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Diffstat (limited to 'Utilities/cmcurl/lib/doh.c')
| -rw-r--r-- | Utilities/cmcurl/lib/doh.c | 998 |
1 files changed, 998 insertions, 0 deletions
diff --git a/Utilities/cmcurl/lib/doh.c b/Utilities/cmcurl/lib/doh.c new file mode 100644 index 0000000..1d928e9 --- /dev/null +++ b/Utilities/cmcurl/lib/doh.c @@ -0,0 +1,998 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) 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.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. + * + * SPDX-License-Identifier: curl + * + ***************************************************************************/ + +#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" +#include "dynbuf.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 + +#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", + "Name too long" +}; + +static const char *doh_strerror(DOHcode code) +{ + if((code >= DOH_OK) && (code <= DOH_DNS_NAME_TOO_LONG)) + return errors[code]; + return "bad error code"; +} +#endif + +/* @unittest 1655 + */ +UNITTEST DOHcode doh_encode(const char *host, + DNStype dnstype, + unsigned char *dnsp, /* buffer */ + size_t len, /* buffer size */ + size_t *olen) /* output length */ +{ + const size_t hostlen = strlen(host); + unsigned char *orig = dnsp; + const char *hostp = host; + + /* The expected output length is 16 bytes more than the length of + * the QNAME-encoding of the host name. + * + * A valid DNS name may not contain a zero-length label, except at + * the end. For this reason, a name beginning with a dot, or + * containing a sequence of two or more consecutive dots, is invalid + * and cannot be encoded as a QNAME. + * + * If the host name ends with a trailing dot, the corresponding + * QNAME-encoding is one byte longer than the host name. If (as is + * also valid) the hostname is shortened by the omission of the + * trailing dot, then its QNAME-encoding will be two bytes longer + * than the host name. + * + * Each [ label, dot ] pair is encoded as [ length, label ], + * preserving overall length. A final [ label ] without a dot is + * also encoded as [ length, label ], increasing overall length + * by one. The encoding is completed by appending a zero byte, + * representing the zero-length root label, again increasing + * the overall length by one. + */ + + size_t expected_len; + DEBUGASSERT(hostlen); + expected_len = 12 + 1 + hostlen + 4; + if(host[hostlen-1]!='.') + expected_len++; + + if(expected_len > (256 + 16)) /* RFCs 1034, 1035 */ + return DOH_DNS_NAME_TOO_LONG; + + if(len < expected_len) + 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 */ + + /* encode each label and store it in the QNAME */ + while(*hostp) { + size_t labellen; + char *dot = strchr(hostp, '.'); + if(dot) + labellen = dot - hostp; + else + labellen = strlen(hostp); + if((labellen > 63) || (!labellen)) { + /* label is too long or too short, error out */ + *olen = 0; + return DOH_DNS_BAD_LABEL; + } + /* label is non-empty, process it */ + *dnsp++ = (unsigned char)labellen; + memcpy(dnsp, hostp, labellen); + dnsp += labellen; + hostp += labellen; + /* advance past dot, but only if there is one */ + if(dot) + hostp++; + } /* next label */ + + *dnsp++ = 0; /* append zero-length label for root */ + + /* There are assigned TYPE codes beyond 255: use range [1..65535] */ + *dnsp++ = (unsigned char)(255 & (dnstype>>8)); /* upper 8 bit TYPE */ + *dnsp++ = (unsigned char)(255 & dnstype); /* lower 8 bit TYPE */ + + *dnsp++ = '\0'; /* upper 8 bit CLASS */ + *dnsp++ = DNS_CLASS_IN; /* IN - "the Internet" */ + + *olen = dnsp - orig; + + /* verify that our estimation of length is valid, since + * this has led to buffer overflows in this function */ + DEBUGASSERT(*olen == expected_len); + return DOH_OK; +} + +static size_t +doh_write_cb(const void *contents, size_t size, size_t nmemb, void *userp) +{ + size_t realsize = size * nmemb; + struct dynbuf *mem = (struct dynbuf *)userp; + + if(Curl_dyn_addn(mem, contents, realsize)) + return 0; + + return realsize; +} + +/* called from multi.c when this DoH transfer is complete */ +static int doh_done(struct Curl_easy *doh, CURLcode result) +{ + struct Curl_easy *data = doh->set.dohfor; + struct dohdata *dohp = data->req.doh; + /* so one of the DoH request done for the 'data' transfer is now complete! */ + dohp->pending--; + infof(data, "a DoH request is completed, %u to go", dohp->pending); + if(result) + infof(data, "DoH request %s", curl_easy_strerror(result)); + + if(!dohp->pending) { + /* DoH completed */ + curl_slist_free_all(dohp->headers); + dohp->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 && \ + result != CURLE_NOT_BUILT_IN && \ + result != CURLE_UNKNOWN_OPTION) \ + goto error; \ +} while(0) + +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]", d); + return CURLE_OUT_OF_MEMORY; + } + + p->dnstype = dnstype; + Curl_dyn_init(&p->serverdoh, DYN_DOH_RESPONSE); + + timeout_ms = Curl_timeleft(data, NULL, TRUE); + if(timeout_ms <= 0) { + result = CURLE_OPERATION_TIMEDOUT; + goto error; + } + /* 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 