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Fix incremental parsing of invalid numbers with exponents, such as "0e+-" and "12.3E12E12", while still allowing "0e+" in non-strict mode.

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Deprecate the json_parse_double() function from json_util.h
This commit is contained in:
Eric Haszlakiewicz
2020-06-27 15:32:19 +00:00
parent 84e6032883
commit 6eac6986c9
6 changed files with 120 additions and 17 deletions
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3
ChangeLog
View File

@@ -27,6 +27,9 @@ Other changes
arrays to be allocated with the exact size needed, when known.
* Parsing of surrogate pairs in unicode escapes now properly handles
incremental parsing.
* 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").
***

80
json_tokener.c
View File

@@ -97,6 +97,8 @@ static const char *json_tokener_errors[] = {
*/
static json_bool json_tokener_validate_utf8(const char c, unsigned int *nBytes);
static int json_tokener_parse_double(const char *buf, int len, double *retval);
const char *json_tokener_error_desc(enum json_tokener_error jerr)
{
int jerr_int = (int)jerr;
@@ -837,6 +839,25 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
int case_len = 0;
int is_exponent = 0;
int negativesign_next_possible_location = 1;
if (printbuf_length(tok->pb) > 0)
{
/* We don't save all state from the previous incremental parse
so we need to re-generate it based on the saved string so far.
*/
char *e_loc = strchr(tok->pb->buf, 'e');
if (!e_loc)
e_loc = strchr(tok->pb->buf, 'E');
if (e_loc)
{
char *last_saved_char =
&tok->pb->buf[printbuf_length(tok->pb) - 1];
is_exponent = 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;
// else leave it set to 1, i.e. start of the new input
}
}
while (c && strchr(json_number_chars, c))
{
++case_len;
@@ -847,8 +868,9 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
* protected from input starting with '.' or
* e/E.
*/
if (c == '.')
switch (c)
{
case '.':
if (tok->is_double != 0)
{
/* '.' can only be found once, and out of the exponent part.
@@ -859,9 +881,9 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
goto out;
}
tok->is_double = 1;
}
if (c == 'e' || c == 'E')
{
break;
case 'e': /* FALLTHRU */
case 'E':
if (is_exponent != 0)
{
/* only one exponent possible */
@@ -872,15 +894,19 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
tok->is_double = 1;
/* the exponent part can begin with a negative sign */
negativesign_next_possible_location = case_len + 1;
}
if (c == '-' && 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;
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;
}
break;
default: break;
}
if (!ADVANCE_CHAR(str, tok) || !PEEK_CHAR(c, tok))
@@ -899,6 +925,22 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
tok->st_pos = 0;
goto redo_char;
}
if (tok->is_double && !(tok->flags & JSON_TOKENER_STRICT))
{
/* Trim some chars off the end, to allow things
like "123e+" to parse ok. */
while (printbuf_length(tok->pb) > 1)
{
char last_char = tok->pb->buf[printbuf_length(tok->pb) - 1];
if (last_char != 'e' && last_char != 'E' &&
last_char != '-' && last_char != '+')
{
break;
}
tok->pb->buf[printbuf_length(tok->pb) - 1] = '\0';
printbuf_length(tok->pb)--;
}
}
}
{
int64_t num64;
@@ -935,7 +977,8 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
}
}
else if (tok->is_double &&
json_parse_double(tok->pb->buf, &numd) == 0)
json_tokener_parse_double(
tok->pb->buf, printbuf_length(tok->pb), &numd) == 0)
{
current = json_object_new_double_s(numd, tok->pb->buf);
if (current == NULL)
@@ -1204,3 +1247,12 @@ size_t json_tokener_get_parse_end(struct json_tokener *tok)
assert(tok->char_offset >= 0); /* Drop this line when char_offset becomes a size_t */
return (size_t)tok->char_offset;
}
static int json_tokener_parse_double(const char *buf, int len, double *retval)
{
char *end;
*retval = strtod(buf, &end);
if (buf + len == end)
return 0; // It worked
return 1;
}

3
json_util.c
View File

@@ -222,6 +222,7 @@ int json_object_to_file(const char *filename, struct json_object *obj)
return json_object_to_file_ext(filename, obj, JSON_C_TO_STRING_PLAIN);
}
// Deprecated json_parse_double function. See json_tokener_parse_double instead.
int json_parse_double(const char *buf, double *retval)
{
char *end;
@@ -250,7 +251,7 @@ int json_parse_uint64(const char *buf, uint64_t *retval)
while (*buf == ' ')
buf++;
if (*buf == '-')
return 1; /* error: uint cannot be negative */
return 1; /* error: uint cannot be negative */
val = strtoull(buf, &end, 10);
if (end != buf)

