mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-27 23:02:20 +00:00
1069 lines
33 KiB
C++
1069 lines
33 KiB
C++
/* 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
|