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-rw-r--r--netwerk/dns/DNSPacket.cpp1068
1 files changed, 1068 insertions, 0 deletions
diff --git a/netwerk/dns/DNSPacket.cpp b/netwerk/dns/DNSPacket.cpp
new file mode 100644
index 0000000000..157effad31
--- /dev/null
+++ b/netwerk/dns/DNSPacket.cpp
@@ -0,0 +1,1068 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DNSPacket.h"
+
+#include "DNS.h"
+#include "mozilla/EndianUtils.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_network.h"
+// Put DNSLogging.h at the end to avoid LOG being overwritten by other headers.
+#include "DNSLogging.h"
+
+#include "nsIInputStream.h"
+
+namespace mozilla {
+namespace net {
+
+static uint16_t get16bit(const unsigned char* aData, unsigned int index) {
+ return ((aData[index] << 8) | aData[index + 1]);
+}
+
+static uint32_t get32bit(const unsigned char* aData, unsigned int index) {
+ return (aData[index] << 24) | (aData[index + 1] << 16) |
+ (aData[index + 2] << 8) | aData[index + 3];
+}
+
+// https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-extended-error-16#section-4
+// This is a list of errors for which we should not fallback to Do53.
+// These are normally DNSSEC failures or explicit filtering performed by the
+// recursive resolver.
+bool hardFail(uint16_t code) {
+ const uint16_t noFallbackErrors[] = {
+ 4, // Forged answer (malware filtering)
+ 6, // DNSSEC Boggus
+ 7, // Signature expired
+ 8, // Signature not yet valid
+ 9, // DNSKEY Missing
+ 10, // RRSIG missing
+ 11, // No ZONE Key Bit set
+ 12, // NSEC Missing
+ 17, // Filtered
+ };
+
+ for (const auto& err : noFallbackErrors) {
+ if (code == err) {
+ return true;
+ }
+ }
+ return false;
+}
+
+// static
+nsresult DNSPacket::ParseSvcParam(unsigned int svcbIndex, uint16_t key,
+ SvcFieldValue& field, uint16_t length,
+ const unsigned char* aBuffer) {
+ switch (key) {
+ case SvcParamKeyMandatory: {
+ if (length % 2 != 0) {
+ // This key should encode a list of uint16_t
+ return NS_ERROR_UNEXPECTED;
+ }
+ while (length > 0) {
+ uint16_t mandatoryKey = get16bit(aBuffer, svcbIndex);
+ length -= 2;
+ svcbIndex += 2;
+
+ if (!IsValidSvcParamKey(mandatoryKey)) {
+ LOG(("The mandatory field includes a key we don't support %u",
+ mandatoryKey));
+ return NS_ERROR_UNEXPECTED;
+ }
+ }
+ break;
+ }
+ case SvcParamKeyAlpn: {
+ field.mValue = AsVariant(SvcParamAlpn());
+ auto& alpnArray = field.mValue.as<SvcParamAlpn>().mValue;
+ while (length > 0) {
+ uint8_t alpnIdLength = aBuffer[svcbIndex++];
+ length -= 1;
+ if (alpnIdLength > length) {
+ return NS_ERROR_UNEXPECTED;
+ }
+
+ alpnArray.AppendElement(
+ nsCString((const char*)&aBuffer[svcbIndex], alpnIdLength));
+ length -= alpnIdLength;
+ svcbIndex += alpnIdLength;
+ }
+ break;
+ }
+ case SvcParamKeyNoDefaultAlpn: {
+ if (length != 0) {
+ // This key should not contain a value
+ return NS_ERROR_UNEXPECTED;
+ }
+ field.mValue = AsVariant(SvcParamNoDefaultAlpn{});
+ break;
+ }
+ case SvcParamKeyPort: {
+ if (length != 2) {
+ // This key should only encode a uint16_t
+ return NS_ERROR_UNEXPECTED;
+ }
+ field.mValue =
+ AsVariant(SvcParamPort{.mValue = get16bit(aBuffer, svcbIndex)});
+ break;
+ }
+ case SvcParamKeyIpv4Hint: {
+ if (length % 4 != 0) {
+ // This key should only encode IPv4 addresses
+ return NS_ERROR_UNEXPECTED;
+ }
+
+ field.mValue = AsVariant(SvcParamIpv4Hint());
+ auto& ipv4array = field.mValue.as<SvcParamIpv4Hint>().mValue;
+ while (length > 0) {
+ NetAddr addr;
+ addr.inet.family = AF_INET;
+ addr.inet.port = 0;
+ addr.inet.ip = ntohl(get32bit(aBuffer, svcbIndex));
+ ipv4array.AppendElement(addr);
+ length -= 4;
+ svcbIndex += 4;
+ }
+ break;
+ }
+ case SvcParamKeyEchConfig: {
+ field.mValue = AsVariant(SvcParamEchConfig{
+ .mValue = nsCString((const char*)(&aBuffer[svcbIndex]), length)});
+ break;
+ }
+ case SvcParamKeyIpv6Hint: {
+ if (length % 16 != 0) {
+ // This key should only encode IPv6 addresses
+ return NS_ERROR_UNEXPECTED;
+ }
+
+ field.mValue = AsVariant(SvcParamIpv6Hint());
+ auto& ipv6array = field.mValue.as<SvcParamIpv6Hint>().mValue;
+ while (length > 0) {
+ NetAddr addr;
+ addr.inet6.family = AF_INET6;
+ addr.inet6.port = 0; // unknown
+ addr.inet6.flowinfo = 0; // unknown
+ addr.inet6.scope_id = 0; // unknown
+ for (int i = 0; i < 16; i++, svcbIndex++) {
+ addr.inet6.ip.u8[i] = aBuffer[svcbIndex];
+ }
+ ipv6array.AppendElement(addr);
+ length -= 16;
+ // no need to increase svcbIndex - we did it in the for above.
