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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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
#include "BodyUtil.h"
#include "nsError.h"
#include "nsString.h"
#include "nsIGlobalObject.h"
#include "mozilla/Encoding.h"
#include "mozilla/dom/MimeType.h"
#include "nsCRT.h"
#include "nsCharSeparatedTokenizer.h"
#include "nsDOMString.h"
#include "nsNetUtil.h"
#include "nsReadableUtils.h"
#include "nsStreamUtils.h"
#include "nsStringStream.h"
#include "nsURLHelper.h"
#include "js/ArrayBuffer.h" // JS::NewArrayBufferWithContents
#include "js/JSON.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/dom/Exceptions.h"
#include "mozilla/dom/FetchUtil.h"
#include "mozilla/dom/File.h"
#include "mozilla/dom/FormData.h"
#include "mozilla/dom/Headers.h"
#include "mozilla/dom/Promise.h"
namespace mozilla::dom {
namespace {
// Reads over a CRLF and positions start after it.
static bool PushOverLine(nsACString::const_iterator& aStart,
const nsACString::const_iterator& aEnd) {
if (*aStart == nsCRT::CR && (aEnd - aStart > 1) && *(++aStart) == nsCRT::LF) {
++aStart; // advance to after CRLF
return true;
}
return false;
}
/**
* A simple multipart/form-data parser as defined in RFC 2388 and RFC 2046.
* This does not respect any encoding specified per entry, using UTF-8
* throughout. This is as the Fetch spec states in the consume body algorithm.
* Borrows some things from Necko's nsMultiMixedConv, but is simpler since
* unlike Necko we do not have to deal with receiving incomplete chunks of data.
*
* This parser will fail the entire parse on any invalid entry, so it will
* never return a partially filled FormData.
* The content-disposition header is used to figure out the name and filename
* entries. The inclusion of the filename parameter decides if the entry is
* inserted into the FormData as a string or a File.
*
* File blobs are copies of the underlying data string since we cannot adopt
* char* chunks embedded within the larger body without significant effort.
* friends to figure out if Fetch ends up copying big blobs to see if this is
* worth optimizing.
*/
class MOZ_STACK_CLASS FormDataParser {
private:
RefPtr<FormData> mFormData;
nsCString mMimeType;
nsCString mMixedCaseMimeType;
nsCString mData;
// Entry state, reset in START_PART.
nsCString mName;
nsCString mFilename;
nsCString mContentType;
enum {
START_PART,
PARSE_HEADER,
PARSE_BODY,
} mState;
nsIGlobalObject* mParentObject;
// Reads over a boundary and sets start to the position after the end of the
// boundary. Returns false if no boundary is found immediately.
bool PushOverBoundary(const nsACString& aBoundaryString,
nsACString::const_iterator& aStart,
nsACString::const_iterator& aEnd) {
// We copy the end iterator to keep the original pointing to the real end
// of the string.
nsACString::const_iterator end(aEnd);
const char* beginning = aStart.get();
if (FindInReadable(aBoundaryString, aStart, end)) {
// We either should find the body immediately, or after 2 chars with the
// 2 chars being '-', everything else is failure.
if ((aStart.get() - beginning) == 0) {
aStart.advance(aBoundaryString.Length());
return true;
}
if ((aStart.get() - beginning) == 2) {
if (*(--aStart) == '-' && *(--aStart) == '-') {
aStart.advance(aBoundaryString.Length() + 2);
return true;
}
}
}
return false;
}
bool ParseHeader(nsACString::const_iterator& aStart,
nsACString::const_iterator& aEnd, bool* aWasEmptyHeader) {
nsAutoCString headerName, headerValue;
if (!FetchUtil::ExtractHeader(aStart, aEnd, headerName, headerValue,
aWasEmptyHeader)) {
return false;
}
if (*aWasEmptyHeader) {
return true;
}
if (headerName.LowerCaseEqualsLiteral("content-disposition")) {
bool seenFormData = false;
for (const nsACString& token :
nsCCharSeparatedTokenizer(headerValue, ';').ToRange()) {
if (token.IsEmpty()) {
continue;
}
if (token.EqualsLiteral("form-data")) {
seenFormData = true;
continue;
}
if (seenFormData && StringBeginsWith(token, "name="_ns)) {
mName = StringTail(token, token.Length() - 5);
mName.Trim(" \"");
continue;
}
if (seenFormData && StringBeginsWith(token, "filename="_ns)) {
mFilename = StringTail(token, token.Length() - 9);
mFilename.Trim(" \"");
continue;
}
}
if (mName.IsVoid()) {
// Could not parse a valid entry name.
return false;
}
} else if (headerName.LowerCaseEqualsLiteral("content-type")) {
mContentType = headerValue;
}
return true;
}
// The end of a body is marked by a CRLF followed by the boundary. So the
// CRLF is part of the boundary and not the body, but any prior CRLFs are
// part of the body. This will position the iterator at the beginning of the
// boundary (after the CRLF).
