968 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			968 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /***************************************************************************
 | |
|  *                                  _   _ ____  _
 | |
|  *  Project                     ___| | | |  _ \| |
 | |
|  *                             / __| | | | |_) | |
 | |
|  *                            | (__| |_| |  _ <| |___
 | |
|  *                             \___|\___/|_| \_\_____|
 | |
|  *
 | |
|  * Copyright (C) 2018 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
 | |
|  *
 | |
|  * This software is licensed as described in the file COPYING, which
 | |
|  * you should have received as part of this distribution. The terms
 | |
|  * are also available at https://curl.haxx.se/docs/copyright.html.
 | |
|  *
 | |
|  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 | |
|  * copies of the Software, and permit persons to whom the Software is
 | |
|  * furnished to do so, under the terms of the COPYING file.
 | |
|  *
 | |
|  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 | |
|  * KIND, either express or implied.
 | |
|  *
 | |
|  ***************************************************************************/
 | |
| 
 | |
| #include "curl_setup.h"
 | |
| 
 | |
| #ifndef CURL_DISABLE_DOH
 | |
| 
 | |
| #include "urldata.h"
 | |
| #include "curl_addrinfo.h"
 | |
| #include "doh.h"
 | |
| 
 | |
| #include "sendf.h"
 | |
| #include "multiif.h"
 | |
| #include "url.h"
 | |
| #include "share.h"
 | |
| #include "curl_base64.h"
 | |
| #include "connect.h"
 | |
| #include "strdup.h"
 | |
| /* The last 3 #include files should be in this order */
 | |
| #include "curl_printf.h"
 | |
| #include "curl_memory.h"
 | |
| #include "memdebug.h"
 | |
| 
 | |
| #define DNS_CLASS_IN 0x01
 | |
| #define DOH_MAX_RESPONSE_SIZE 3000 /* bytes */
 | |
| 
 | |
| #ifndef CURL_DISABLE_VERBOSE_STRINGS
 | |
| static const char * const errors[]={
 | |
|   "",
 | |
|   "Bad label",
 | |
|   "Out of range",
 | |
|   "Label loop",
 | |
|   "Too small",
 | |
|   "Out of memory",
 | |
|   "RDATA length",
 | |
|   "Malformat",
 | |
|   "Bad RCODE",
 | |
|   "Unexpected TYPE",
 | |
|   "Unexpected CLASS",
 | |
|   "No content",
 | |
|   "Bad ID"
 | |
| };
 | |
| 
 | |
| static const char *doh_strerror(DOHcode code)
 | |
| {
 | |
|   if((code >= DOH_OK) && (code <= DOH_DNS_BAD_ID))
 | |
|     return errors[code];
 | |
|   return "bad error code";
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifdef DEBUGBUILD
 | |
| #define UNITTEST
 | |
| #else
 | |
| #define UNITTEST static
 | |
| #endif
 | |
| 
 | |
| UNITTEST DOHcode doh_encode(const char *host,
 | |
|                             DNStype dnstype,
 | |
|                             unsigned char *dnsp, /* buffer */
 | |
|                             size_t len,  /* buffer size */
 | |
|                             size_t *olen) /* output length */
 | |
| {
 | |
|   size_t hostlen = strlen(host);
 | |
|   unsigned char *orig = dnsp;
 | |
|   const char *hostp = host;
 | |
| 
 | |
|   if(len < (12 + hostlen + 4))
 | |
|     return DOH_TOO_SMALL_BUFFER;
 | |
| 
 | |
|   *dnsp++ = 0; /* 16 bit id */
 | |
|   *dnsp++ = 0;
 | |
|   *dnsp++ = 0x01; /* |QR|   Opcode  |AA|TC|RD| Set the RD bit */
 | |
|   *dnsp++ = '\0'; /* |RA|   Z    |   RCODE   |                */
 | |
|   *dnsp++ = '\0';
 | |
|   *dnsp++ = 1;    /* QDCOUNT (number of entries in the question section) */
 | |
|   *dnsp++ = '\0';
 | |
|   *dnsp++ = '\0'; /* ANCOUNT */
 | |
|   *dnsp++ = '\0';
 | |
|   *dnsp++ = '\0'; /* NSCOUNT */
 | |
|   *dnsp++ = '\0';
 | |
|   *dnsp++ = '\0'; /* ARCOUNT */
 | |
| 
 | |
|   /* store a QNAME */
 | |
|   do {
 | |
|     char *dot = strchr(hostp, '.');
 | |
|     size_t labellen;
 | |
|     bool found = false;
 | |
|     if(dot) {
 | |
|       found = true;
 | |
|       labellen = dot - hostp;
 | |
|     }
 | |
|     else
 | |
|       labellen = strlen(hostp);
 | |
|     if(labellen > 63) {
 | |
|       /* too long label, error out */
 | |
|       *olen = 0;
 | |
|       return DOH_DNS_BAD_LABEL;