+ }
+ break;
+ }
+ case SvcParamKeyODoHConfig: {
+ field.mValue = AsVariant(SvcParamODoHConfig{
+ .mValue = nsCString((const char*)(&aBuffer[svcbIndex]), length)});
+ break;
+ }
+ default: {
+ // Unespected type. We'll just ignore it.
+ return NS_OK;
+ break;
+ }
+ }
+ return NS_OK;
+}
+
+nsresult DNSPacket::PassQName(unsigned int& index,
+ const unsigned char* aBuffer) {
+ uint8_t length;
+ do {
+ if (mBodySize < (index + 1)) {
+ LOG(("TRR: PassQName:%d fail at index %d\n", __LINE__, index));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ length = static_cast<uint8_t>(aBuffer[index]);
+ if ((length & 0xc0) == 0xc0) {
+ // name pointer, advance over it and be done
+ if (mBodySize < (index + 2)) {
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ index += 2;
+ break;
+ }
+ if (length & 0xc0) {
+ LOG(("TRR: illegal label length byte (%x) at index %d\n", length, index));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ // pass label
+ if (mBodySize < (index + 1 + length)) {
+ LOG(("TRR: PassQName:%d fail at index %d\n", __LINE__, index));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ index += 1 + length;
+ } while (length);
+ return NS_OK;
+}
+
+// GetQname: retrieves the qname (stores in 'aQname') and stores the index
+// after qname was parsed into the 'aIndex'.
+nsresult DNSPacket::GetQname(nsACString& aQname, unsigned int& aIndex,
+ const unsigned char* aBuffer) {
+ uint8_t clength = 0;
+ unsigned int cindex = aIndex;
+ unsigned int loop = 128; // a valid DNS name can never loop this much
+ unsigned int endindex = 0; // index position after this data
+ do {
+ if (cindex >= mBodySize) {
+ LOG(("TRR: bad Qname packet\n"));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ clength = static_cast<uint8_t>(aBuffer[cindex]);
+ if ((clength & 0xc0) == 0xc0) {
+ // name pointer, get the new offset (14 bits)
+ if ((cindex + 1) >= mBodySize) {
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ // extract the new index position for the next label
+ uint16_t newpos = (clength & 0x3f) << 8 | aBuffer[cindex + 1];
+ if (!endindex) {
+ // only update on the first "jump"
+ endindex = cindex + 2;
+ }
+ cindex = newpos;
+ continue;
+ }
+ if (clength & 0xc0) {
+ // any of those bits set individually is an error
+ LOG(("TRR: bad Qname packet\n"));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+
+ cindex++;
+
+ if (clength) {
+ if (!aQname.IsEmpty()) {
+ aQname.Append(".");
+ }
+ if ((cindex + clength) > mBodySize) {
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ aQname.Append((const char*)(&aBuffer[cindex]), clength);
+ cindex += clength; // skip label
+ }
+ } while (clength && --loop);
+
+ if (!loop) {
+ LOG(("DNSPacket::DohDecode pointer loop error\n"));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ if (!endindex) {
+ // there was no "jump"
+ endindex = cindex;
+ }
+ aIndex = endindex;
+ return NS_OK;
+}
+
+nsresult DOHresp::Add(uint32_t TTL, unsigned char const* dns,
+ unsigned int index, uint16_t len, bool aLocalAllowed) {
+ NetAddr addr;
+ if (4 == len) {
+ // IPv4
+ addr.inet.family = AF_INET;
+ addr.inet.port = 0; // unknown
+ addr.inet.ip = ntohl(get32bit(dns, index));
+ } else if (16 == len) {
+ // IPv6
+ addr.inet6.family = AF_INET6;
+ addr.inet6.port = 0; // unknown
+ addr.inet6.flowinfo = 0; // unknown
+ addr.inet6.scope_id = 0; // unknown
+ for (int i = 0; i < 16; i++, index++) {
+ addr.inet6.ip.u8[i] = dns[index];
+ }
+ } else {
+ return NS_ERROR_UNEXPECTED;
+ }
+
+ if (addr.IsIPAddrLocal() && !aLocalAllowed) {
+ return NS_ERROR_FAILURE;
+ }
+
+ // While the DNS packet might return individual TTLs for each address,
+ // we can only return one value in the AddrInfo class so pick the
+ // lowest number.