bool ParseBody(const nsACString& aBoundaryString,
nsACString::const_iterator& aStart,
nsACString::const_iterator& aEnd) {
const char* beginning = aStart.get();
// Find the boundary marking the end of the body.
nsACString::const_iterator end(aEnd);
if (!FindInReadable(aBoundaryString, aStart, end)) {
return false;
}
// We found a boundary, strip the just prior CRLF, and consider
// everything else the body section.
if (aStart.get() - beginning < 2) {
// Only the first entry can have a boundary right at the beginning. Even
// an empty body will have a CRLF before the boundary. So this is
// a failure.
return false;
}
// Check that there is a CRLF right before the boundary.
aStart.advance(-2);
// Skip optional hyphens.
if (*aStart == '-' && *(aStart.get() + 1) == '-') {
if (aStart.get() - beginning < 2) {
return false;
}
aStart.advance(-2);
}
if (*aStart != nsCRT::CR || *(aStart.get() + 1) != nsCRT::LF) {
return false;
}
nsAutoCString body(beginning, aStart.get() - beginning);
// Restore iterator to after the \r\n as we promised.
// We do not need to handle the extra hyphens case since our boundary
// parser in PushOverBoundary()
aStart.advance(2);
if (!mFormData) {
mFormData = new FormData();
}
NS_ConvertUTF8toUTF16 name(mName);
if (mFilename.IsVoid()) {
ErrorResult rv;
mFormData->Append(name, NS_ConvertUTF8toUTF16(body), rv);
MOZ_ASSERT(!rv.Failed());
} else {
// Unfortunately we've to copy the data first since all our strings are
// going to free it. We also need fallible alloc, so we can't just use
// ToNewCString().
char* copy = static_cast<char*>(moz_xmalloc(body.Length()));
nsCString::const_iterator bodyIter, bodyEnd;
body.BeginReading(bodyIter);
body.EndReading(bodyEnd);
char* p = copy;
while (bodyIter != bodyEnd) {
*p++ = *bodyIter++;
}
p = nullptr;
RefPtr<Blob> file = File::CreateMemoryFileWithCustomLastModified(
mParentObject, reinterpret_cast<void*>(copy), body.Length(),
NS_ConvertUTF8toUTF16(mFilename), NS_ConvertUTF8toUTF16(mContentType),
/* aLastModifiedDate */ 0);
if (NS_WARN_IF(!file)) {
return false;
}
Optional<nsAString> dummy;
ErrorResult rv;
mFormData->Append(name, *file, dummy, rv);
if (NS_WARN_IF(rv.Failed())) {
rv.SuppressException();
return false;
}
}
return true;
}
public:
FormDataParser(const nsACString& aMimeType,
const nsACString& aMixedCaseMimeType, const nsACString& aData,
nsIGlobalObject* aParent)
: mMimeType(aMimeType),
mMixedCaseMimeType(aMixedCaseMimeType),
mData(aData),
mState(START_PART),
mParentObject(aParent) {}
bool Parse() {
if (mData.IsEmpty()) {
return false;
}
// Determine boundary from mimetype.
RefPtr<CMimeType> parsed = CMimeType::Parse(mMixedCaseMimeType);
if (!parsed) {
return false;
}
nsAutoCString boundaryString;
if (!parsed->GetParameterValue("boundary"_ns, boundaryString)) {
return false;
}
nsACString::const_iterator start, end;
mData.BeginReading(start);
// This should ALWAYS point to the end of data.
// Helpers make copies.
mData.EndReading(end);
while (start != end) {
switch (mState) {
case START_PART:
mName.SetIsVoid(true);
mFilename.SetIsVoid(true);
mContentType = "text/plain"_ns;
while (start != end && NS_IsHTTPWhitespace(*start)) {
++start;
}
// MUST start with boundary.
if (!PushOverBoundary(boundaryString, start, end)) {
return false;
}
if (start != end && *start == '-') {
// End of data.
