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Explicitly handle NaN values when converting to int

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Json objects of type double with the value NaN could cause undefined
behavior when casting double to int in `json_object_get_int`.
This commit is contained in:
Simon Resch
2024-11-14 13:47:18 +01:00
parent 565f181f65
commit 8c13801f2c
5 changed files with 51 additions and 8 deletions
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18
json_object.c
View File

@@ -721,6 +721,7 @@ int32_t json_object_get_int(const struct json_object *jso)
int64_t cint64 = 0;
double cdouble;
enum json_type o_type;
errno = 0;
if (!jso)
return 0;
@@ -767,6 +768,11 @@ int32_t json_object_get_int(const struct json_object *jso)
return INT32_MIN;
if (cdouble >= INT32_MAX)
return INT32_MAX;
if (isnan(cdouble))
{
errno = EINVAL;
return INT32_MIN;
}
return (int32_t)cdouble;
case json_type_boolean: return JC_BOOL_C(jso)->c_boolean;
default: return 0;
@@ -801,6 +807,7 @@ struct json_object *json_object_new_uint64(uint64_t i)
int64_t json_object_get_int64(const struct json_object *jso)
{
int64_t cint;
errno = 0;
if (!jso)
return 0;
@@ -826,6 +833,11 @@ int64_t json_object_get_int64(const struct json_object *jso)
return INT64_MAX;
if (JC_DOUBLE_C(jso)->c_double <= INT64_MIN)
return INT64_MIN;
if (isnan(JC_DOUBLE_C(jso)->c_double))
{
errno = EINVAL;
return INT64_MIN;
}
return (int64_t)JC_DOUBLE_C(jso)->c_double;
case json_type_boolean: return JC_BOOL_C(jso)->c_boolean;
case json_type_string:
@@ -839,6 +851,7 @@ int64_t json_object_get_int64(const struct json_object *jso)
uint64_t json_object_get_uint64(const struct json_object *jso)
{
uint64_t cuint;
errno = 0;
if (!jso)
return 0;
@@ -864,6 +877,11 @@ uint64_t json_object_get_uint64(const struct json_object *jso)
return UINT64_MAX;
if (JC_DOUBLE_C(jso)->c_double < 0)
return 0;
if (isnan(JC_DOUBLE_C(jso)->c_double))
{
errno = EINVAL;
return 0;
}
return (uint64_t)JC_DOUBLE_C(jso)->c_double;
case json_type_boolean: return JC_BOOL_C(jso)->c_boolean;
case json_type_string:

24
json_object.h
View File

@@ -693,7 +693,7 @@ JSON_EXPORT struct json_object *json_object_new_boolean(json_bool b);
* The type is coerced to a json_bool if the passed object is not a json_bool.
* integer and double objects will return 0 if there value is zero
* or 1 otherwise. If the passed object is a string it will return
* 1 if it has a non zero length.
* 1 if it has a non zero length.
* If any other object type is passed 0 will be returned, even non-empty
* json_type_array and json_type_object objects.
*
@@ -739,9 +739,11 @@ JSON_EXPORT struct json_object *json_object_new_uint64(uint64_t i);
/** Get the int value of a json_object
*
* The type is coerced to a int if the passed object is not a int.
* double objects will return their integer conversion. Strings will be
* parsed as an integer. If no conversion exists then 0 is returned
* and errno is set to EINVAL. null is equivalent to 0 (no error values set)
* double objects will return their integer conversion except for NaN values
* which return INT32_MIN and the errno is set to EINVAL.
* Strings will be parsed as an integer. If no conversion exists then 0 is
* returned and errno is set to EINVAL. null is equivalent to 0 (no error values
* set)
*
* Note that integers are stored internally as 64-bit values.
* If the value of too big or too small to fit into 32-bit, INT32_MAX or
@@ -783,8 +785,11 @@ JSON_EXPORT int json_object_int_inc(struct json_object *obj, int64_t val);
/** Get the int value of a json_object
*
* The type is coerced to a int64 if the passed object is not a int64.
* double objects will return their int64 conversion. Strings will be
* parsed as an int64. If no conversion exists then 0 is returned.
* double objects will return their int64 conversion except for NaN values
* which return INT64_MIN and the errno is set to EINVAL.
* Strings will be parsed as an int64. If no conversion exists then 0 is
* returned and errno is set to EINVAL. null is equivalent to 0 (no error values
* set)
*
* NOTE: Set errno to 0 directly before a call to this function to determine
* whether or not conversion was successful (it does not clear the value for
@@ -798,8 +803,11 @@ JSON_EXPORT int64_t json_object_get_int64(const struct json_object *obj);
/** Get the uint value of a json_object
*
* The type is coerced to a uint64 if the passed object is not a uint64.
* double objects will return their uint64 conversion. Strings will be
* parsed as an uint64. If no conversion exists then 0 is returned.
* double objects will return their uint64 conversion except for NaN values
* which return 0 and the errno is set to EINVAL.
* Strings will be parsed as an uint64. If no conversion exists then 0 is
* returned and errno is set to EINVAL. null is equivalent to 0 (no error values
* set)
*
* NOTE: Set errno to 0 directly before a call to this function to determine
* whether or not conversion was successful (it does not clear the value for