+ if (mTtl < TTL) {
+ mTtl = TTL;
+ }
+
+ if (LOG_ENABLED()) {
+ char buf[128];
+ addr.ToStringBuffer(buf, sizeof(buf));
+ LOG(("DOHresp:Add %s\n", buf));
+ }
+ mAddresses.AppendElement(addr);
+ return NS_OK;
+}
+
+nsresult DNSPacket::OnDataAvailable(nsIRequest* aRequest,
+ nsIInputStream* aInputStream,
+ uint64_t aOffset, const uint32_t aCount) {
+ if (aCount + mBodySize > MAX_SIZE) {
+ LOG(("DNSPacket::OnDataAvailable:%d fail\n", __LINE__));
+ return NS_ERROR_FAILURE;
+ }
+ uint32_t count;
+ nsresult rv =
+ aInputStream->Read((char*)mResponse + mBodySize, aCount, &count);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+ MOZ_ASSERT(count == aCount);
+ mBodySize += aCount;
+ return NS_OK;
+}
+
+const uint8_t kDNS_CLASS_IN = 1;
+
+nsresult DNSPacket::EncodeRequest(nsCString& aBody, const nsACString& aHost,
+ uint16_t aType, bool aDisableECS) {
+ aBody.Truncate();
+ // Header
+ aBody += '\0';
+ aBody += '\0'; // 16 bit id
+ aBody += 0x01; // |QR| Opcode |AA|TC|RD| Set the RD bit
+ aBody += '\0'; // |RA| Z | RCODE |
+ aBody += '\0';
+ aBody += 1; // QDCOUNT (number of entries in the question section)
+ aBody += '\0';
+ aBody += '\0'; // ANCOUNT
+ aBody += '\0';
+ aBody += '\0'; // NSCOUNT
+
+ char additionalRecords =
+ (aDisableECS || StaticPrefs::network_trr_padding()) ? 1 : 0;
+ aBody += '\0'; // ARCOUNT
+ aBody += additionalRecords; // ARCOUNT low byte for EDNS(0)
+
+ // Question
+
+ // The input host name should be converted to a sequence of labels, where
+ // each label consists of a length octet followed by that number of
+ // octets. The domain name terminates with the zero length octet for the
+ // null label of the root.
+ // Followed by 16 bit QTYPE and 16 bit QCLASS
+
+ int32_t index = 0;
+ int32_t offset = 0;
+ do {
+ bool dotFound = false;
+ int32_t labelLength;
+ index = aHost.FindChar('.', offset);
+ if (kNotFound != index) {
+ dotFound = true;
+ labelLength = index - offset;
+ } else {
+ labelLength = aHost.Length() - offset;
+ }
+ if (labelLength > 63) {
+ // too long label!
+ SetDNSPacketStatus(DNSPacketStatus::EncodeError);
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ if (labelLength > 0) {
+ aBody += static_cast<unsigned char>(labelLength);
+ nsDependentCSubstring label = Substring(aHost, offset, labelLength);
+ aBody.Append(label);
+ }
+ if (!dotFound) {
+ aBody += '\0'; // terminate with a final zero
+ break;
+ }
+ offset += labelLength + 1; // move over label and dot
+ } while (true);
+
+ aBody += static_cast<uint8_t>(aType >> 8); // upper 8 bit TYPE
+ aBody += static_cast<uint8_t>(aType);
+ aBody += '\0'; // upper 8 bit CLASS
+ aBody += kDNS_CLASS_IN; // IN - "the Internet"
+
+ if (additionalRecords) {
+ // EDNS(0) is RFC 6891, ECS is RFC 7871
+ aBody += '\0'; // NAME | domain name | MUST be 0 (root domain) |
+ aBody += '\0';
+ aBody += 41; // TYPE | u_int16_t | OPT (41) |
+ aBody += 16; // CLASS | u_int16_t | requestor's UDP payload size |
+ aBody +=
+ '\0'; // advertise 4K (high-byte: 16 | low-byte: 0), ignored by DoH
+ aBody += '\0'; // TTL | u_int32_t | extended RCODE and flags |
+ aBody += '\0';
+ aBody += '\0';
+ aBody += '\0';
+
+ // calculate padding length