if (!mFormData) {
mFormData = new FormData();
}
return true;
}
if (!PushOverLine(start, end)) {
return false;
}
mState = PARSE_HEADER;
break;
case PARSE_HEADER:
bool emptyHeader;
if (!ParseHeader(start, end, &emptyHeader)) {
return false;
}
if (emptyHeader && !PushOverLine(start, end)) {
return false;
}
mState = emptyHeader ? PARSE_BODY : PARSE_HEADER;
break;
case PARSE_BODY:
if (mName.IsVoid()) {
NS_WARNING(
"No content-disposition header with a valid name was "
"found. Failing at body parse.");
return false;
}
if (!ParseBody(boundaryString, start, end)) {
return false;
}
mState = START_PART;
break;
default:
MOZ_CRASH("Invalid case");
}
}
MOZ_ASSERT_UNREACHABLE("Should never reach here.");
return false;
}
already_AddRefed<FormData> GetFormData() { return mFormData.forget(); }
};
} // namespace
// static
void BodyUtil::ConsumeArrayBuffer(JSContext* aCx,
JS::MutableHandle<JSObject*> aValue,
uint32_t aInputLength,
UniquePtr<uint8_t[], JS::FreePolicy> aInput,
ErrorResult& aRv) {
aRv.MightThrowJSException();
JS::Rooted<JSObject*> arrayBuffer(aCx);
arrayBuffer =
JS::NewArrayBufferWithContents(aCx, aInputLength, std::move(aInput));
if (!arrayBuffer) {
aRv.StealExceptionFromJSContext(aCx);
return;
}
aValue.set(arrayBuffer);
}
// static
already_AddRefed<Blob> BodyUtil::ConsumeBlob(nsIGlobalObject* aParent,
const nsString& aMimeType,
uint32_t aInputLength,
uint8_t* aInput,
ErrorResult& aRv) {
RefPtr<Blob> blob = Blob::CreateMemoryBlob(
aParent, reinterpret_cast<void*>(aInput), aInputLength, aMimeType);
if (!blob) {
aRv.Throw(NS_ERROR_DOM_UNKNOWN_ERR);
return nullptr;
}
return blob.forget();
}
// static
void BodyUtil::ConsumeBytes(JSContext* aCx, JS::MutableHandle<JSObject*> aValue,
uint32_t aInputLength,
UniquePtr<uint8_t[], JS::FreePolicy> aInput,
ErrorResult& aRv) {
aRv.MightThrowJSException();
JS::Rooted<JSObject*> arrayBuffer(aCx);
ConsumeArrayBuffer(aCx, &arrayBuffer, aInputLength, std::move(aInput), aRv);
if (aRv.Failed()) {
return;
}
JS::Rooted<JSObject*> bytes(
aCx, JS_NewUint8ArrayWithBuffer(aCx, arrayBuffer, 0, aInputLength));
if (!bytes) {
aRv.StealExceptionFromJSContext(aCx);
return;
}
aValue.set(bytes);
}
// static
already_AddRefed<FormData> BodyUtil::ConsumeFormData(
nsIGlobalObject* aParent, const nsCString& aMimeType,
const nsACString& aMixedCaseMimeType, const nsCString& aStr,
ErrorResult& aRv) {
constexpr auto formDataMimeType = "multipart/form-data"_ns;
// Allow semicolon separated boundary/encoding suffix like
// multipart/form-data; boundary= but disallow multipart/form-datafoobar.
bool isValidFormDataMimeType = StringBeginsWith(aMimeType, formDataMimeType);
if (isValidFormDataMimeType &&
aMimeType.Length() > formDataMimeType.Length()) {
isValidFormDataMimeType = aMimeType[formDataMimeType.Length()] == ';';
}
if (isValidFormDataMimeType) {
FormDataParser parser(aMimeType, aMixedCaseMimeType, aStr, aParent);
if (!parser.Parse()) {
aRv.ThrowTypeError<MSG_BAD_FORMDATA>();
return nullptr;
}
RefPtr<FormData> fd = parser.GetFormData();
MOZ_ASSERT(fd);
return fd.forget();
}
constexpr auto urlDataMimeType = "application/x-www-form-urlencoded"_ns;
bool isValidUrlEncodedMimeType = StringBeginsWith(aMimeType, urlDataMimeType);
if (isValidUrlEncodedMimeType &&
aMimeType.Length() > urlDataMimeType.Length()) {
isValidUrlEncodedMimeType = aMimeType[urlDataMimeType.Length()] == ';';
}
if (isValidUrlEncodedMimeType) {
RefPtr<FormData> fd = new FormData(aParent);
DebugOnly<bool> status = URLParams::Parse(
aStr, true, [&fd](const nsACString& aName, const nsACString& aValue) {
IgnoredErrorResult rv;
fd->Append(NS_ConvertUTF8toUTF16(aName),
NS_ConvertUTF8toUTF16(aValue), rv);
MOZ_ASSERT(!rv.Failed());
return true;
});
MOZ_ASSERT(status);
return fd.forget();
}
aRv.ThrowTypeError<MSG_BAD_FORMDATA>();
return nullptr;
}
// static
nsresult BodyUtil::ConsumeText(uint32_t aInputLength, uint8_t* aInput,
nsString& aText) {
nsresult rv =
UTF_8_ENCODING->DecodeWithBOMRemoval(Span(aInput, aInputLength), aText);
if (NS_FAILED(rv)) {
return rv;
}
return NS_OK;
}
// static
void BodyUtil::ConsumeJson(JSContext* aCx, JS::MutableHandle<JS::Value> aValue,
const nsString& aStr, ErrorResult& aRv) {
aRv.MightThrowJSException();
JS::Rooted<JS::Value> json(aCx);
if (!JS_ParseJSON(aCx, aStr.get(), aStr.Length(), &json)) {
if (!JS_IsExceptionPending(aCx)) {
aRv.Throw(NS_ERROR_DOM_UNKNOWN_ERR);
return;
}
JS::Rooted<JS::Value> exn(aCx);
DebugOnly<bool> gotException = JS_GetPendingException(aCx, &exn);
MOZ_ASSERT(gotException);
JS_ClearPendingException(aCx);
aRv.ThrowJSException(aCx, exn);
return;
}
aValue.set(json);
}
} // namespace mozilla::dom