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In JSONParser::getToken handle legal control chars early

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Also, reject them in strings.
This commit is contained in:
m-holger 2023-01-29 15:21:29 +00:00
parent f5b7448a27
commit ee32235f54
11 changed files with 313 additions and 292 deletions
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580
libqpdf/JSON.cc
View File

@ -723,10 +723,11 @@ JSONParser::handle_u_code(
void
JSONParser::tokenError()
{
if (bytes == 0) {
if (done) {
QTC::TC("libtests", "JSON parse ls premature end of input");
throw std::runtime_error("JSON: premature end of input");
}
if (lex_state == ls_u4) {
QTC::TC("libtests", "JSON parse bad hex after u");
throw std::runtime_error(
@ -737,6 +738,11 @@ JSONParser::tokenError()
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": keyword: unexpected character " + std::string(p, 1));
} else if (lex_state == ls_string) {
QTC::TC("libtests", "JSON parse control char in string");
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": control character in string (missing \"?)");
} else if (lex_state == ls_backslash) {
QTC::TC("libtests", "JSON parse backslash bad character");
throw std::runtime_error(
@ -779,6 +785,7 @@ JSONParser::tokenError()
"JSON: offset " + std::to_string(offset) +
": numeric literal: unexpected character " + std::string(p, 1));
}
throw std::logic_error("JSON::tokenError : unhandled error");
}
void
@ -792,7 +799,7 @@ JSONParser::getToken()
unsigned long high_surrogate = 0;
qpdf_offset_t high_offset = 0;
while (!done) {
while (true) {
if (p == (buf + bytes)) {
p = buf;
bytes = is.read(buf, sizeof(buf));
@ -808,307 +815,320 @@ JSONParser::getToken()
// end the current token (unless we are still before the start
// of the token).
if (lex_state == ls_top) {
// Continue with token
++p;
++offset;
} else {
// done
break;
}
} else {
QTC::TC("libtests", "JSON parse null character");
throw std::runtime_error(
"JSON: control or null character at offset " +
std::to_string(offset));
}
}
action = append;
switch (lex_state) {
case ls_top:
token_start = offset;
if (*p == '"') {
lex_state = ls_string;
action = ignore;
} else if (QUtil::is_space(*p)) {
action = ignore;
} else if (*p == ',') {
lex_state = ls_comma;
action = ignore;
ready = true;
} else if (*p == ':') {
lex_state = ls_colon;
action = ignore;
ready = true;
} else if (*p == '{') {
lex_state = ls_begin_dict;
action = ignore;
ready = true;
} else if (*p == '}') {
lex_state = ls_end_dict;
action = ignore;
ready = true;
} else if (*p == '[') {
lex_state = ls_begin_array;
action = ignore;
ready = true;
} else if (*p == ']') {
lex_state = ls_end_array;
action = ignore;
ready = true;
} else if ((*p >= 'a') && (*p <= 'z')) {
lex_state = ls_alpha;
} else if (*p == '-') {
lex_state = ls_number_minus;
} else if ((*p >= '1') && (*p <= '9')) {
lex_state = ls_number_before_point;
} else if (*p == '0') {
lex_state = ls_number_leading_zero;
} else {
QTC::TC("libtests", "JSON parse bad character");
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": unexpected character " + std::string(p, 1));
}
break;
case ls_number_minus:
if ((*p >= '1') && (*p <= '9')) {
lex_state = ls_number_before_point;
} else if (*p == '0') {
lex_state = ls_number_leading_zero;
} else {
QTC::TC("libtests", "JSON parse number minus no digits");
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": numeric literal: no digit after minus sign");
}
break;
case ls_number_leading_zero:
if (*p == '.') {
lex_state = ls_number_point;
} else if (QUtil::is_space(*p)) {
lex_state = ls_number;
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
lex_state = ls_number;
action = reread;
ready = true;
} else if (*p == 'e' || *p == 'E') {
lex_state = ls_number_e;
} else {
QTC::TC("libtests", "JSON parse leading zero");
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": number with leading zero");
}
break;
case ls_number_before_point:
if ((*p >= '0') && (*p <= '9')) {
// continue
} else if (*p == '.') {
lex_state = ls_number_point;
} else if (QUtil::is_space(*p)) {
lex_state = ls_number;
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
lex_state = ls_number;
action = reread;
ready = true;
} else if (*p == 'e' || *p == 'E') {