+ unsigned int paddingLen = 0;
+ unsigned int rdlen = 0;
+ bool padding = StaticPrefs::network_trr_padding();
+ if (padding) {
+ // always add padding specified in rfc 7830 when this config is enabled
+ // to allow the reponse to be padded as well
+
+ // two bytes RDLEN, 4 bytes padding header
+ unsigned int packetLen = aBody.Length() + 2 + 4;
+ if (aDisableECS) {
+ // 8 bytes for disabling ecs
+ packetLen += 8;
+ }
+
+ // clamp the padding length, because the padding extension only allows up
+ // to 2^16 - 1 bytes padding and adding too much padding wastes resources
+ uint32_t padTo = std::clamp<uint32_t>(
+ StaticPrefs::network_trr_padding_length(), 0, 1024);
+
+ // Calculate number of padding bytes. The second '%'-operator is necessary
+ // because we prefer to add 0 bytes padding rather than padTo bytes
+ if (padTo > 0) {
+ paddingLen = (padTo - (packetLen % padTo)) % padTo;
+ }
+ // padding header + padding length
+ rdlen += 4 + paddingLen;
+ }
+ if (aDisableECS) {
+ rdlen += 8;
+ }
+
+ // RDLEN | u_int16_t | length of all RDATA |
+ aBody += (char)((rdlen >> 8) & 0xff); // upper 8 bit RDLEN
+ aBody += (char)(rdlen & 0xff);
+
+ // RDATA | octet stream | {attribute,value} pairs |
+ // The RDATA is just the ECS option setting zero subnet prefix
+
+ if (aDisableECS) {
+ aBody += '\0'; // upper 8 bit OPTION-CODE ECS
+ aBody += 8; // OPTION-CODE, 2 octets, for ECS is 8
+
+ aBody += '\0'; // upper 8 bit OPTION-LENGTH
+ aBody += 4; // OPTION-LENGTH, 2 octets, contains the length of the
+ // payload after OPTION-LENGTH
+ aBody += '\0'; // upper 8 bit FAMILY. IANA Address Family Numbers
+ // registry, not the AF_* constants!
+ aBody += 1; // FAMILY (Ipv4), 2 octets
+
+ aBody += '\0'; // SOURCE PREFIX-LENGTH | SCOPE PREFIX-LENGTH |
+ aBody += '\0';
+
+ // ADDRESS, minimum number of octets == nothing because zero bits
+ }
+
+ if (padding) {
+ aBody += '\0'; // upper 8 bit option OPTION-CODE PADDING
+ aBody += 12; // OPTION-CODE, 2 octets, for PADDING is 12
+
+ // OPTION-LENGTH, 2 octets
+ aBody += (char)((paddingLen >> 8) & 0xff);
+ aBody += (char)(paddingLen & 0xff);
+ for (unsigned int i = 0; i < paddingLen; i++) {
+ aBody += '\0';
+ }
+ }
+ }
+
+ SetDNSPacketStatus(DNSPacketStatus::Success);
+ return NS_OK;
+}
+
+Result<uint8_t, nsresult> DNSPacket::GetRCode() const {
+ if (mBodySize < 12) {
+ LOG(("DNSPacket::GetRCode - packet too small"));
+ return Err(NS_ERROR_ILLEGAL_VALUE);
+ }
+
+ return mResponse[3] & 0x0F;
+}
+
+Result<bool, nsresult> DNSPacket::RecursionAvailable() const {
+ if (mBodySize < 12) {
+ LOG(("DNSPacket::GetRCode - packet too small"));
+ return Err(NS_ERROR_ILLEGAL_VALUE);
+ }
+
+ return mResponse[3] & 0x80;
+}
+
+nsresult DNSPacket::DecodeInternal(
+ nsCString& aHost, enum TrrType aType, nsCString& aCname, bool aAllowRFC1918,
+ DOHresp& aResp, TypeRecordResultType& aTypeResult,
+ nsClassHashtable<nsCStringHashKey, DOHresp>& aAdditionalRecords,
+ uint32_t& aTTL, const unsigned char* aBuffer, uint32_t aLen) {
+ // The response has a 12 byte header followed by the question (returned)
+ // and then the answer. The answer section itself contains the name, type
+ // and class again and THEN the record data.