 | |
|     }
 | |
|     *dnsp++ = (unsigned char)labellen;
 | |
|     memcpy(dnsp, hostp, labellen);
 | |
|     dnsp += labellen;
 | |
|     hostp += labellen + 1;
 | |
|     if(!found) {
 | |
|       *dnsp++ = 0; /* terminating zero */
 | |
|       break;
 | |
|     }
 | |
|   } while(1);
 | |
| 
 | |
|   *dnsp++ = '\0'; /* upper 8 bit TYPE */
 | |
|   *dnsp++ = (unsigned char)dnstype;
 | |
|   *dnsp++ = '\0'; /* upper 8 bit CLASS */
 | |
|   *dnsp++ = DNS_CLASS_IN; /* IN - "the Internet" */
 | |
| 
 | |
|   *olen = dnsp - orig;
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static size_t
 | |
| doh_write_cb(void *contents, size_t size, size_t nmemb, void *userp)
 | |
| {
 | |
|   size_t realsize = size * nmemb;
 | |
|   struct dohresponse *mem = (struct dohresponse *)userp;
 | |
| 
 | |
|   if((mem->size + realsize) > DOH_MAX_RESPONSE_SIZE)
 | |
|     /* suspiciously much for us */
 | |
|     return 0;
 | |
| 
 | |
|   mem->memory = Curl_saferealloc(mem->memory, mem->size + realsize);
 | |
|   if(!mem->memory)
 | |
|     /* out of memory! */
 | |
|     return 0;
 | |
| 
 | |
|   memcpy(&(mem->memory[mem->size]), contents, realsize);
 | |
|   mem->size += realsize;
 | |
| 
 | |
|   return realsize;
 | |
| }
 | |
| 
 | |
| /* called from multi.c when this DOH transfer is complete */
 | |
| static int Curl_doh_done(struct Curl_easy *doh, CURLcode result)
 | |
| {
 | |
|   struct Curl_easy *data = doh->set.dohfor;
 | |
|   /* so one of the DOH request done for the 'data' transfer is now complete! */
 | |
|   data->req.doh.pending--;
 | |
|   infof(data, "a DOH request is completed, %u to go\n", data->req.doh.pending);
 | |
|   if(result)
 | |
|     infof(data, "DOH request %s\n", curl_easy_strerror(result));
 | |
| 
 | |
|   if(!data->req.doh.pending) {
 | |
|     /* DOH completed */
 | |
|     curl_slist_free_all(data->req.doh.headers);
 | |
|     data->req.doh.headers = NULL;
 | |
|     Curl_expire(data, 0, EXPIRE_RUN_NOW);
 | |
|   }
 | |
|   return 0;
 | |
| }
 | |
| 
 | |
| #define ERROR_CHECK_SETOPT(x,y) \
 | |
| do {                                      \
 | |
|   result = curl_easy_setopt(doh, x, y);   \
 | |
|   if(result)                              \
 | |
|     goto error;                           \
 | |
| } WHILE_FALSE
 | |
| 
 | |
| static CURLcode dohprobe(struct Curl_easy *data,
 | |
|                          struct dnsprobe *p, DNStype dnstype,
 | |
|                          const char *host,
 | |
|                          const char *url, CURLM *multi,
 | |
|                          struct curl_slist *headers)
 | |
| {
 | |
|   struct Curl_easy *doh = NULL;
 | |
|   char *nurl = NULL;
 | |
|   CURLcode result = CURLE_OK;
 | |
|   timediff_t timeout_ms;
 | |
|   DOHcode d = doh_encode(host, dnstype, p->dohbuffer, sizeof(p->dohbuffer),
 | |
|                          &p->dohlen);
 | |
|   if(d) {
 | |
|     failf(data, "Failed to encode DOH packet [%d]\n", d);
 | |
|     return CURLE_OUT_OF_MEMORY;
 | |
|   }
 | |
| 
 | |
|   p->dnstype = dnstype;
 | |
|   p->serverdoh.memory = NULL;
 | |
|   /* the memory will be grown as needed by realloc in the doh_write_cb
 | |
|      function */
 | |
|   p->serverdoh.size = 0;
 | |
| 
 | |
|   /* Note: this is code for sending the DoH request with GET but there's still
 | |
|      no logic that actually enables this. We should either add that ability or
 | |
|      yank out the GET code. Discuss! */
 | |
|   if(data->set.doh_get) {
 | |
|     char *b64;
 | |
|     size_t b64len;
 | |
|     result = Curl_base64url_encode(data, (char *)p->dohbuffer, p->dohlen,
 | |
|                                    &b64, &b64len);
 | |
|     if(result)
 | |
|       goto error;
 | |
|     nurl = aprintf("%s?dns=%s", url, b64);
 | |
|     free(b64);
 | |
|     if(!nurl) {
 | |
|       result = CURLE_OUT_OF_MEMORY;
 | |
|       goto error;
 | |
|     }
 | |
|     url = nurl;
 | |
|   }
 | |
| 
 | |
|   timeout_ms = Curl_timeleft(data, NULL, TRUE);
 | |
| 
 | |
|   /* Curl_open() is the internal version of curl_easy_init() */
 | |
|   result = Curl_open(&doh);
 | |
|   if(!result) {
