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In the json_tokener_state_number case, explicitly adjust what "number" characters are allowed based on the exact micro-state that we're in, and check for invalid following characters in a different way, to allow a valid json_type_number object to be returned at the top level.

This causes previously failing strings like "123-456" to return a valid json_object with the appropriate value.  If you care about the trailing content, call json_tokener_parse_ex() and check the parse end point with json_tokener_get_parse_end().
tags/json-c-0.15-20200726
Eric Haszlakiewicz 5 years ago
parent
commit
f23486a321
6 changed files with 92 additions and 50 deletions
  1. +3
    -0
      ChangeLog
  2. +0
    -1
      json_object.c
  3. +0
    -1
      json_object_private.h
  4. +46
    -31
      json_tokener.c
  5. +29
    -13
      tests/test_parse.c
  6. +14
    -4
      tests/test_parse.expected

+ 3
- 0
ChangeLog View File

@@ -30,6 +30,9 @@ Other changes
* Fix incremental parsing of numbers, especially those with exponents, e.g.
so parsing "[0", "e+", "-]" now properly returns an error.
Strict mode now rejects missing exponents ("0e").
* Successfully return number objects at the top level even when they are
followed by a "-", "." or "e". This makes parsing things like "123-45"
behave consistently with things like "123xyz".


***


+ 0
- 1
json_object.c View File

@@ -54,7 +54,6 @@
// Don't define this. It's not thread-safe.
/* #define REFCOUNT_DEBUG 1 */

const char *json_number_chars = "0123456789.+-eE";
const char *json_hex_chars = "0123456789abcdefABCDEF";

static void json_object_generic_delete(struct json_object *jso);


+ 0
- 1
json_object_private.h View File

@@ -98,7 +98,6 @@ struct json_object_string

void _json_c_set_last_err(const char *err_fmt, ...);

extern const char *json_number_chars;
extern const char *json_hex_chars;

#ifdef __cplusplus


+ 46
- 31
json_tokener.c View File

@@ -193,7 +193,17 @@ struct json_object *json_tokener_parse_verbose(const char *str, enum json_tokene
return NULL;
obj = json_tokener_parse_ex(tok, str, -1);
*error = tok->err;
if (tok->err != json_tokener_success)
if (tok->err != json_tokener_success
#if 0
/* This would be a more sensible default, and cause parsing
* things like "null123" to fail when the caller can't know
* where the parsing left off, but starting to fail would
* be a notable behaviour change. Save for a 1.0 release.
*/
|| json_tokener_get_parse_end(tok) != strlen(str)
#endif
)

{
if (obj != NULL)
json_object_put(obj);
@@ -838,7 +848,8 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
const char *case_start = str;
int case_len = 0;
int is_exponent = 0;
int negativesign_next_possible_location = 1;
int neg_sign_ok = 1;
int pos_sign_ok = 0;
if (printbuf_length(tok->pb) > 0)
{
/* We don't save all state from the previous incremental parse
@@ -852,14 +863,26 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
char *last_saved_char =
&tok->pb->buf[printbuf_length(tok->pb) - 1];
is_exponent = 1;
pos_sign_ok = neg_sign_ok = 1;
/* If the "e" isn't at the end, we can't start with a '-' */
if (e_loc != last_saved_char)
negativesign_next_possible_location = -1;
{
neg_sign_ok = 0;
pos_sign_ok = 0;
}
// else leave it set to 1, i.e. start of the new input
}
}
while (c && strchr(json_number_chars, c))

while (c &&
((c >= '0' && c <= '9') ||
(!is_exponent && (c=='e' || c=='E')) ||
(neg_sign_ok && c=='-') ||
(pos_sign_ok && c=='+') ||
(!tok->is_double && c=='.')
))
{
pos_sign_ok = neg_sign_ok = 0;
++case_len;