+
+ // www.example.com response:
+ // header:
+ // abcd 8180 0001 0001 0000 0000
+ // the question:
+ // 0377 7777 0765 7861 6d70 6c65 0363 6f6d 0000 0100 01
+ // the answer:
+ // 03 7777 7707 6578 616d 706c 6503 636f 6d00 0001 0001
+ // 0000 0080 0004 5db8 d822
+
+ unsigned int index = 12;
+ uint8_t length;
+ nsAutoCString host;
+ nsresult rv;
+ uint16_t extendedError = UINT16_MAX;
+
+ LOG(("doh decode %s %d bytes\n", aHost.get(), aLen));
+
+ aCname.Truncate();
+
+ if (aLen < 12 || aBuffer[0] || aBuffer[1]) {
+ LOG(("TRR bad incoming DOH, eject!\n"));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ uint8_t rcode = mResponse[3] & 0x0F;
+ LOG(("TRR Decode %s RCODE %d\n", PromiseFlatCString(aHost).get(), rcode));
+
+ uint16_t questionRecords = get16bit(aBuffer, 4); // qdcount
+ // iterate over the single(?) host name in question
+ while (questionRecords) {
+ do {
+ if (aLen < (index + 1)) {
+ LOG(("TRR Decode 1 index: %u size: %u", index, aLen));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ length = static_cast<uint8_t>(aBuffer[index]);
+ if (length) {
+ if (host.Length()) {
+ host.Append(".");
+ }
+ if (aLen < (index + 1 + length)) {
+ LOG(("TRR Decode 2 index: %u size: %u len: %u", index, aLen, length));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ host.Append(((char*)aBuffer) + index + 1, length);
+ }
+ index += 1 + length; // skip length byte + label
+ } while (length);
+ if (aLen < (index + 4)) {
+ LOG(("TRR Decode 3 index: %u size: %u", index, aLen));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ index += 4; // skip question's type, class
+ questionRecords--;
+ }
+
+ // Figure out the number of answer records from ANCOUNT
+ uint16_t answerRecords = get16bit(aBuffer, 6);
+
+ LOG(("TRR Decode: %d answer records (%u bytes body) %s index=%u\n",
+ answerRecords, aLen, host.get(), index));
+
+ while (answerRecords) {
+ nsAutoCString qname;
+ rv = GetQname(qname, index, aBuffer);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+ // 16 bit TYPE
+ if (aLen < (index + 2)) {
+ LOG(("TRR: Dohdecode:%d fail at index %d\n", __LINE__, index + 2));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ uint16_t TYPE = get16bit(aBuffer, index);
+
+ index += 2;
+
+ // 16 bit class
+ if (aLen < (index + 2)) {
+ LOG(("TRR: Dohdecode:%d fail at index %d\n", __LINE__, index + 2));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ uint16_t CLASS = get16bit(aBuffer, index);
+ if (kDNS_CLASS_IN != CLASS) {
+ LOG(("TRR bad CLASS (%u) at index %d\n", CLASS, index));
+ return NS_ERROR_UNEXPECTED;
+ }
+ index += 2;
+
+ // 32 bit TTL (seconds)
+ if (aLen < (index + 4)) {
+ LOG(("TRR: Dohdecode:%d fail at index %d\n", __LINE__, index));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ uint32_t TTL = get32bit(aBuffer, index);
+ index += 4;
+
+ // 16 bit RDLENGTH
+ if (aLen < (index + 2)) {
+ LOG(("TRR: Dohdecode:%d fail at index %d\n", __LINE__, index));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ uint16_t RDLENGTH = get16bit(aBuffer, index);
+ index += 2;
+
+ if (aLen < (index + RDLENGTH)) {
+ LOG(("TRR: Dohdecode:%d fail RDLENGTH=%d at index %d\n", __LINE__,
+ RDLENGTH, index));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+
+ if ((TYPE != TRRTYPE_CNAME) && (TYPE != TRRTYPE_HTTPSSVC) &&
+ (TYPE != static_cast<uint16_t>(aType))) {
+ // Not the same type as was asked for nor CNAME
+ LOG(("TRR: Dohdecode:%d asked for type %d got %d\n", __LINE__, aType,
+ TYPE));
+ index += RDLENGTH;
+ answerRecords--;
+ continue;
+ }
+
+ // We check if the qname is a case-insensitive match for the host or the
+ // FQDN version of the host
+ bool responseMatchesQuestion =
+ (qname.Length() == aHost.Length() ||
+ (aHost.Length() == qname.Length() + 1 && aHost.Last() == '.')) &&
+ StringBeginsWith(aHost, qname, nsCaseInsensitiveCStringComparator);
+
+ if (responseMatchesQuestion) {
+ // RDATA
+ // - A (TYPE 1): 4 bytes
+ // - AAAA (TYPE 28): 16 bytes
+ // - NS (TYPE 2): N bytes
+
+ switch (TYPE) {
+ case TRRTYPE_A:
+ if (RDLENGTH != 4) {
+ LOG(("TRR bad length for A (%u)\n", RDLENGTH));
+ return NS_ERROR_UNEXPECTED;
+ }
+ rv = aResp.Add(TTL, aBuffer, index, RDLENGTH, aAllowRFC1918);