 | |
|     /* pass in the struct pointer via a local variable to please coverity and
 | |
|        the gcc typecheck helpers */
 | |
|     struct dohresponse *resp = &p->serverdoh;
 | |
|     ERROR_CHECK_SETOPT(CURLOPT_URL, url);
 | |
|     ERROR_CHECK_SETOPT(CURLOPT_WRITEFUNCTION, doh_write_cb);
 | |
|     ERROR_CHECK_SETOPT(CURLOPT_WRITEDATA, resp);
 | |
|     if(!data->set.doh_get) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDS, p->dohbuffer);
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDSIZE, (long)p->dohlen);
 | |
|     }
 | |
|     ERROR_CHECK_SETOPT(CURLOPT_HTTPHEADER, headers);
 | |
| #ifdef USE_NGHTTP2
 | |
|     ERROR_CHECK_SETOPT(CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2TLS);
 | |
| #endif
 | |
| #ifndef CURLDEBUG
 | |
|     /* enforce HTTPS if not debug */
 | |
|     ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
 | |
| #endif
 | |
|     ERROR_CHECK_SETOPT(CURLOPT_TIMEOUT_MS, (long)timeout_ms);
 | |
|     if(data->set.verbose)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_VERBOSE, 1L);
 | |
|     if(data->set.no_signal)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_NOSIGNAL, 1L);
 | |
| 
 | |
|     /* Inherit *some* SSL options from the user's transfer. This is a
 | |
|        best-guess as to which options are needed for compatibility. #3661 */
 | |
|     if(data->set.ssl.falsestart)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_FALSESTART, 1L);
 | |
|     if(data->set.ssl.primary.verifyhost)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYHOST, 2L);
 | |
|     if(data->set.proxy_ssl.primary.verifyhost)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_PROXY_SSL_VERIFYHOST, 2L);
 | |
|     if(data->set.ssl.primary.verifypeer)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYPEER, 1L);
 | |
|     if(data->set.proxy_ssl.primary.verifypeer)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_PROXY_SSL_VERIFYPEER, 1L);
 | |
|     if(data->set.ssl.primary.verifystatus)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYSTATUS, 1L);
 | |
|     if(data->set.str[STRING_SSL_CAFILE_ORIG]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_CAINFO,
 | |
|         data->set.str[STRING_SSL_CAFILE_ORIG]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_CAFILE_PROXY]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_PROXY_CAINFO,
 | |
|         data->set.str[STRING_SSL_CAFILE_PROXY]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_CAPATH_ORIG]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_CAPATH,
 | |
|         data->set.str[STRING_SSL_CAPATH_ORIG]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_CAPATH_PROXY]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_PROXY_CAPATH,
 | |
|         data->set.str[STRING_SSL_CAPATH_PROXY]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_CRLFILE_ORIG]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_CRLFILE,
 | |
|         data->set.str[STRING_SSL_CRLFILE_ORIG]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_CRLFILE_PROXY]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_PROXY_CRLFILE,
 | |
|         data->set.str[STRING_SSL_CRLFILE_PROXY]);
 | |
|     }
 | |
|     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,
 | |
|         data->set.str[STRING_SSL_RANDOM_FILE]);
 | |
|     }
 | |
|     if(data->set.str[STRING_SSL_EGDSOCKET]) {
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_EGDSOCKET,
 | |
|         data->set.str[STRING_SSL_EGDSOCKET]);
 | |
|     }
 | |
|     if(data->set.ssl.no_revoke)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_SSL_OPTIONS, CURLSSLOPT_NO_REVOKE);
 | |
|     if(data->set.proxy_ssl.no_revoke)
 | |
|       ERROR_CHECK_SETOPT(CURLOPT_PROXY_SSL_OPTIONS, CURLSSLOPT_NO_REVOKE);
 | |
|     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);
 | |
| 
 | |
|     doh->set.fmultidone = Curl_doh_done;
 | |
|     doh->set.dohfor = data; /* identify for which transfer this is done */
 | |
|     p->easy = doh;
 | |
| 
 | |
|     /* add this transfer to the multi handle */
 | |
|     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.