/* non-digit characters checks */
@@ -871,40 +894,16 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
switch (c)
{
case '.':
if (tok->is_double != 0)
{
/* '.' can only be found once, and out of the exponent part.
* Thus, if the input is already flagged as double, it
* is invalid.
*/
tok->err = json_tokener_error_parse_number;
goto out;
}
tok->is_double = 1;
pos_sign_ok = 1;
neg_sign_ok = 1;
break;
case 'e': /* FALLTHRU */
case 'E':
if (is_exponent != 0)
{
/* only one exponent possible */
tok->err = json_tokener_error_parse_number;
goto out;
}
is_exponent = 1;
tok->is_double = 1;
/* the exponent part can begin with a negative sign */
negativesign_next_possible_location = case_len + 1;
break;
case '-':
if (case_len != negativesign_next_possible_location)
{
/* If the negative sign is not where expected (ie
* start of input or start of exponent part), the
* input is invalid.
*/
tok->err = json_tokener_error_parse_number;
goto out;
}
pos_sign_ok = neg_sign_ok = 1;
break;
default: break;
}
@@ -915,6 +914,22 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
goto out;
}
}
/*
Now we know c isn't a valid number char, but check whether
it might have been intended to be, and return a potentially
more understandable error right away.
However, if we're at the top-level, use the number as-is
because c can be part of a new object to parse on the
next call to json_tokener_parse().
*/
if (tok->depth > 0 &&
c != ',' && c != ']' && c != '}' && c != '/' &&
c != 'I' && c != 'i' &&
!isspace((unsigned char)c))
{
tok->err = json_tokener_error_parse_number;
goto out;
}
if (case_len > 0)
printbuf_memappend_fast(tok->pb, case_start, case_len);



+ 29
- 13
tests/test_parse.c View File

@@ -141,16 +141,18 @@ static void test_basic_parse()

single_basic_parse("12", 0);
single_basic_parse("12.3", 0);
single_basic_parse("12.3.4", 0); /* non-sensical, returns null */
/* was returning (int)2015 before patch, should return null */
single_basic_parse("2015-01-15", 0);

/* ...but this works. It's rather inconsistent, and a future major release
* should change the behavior so it either always returns null when extra
* bytes are present (preferred), or always return object created from as much
* as was able to be parsed.
/* Even though, when using json_tokener_parse() there's no way to
* know when there is more data after the parsed object,
* an object is successfully returned anyway (in some cases)
*/

single_basic_parse("12.3.4", 0);
single_basic_parse("2015-01-15", 0);
single_basic_parse("12.3xxx", 0);
single_basic_parse("12.3{\"a\":123}", 0);
single_basic_parse("12.3\n", 0);
single_basic_parse("12.3 ", 0);

single_basic_parse("{\"FoO\" : -12.3E512}", 0);
single_basic_parse("{\"FoO\" : -12.3e512}", 0);
@@ -368,7 +370,10 @@ struct incremental_step
{"[0e-]", -1, -1, json_tokener_success, 1},
{"[0e-]", -1, 4, json_tokener_error_parse_number, 1, JSON_TOKENER_STRICT},

{"0e+-", 5, 3, json_tokener_error_parse_number, 1},
/* You might expect this to fail, but it won't because
it's a valid partial parse; note the char_offset: */
{"0e+-", 5, 3, json_tokener_success, 1},
{"0e+-", 5, 3, json_tokener_error_parse_number, 1, JSON_TOKENER_STRICT},
{"[0e+-]", -1, 4, json_tokener_error_parse_number, 1},

/* Similar tests for other kinds of objects: */
@@ -447,11 +452,22 @@ struct incremental_step
{"{\"a\":1}{\"b\":2}", 15, 7, json_tokener_success, 0},
{&"{\"a\":1}{\"b\":2}"[7], 8, 7, json_tokener_success, 1},

/* Some bad formatting. Check we get the correct error status
* XXX this means we can't have two numbers in the incremental parse
* XXX stream with the second one being a negative number!
*/
{"2015-01-15", 10, 4, json_tokener_error_parse_number, 1},
/*
* Though this may seem invalid at first glance, it
* parses as three separate numbers, 2015, -1 and -15
* Of course, simply pasting together a stream of arbitrary
* positive numbers won't work, since there'll be no way to
* tell where in e.g. "2015015" the next number stats, so
* a reliably parsable stream must not include json_type_int
* or json_type_double objects without some other delimiter.
* e.g. whitespace
*/
{&"2015-01-15"[0], 11, 4, json_tokener_success, 1},
{&"2015-01-15"[4], 7, 3, json_tokener_success, 1},
{&"2015-01-15"[7], 4, 3, json_tokener_success, 1},
{&"2015 01 15"[0], 11, 5, json_tokener_success, 1},
{&"2015 01 15"[4], 7, 4, json_tokener_success, 1},
{&"2015 01 15"[7], 4, 3, json_tokener_success, 1},