+ if (NS_FAILED(rv)) {
+ LOG(
+ ("TRR:DohDecode failed: local IP addresses or unknown IP "
+ "family\n"));
+ return rv;
+ }
+ break;
+ case TRRTYPE_AAAA:
+ if (RDLENGTH != 16) {
+ LOG(("TRR bad length for AAAA (%u)\n", RDLENGTH));
+ return NS_ERROR_UNEXPECTED;
+ }
+ rv = aResp.Add(TTL, aBuffer, index, RDLENGTH, aAllowRFC1918);
+ if (NS_FAILED(rv)) {
+ LOG(("TRR got unique/local IPv6 address!\n"));
+ return rv;
+ }
+ break;
+
+ case TRRTYPE_NS:
+ break;
+ case TRRTYPE_CNAME:
+ if (aCname.IsEmpty()) {
+ nsAutoCString qname;
+ unsigned int qnameindex = index;
+ rv = GetQname(qname, qnameindex, aBuffer);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+ if (!qname.IsEmpty()) {
+ ToLowerCase(qname);
+ aCname = qname;
+ LOG(("DNSPacket::DohDecode CNAME host %s => %s\n", host.get(),
+ aCname.get()));
+ } else {
+ LOG(("DNSPacket::DohDecode empty CNAME for host %s!\n",
+ host.get()));
+ }
+ } else {
+ LOG(("DNSPacket::DohDecode CNAME - ignoring another entry\n"));
+ }
+ break;
+ case TRRTYPE_TXT: {
+ // TXT record RRDATA sections are a series of character-strings
+ // each character string is a length byte followed by that many data
+ // bytes
+ nsAutoCString txt;
+ unsigned int txtIndex = index;
+ uint16_t available = RDLENGTH;
+
+ while (available > 0) {
+ uint8_t characterStringLen = aBuffer[txtIndex++];
+ available--;
+ if (characterStringLen > available) {
+ LOG(("DNSPacket::DohDecode MALFORMED TXT RECORD\n"));
+ break;
+ }
+ txt.Append((const char*)(&aBuffer[txtIndex]), characterStringLen);
+ txtIndex += characterStringLen;
+ available -= characterStringLen;
+ }
+
+ if (!aTypeResult.is<TypeRecordTxt>()) {
+ aTypeResult = AsVariant(CopyableTArray<nsCString>());
+ }
+
+ {
+ auto& results = aTypeResult.as<TypeRecordTxt>();
+ results.AppendElement(txt);
+ }
+ if (aTTL > TTL) {
+ aTTL = TTL;
+ }
+ LOG(("DNSPacket::DohDecode TXT host %s => %s\n", host.get(),
+ txt.get()));
+
+ break;
+ }
+ case TRRTYPE_HTTPSSVC: {
+ struct SVCB parsed;
+ int32_t lastSvcParamKey = -1;
+
+ unsigned int svcbIndex = index;
+ CheckedInt<uint16_t> available = RDLENGTH;
+
+ // Should have at least 2 bytes for the priority and one for the
+ // qname length.
+ if (available.value() < 3) {
+ return NS_ERROR_UNEXPECTED;
+ }
+
+ parsed.mSvcFieldPriority = get16bit(aBuffer, svcbIndex);
+ svcbIndex += 2;
+
+ rv = GetQname(parsed.mSvcDomainName, svcbIndex, aBuffer);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+
+ if (parsed.mSvcDomainName.IsEmpty()) {
+ if (parsed.mSvcFieldPriority == 0) {
+ // For AliasMode SVCB RRs, a TargetName of "." indicates that the
+ // service is not available or does not exist.
+ continue;
+ }
+
+ // For ServiceMode SVCB RRs, if TargetName has the value ".",
+ // then the owner name of this record MUST be used as
+ // the effective TargetName.
+ // When the qname is port prefix name, we need to use the
+ // original host name as TargetName.
+ if (mOriginHost) {
+ parsed.mSvcDomainName = *mOriginHost;
+ } else {
+ parsed.mSvcDomainName = qname;
+ }
+ }
+
+ available -= (svcbIndex - index);
+ if (!available.isValid()) {
+ return NS_ERROR_UNEXPECTED;
+ }
+ aTTL = TTL;
+ while (available.value() >= 4) {
+ // Every SvcFieldValues must have at least 4 bytes for the
+ // SvcParamKey (2 bytes) and length of SvcParamValue (2 bytes)
+ // If the length ever goes above the available data, meaning if
+ // available ever underflows, then that is an error.
+ struct SvcFieldValue value;
+ uint16_t key = get16bit(aBuffer, svcbIndex);
+ svcbIndex += 2;
+
+ // 2.2 Clients MUST consider an RR malformed if SvcParamKeys are
+ // not in strictly increasing numeric order.
+ if (key <= lastSvcParamKey) {
+ LOG(("SvcParamKeys not in increasing order"));
+ return NS_ERROR_UNEXPECTED;
+ }
+ lastSvcParamKey = key;
+
+ uint16_t len = get16bit(aBuffer, svcbIndex);
+ svcbIndex += 2;
+
+ available -= 4 + len;
+ if (!available.isValid()) {
+ return NS_ERROR_UNEXPECTED;
+ }
+
+ rv = ParseSvcParam(svcbIndex, key, value, len, aBuffer);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+ svcbIndex += len;
+
+ // If this is an unknown key, we will simply ignore it.
