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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.

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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().
This commit is contained in:
Eric Haszlakiewicz
2020-06-29 02:14:26 +00:00
parent 6eac6986c9
commit f23486a321
6 changed files with 92 additions and 50 deletions
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77
json_tokener.c
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@@ -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);