/* Strings have a well defined end point, so we can stop at the quote */
{"\"blue\"", -1, -1, json_tokener_success, 0},


+ 14
- 4
tests/test_parse.expected View File

@@ -40,9 +40,13 @@ new_obj.to_string(nAn)=NaN
new_obj.to_string(iNfinity)=Infinity
new_obj.to_string(12)=12
new_obj.to_string(12.3)=12.3
new_obj.to_string(12.3.4)=null
new_obj.to_string(2015-01-15)=null
new_obj.to_string(12.3.4)=12.3
new_obj.to_string(2015-01-15)=2015
new_obj.to_string(12.3xxx)=12.3
new_obj.to_string(12.3{"a":123})=12.3
new_obj.to_string(12.3
)=12.3
new_obj.to_string(12.3 )=12.3
new_obj.to_string({"FoO" : -12.3E512})={ "FoO": -12.3E512 }
new_obj.to_string({"FoO" : -12.3e512})={ "FoO": -12.3e512 }
new_obj.to_string({"FoO" : -12.3E51.2})=null
@@ -162,6 +166,7 @@ json_tokener_parse_ex(tok, 0e- , 4) ... OK: got object of type [double
json_tokener_parse_ex(tok, 0e- , 4) ... OK: got correct error: unexpected end of data
json_tokener_parse_ex(tok, [0e-] , 5) ... OK: got object of type [array]: [ 0 ]
json_tokener_parse_ex(tok, [0e-] , 5) ... OK: got correct error: number expected
json_tokener_parse_ex(tok, 0e+- , 5) ... OK: got object of type [double]: 0
json_tokener_parse_ex(tok, 0e+- , 5) ... OK: got correct error: number expected
json_tokener_parse_ex(tok, [0e+-] , 6) ... OK: got correct error: number expected
json_tokener_parse_ex(tok, false , 5) ... OK: got correct error: continue
@@ -215,7 +220,12 @@ json_tokener_parse_ex(tok, nullx , 6) ... OK: got object of type [null]:
json_tokener_parse_ex(tok, x , 2) ... OK: got correct error: unexpected character
json_tokener_parse_ex(tok, {"a":1}{"b":2}, 15) ... OK: got object of type [object]: { "a": 1 }
json_tokener_parse_ex(tok, {"b":2} , 8) ... OK: got object of type [object]: { "b": 2 }
json_tokener_parse_ex(tok, 2015-01-15 , 10) ... OK: got correct error: number expected
json_tokener_parse_ex(tok, 2015-01-15 , 11) ... OK: got object of type [int]: 2015
json_tokener_parse_ex(tok, -01-15 , 7) ... OK: got object of type [int]: -1
json_tokener_parse_ex(tok, -15 , 4) ... OK: got object of type [int]: -15
json_tokener_parse_ex(tok, 2015 01 15 , 11) ... OK: got object of type [int]: 2015
json_tokener_parse_ex(tok, 01 15 , 7) ... OK: got object of type [int]: 1
json_tokener_parse_ex(tok, 15 , 4) ... OK: got object of type [int]: 15
json_tokener_parse_ex(tok, "blue" , 6) ... OK: got object of type [string]: "blue"
json_tokener_parse_ex(tok, "\"" , 4) ... OK: got object of type [string]: "\""
json_tokener_parse_ex(tok, "\\" , 4) ... OK: got object of type [string]: "\\"
@@ -265,5 +275,5 @@ json_tokener_parse_ex(tok, "\ud855
json_tokener_parse_ex(tok, "\ud0031À" , 10) ... OK: got correct error: invalid utf-8 string
json_tokener_parse_ex(tok, 11�11 , 5) ... OK: got correct error: invalid utf-8 string
json_tokener_parse_ex(tok, {"1�":1} , 8) ... OK: got correct error: invalid utf-8 string
End Incremental Tests OK=179 ERROR=0
End Incremental Tests OK=185 ERROR=0
==================================

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