port;
 | |
| 
 | |
|   DEBUGASSERT(!data->req.doh);
 | |
|   DEBUGASSERT(conn);
 | |
| 
 | |
|   /* start clean, consider allocating this struct on demand */
 | |
|   dohp = data->req.doh = calloc(sizeof(struct dohdata), 1);
 | |
|   if(!dohp)
 | |
|     return NULL;
 | |
| 
 | |
|   conn->bits.doh = TRUE;
 | |
|   dohp->host = hostname;
 | |
|   dohp->port = port;
 | |
|   dohp->headers =
 | |
|     curl_slist_append(NULL,
 | |
|                       "Content-Type: application/dns-message");
 | |
|   if(!dohp->headers)
 | |
|     goto error;
 | |
| 
 | |
|   /* create IPv4 DoH request */
 | |
|   result = dohprobe(data, &dohp->probe[DOH_PROBE_SLOT_IPADDR_V4],
 | |
|                     DNS_TYPE_A, hostname, data->set.str[STRING_DOH],
 | |
|                     data->multi, dohp->headers);
 | |
|   if(result)
 | |
|     goto error;
 | |
|   dohp->pending++;
 | |
| 
 | |
|   if(Curl_ipv6works(data)) {
 | |
|     /* create IPv6 DoH request */
 | |
|     result = dohprobe(data, &dohp->probe[DOH_PROBE_SLOT_IPADDR_V6],
 | |
|                       DNS_TYPE_AAAA, hostname, data->set.str[STRING_DOH],
 | |
|                       data->multi, dohp->headers);
 | |
|     if(result)
 | |
|       goto error;
 | |
|     dohp->pending++;
 | |
|   }
 | |
|   return NULL;
 | |
| 
 | |
|   error:
 | |
|   curl_slist_free_all(dohp->headers);
 | |
|   data->req.doh->headers = NULL;
 | |
|   for(slot = 0; slot < DOH_PROBE_SLOTS; slot++) {
 | |
|     Curl_close(&dohp->probe[slot].easy);
 | |
|   }
 | |
|   Curl_safefree(data->req.doh);
 | |
|   return NULL;
 | |
| }
 | |
| 
 | |
| static DOHcode skipqname(const unsigned char *doh, size_t dohlen,
 | |
|                          unsigned int *indexp)
 | |
| {
 | |
|   unsigned char length;
 | |
|   do {
 | |
|     if(dohlen < (*indexp + 1))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
|     length = doh[*indexp];
 | |
|     if((length & 0xc0) == 0xc0) {
 | |
|       /* name pointer, advance over it and be done */
 | |
|       if(dohlen < (*indexp + 2))
 | |
|         return DOH_DNS_OUT_OF_RANGE;
 | |
|       *indexp += 2;
 | |
|       break;
 | |
|     }
 | |
|     if(length & 0xc0)
 | |
|       return DOH_DNS_BAD_LABEL;
 | |
|     if(dohlen < (*indexp + 1 + length))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
|     *indexp += 1 + length;
 | |
|   } while(length);
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static unsigned short get16bit(const unsigned char *doh, int index)
 | |
| {
 | |
|   return (unsigned short)((doh[index] << 8) | doh[index + 1]);
 | |
| }
 | |
| 
 | |
| static unsigned int get32bit(const unsigned char *doh, int index)
 | |
| {
 | |
|    /* make clang and gcc optimize this to bswap by incrementing
 | |
|       the pointer first. */
 | |
|    doh += index;
 | |
| 
 | |
|    /* avoid undefined behavior by casting to unsigned before shifting
 | |
|       24 bits, possibly into the sign bit. codegen is same, but
 | |
|       ub sanitizer won't be upset */
 | |
|   return ( (unsigned)doh[0] << 24) | (doh[1] << 16) |(doh[2] << 8) | doh[3];
 | |
| }
 | |
| 
 | |
| static DOHcode store_a(const unsigned char *doh, int index, struct dohentry *d)
 | |
| {
 | |
|   /* silently ignore addresses over the limit */
 | |
|   if(d->numaddr < DOH_MAX_ADDR) {
 | |
|     struct dohaddr *a = &d->addr[d->numaddr];
 | |
|     a->type = DNS_TYPE_A;
