Skip to content

Fix #880 Max recursion depth for cJSON_Duplicate to prevent stack exhaustion #888

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Alanscut merged 2 commits into from
Sep 23, 2024
Merged

Fix #880 Max recursion depth for cJSON_Duplicate to prevent stack exhaustion #888

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
0719f72
Added max recusrion depth for cJSONDuplicate to prevent stack exhaust…
vwvw Aug 30, 2024
4525479
Wrong counter increment
vwvw Aug 30, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 11 additions & 1 deletion cJSON.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2726,7 +2726,14 @@ CJSON_PUBLIC(cJSON *) cJSON_CreateStringArray(const char *const *strings, int co
}

/* Duplication */
cJSON * cJSON_Duplicate_rec(const cJSON *item, size_t depth, cJSON_bool recurse);

CJSON_PUBLIC(cJSON *) cJSON_Duplicate(const cJSON *item, cJSON_bool recurse)
{
return cJSON_Duplicate_rec(item, 0, recurse );
}

cJSON * cJSON_Duplicate_rec(const cJSON *item, size_t depth, cJSON_bool recurse)
{
cJSON *newitem = NULL;
cJSON *child = NULL;
Expand Down Expand Up @@ -2773,7 +2780,10 @@ CJSON_PUBLIC(cJSON *) cJSON_Duplicate(const cJSON *item, cJSON_bool recurse)
child = item->child;
while (child != NULL)
{
newchild = cJSON_Duplicate(child, true); /* Duplicate (with recurse) each item in the ->next chain */
if(depth >= CJSON_CIRCULAR_LIMIT) {
goto fail;
}
newchild = cJSON_Duplicate_rec(child, depth + 1, true); /* Duplicate (with recurse) each item in the ->next chain */
if (!newchild)
{
goto fail;
Expand Down
6 changes: 6 additions & 0 deletions cJSON.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -137,6 +137,12 @@ typedef int cJSON_bool;
#define CJSON_NESTING_LIMIT 1000
#endif

/* Limits the length of circular references can be before cJSON rejects to parse them.
* This is to prevent stack overflows. */
#ifndef CJSON_CIRCULAR_LIMIT
#define CJSON_CIRCULAR_LIMIT 10000
#endif

/* returns the version of cJSON as a string */
CJSON_PUBLIC(const char*) cJSON_Version(void);

Expand Down
18 changes: 18 additions & 0 deletions tests/misc_tests.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -219,6 +219,23 @@ static void cjson_should_not_parse_to_deeply_nested_jsons(void)
TEST_ASSERT_NULL_MESSAGE(cJSON_Parse(deep_json), "To deep JSONs should not be parsed.");
}

static void cjson_should_not_follow_too_deep_circular_references(void)
{
cJSON *o = cJSON_CreateArray();
cJSON *a = cJSON_CreateArray();
cJSON *b = cJSON_CreateArray();
cJSON *x;

cJSON_AddItemToArray(o, a);
cJSON_AddItemToArray(a, b);
cJSON_AddItemToArray(b, o);

x = cJSON_Duplicate(o, 1);
TEST_ASSERT_NULL(x);
cJSON_DetachItemFromArray(b, 0);
cJSON_Delete(o);
}

static void cjson_set_number_value_should_set_numbers(void)
{
cJSON number[1] = {{NULL, NULL, NULL, cJSON_Number, NULL, 0, 0, NULL}};
Expand Down Expand Up @@ -744,6 +761,7 @@ int CJSON_CDECL main(void)
RUN_TEST(cjson_get_object_item_case_sensitive_should_not_crash_with_array);
RUN_TEST(typecheck_functions_should_check_type);
RUN_TEST(cjson_should_not_parse_to_deeply_nested_jsons);
RUN_TEST(cjson_should_not_follow_too_deep_circular_references);
RUN_TEST(cjson_set_number_value_should_set_numbers);
RUN_TEST(cjson_detach_item_via_pointer_should_detach_items);
RUN_TEST(cjson_replace_item_via_pointer_should_replace_items);
Expand Down