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Implement stack size limitation for iterative parsing.

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This commit is contained in:
thebusytypist 2014-07-15 14:16:06 +08:00
parent 46e89dad0d
commit 1f53c6c041
5 changed files with 72 additions and 23 deletions
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45
include/rapidjson/document.h
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@ -1221,12 +1221,13 @@ public:
\tparam SourceEncoding Encoding of input stream
\tparam InputStream Type of input stream, implementing Stream concept
\param is Input stream to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
\return The document itself for fluent API.
*/
template <unsigned parseFlags, typename SourceEncoding, typename InputStream>
GenericDocument& ParseStream(InputStream& is) {
GenericDocument& ParseStream(InputStream& is, size_t limit = 0) {
ValueType::SetNull(); // Remove existing root if exist
GenericReader<SourceEncoding, Encoding, Allocator> reader(&GetAllocator());
GenericReader<SourceEncoding, Encoding, Allocator> reader(limit, &GetAllocator());
ClearStackOnExit scope(*this);
parseResult_ = reader.template Parse<parseFlags>(is, *this);
if (parseResult_) {
@ -1240,21 +1241,23 @@ public:
/*! \tparam parseFlags Combination of \ref ParseFlag.
\tparam InputStream Type of input stream, implementing Stream concept
\param is Input stream to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
\return The document itself for fluent API.
*/
template <unsigned parseFlags, typename InputStream>
GenericDocument& ParseStream(InputStream& is) {
return ParseStream<parseFlags,Encoding,InputStream>(is);
GenericDocument& ParseStream(InputStream& is, size_t limit = 0) {
return ParseStream<parseFlags,Encoding,InputStream>(is, limit);
}
//! Parse JSON text from an input stream (with \ref kParseDefaultFlags)
/*! \tparam InputStream Type of input stream, implementing Stream concept
\param is Input stream to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
\return The document itself for fluent API.
*/
template <typename InputStream>
GenericDocument& ParseStream(InputStream& is) {
return ParseStream<kParseDefaultFlags, Encoding, InputStream>(is);
GenericDocument& ParseStream(InputStream& is, size_t limit = 0) {
return ParseStream<kParseDefaultFlags, Encoding, InputStream>(is, limit);
}
//!@}
@ -1265,30 +1268,33 @@ public:
/*! \tparam parseFlags Combination of \ref ParseFlag.
\tparam SourceEncoding Transcoding from input Encoding
\param str Mutable zero-terminated string to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
\return The document itself for fluent API.
*/
template <unsigned parseFlags, typename SourceEncoding>
GenericDocument& ParseInsitu(Ch* str) {
GenericDocument& ParseInsitu(Ch* str, size_t limit = 0) {
GenericInsituStringStream<Encoding> s(str);
return ParseStream<parseFlags | kParseInsituFlag, SourceEncoding>(s);
return ParseStream<parseFlags | kParseInsituFlag, SourceEncoding>(s, limit);
}
//! Parse JSON text from a mutable string
/*! \tparam parseFlags Combination of \ref ParseFlag.
\param str Mutable zero-terminated string to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
\return The document itself for fluent API.
*/
template <unsigned parseFlags>
GenericDocument& ParseInsitu(Ch* str) {
return ParseInsitu<parseFlags, Encoding>(str);
GenericDocument& ParseInsitu(Ch* str, size_t limit = 0) {
return ParseInsitu<parseFlags, Encoding>(str, limit);
}
//! Parse JSON text from a mutable string (with \ref kParseDefaultFlags)
/*! \param str Mutable zero-terminated string to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
\return The document itself for fluent API.
*/
GenericDocument& ParseInsitu(Ch* str) {
return ParseInsitu<kParseDefaultFlags, Encoding>(str);
GenericDocument& ParseInsitu(Ch* str, size_t limit = 0) {
return ParseInsitu<kParseDefaultFlags, Encoding>(str, limit);
}
//!@}
@ -1299,28 +1305,31 @@ public:
/*! \tparam parseFlags Combination of \ref ParseFlag (must not contain \ref kParseInsituFlag).
\tparam SourceEncoding Transcoding from input Encoding
\param str Read-only zero-terminated string to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
*/
template <unsigned parseFlags, typename SourceEncoding>
GenericDocument& Parse(const Ch* str) {
GenericDocument& Parse(const Ch* str, size_t limit = 0) {
RAPIDJSON_ASSERT(!(parseFlags & kParseInsituFlag));
GenericStringStream<SourceEncoding> s(str);
return ParseStream<parseFlags, SourceEncoding>(s);
return ParseStream<parseFlags, SourceEncoding>(s, limit);
}
//! Parse JSON text from a read-only string
/*! \tparam parseFlags Combination of \ref ParseFlag (must not contain \ref kParseInsituFlag).
\param str Read-only zero-terminated string to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
*/
template <unsigned parseFlags>
GenericDocument& Parse(const Ch* str) {
return Parse<parseFlags, Encoding>(str);
GenericDocument& Parse(const Ch* str, size_t limit = 0) {
return Parse<parseFlags, Encoding>(str, limit);
}
//! Parse JSON text from a read-only string (with \ref kParseDefaultFlags)
/*! \param str Read-only zero-terminated string to be parsed.
\param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
*/
GenericDocument& Parse(const Ch* str) {
return Parse<kParseDefaultFlags>(str);
GenericDocument& Parse(const Ch* str, size_t limit = 0) {
return Parse<kParseDefaultFlags>(str, limit);
}
//!@}