 | |
|     memcpy(&a->ip.v4, &doh[index], 4);
 | |
|     d->numaddr++;
 | |
|   }
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static DOHcode store_aaaa(const unsigned char *doh,
 | |
|                           int index,
 | |
|                           struct dohentry *d)
 | |
| {
 | |
|   /* silently ignore addresses over the limit */
 | |
|   if(d->numaddr < DOH_MAX_ADDR) {
 | |
|     struct dohaddr *a = &d->addr[d->numaddr];
 | |
|     a->type = DNS_TYPE_AAAA;
 | |
|     memcpy(&a->ip.v6, &doh[index], 16);
 | |
|     d->numaddr++;
 | |
|   }
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static DOHcode store_cname(const unsigned char *doh,
 | |
|                            size_t dohlen,
 | |
|                            unsigned int index,
 | |
|                            struct dohentry *d)
 | |
| {
 | |
|   struct dynbuf *c;
 | |
|   unsigned int loop = 128; /* a valid DNS name can never loop this much */
 | |
|   unsigned char length;
 | |
| 
 | |
|   if(d->numcname == DOH_MAX_CNAME)
 | |
|     return DOH_OK; /* skip! */
 | |
| 
 | |
|   c = &d->cname[d->numcname++];
 | |
|   do {
 | |
|     if(index >= dohlen)
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
|     length = doh[index];
 | |
|     if((length & 0xc0) == 0xc0) {
 | |
|       int newpos;
 | |
|       /* name pointer, get the new offset (14 bits) */
 | |
|       if((index + 1) >= dohlen)
 | |
|         return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|       /* move to the new index */
 | |
|       newpos = (length & 0x3f) << 8 | doh[index + 1];
 | |
|       index = newpos;
 | |
|       continue;
 | |
|     }
 | |
|     else if(length & 0xc0)
 | |
|       return DOH_DNS_BAD_LABEL; /* bad input */
 | |
|     else
 | |
|       index++;
 | |
| 
 | |
|     if(length) {
 | |
|       if(Curl_dyn_len(c)) {
 | |
|         if(Curl_dyn_add(c, "."))
 | |
|           return DOH_OUT_OF_MEM;
 | |
|       }
 | |
|       if((index + length) > dohlen)
 | |
|         return DOH_DNS_BAD_LABEL;
 | |
| 
 | |
|       if(Curl_dyn_addn(c, &doh[index], length))
 | |
|         return DOH_OUT_OF_MEM;
 | |
|       index += length;
 | |
|     }
 | |
|   } while(length && --loop);
 | |
| 
 | |
|   if(!loop)
 | |
|     return DOH_DNS_LABEL_LOOP;
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static DOHcode rdata(const unsigned char *doh,
 | |
|                      size_t dohlen,
 | |
|                      unsigned short rdlength,
 | |
|                      unsigned short type,
 | |
|                      int index,
 | |
|                      struct dohentry *d)
 | |
| {
 | |
|   /* RDATA
 | |
|      - A (TYPE 1):  4 bytes
 | |
|      - AAAA (TYPE 28): 16 bytes
 | |
|      - NS (TYPE 2): N bytes */
 | |
|   DOHcode rc;
 | |
| 
 | |
|   switch(type) {
 | |
|   case DNS_TYPE_A:
 | |
|     if(rdlength != 4)
 | |
|       return DOH_DNS_RDATA_LEN;
 | |
|     rc = store_a(doh, index, d);
 | |
|     if(rc)
 | |
|       return rc;
 | |
|     break;
 | |
|   case DNS_TYPE_AAAA:
 | |
|     if(rdlength != 16)
 | |
|       return DOH_DNS_RDATA_LEN;
 | |
|     rc = store_aaaa(doh, index, d);
 | |
|     if(rc)
 | |
|       return rc;
 | |
|     break;
 | |
|   case DNS_TYPE_CNAME:
 | |
|     rc = store_cname(doh, dohlen, index, d);
 | |
|     if(rc)
 | |
|       return rc;
 | |
|     break;
 | |
|   case DNS_TYPE_DNAME:
 | |