 | |
|  */
 | |
| 
 | |
| Curl_addrinfo *Curl_doh(struct connectdata *conn,
 | |
|                         const char *hostname,
 | |
|                         int port,
 | |
|                         int *waitp)
 | |
| {
 | |
|   struct Curl_easy *data = conn->data;
 | |
|   CURLcode result = CURLE_OK;
 | |
|   *waitp = TRUE; /* this never returns synchronously */
 | |
|   (void)conn;
 | |
|   (void)hostname;
 | |
|   (void)port;
 | |
| 
 | |
|   /* start clean, consider allocating this struct on demand */
 | |
|   memset(&data->req.doh, 0, sizeof(struct dohdata));
 | |
| 
 | |
|   data->req.doh.host = hostname;
 | |
|   data->req.doh.port = port;
 | |
|   data->req.doh.headers =
 | |
|     curl_slist_append(NULL,
 | |
|                       "Content-Type: application/dns-message");
 | |
|   if(!data->req.doh.headers)
 | |
|     goto error;
 | |
| 
 | |
|   if(conn->ip_version != CURL_IPRESOLVE_V6) {
 | |
|     /* create IPv4 DOH request */
 | |
|     result = dohprobe(data, &data->req.doh.probe[0], DNS_TYPE_A,
 | |
|                       hostname, data->set.str[STRING_DOH],
 | |
|                       data->multi, data->req.doh.headers);
 | |
|     if(result)
 | |
|       goto error;
 | |
|     data->req.doh.pending++;
 | |
|   }
 | |
| 
 | |
|   if(conn->ip_version != CURL_IPRESOLVE_V4) {
 | |
|     /* create IPv6 DOH request */
 | |
|     result = dohprobe(data, &data->req.doh.probe[1], DNS_TYPE_AAAA,
 | |
|                       hostname, data->set.str[STRING_DOH],
 | |
|                       data->multi, data->req.doh.headers);
 | |
|     if(result)
 | |
|       goto error;
 | |
|     data->req.doh.pending++;
 | |
|   }
 | |
|   return NULL;
 | |
| 
 | |
|   error:
 | |
|   curl_slist_free_all(data->req.doh.headers);
 | |
|   data->req.doh.headers = NULL;
 | |
|   curl_easy_cleanup(data->req.doh.probe[0].easy);
 | |
|   data->req.doh.probe[0].easy = NULL;
 | |
|   curl_easy_cleanup(data->req.doh.probe[1].easy);
 | |
|   data->req.doh.probe[1].easy = NULL;
 | |
|   return NULL;
 | |
| }
 | |
| 
 | |
| static DOHcode skipqname(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(unsigned char *doh, int index)
 | |
| {
 | |
|   return (unsigned short)((doh[index] << 8) | doh[index + 1]);
 | |
| }
 | |
| 
 | |
| static unsigned int get32bit(unsigned char *doh, int index)
 | |
| {
 | |
|   return (doh[index] << 24) | (doh[index + 1] << 16) |
 | |
|     (doh[index + 2] << 8) | doh[index + 3];
 | |
| }
 | |
| 
 | |
| static DOHcode store_a(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(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 cnameappend(struct cnamestore *c,
 | |
|                            unsigned char *src,
 | |
|                            size_t len)
 | |
| {
 | |
|   if(!c->alloc) {
 | |
|     c->allocsize = len + 1;
 | |
|     c->alloc = malloc(c->allocsize);
 | |
|     if(!c->alloc)
 | |
|       return DOH_OUT_OF_MEM;
 | |
|   }
 | |
|   else if(c->allocsize < (c->allocsize + len + 1)) {
 | |
|     char *ptr;
 | |
|     c->allocsize += len + 1;
 | |
|     ptr = realloc(c->alloc, c->allocsize);
 | |
|     if(!ptr) {
 | |
|       free(c->alloc);
 | |
|       return DOH_OUT_OF_MEM;
 | |
|     }
 | |
|     c->alloc = ptr;
 | |
|   }
 | |
|   memcpy(&c->alloc[c->len], src, len);
 | |