3
tests/test_cast.c
View File

@@ -36,6 +36,7 @@ int main(int argc, char **argv)
\"array_with_zero\": [ 0 ],\n\
\"empty_object\": {},\n\
\"nonempty_object\": { \"a\": 123 },\n\
\"nan\": NaN,\n\
}";
/* Note: 2147483649 = INT_MAX + 2 */
/* Note: 9223372036854775809 = INT64_MAX + 2 */
@@ -62,6 +63,7 @@ int main(int argc, char **argv)
getit(new_obj, "array_with_zero");
getit(new_obj, "empty_object");
getit(new_obj, "nonempty_object");
getit(new_obj, "nan");
// Now check the behaviour of the json_object_is_type() function.
printf("\n================================\n");
@@ -75,6 +77,7 @@ int main(int argc, char **argv)
checktype(new_obj, "int64_number");
checktype(new_obj, "negative_number");
checktype(new_obj, "a_null");
checktype(new_obj, "nan");
json_object_put(new_obj);

8
tests/test_cast.expected
View File

@@ -12,6 +12,7 @@ Parsed input: {
"array_with_zero": [ 0 ],
"empty_object": {},
"nonempty_object": { "a": 123 },
"nan": NaN,
}
Result is not NULL
new_obj.string_of_digits json_object_get_type()=string
@@ -92,6 +93,12 @@ new_obj.nonempty_object json_object_get_int64()=0
new_obj.nonempty_object json_object_get_uint64()=0
new_obj.nonempty_object json_object_get_boolean()=0
new_obj.nonempty_object json_object_get_double()=0.000000
new_obj.nan json_object_get_type()=double
new_obj.nan json_object_get_int()=-2147483648
new_obj.nan json_object_get_int64()=-9223372036854775808
new_obj.nan json_object_get_uint64()=0
new_obj.nan json_object_get_boolean()=1
new_obj.nan json_object_get_double()=nan
================================
json_object_is_type: null,boolean,double,int,object,array,string
@@ -104,3 +111,4 @@ new_obj.boolean_false : 0,1,0,0,0,0,0
new_obj.int64_number : 0,0,0,1,0,0,0
new_obj.negative_number : 0,0,0,1,0,0,0
new_obj.a_null : 1,0,0,0,0,0,0
new_obj.nan : 0,0,1,0,0,0,0

6
tests/test_int_get.c
View File

@@ -4,6 +4,7 @@
#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <math.h>
#include "json.h"
@@ -25,6 +26,7 @@
#define N_I64 json_object_new_int64
#define N_U64 json_object_new_uint64
#define N_STR json_object_new_string
#define N_DBL json_object_new_double
int main(int argc, char **argv)
{
@@ -45,6 +47,8 @@ int main(int argc, char **argv)
CHECK_GET_INT(N_I64(INT64_MIN), INT32_MIN && errno == 0);
CHECK_GET_INT(N_STR(I64_MAX_S), INT32_MAX && errno == 0);
CHECK_GET_INT(N_STR(I64_MIN_S), INT32_MIN && errno == 0);
CHECK_GET_INT(N_DBL(NAN), INT32_MIN && errno == EINVAL);
printf("INT GET PASSED\n");
CHECK_GET_INT64(N_I64(INT64_MAX), INT64_MAX && errno == 0);
@@ -53,11 +57,13 @@ int main(int argc, char **argv)
CHECK_GET_INT64(N_STR(I64_MIN_S), INT64_MIN && errno == 0);
CHECK_GET_INT64(N_STR(I64_OVER), INT64_MAX && errno == ERANGE);
CHECK_GET_INT64(N_STR(I64_UNDER), INT64_MIN && errno == ERANGE);
CHECK_GET_INT64(N_DBL(NAN), INT64_MIN && errno == EINVAL);
printf("INT64 GET PASSED\n");
CHECK_GET_UINT64(N_U64(UINT64_MAX), UINT64_MAX && errno == 0);
CHECK_GET_UINT64(N_U64(-1), UINT64_MAX && errno == 0);
CHECK_GET_UINT64(N_STR(U64_OUT_S), UINT64_MAX && errno == ERANGE);
CHECK_GET_UINT64(N_DBL(NAN), 0 && errno == EINVAL);
printf("UINT64 GET PASSED\n");
printf("PASSED\n");