1
include/rapidjson/error/en.h
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@ -40,6 +40,7 @@ inline const RAPIDJSON_ERROR_CHARTYPE* GetParseError_En(ParseErrorCode parseErro
case kParseErrorTermination: return RAPIDJSON_ERROR_STRING("Terminate parsing due to Handler error.");
case kParseErrorUnspecificSyntaxError: return RAPIDJSON_ERROR_STRING("Unspecific syntax error.");
case kParseErrorStackSizeLimitExceeded: return RAPIDJSON_ERROR_STRING("Parsing stack size limit is exceeded.");
default:
return RAPIDJSON_ERROR_STRING("Unknown error.");

3
include/rapidjson/error/error.h
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@ -59,7 +59,8 @@ enum ParseErrorCode {
kParseErrorNumberMissExponent, //!< Miss exponent in number.
kParseErrorTermination, //!< Parsing was terminated.
kParseErrorUnspecificSyntaxError //!< Unspecific syntax error.
kParseErrorUnspecificSyntaxError, //!< Unspecific syntax error.
kParseErrorStackSizeLimitExceeded //!< Parsing stack size limit is exceeded.
};
//! Result of parsing (wraps ParseErrorCode)

32
include/rapidjson/reader.h
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@ -272,10 +272,11 @@ public:
typedef typename SourceEncoding::Ch Ch; //!< SourceEncoding character type
//! Constructor.
/*! \param allocator Optional allocator for allocating stack memory. (Only use for non-destructive parsing)
/*! \param limit Parsing stack size limit(in bytes). Pass 0 means no limit.
\param allocator Optional allocator for allocating stack memory. (Only use for non-destructive parsing)
\param stackCapacity stack capacity in bytes for storing a single decoded string. (Only use for non-destructive parsing)
*/
GenericReader(Allocator* allocator = 0, size_t stackCapacity = kDefaultStackCapacity) : stack_(allocator, stackCapacity), parseResult_() {}
GenericReader(size_t limit = 0, Allocator* allocator = 0, size_t stackCapacity = kDefaultStackCapacity) : stack_(allocator, stackCapacity), kStackSizeLimit(limit), parseResult_() {}
//! Parse JSON text.
/*! \tparam parseFlags Combination of \ref ParseFlag.
@ -569,8 +570,14 @@ private:
if (c == '\\') { // Escape
is.Take();
Ch e = is.Take();
if ((sizeof(Ch) == 1 || unsigned(e) < 256) && escape[(unsigned char)e])
if ((sizeof(Ch) == 1 || unsigned(e) < 256) && escape[(unsigned char)e]) {
if (!(parseFlags & kParseInsituFlag)) {
if (!IsStackSpaceSufficient<Ch>(1)) {
RAPIDJSON_PARSE_ERROR(kParseErrorStackSizeLimitExceeded, is.Tell() - 1);
}
}
os.Put(escape[(unsigned char)e]);
}
else if (e == 'u') { // Unicode
unsigned codepoint = ParseHex4(is);
if (codepoint >= 0xD800 && codepoint <= 0xDBFF) {
@ -589,6 +596,11 @@ private:
}
else if (c == '"') { // Closing double quote
is.Take();
if (!(parseFlags & kParseInsituFlag)) {
if (!IsStackSpaceSufficient<Ch>(1)) {
RAPIDJSON_PARSE_ERROR(kParseErrorStackSizeLimitExceeded, is.Tell() - 1);
}
}
os.Put('\0'); // null-terminate the string
return;
}
@ -1038,8 +1050,16 @@ private:
else if (src == IterativeParsingKeyValueDelimiterState)
n = IterativeParsingMemberValueState;
// Push current state.
if (!IsStackSpaceSufficient<IterativeParsingState>(1)) {
RAPIDJSON_PARSE_ERROR_NORETURN(kParseErrorStackSizeLimitExceeded, is.Tell());
return IterativeParsingErrorState;
}
*stack_.template Push<IterativeParsingState>(1) = n;
// Initialize and push the member/element count.
if (!IsStackSpaceSufficient<int>(1)) {
RAPIDJSON_PARSE_ERROR_NORETURN(kParseErrorStackSizeLimitExceeded, is.Tell());
return IterativeParsingErrorState;
}
*stack_.template Push<int>(1) = 0;
// Call handler
if (dst == IterativeParsingObjectInitialState)
@ -1206,7 +1226,13 @@ private:
return parseResult_;
}
template <typename T>
bool IsStackSpaceSufficient(size_t count) const {
return kStackSizeLimit == 0 || (stack_.GetSize() + sizeof(T) * count <= kStackSizeLimit);
}
static const size_t kDefaultStackCapacity = 256; //!< Default stack capacity in bytes for storing a single decoded string.
const size_t kStackSizeLimit; //!< Stack size limit(in bytes). A value of 0 means no limit.
internal::Stack<Allocator> stack_; //!< A stack for storing decoded string temporarily during non-destructive parsing.
ParseResult parseResult_;
}; // class GenericReader

12
test/unittest/readertest.cpp
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@ -1288,6 +1288,18 @@ TEST(Reader, IterativeParsing_ShortCircuit) {
}
}
TEST(Reader, IterativeParsing_LimitStackSize) {
BaseReaderHandler<> handler;
Reader reader(20);
StringStream is("[[[]]]");
ParseResult r = reader.Parse<kParseIterativeFlag>(is, handler);
EXPECT_TRUE(reader.HasParseError());
EXPECT_EQ(kParseErrorStackSizeLimitExceeded, r.Code());
EXPECT_EQ(2, r.Offset());
}
#ifdef __GNUC__
RAPIDJSON_DIAG_POP
#endif