|   c->len += len;
 | |
|   c->alloc[c->len] = 0; /* keep it zero terminated */
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static DOHcode store_cname(unsigned char *doh,
 | |
|                            size_t dohlen,
 | |
|                            unsigned int index,
 | |
|                            struct dohentry *d)
 | |
| {
 | |
|   struct cnamestore *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 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) {
 | |
|       DOHcode rc;
 | |
|       if(c->len) {
 | |
|         rc = cnameappend(c, (unsigned char *)".", 1);
 | |
|         if(rc)
 | |
|           return rc;
 | |
|       }
 | |
|       if((index + length) > dohlen)
 | |
|         return DOH_DNS_BAD_LABEL;
 | |
| 
 | |
|       rc = cnameappend(c, &doh[index], length);
 | |
|       if(rc)
 | |
|         return rc;
 | |
|       index += length;
 | |
|     }
 | |
|   } while(length && --loop);
 | |
| 
 | |
|   if(!loop)
 | |
|     return DOH_DNS_LABEL_LOOP;
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static DOHcode rdata(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;
 | |
|   default:
 | |
|     /* unsupported type, just skip it */
 | |
|     break;
 | |
|   }
 | |
|   return DOH_OK;
 | |
| }
 | |
| 
 | |
| static void init_dohentry(struct dohentry *de)
 | |
| {
 | |
|   memset(de, 0, sizeof(*de));
 | |
|   de->ttl = INT_MAX;
 | |
| }
 | |
| 
 | |
| 
 | |
| UNITTEST DOHcode doh_decode(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) && (type != dnstype))
 | |
|       /* Not the same type as was asked for nor CNAME */
 | |
|       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,
 | |
|                     struct dohentry *d)
 | |
| {
 | |
|   int i;
 | |
|   infof(data, "TTL: %u seconds\n", d->ttl);
 | |
|   for(i = 0; i < d->numaddr; i++) {
 | |
|     struct dohaddr *a = &d->addr[i];
 | |
|     if(a->type == DNS_TYPE_A) {
 | |
|       infof(data, "DOH A: %u.%u.%u.%u\n",
 | |
|             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\n", buffer);
 | |
|     }
 | |
|   }
 | |
|   for(i = 0; i < d->numcname; i++) {
 | |
|     infof(data, "CNAME: %s\n", d->cname[i].alloc);
 | |
|   }
 | |
| }
 | |
| #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 Curl_addrinfo *
 | |
| doh2ai(const struct dohentry *de, const char *hostname, int port)
 | |
| {
 | |
|   Curl_addrinfo *ai;
 | |
|   Curl_addrinfo *prevai = NULL;
 | |
|   Curl_addrinfo *firstai = NULL;
 | |
|   struct sockaddr_in *addr;
 | |
| #ifdef ENABLE_IPV6
 | |
|   struct sockaddr_in6 *addr6;
 | |
| #endif
 | |
|   CURLcode result = CURLE_OK;
 | |
|   int i;
 | |
| 
 | |
|   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(Curl_addrinfo));
 | |
|     if(!ai) {
 | |
|       result = CURLE_OUT_OF_MEMORY;
 | |
|       break;
 | |
|     }
 | |
|     ai->ai_canonname = strdup(hostname);
 | |
|     if(!ai->ai_canonname) {
 | |
|       result = CURLE_OUT_OF_MEMORY;
 | |
|       free(ai);
 | |
|       break;
 | |
|     }
 | |
|     ai->ai_addr = calloc(1, ss_size);
 | |
|     if(!ai->ai_addr) {
 | |
|       result = CURLE_OUT_OF_MEMORY;
 | |
|       free(ai->ai_canonname);
 | |
|       free(ai);
 | |
|       break;
 | |
|     }
 | |
| 
 | |