+ // We also don't need to record SvcParamKeyMandatory
+ if (key == SvcParamKeyMandatory || !IsValidSvcParamKey(key)) {
+ continue;
+ }
+
+ if (value.mValue.is<SvcParamIpv4Hint>() ||
+ value.mValue.is<SvcParamIpv6Hint>()) {
+ parsed.mHasIPHints = true;
+ }
+ if (value.mValue.is<SvcParamEchConfig>()) {
+ parsed.mHasEchConfig = true;
+ parsed.mEchConfig = value.mValue.as<SvcParamEchConfig>().mValue;
+ }
+ if (value.mValue.is<SvcParamODoHConfig>()) {
+ parsed.mODoHConfig = value.mValue.as<SvcParamODoHConfig>().mValue;
+ }
+ parsed.mSvcFieldValue.AppendElement(value);
+ }
+
+ if (aType != TRRTYPE_HTTPSSVC) {
+ // Ignore the entry that we just parsed if we didn't ask for it.
+ break;
+ }
+
+ // Check for AliasForm
+ if (aCname.IsEmpty() && parsed.mSvcFieldPriority == 0) {
+ // Alias form SvcDomainName must not have the "." value (empty)
+ if (parsed.mSvcDomainName.IsEmpty()) {
+ return NS_ERROR_UNEXPECTED;
+ }
+ aCname = parsed.mSvcDomainName;
+ // If aliasForm is present, Service form must be ignored.
+ aTypeResult = mozilla::AsVariant(Nothing());
+ ToLowerCase(aCname);
+ LOG(("DNSPacket::DohDecode HTTPSSVC AliasForm host %s => %s\n",
+ host.get(), aCname.get()));
+ break;
+ }
+
+ if (!aTypeResult.is<TypeRecordHTTPSSVC>()) {
+ aTypeResult = mozilla::AsVariant(CopyableTArray<SVCB>());
+ }
+ {
+ auto& results = aTypeResult.as<TypeRecordHTTPSSVC>();
+ results.AppendElement(parsed);
+ }
+
+ break;
+ }
+ default:
+ // skip unknown record types
+ LOG(("TRR unsupported TYPE (%u) RDLENGTH %u\n", TYPE, RDLENGTH));
+ break;
+ }
+ } else {
+ LOG(("TRR asked for %s data but got %s\n", aHost.get(), qname.get()));
+ }
+
+ index += RDLENGTH;
+ LOG(("done with record type %u len %u index now %u of %u\n", TYPE, RDLENGTH,
+ index, aLen));
+ answerRecords--;
+ }
+
+ // NSCOUNT
+ uint16_t nsRecords = get16bit(aBuffer, 8);
+ LOG(("TRR Decode: %d ns records (%u bytes body)\n", nsRecords, aLen));
+ while (nsRecords) {
+ rv = PassQName(index, aBuffer);
+ if (NS_FAILED(rv)) {
+ return rv;
+ }
+
+ if (aLen < (index + 8)) {
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ index += 2; // type
+ index += 2; // class
+ index += 4; // ttl
+
+ // 16 bit RDLENGTH
+ if (aLen < (index + 2)) {
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ uint16_t RDLENGTH = get16bit(aBuffer, index);
+ index += 2;
+ if (aLen < (index + RDLENGTH)) {
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ index += RDLENGTH;
+ LOG(("done with nsRecord now %u of %u\n", index, aLen));
+ nsRecords--;
+ }
+
+ // additional resource records
+ uint16_t arRecords = get16bit(aBuffer, 10);
+ LOG(("TRR Decode: %d additional resource records (%u bytes body)\n",
+ arRecords, aLen));
+
+ while (arRecords) {
+ nsAutoCString qname;
+ rv = GetQname(qname, index, aBuffer);
+ if (NS_FAILED(rv)) {
+ LOG(("Bad qname for additional record"));
+ return rv;
+ }
+
+ if (aLen < (index + 8)) {
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+ uint16_t type = get16bit(aBuffer, index);
+ index += 2;
+ // The next two bytes encode class
+ // (or udpPayloadSize when type is TRRTYPE_OPT)
+ uint16_t cls = get16bit(aBuffer, index);
+ index += 2;
+ // The next 4 bytes encode TTL
+ // (or extRCode + ednsVersion + flags when type is TRRTYPE_OPT)
+ uint32_t ttl = get32bit(aBuffer, index);
+ index += 4;
+ // cls and ttl are unused when type is TRRTYPE_OPT
+
+ // 16 bit RDLENGTH
+ if (aLen < (index + 2)) {
+ LOG(("Record too small"));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+
+ uint16_t rdlength = get16bit(aBuffer, index);
+ index += 2;
+ if (aLen < (index + rdlength)) {
+ LOG(("rdlength too big"));
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+
+ auto parseRecord = [&]() {