lex_state = ls_number_e;
} else {
tokenError();
}
break;
case ls_number_point:
if ((*p >= '0') && (*p <= '9')) {
lex_state = ls_number_after_point;
} else {
tokenError();
}
break;
case ls_number_after_point:
if ((*p >= '0') && (*p <= '9')) {
// continue
} else if (QUtil::is_space(*p)) {
lex_state = ls_number;
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
lex_state = ls_number;
action = reread;
ready = true;
} else if (*p == 'e' || *p == 'E') {
lex_state = ls_number_e;
} else {
tokenError();
}
break;
case ls_number_e:
if ((*p >= '0') && (*p <= '9')) {
lex_state = ls_number;
} else if ((*p == '+') || (*p == '-')) {
lex_state = ls_number_e_sign;
} else {
tokenError();
}
break;
case ls_number_e_sign:
if ((*p >= '0') && (*p <= '9')) {
lex_state = ls_number;
} else {
tokenError();
}
break;
case ls_number:
// We only get here after we have seen an exponent.
if ((*p >= '0') && (*p <= '9')) {
// continue
} else if (QUtil::is_space(*p)) {
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
action = reread;
ready = true;
} else {
tokenError();
}
break;
case ls_alpha:
if ((*p >= 'a') && (*p <= 'z')) {
// okay
} else if (QUtil::is_space(*p)) {
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
action = reread;
ready = true;
} else {
tokenError();
}
break;
case ls_string:
if (*p == '"') {
if (high_offset) {
QTC::TC("libtests", "JSON 16 dangling high");
throw std::runtime_error(
"JSON: offset " + std::to_string(high_offset) +
": UTF-16 high surrogate not followed by low "
"surrogate");
}
action = ignore;
ready = true;
} else if (*p == '\\') {
lex_state = ls_backslash;
action = ignore;
}
break;
case ls_backslash:
action = ignore;
lex_state = ls_string;
switch (*p) {
case '\\':
case '\"':
case '/':
// \/ is allowed in json input, but so is /, so we
// don't map / to \/ in output.
token += *p;
break;
case 'b':
token += '\b';
break;
case 'f':
token += '\f';
break;
case 'n':
token += '\n';
break;
case 'r':
token += '\r';
break;
case 't':
token += '\t';
break;
case 'u':
lex_state = ls_u4;
u_count = 0;
u_value = 0;
break;
default:
lex_state = ls_backslash;
tokenError();
}
break;
case ls_u4:
using ui = unsigned int;
action = ignore;
if ('0' <= *p && *p <= '9') {
u_value = 16 * u_value + (ui(*p) - ui('0'));
} else if ('a' <= *p && *p <= 'f') {
u_value = 16 * u_value + (10 + ui(*p) - ui('a'));
} else if ('A' <= *p && *p <= 'F') {
u_value = 16 * u_value + (10 + ui(*p) - ui('A'));
} else {
tokenError();
}
if (++u_count == 4) {
handle_u_code(
u_value, offset - 5, high_surrogate, high_offset, token);
lex_state = ls_string;
}
break;
default:
throw std::logic_error(
"JSONParser::getToken : trying to handle delimiter state");
}
switch (action) {
case reread:
break;
case append:
token.append(1, *p);
// fall through
case ignore:
++p;
++offset;
break;
}
if (ready) {
break;
}
}
if (done) {
if (!token.empty() && !ready) {
} else {
action = append;
switch (lex_state) {
case ls_top:
// Can't happen
throw std::logic_error("tok_start set in ls_top while parsing");
token_start = offset;
if (*p == '"') {
lex_state = ls_string;
action = ignore;
} else if (*p == ' ') {
action = ignore;
} else if (*p == ',') {
lex_state = ls_comma;
action = ignore;
ready = true;
} else if (*p == ',') {
lex_state = ls_comma;
action = ignore;
ready = true;
} else if (*p == ':') {
lex_state = ls_colon;
action = ignore;
ready = true;
} else if (*p == '{') {
lex_state = ls_begin_dict;
action = ignore;
ready = true;
} else if (*p == '}') {
lex_state = ls_end_dict;
action = ignore;
ready = true;
} else if (*p == '[') {
lex_state = ls_begin_array;
action = ignore;
ready = true;
} else if (*p == ']') {
lex_state = ls_end_array;
action = ignore;
ready = true;
} else if ((*p >= 'a') && (*p <= 'z')) {
lex_state = ls_alpha;
} else if (*p == '-') {
lex_state = ls_number_minus;
} else if ((*p >= '1') && (*p <= '9')) {
lex_state = ls_number_before_point;
} else if (*p == '0') {
lex_state = ls_number_leading_zero;
} else {
QTC::TC("libtests", "JSON parse bad character");
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": unexpected character " + std::string(p, 1));
}
break;
case ls_number_minus:
if ((*p >= '1') && (*p <= '9')) {
lex_state = ls_number_before_point;
} else if (*p == '0') {
lex_state = ls_number_leading_zero;