|     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 = (CURL_SA_FAMILY_T)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 = (CURL_SA_FAMILY_T)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++) {
 | |
|     free(d->cname[i].alloc);
 | |
|   }
 | |
| }
 | |
| 
 | |
| CURLcode Curl_doh_is_resolved(struct connectdata *conn,
 | |
|                               struct Curl_dns_entry **dnsp)
 | |
| {
 | |
|   struct Curl_easy *data = conn->data;
 | |
|   *dnsp = NULL; /* defaults to no response */
 | |
| 
 | |
|   if(!data->req.doh.probe[0].easy && !data->req.doh.probe[1].easy) {
 | |
|     failf(data, "Could not DOH-resolve: %s", conn->async.hostname);
 | |
|     return conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
 | |
|       CURLE_COULDNT_RESOLVE_HOST;
 | |
|   }
 | |
|   else if(!data->req.doh.pending) {
 | |
|     DOHcode rc;
 | |
|     DOHcode rc2;
 | |
|     struct dohentry de;
 | |
|     /* remove DOH handles from multi handle and close them */
 | |
|     curl_multi_remove_handle(data->multi, data->req.doh.probe[0].easy);
 | |
|     Curl_close(data->req.doh.probe[0].easy);
 | |
|     curl_multi_remove_handle(data->multi, data->req.doh.probe[1].easy);
 | |
|     Curl_close(data->req.doh.probe[1].easy);
 | |
| 
 | |
|     /* parse the responses, create the struct and return it! */
 | |
|     init_dohentry(&de);
 | |
|     rc = doh_decode(data->req.doh.probe[0].serverdoh.memory,
 | |
|                     data->req.doh.probe[0].serverdoh.size,
 | |
|                     data->req.doh.probe[0].dnstype,
 | |
|                     &de);
 | |
|     free(data->req.doh.probe[0].serverdoh.memory);
 | |
|     if(rc) {
 | |
|       infof(data, "DOH: %s type %s for %s\n", doh_strerror(rc),
 | |
|             type2name(data->req.doh.probe[0].dnstype),
 | |
|             data->req.doh.host);
 | |
|     }
 | |
|     rc2 = doh_decode(data->req.doh.probe[1].serverdoh.memory,
 | |
|                      data->req.doh.probe[1].serverdoh.size,
 | |
|                      data->req.doh.probe[1].dnstype,
 | |
|                      &de);
 | |
|     free(data->req.doh.probe[1].serverdoh.memory);
 | |
|     if(rc2) {
 | |
|       infof(data, "DOH: %s type %s for %s\n", doh_strerror(rc2),
 | |
|             type2name(data->req.doh.probe[1].dnstype),
 | |
|             data->req.doh.host);
 | |
|     }
 | |
|     if(!rc || !rc2) {
 | |
|       struct Curl_dns_entry *dns;
 | |
|       struct Curl_addrinfo *ai;
 | |
| 
 | |
|       infof(data, "DOH Host name: %s\n", data->req.doh.host);
 | |
|       showdoh(data, &de);
 | |
| 
 | |
|       ai = doh2ai(&de, data->req.doh.host, data->req.doh.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, data->req.doh.host, data->req.doh.port);
 | |
| 
 | |
|       if(data->share)
 | |
|         Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 | |
| 
 | |
|       de_cleanup(&de);
 | |
|       if(!dns)
 | |
|         /* returned failure, bail out nicely */
 | |
|         Curl_freeaddrinfo(ai);
 | |
|       else {
 | |
|         conn->async.dns = dns;
 | |
|         *dnsp = dns;
 | |
|         return CURLE_OK;
 | |
|       }
 | |
|     }
 | |
|     de_cleanup(&de);
 | |
| 
 | |
|     return CURLE_COULDNT_RESOLVE_HOST;
 | |
|   }
 | |
| 
 | |
|   return CURLE_OK;
 | |
| }
 | |
| 
 | |
| #endif /* CURL_DISABLE_DOH */
 |