|     /* explicit for clarity; just skip; rely on synthesized CNAME  */
 | |
|     break;
 | |
|   default:
 | |
|     /* unsupported type, just skip it */
 | |
|     break;
 | |
|   }
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| UNITTEST void de_init(struct dohentry *de)
 | |
| {
 | |
|   int i;
 | |
|   memset(de, 0, sizeof(*de));
 | |
|   de->ttl = INT_MAX;
 | |
|   for(i = 0; i < DOH_MAX_CNAME; i++)
 | |
|     Curl_dyn_init(&de->cname[i], DYN_DOH_CNAME);
 | |
| }
 | |
| 
 | |
| 
 | |
| UNITTEST DOHcode doh_decode(const unsigned char *doh,
 | |
|                             size_t dohlen,
 | |
|                             DNStype dnstype,
 | |
|                             struct dohentry *d)
 | |
| {
 | |
|   unsigned char rcode;
 | |
|   unsigned short qdcount;
 | |
|   unsigned short ancount;
 | |
|   unsigned short type = 0;
 | |
|   unsigned short rdlength;
 | |
|   unsigned short nscount;
 | |
|   unsigned short arcount;
 | |
|   unsigned int index = 12;
 | |
|   DOHcode rc;
 | |
| 
 | |
|   if(dohlen < 12)
 | |
|     return DOH_TOO_SMALL_BUFFER; /* too small */
 | |
|   if(!doh || doh[0] || doh[1])
 | |
|     return DOH_DNS_BAD_ID; /* bad ID */
 | |
|   rcode = doh[3] & 0x0f;
 | |
|   if(rcode)
 | |
|     return DOH_DNS_BAD_RCODE; /* bad rcode */
 | |
| 
 | |
|   qdcount = get16bit(doh, 4);
 | |
|   while(qdcount) {
 | |
|     rc = skipqname(doh, dohlen, &index);
 | |
|     if(rc)
 | |
|       return rc; /* bad qname */
 | |
|     if(dohlen < (index + 4))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
|     index += 4; /* skip question's type and class */
 | |
|     qdcount--;
 | |
|   }
 | |
| 
 | |
|   ancount = get16bit(doh, 6);
 | |
|   while(ancount) {
 | |
|     unsigned short class;
 | |
|     unsigned int ttl;
 | |
| 
 | |
|     rc = skipqname(doh, dohlen, &index);
 | |
|     if(rc)
 | |
|       return rc; /* bad qname */
 | |
| 
 | |
|     if(dohlen < (index + 2))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     type = get16bit(doh, index);
 | |
|     if((type != DNS_TYPE_CNAME)    /* may be synthesized from DNAME */
 | |
|        && (type != DNS_TYPE_DNAME) /* if present, accept and ignore */
 | |
|        && (type != dnstype))
 | |
|       /* Not the same type as was asked for nor CNAME nor DNAME */
 | |
|       return DOH_DNS_UNEXPECTED_TYPE;
 | |
|     index += 2;
 | |
| 
 | |
|     if(dohlen < (index + 2))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
|     class = get16bit(doh, index);
 | |
|     if(DNS_CLASS_IN != class)
 | |
|       return DOH_DNS_UNEXPECTED_CLASS; /* unsupported */
 | |
|     index += 2;
 | |
| 
 | |
|     if(dohlen < (index + 4))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     ttl = get32bit(doh, index);
 | |
|     if(ttl < d->ttl)
 | |
|       d->ttl = ttl;
 | |
|     index += 4;
 | |
| 
 | |
|     if(dohlen < (index + 2))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     rdlength = get16bit(doh, index);
 | |
|     index += 2;
 | |
|     if(dohlen < (index + rdlength))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     rc = rdata(doh, dohlen, rdlength, type, index, d);
 | |
|     if(rc)
 | |
|       return rc; /* bad rdata */
 | |
|     index += rdlength;
 | |
|     ancount--;
 | |
|   }
 | |
| 
 | |
|   nscount = get16bit(doh, 8);
 | |
|   while(nscount) {
 | |
|     rc = skipqname(doh, dohlen, &index);
 | |