} else {
QTC::TC("libtests", "JSON parse number minus no digits");
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": numeric literal: no digit after minus sign");
}
break;
case ls_number_leading_zero:
if (*p == '.') {
lex_state = ls_number_point;
} else if (*p == ' ') {
lex_state = ls_number;
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
lex_state = ls_number;
action = reread;
ready = true;
} else if (*p == 'e' || *p == 'E') {
lex_state = ls_number_e;
} else {
QTC::TC("libtests", "JSON parse leading zero");
throw std::runtime_error(
"JSON: offset " + std::to_string(offset) +
": number with leading zero");
}
break;
case ls_number_before_point:
if ((*p >= '0') && (*p <= '9')) {
// continue
} else if (*p == '.') {
lex_state = ls_number_point;
} else if (*p == ' ') {
lex_state = ls_number;
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
lex_state = ls_number;
action = reread;
ready = true;
} else if (*p == 'e' || *p == 'E') {
lex_state = ls_number_e;
} else {
tokenError();
}
break;
case ls_number_point:
if ((*p >= '0') && (*p <= '9')) {
lex_state = ls_number_after_point;
} else {
tokenError();
}
break;
case ls_number_after_point:
lex_state = ls_number;
if ((*p >= '0') && (*p <= '9')) {
// continue
} else if (*p == ' ') {
lex_state = ls_number;
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
lex_state = ls_number;
action = reread;
ready = true;
} else if (*p == 'e' || *p == 'E') {
lex_state = ls_number_e;
} else {
tokenError();
}
break;
case ls_number_e:
if ((*p >= '0') && (*p <= '9')) {
lex_state = ls_number;
} else if ((*p == '+') || (*p == '-')) {
lex_state = ls_number_e_sign;
} else {
tokenError();
}
break;
case ls_number_e_sign:
if ((*p >= '0') && (*p <= '9')) {
lex_state = ls_number;
} else {
tokenError();
}
break;
case ls_number:
// We only get here after we have seen an exponent.
if ((*p >= '0') && (*p <= '9')) {
// continue
} else if (*p == ' ') {
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
action = reread;
ready = true;
} else {
tokenError();
}
break;
case ls_alpha:
// terminal state
if ((*p >= 'a') && (*p <= 'z')) {
// okay
} else if (*p == ' ') {
action = ignore;
ready = true;
} else if (strchr("{}[]:,", *p)) {
action = reread;
ready = true;
} else {
tokenError();
}
break;
case ls_string:
if (*p == '"') {
if (high_offset) {
QTC::TC("libtests", "JSON 16 dangling high");
throw std::runtime_error(
"JSON: offset " + std::to_string(high_offset) +
": UTF-16 high surrogate not followed by low "
"surrogate");
}
action = ignore;
ready = true;
} else if (*p == '\\') {
lex_state = ls_backslash;
action = ignore;
}
break;
case ls_backslash:
action = ignore;
lex_state = ls_string;
switch (*p) {
case '\\':
case '\"':
case '/':
// \/ is allowed in json input, but so is /, so we
// don't map / to \/ in output.
token += *p;
break;
case 'b':
token += '\b';
break;
case 'f':
token += '\f';
break;
case 'n':
token += '\n';
break;
case 'r':
token += '\r';
break;
case 't':
token += '\t';
break;
case 'u':
lex_state = ls_u4;
u_count = 0;
u_value = 0;
break;
default:
lex_state = ls_backslash;
tokenError();
}
break;
case ls_u4:
using ui = unsigned int;
action = ignore;
if ('0' <= *p && *p <= '9') {
u_value = 16 * u_value + (ui(*p) - ui('0'));
} else if ('a' <= *p && *p <= 'f') {
u_value = 16 * u_value + (10 + ui(*p) - ui('a'));
} else if ('A' <= *p && *p <= 'F') {
u_value = 16 * u_value + (10 + ui(*p) - ui('A'));
} else {
tokenError();
}
if (++u_count == 4) {
handle_u_code(
u_value,
offset - 5,
high_surrogate,
high_offset,
token);
lex_state = ls_string;
}
break;
default:
tokenError();
throw std::logic_error(
"JSONParser::getToken : trying to handle delimiter state");
}
switch (action) {
case reread:
break;
case append:
token.append(1, *p);
// fall through
case ignore:
++p;
++offset;
break;
}
if (ready) {
return;
}
}
}
// We only get here if on end of input or if the last character was a
// control character.
if (!token.empty()) {
switch (lex_state) {
case ls_top:
// Can't happen
throw std::logic_error("tok_start set in ls_top while parsing");
break;
case ls_number_leading_zero:
case ls_number_before_point:
case ls_number_after_point:
lex_state = ls_number;
break;
case ls_number:
case ls_alpha:
// terminal state
break;
default:
tokenError();
}
}
}