dynbuf *resp = &p->serverdoh; + doh->state.internal = true; + ERROR_CHECK_SETOPT(CURLOPT_URL, url); + ERROR_CHECK_SETOPT(CURLOPT_DEFAULT_PROTOCOL, "https"); + ERROR_CHECK_SETOPT(CURLOPT_WRITEFUNCTION, doh_write_cb); + ERROR_CHECK_SETOPT(CURLOPT_WRITEDATA, resp); + ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDS, p->dohbuffer); + ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDSIZE, (long)p->dohlen); + ERROR_CHECK_SETOPT(CURLOPT_HTTPHEADER, headers); +#ifdef USE_HTTP2 + ERROR_CHECK_SETOPT(CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2TLS); + ERROR_CHECK_SETOPT(CURLOPT_PIPEWAIT, 1L); +#endif +#ifndef CURLDEBUG + /* enforce HTTPS if not debug */ + ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTPS); +#else + /* in debug mode, also allow http */ + ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTP|CURLPROTO_HTTPS); +#endif + ERROR_CHECK_SETOPT(CURLOPT_TIMEOUT_MS, (long)timeout_ms); + ERROR_CHECK_SETOPT(CURLOPT_SHARE, data->share); + if(data->set.err && data->set.err != stderr) + ERROR_CHECK_SETOPT(CURLOPT_STDERR, data->set.err); + if(data->set.verbose) + ERROR_CHECK_SETOPT(CURLOPT_VERBOSE, 1L); + if(data->set.no_signal) + ERROR_CHECK_SETOPT(CURLOPT_NOSIGNAL, 1L); + + ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYHOST, + data->set.doh_verifyhost ? 2L : 0L); + ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYPEER, + data->set.doh_verifypeer ? 1L : 0L); + ERROR_CHECK_SETOPT(CURLOPT_SSL_VERIFYSTATUS, + data->set.doh_verifystatus ? 1L : 0L); + + /* Inherit *some* SSL options from the user's transfer. This is a + best-guess as to which options are needed for compatibility. #3661 + + Note DoH does not inherit the user's proxy server so proxy SSL settings + have no effect and are not inherited. If that changes then two new + options should be added to check doh proxy insecure separately, + CURLOPT_DOH_PROXY_SSL_VERIFYHOST and CURLOPT_DOH_PROXY_SSL_VERIFYPEER. + */ + if(data->set.ssl.falsestart) + ERROR_CHECK_SETOPT(CURLOPT_SSL_FALSESTART, 1L); + if(data->set.str[STRING_SSL_CAFILE]) { + ERROR_CHECK_SETOPT(CURLOPT_CAINFO, + data->set.str[STRING_SSL_CAFILE]); + } + if(data->set.blobs[BLOB_CAINFO]) { + ERROR_CHECK_SETOPT(CURLOPT_CAINFO_BLOB, + data->set.blobs[BLOB_CAINFO]); + } + if(data->set.str[STRING_SSL_CAPATH]) { + ERROR_CHECK_SETOPT(CURLOPT_CAPATH, + 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.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.fdebug) + ERROR_CHECK_SETOPT(CURLOPT_DEBUGFUNCTION, data->set.fdebug); + if(data->set.debugdata) + ERROR_CHECK_SETOPT(CURLOPT_DEBUGDATA, data->set.debugdata); + 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 handles must not inherit private_data. The handles may be passed to + the user via callbacks and the user will be able to identify them as + internal handles because private data is not set. The user can then set + private_data via CURLOPT_PRIVATE if they so choose. */ + 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 = FALSE; + (void)hostname; + (void)port; + + DEBUGASSERT(!data->req.doh); + DEBUGASSERT(conn); + + /* start clean, consider allocating this struct on demand */ + dohp = data->req.doh = calloc(1, sizeof(struct dohdata)); + 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++; + +#ifdef ENABLE_IPV6 + if((conn->ip_version != CURL_IPRESOLVE_V4) && 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++; + } +#endif + *waitp = TRUE; /* this never returns synchronously */ + return NULL; + +error: + curl_slist_free_all(dohp->headers); + data->req.doh->headers = NULL; + for(slot = 0; slot < DOH_PROBE_SLOTS; slot++) { + (void)curl_multi_remove_handle(data->multi, dohp->probe[slot].easy); + 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_addn(c, STRCONST("."))) + 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 CURLcode doh2ai(const struct dohentry *de, const char *hostname, + int port, struct Curl_addrinfo **aip) +{ + 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 null-terminator */ + + DEBUGASSERT(de); + + if(!de->numaddr) + return CURLE_COULDNT_RESOLVE_HOST; + + 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; + } + *aip = firstai; + + return result; +} + +#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) +{ + struct connectdata *conn = data->conn; + 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", conn->resolve_async.hostname); + return CONN_IS_PROXIED(data->conn)?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); +#ifndef CURL_DISABLE_VERBOSE_STRINGS + if(rc[slot]) { + infof(data, "DoH: %s type %s for %s", doh_strerror(rc[slot]), + type2name(p->dnstype), dohp->host); + } +#endif + } /* 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); + + result = doh2ai(&de, dohp->host, dohp->port, &ai); + if(result) { + de_cleanup(&de); + return result; + } + + 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, 0, dohp->port); + + if(data->share) + Curl_share_unlock(data, CURL_LOCK_DATA_DNS); + + if(!dns) { + /* returned failure, bail out nicely */ + Curl_freeaddrinfo(ai); + } + else { + conn->resolve_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 */ |