3
json_util.h
View File

@@ -103,6 +103,9 @@ JSON_EXPORT const char *json_util_get_last_err(void);
/* these parsing helpers return zero on success */
JSON_EXPORT int json_parse_int64(const char *buf, int64_t *retval);
JSON_EXPORT int json_parse_uint64(const char *buf, uint64_t *retval);
/**
* @deprecated
*/
JSON_EXPORT int json_parse_double(const char *buf, double *retval);
/**

27
tests/test_parse.c
View File

@@ -343,9 +343,34 @@ struct incremental_step
/* This should parse as the number 12, since it continues the "1" */
{"2", 2, 1, json_tokener_success, 0},
{"12{", 3, 2, json_tokener_success, 1},
/* Parse number in strict model */
/* Parse number in strict mode */
{"[02]", -1, 3, json_tokener_error_parse_number, 1, JSON_TOKENER_STRICT},
{"0e+0", 5, 4, json_tokener_success, 1},
{"[0e+0]", -1, -1, json_tokener_success, 1},
/* The behavior when missing the exponent varies slightly */
{"0e", 2, 2, json_tokener_continue, 1},
{"0e", 3, 2, json_tokener_success, 1},
{"0e", 3, 2, json_tokener_error_parse_eof, 1, JSON_TOKENER_STRICT},
{"[0e]", -1, -1, json_tokener_success, 1},
{"[0e]", -1, 3, json_tokener_error_parse_number, 1, JSON_TOKENER_STRICT},
{"0e+", 3, 3, json_tokener_continue, 1},
{"0e+", 4, 3, json_tokener_success, 1},
{"0e+", 4, 3, json_tokener_error_parse_eof, 1, JSON_TOKENER_STRICT},
{"[0e+]", -1, -1, json_tokener_success, 1},
{"[0e+]", -1, 4, json_tokener_error_parse_number, 1, JSON_TOKENER_STRICT},
{"0e-", 3, 3, json_tokener_continue, 1},
{"0e-", 4, 3, json_tokener_success, 1},
{"0e-", 4, 3, json_tokener_error_parse_eof, 1, JSON_TOKENER_STRICT},
{"[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},
{"[0e+-]", -1, 4, json_tokener_error_parse_number, 1},
/* Similar tests for other kinds of objects: */
/* These could all return success immediately, since regardless of
what follows the false/true/null token we *will* return a json object,

21
tests/test_parse.expected
View File

@@ -145,6 +145,25 @@ json_tokener_parse_ex(tok, 1 , 1) ... OK: got correct error: continu
json_tokener_parse_ex(tok, 2 , 2) ... OK: got object of type [int]: 12
json_tokener_parse_ex(tok, 12{ , 3) ... OK: got object of type [int]: 12
json_tokener_parse_ex(tok, [02] , 4) ... OK: got correct error: number expected
json_tokener_parse_ex(tok, 0e+0 , 5) ... OK: got object of type [double]: 0e+0
json_tokener_parse_ex(tok, [0e+0] , 6) ... OK: got object of type [array]: [ 0e+0 ]
json_tokener_parse_ex(tok, 0e , 2) ... OK: got correct error: continue
json_tokener_parse_ex(tok, 0e , 3) ... OK: got object of type [double]: 0
json_tokener_parse_ex(tok, 0e , 3) ... OK: got correct error: unexpected end of data
json_tokener_parse_ex(tok, [0e] , 4) ... OK: got object of type [array]: [ 0 ]
json_tokener_parse_ex(tok, [0e] , 4) ... OK: got correct error: number expected
json_tokener_parse_ex(tok, 0e+ , 3) ... OK: got correct error: continue
json_tokener_parse_ex(tok, 0e+ , 4) ... OK: got object of type [double]: 0
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- , 3) ... OK: got correct error: continue
json_tokener_parse_ex(tok, 0e- , 4) ... OK: got object of type [double]: 0
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 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
json_tokener_parse_ex(tok, false , 6) ... OK: got object of type [boolean]: false
json_tokener_parse_ex(tok, true , 4) ... OK: got correct error: continue
@@ -246,5 +265,5 @@ json_tokener_parse_ex(tok, "\ud855
json_tokener_parse_ex(tok, "\ud0031<33>" , 10) ... OK: got correct error: invalid utf-8 string
json_tokener_parse_ex(tok, 11<31>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=160 ERROR=0
End Incremental Tests OK=179 ERROR=0
==================================