|     if(rc)
 | |
|       return rc; /* bad qname */
 | |
| 
 | |
|     if(dohlen < (index + 8))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     index += 2 + 2 + 4; /* type, class and ttl */
 | |
| 
 | |
|     if(dohlen < (index + 2))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     rdlength = get16bit(doh, index);
 | |
|     index += 2;
 | |
|     if(dohlen < (index + rdlength))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
|     index += rdlength;
 | |
|     nscount--;
 | |
|   }
 | |
| 
 | |
|   arcount = get16bit(doh, 10);
 | |
|   while(arcount) {
 | |
|     rc = skipqname(doh, dohlen, &index);
 | |
|     if(rc)
 | |
|       return rc; /* bad qname */
 | |
| 
 | |
|     if(dohlen < (index + 8))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     index += 2 + 2 + 4; /* type, class and ttl */
 | |
| 
 | |
|     if(dohlen < (index + 2))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
| 
 | |
|     rdlength = get16bit(doh, index);
 | |
|     index += 2;
 | |
|     if(dohlen < (index + rdlength))
 | |
|       return DOH_DNS_OUT_OF_RANGE;
 | |
|     index += rdlength;
 | |
|     arcount--;
 | |
|   }
 | |
| 
 | |
|   if(index != dohlen)
 | |
|     return DOH_DNS_MALFORMAT; /* something is wrong */
 | |
| 
 | |
|   if((type != DNS_TYPE_NS) && !d->numcname && !d->numaddr)
 | |
|     /* nothing stored! */
 | |
|     return DOH_NO_CONTENT;
 | |
| 
 | |
|   return DOH_OK; /* ok */
 | |
| }
 | |
| 
 | |
| #ifndef CURL_DISABLE_VERBOSE_STRINGS
 | |
| static void showdoh(struct Curl_easy *data,
 | |
|                     const struct dohentry *d)
 | |
| {
 | |
|   int i;
 | |
|   infof(data, "TTL: %u seconds", d->ttl);
 | |
|   for(i = 0; i < d->numaddr; i++) {
 | |
|     const struct dohaddr *a = &d->addr[i];
 | |
|     if(a->type == DNS_TYPE_A) {
 | |
|       infof(data, "DoH A: %u.%u.%u.%u",
 | |
|             a->ip.v4[0], a->ip.v4[1],
 | |
|             a->ip.v4[2], a->ip.v4[3]);
 | |
|     }
 | |
|     else if(a->type == DNS_TYPE_AAAA) {
 | |
|       int j;
 | |
|       char buffer[128];
 | |
|       char *ptr;
 | |
|       size_t len;
 | |
|       msnprintf(buffer, 128, "DoH AAAA: ");
 | |
|       ptr = &buffer[10];
 | |
|       len = 118;
 | |
|       for(j = 0; j < 16; j += 2) {
 | |
|         size_t l;
 | |
|         msnprintf(ptr, len, "%s%02x%02x", j?":":"", d->addr[i].ip.v6[j],
 | |
|                   d->addr[i].ip.v6[j + 1]);
 | |
|         l = strlen(ptr);
 | |
|         len -= l;
 | |
|         ptr += l;
 | |
|       }
 | |
|       infof(data, "%s", buffer);
 | |
|     }
 | |
|   }
 | |
|   for(i = 0; i < d->numcname; i++) {
 | |
|     infof(data, "CNAME: %s", Curl_dyn_ptr(&d->cname[i]));
 | |
|   }
 | |
| }
 | |
| #else
 | |
| #define showdoh(x,y)
 | |
| #endif
 | |
| 
 | |
| /*
 | |
|  * doh2ai()
 | |
|  *
 | |
|  * This function returns a pointer to the first element of a newly allocated
 | |
|  * Curl_addrinfo struct linked list filled with the data from a set of DoH
 | |
|  * lookups.  Curl_addrinfo is meant to work like the addrinfo struct does for
 | |
|  * a IPv6 stack, but usable also for IPv4, all hosts and environments.
 | |
|  *
 | |
|  * The memory allocated by this function *MUST* be free'd later on calling
 | |
|  * Curl_freeaddrinfo().  For each successful call to this function there
 | |
|  * must be an associated call later to Curl_freeaddrinfo().