+ LOG(("Parsing additional record type: %u", type));
+ auto* entry = aAdditionalRecords.GetOrInsertNew(qname);
+
+ switch (type) {
+ case TRRTYPE_A:
+ if (kDNS_CLASS_IN != cls) {
+ LOG(("NOT IN - returning"));
+ return;
+ }
+ if (rdlength != 4) {
+ LOG(("TRR bad length for A (%u)\n", rdlength));
+ return;
+ }
+ rv = entry->Add(ttl, aBuffer, index, rdlength, aAllowRFC1918);
+ if (NS_FAILED(rv)) {
+ LOG(
+ ("TRR:DohDecode failed: local IP addresses or unknown IP "
+ "family\n"));
+ return;
+ }
+ break;
+ case TRRTYPE_AAAA:
+ if (kDNS_CLASS_IN != cls) {
+ LOG(("NOT IN - returning"));
+ return;
+ }
+ if (rdlength != 16) {
+ LOG(("TRR bad length for AAAA (%u)\n", rdlength));
+ return;
+ }
+ rv = entry->Add(ttl, aBuffer, index, rdlength, aAllowRFC1918);
+ if (NS_FAILED(rv)) {
+ LOG(("TRR got unique/local IPv6 address!\n"));
+ return;
+ }
+ break;
+ case TRRTYPE_OPT: { // OPT
+ LOG(("Parsing opt rdlen: %u", rdlength));
+ unsigned int offset = 0;
+ while (offset + 2 <= rdlength) {
+ uint16_t optCode = get16bit(aBuffer, index + offset);
+ LOG(("optCode: %u", optCode));
+ offset += 2;
+ if (offset + 2 > rdlength) {
+ break;
+ }
+ uint16_t optLen = get16bit(aBuffer, index + offset);
+ LOG(("optLen: %u", optLen));
+ offset += 2;
+ if (offset + optLen > rdlength) {
+ LOG(("offset: %u, optLen: %u, rdlen: %u", offset, optLen,
+ rdlength));
+ break;
+ }
+
+ LOG(("OPT: code: %u len:%u", optCode, optLen));
+
+ if (optCode != 15) {
+ offset += optLen;
+ continue;
+ }
+
+ // optCode == 15; Extended DNS error
+
+ if (offset + 2 > rdlength || optLen < 2) {
+ break;
+ }
+ extendedError = get16bit(aBuffer, index + offset);
+
+ LOG(("Extended error code: %u message: %s", extendedError,
+ nsAutoCString((char*)aBuffer + index + offset + 2, optLen - 2)
+ .get()));
+ offset += optLen;
+ }
+ break;
+ }
+ default:
+ break;
+ }
+ };
+
+ parseRecord();
+
+ index += rdlength;
+ LOG(("done with additional rr now %u of %u\n", index, aLen));
+ arRecords--;
+ }
+
+ if (index != aLen) {
+ LOG(("DohDecode failed to parse entire response body, %u out of %u bytes\n",
+ index, aLen));
+ // failed to parse 100%, do not continue
+ return NS_ERROR_ILLEGAL_VALUE;
+ }
+
+ if (aType == TRRTYPE_NS && rcode != 0) {
+ return NS_ERROR_UNKNOWN_HOST;
+ }
+
+ if ((aType != TRRTYPE_NS) && aCname.IsEmpty() && aResp.mAddresses.IsEmpty() &&
+ aTypeResult.is<TypeRecordEmpty>()) {
+ // no entries were stored!
+ LOG(("TRR: No entries were stored!\n"));
+
+ if (extendedError != UINT16_MAX && hardFail(extendedError)) {
+ return NS_ERROR_DEFINITIVE_UNKNOWN_HOST;
+ }
+ return NS_ERROR_UNKNOWN_HOST;
+ }
+
+ // https://tools.ietf.org/html/draft-ietf-dnsop-svcb-httpssvc-03#page-14
+ // If one or more SVCB records of ServiceForm SvcRecordType are returned for
+ // HOST, clients should select the highest-priority option with acceptable
+ // parameters.
+ if (aTypeResult.is<TypeRecordHTTPSSVC>()) {
+ auto& results = aTypeResult.as<TypeRecordHTTPSSVC>();
+ results.Sort();
+ }
+
+ return NS_OK;
+}
+
+//
+// DohDecode() collects the TTL and the IP addresses in the response
+//
+nsresult DNSPacket::Decode(
+ nsCString& aHost, enum TrrType aType, nsCString& aCname, bool aAllowRFC1918,
+ DOHresp& aResp, TypeRecordResultType& aTypeResult,
+ nsClassHashtable<nsCStringHashKey, DOHresp>& aAdditionalRecords,
+ uint32_t& aTTL) {
+ nsresult rv =
+ DecodeInternal(aHost, aType, aCname, aAllowRFC1918, aResp, aTypeResult,
+ aAdditionalRecords, aTTL, mResponse, mBodySize);
+ SetDNSPacketStatus(NS_SUCCEEDED(rv) ? DNSPacketStatus::Success
+ : DNSPacketStatus::DecodeError);
+ return rv;
+}
+
+} // namespace net
+} // namespace mozilla
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