1
libtests/libtests.testcov
View File

@ -79,6 +79,7 @@ JSON parse number minus no digits 0
JSON parse incomplete number 0
JSON parse keyword bad character 0
JSON parse backslash bad character 0
JSON parse control char in string 0
JSON parse leading zero 0
JSON parse ls premature end of input 0
JSON parse bad hex after u 0

8
libtests/qtest/json_parse.test
View File

@ -125,10 +125,10 @@ my @bad = (
"e after minus", # 42
"missing digit after e", # 43
"missing digit after e+/-", # 44
# "tab char in string", # 45
# "cr char in string", # 46
# "lf char in string", # 47
# "bs char in string", # 48
"tab char in string", # 45
"cr char in string", # 46
"lf char in string", # 47
"bs char in string", # 48
);
my $i = 0;

2
libtests/qtest/json_parse/bad-01.out
View File

@ -1 +1 @@
exception: bad-01.json: JSON: offset 9: material follows end of object: junk
exception: bad-01.json: JSON: offset 8: material follows end of object: junk

2
libtests/qtest/json_parse/bad-02.out
View File

@ -1 +1 @@
exception: bad-02.json: JSON: offset 11: material follows end of object: junk
exception: bad-02.json: JSON: offset 10: material follows end of object: junk

2
libtests/qtest/json_parse/bad-03.out
View File

@ -1 +1 @@
exception: bad-03.json: JSON: offset 16: material follows end of object: junk
exception: bad-03.json: JSON: offset 15: material follows end of object: junk

2
libtests/qtest/json_parse/bad-27.out
View File

@ -1 +1 @@
exception: bad-27.json: JSON: premature end of input
exception: bad-27.json: JSON: offset 5: control character in string (missing "?)

2
libtests/qtest/json_parse/bad-45.out
View File

@ -1 +1 @@
"Tab in str\ting"
exception: bad-45.json: JSON: offset 11: control character in string (missing "?)

2
libtests/qtest/json_parse/bad-46.out
View File

@ -1 +1 @@
"cr in str\ring"
exception: bad-46.json: JSON: offset 10: control character in string (missing "?)

2
libtests/qtest/json_parse/bad-47.out
View File

@ -1 +1 @@
"lf in str\ning"
exception: bad-47.json: JSON: offset 10: control character in string (missing "?)