 | |
|  */
 | |
| 
 | |
| static struct Curl_addrinfo *
 | |
| doh2ai(const struct dohentry *de, const char *hostname, int port)
 | |
| {
 | |
|   struct Curl_addrinfo *ai;
 | |
|   struct Curl_addrinfo *prevai = NULL;
 | |
|   struct Curl_addrinfo *firstai = NULL;
 | |
|   struct sockaddr_in *addr;
 | |
| #ifdef ENABLE_IPV6
 | |
|   struct sockaddr_in6 *addr6;
 | |
| #endif
 | |
|   CURLcode result = CURLE_OK;
 | |
|   int i;
 | |
|   size_t hostlen = strlen(hostname) + 1; /* include zero terminator */
 | |
| 
 | |
|   if(!de)
 | |
|     /* no input == no output! */
 | |
|     return NULL;
 | |
| 
 | |
|   for(i = 0; i < de->numaddr; i++) {
 | |
|     size_t ss_size;
 | |
|     CURL_SA_FAMILY_T addrtype;
 | |
|     if(de->addr[i].type == DNS_TYPE_AAAA) {
 | |
| #ifndef ENABLE_IPV6
 | |
|       /* we can't handle IPv6 addresses */
 | |
|       continue;
 | |
| #else
 | |
|       ss_size = sizeof(struct sockaddr_in6);
 | |
|       addrtype = AF_INET6;
 | |
| #endif
 | |
|     }
 | |
|     else {
 | |
|       ss_size = sizeof(struct sockaddr_in);
 | |
|       addrtype = AF_INET;
 | |
|     }
 | |
| 
 | |
|     ai = calloc(1, sizeof(struct Curl_addrinfo) + ss_size + hostlen);
 | |
|     if(!ai) {
 | |
|       result = CURLE_OUT_OF_MEMORY;
 | |
|       break;
 | |
|     }
 | |
|     ai->ai_addr = (void *)((char *)ai + sizeof(struct Curl_addrinfo));
 | |
|     ai->ai_canonname = (void *)((char *)ai->ai_addr + ss_size);
 | |
|     memcpy(ai->ai_canonname, hostname, hostlen);
 | |
| 
 | |
|     if(!firstai)
 | |
|       /* store the pointer we want to return from this function */
 | |
|       firstai = ai;
 | |
| 
 | |
|     if(prevai)
 | |
|       /* make the previous entry point to this */
 | |
|       prevai->ai_next = ai;
 | |
| 
 | |
|     ai->ai_family = addrtype;
 | |
| 
 | |
|     /* we return all names as STREAM, so when using this address for TFTP
 | |
|        the type must be ignored and conn->socktype be used instead! */
 | |
|     ai->ai_socktype = SOCK_STREAM;
 | |
| 
 | |
|     ai->ai_addrlen = (curl_socklen_t)ss_size;
 | |
| 
 | |
|     /* leave the rest of the struct filled with zero */
 | |
| 
 | |
|     switch(ai->ai_family) {
 | |
|     case AF_INET:
 | |
|       addr = (void *)ai->ai_addr; /* storage area for this info */
 | |
|       DEBUGASSERT(sizeof(struct in_addr) == sizeof(de->addr[i].ip.v4));
 | |
|       memcpy(&addr->sin_addr, &de->addr[i].ip.v4, sizeof(struct in_addr));
 | |
|       addr->sin_family = addrtype;
 | |
|       addr->sin_port = htons((unsigned short)port);
 | |
|       break;
 | |
| 
 | |
| #ifdef ENABLE_IPV6
 | |
|     case AF_INET6:
 | |
|       addr6 = (void *)ai->ai_addr; /* storage area for this info */
 | |
|       DEBUGASSERT(sizeof(struct in6_addr) == sizeof(de->addr[i].ip.v6));
 | |
|       memcpy(&addr6->sin6_addr, &de->addr[i].ip.v6, sizeof(struct in6_addr));
 | |
|       addr6->sin6_family = addrtype;
 | |
|       addr6->sin6_port = htons((unsigned short)port);
 | |
|       break;
 | |
| #endif
 | |
|     }
 | |
| 
 | |
|     prevai = ai;
 | |
|   }
 | |
| 
 | |
|   if(result) {
 | |
|     Curl_freeaddrinfo(firstai);
 | |
|     firstai = NULL;
 | |
|   }
 | |
| 
 | |
|   return firstai;
 | |
| }
 | |
| 
 | |
| #ifndef CURL_DISABLE_VERBOSE_STRINGS
 | |
| static const char *type2name(DNStype dnstype)
 | |
| {
 | |
|   return (dnstype == DNS_TYPE_A)?"A":"AAAA";
 | |
| }
 | |
| #endif
 | |
| 
 | |
| UNITTEST void de_cleanup(struct dohentry *d)
 | |
| {
 | |
|   int i = 0;
 | |
|   for(i = 0; i < d->numcname; i++) {
 | |
|     Curl_dyn_free(&d->cname[i]);
 | |
|   }
 | |
| }
 | |
| 
 | |
| CURLcode Curl_doh_is_resolved(struct Curl_easy *data,
 | |
|                               struct Curl_dns_entry **dnsp)
 | |
| {
 | |
|   CURLcode result;
 | |
|   struct dohdata *dohp = data->req.doh;
 | |
|   *dnsp = NULL; /* defaults to no response */
 | |
|   if(!dohp)
 | |
|     return CURLE_OUT_OF_MEMORY;
 | |
| 
 | |
|   if(!dohp->probe[DOH_PROBE_SLOT_IPADDR_V4].easy &&
 | |
|      !dohp->probe[DOH_PROBE_SLOT_IPADDR_V6].easy) {
 | |
|     failf(data, "Could not DoH-resolve: %s", data->state.async.hostname);
 | |
|     return data->conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
 | |
|       CURLE_COULDNT_RESOLVE_HOST;
 | |
|   }
 | |
|   else if(!dohp->pending) {
 | |
|     DOHcode rc[DOH_PROBE_SLOTS] = {
 | |
|       DOH_OK, DOH_OK
 | |
|     };
 | |
|     struct dohentry de;
 | |
|     int slot;
 | |
|     /* remove DoH handles from multi handle and close them */
 | |
|     for(slot = 0; slot < DOH_PROBE_SLOTS; slot++) {
 | |
|       curl_multi_remove_handle(data->multi, dohp->probe[slot].easy);
 | |
|       Curl_close(&dohp->probe[slot].easy);
 | |
|     }
 | |
|     /* parse the responses, create the struct and return it! */
 | |
|     de_init(&de);
 | |
|     for(slot = 0; slot < DOH_PROBE_SLOTS; slot++) {
 | |
|       struct dnsprobe *p = &dohp->probe[slot];
 | |
|       if(!p->dnstype)
 | |
|         continue;
 | |
|       rc[slot] = doh_decode(Curl_dyn_uptr(&p->serverdoh),
 | |
|                             Curl_dyn_len(&p->serverdoh),
 | |
|                             p->dnstype,
 | |
|                             &de);
 | |
|       Curl_dyn_free(&p->serverdoh);
 | |
|       if(rc[slot]) {
 | |
|         infof(data, "DoH: %s type %s for %s", doh_strerror(rc[slot]),
 | |
|               type2name(p->dnstype), dohp->host);
 | |
|       }
 | |
|     } /* next slot */
 | |
| 
 | |
|     result = CURLE_COULDNT_RESOLVE_HOST; /* until we know better */
 | |
|     if(!rc[DOH_PROBE_SLOT_IPADDR_V4] || !rc[DOH_PROBE_SLOT_IPADDR_V6]) {
 | |
|       /* we have an address, of one kind or other */
 | |
|       struct Curl_dns_entry *dns;
 | |
|       struct Curl_addrinfo *ai;
 | |
| 
 | |
|       infof(data, "DoH Host name: %s", dohp->host);
 | |
|       showdoh(data, &de);
 | |
| 
 | |
|       ai = doh2ai(&de, dohp->host, dohp->port);
 | |
|       if(!ai) {
 | |
|         de_cleanup(&de);
 | |
|         return CURLE_OUT_OF_MEMORY;
 | |
|       }
 | |
| 
 | |
|       if(data->share)
 | |
|         Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
 | |
| 
 | |
|       /* we got a response, store it in the cache */
 | |
|       dns = Curl_cache_addr(data, ai, dohp->host, dohp->port);
 | |
| 
 | |
|       if(data->share)
 | |
|         Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 | |
| 
 | |
|       if(!dns) {
 | |
|         /* returned failure, bail out nicely */
 | |
|         Curl_freeaddrinfo(ai);
 | |
|       }
 | |
|       else {
 | |
|         data->state.async.dns = dns;
 | |
|         *dnsp = dns;
 | |
|         result = CURLE_OK;      /* address resolution OK */
 | |
|       }
 | |
|     } /* address processing done */
 | |
| 
 | |
|     /* Now process any build-specific attributes retrieved from DNS */
 | |
| 
 | |
|     /* All done */
 | |
|     de_cleanup(&de);
 | |
|     Curl_safefree(data->req.doh);
 | |
|     return result;
 | |
| 
 | |
|   } /* !dohp->pending */
 | |
| 
 | |
|   /* else wait for pending DoH transactions to complete */
 | |
|   return CURLE_OK;
 | |
| }
 | |
| 
 | |
| #endif /* CURL_DISABLE_DOH */
 |