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mirror of https://github.com/DaveGamble/cJSON synced 2024-12-24 07:32:05 +00:00

parse_string: Use parsebuffer

This commit is contained in:
Max Bruckner 2017-03-12 21:44:28 +01:00
parent f69b109c9f
commit 778a0c146f
2 changed files with 36 additions and 26 deletions

42
cJSON.c
View File

@ -662,17 +662,17 @@ fail:
} }
/* Parse the input text into an unescaped cinput, and populate item. */ /* Parse the input text into an unescaped cinput, and populate item. */
static const unsigned char *parse_string(cJSON * const item, const unsigned char * const input, const unsigned char ** const error_pointer, const internal_hooks * const hooks) static const unsigned char *parse_string(cJSON * const item, parse_buffer * const input_buffer, const unsigned char ** const error_pointer, const internal_hooks * const hooks)
{ {
const unsigned char *input_pointer = input + 1; const unsigned char *input_pointer = buffer_at_offset(input_buffer) + 1;
const unsigned char *input_end = input + 1; const unsigned char *input_end = buffer_at_offset(input_buffer) + 1;
unsigned char *output_pointer = NULL; unsigned char *output_pointer = NULL;
unsigned char *output = NULL; unsigned char *output = NULL;
/* not a string */ /* not a string */
if (*input != '\"') if (buffer_at_offset(input_buffer)[0] != '\"')
{ {
*error_pointer = input; *error_pointer = buffer_at_offset(input_buffer);
goto fail; goto fail;
} }
@ -680,12 +680,12 @@ static const unsigned char *parse_string(cJSON * const item, const unsigned char
/* calculate approximate size of the output (overestimate) */ /* calculate approximate size of the output (overestimate) */
size_t allocation_length = 0; size_t allocation_length = 0;
size_t skipped_bytes = 0; size_t skipped_bytes = 0;
while ((*input_end != '\"') && (*input_end != '\0')) while ((*input_end != '\"') && ((size_t)(input_end - input_buffer->content) < input_buffer->length))
{ {
/* is escape sequence */ /* is escape sequence */
if (input_end[0] == '\\') if (input_end[0] == '\\')
{ {
if (input_end[1] == '\0') if ((size_t)(input_end + 1 - input_buffer->content) >= input_buffer->length)
{ {
/* prevent buffer overflow when last input character is a backslash */ /* prevent buffer overflow when last input character is a backslash */
goto fail; goto fail;
@ -695,13 +695,13 @@ static const unsigned char *parse_string(cJSON * const item, const unsigned char
} }
input_end++; input_end++;
} }
if (*input_end == '\0') if (*input_end != '\"')
{ {
goto fail; /* string ended unexpectedly */ goto fail; /* string ended unexpectedly */
} }
/* This is at most how much we need for the output */ /* This is at most how much we need for the output */
allocation_length = (size_t) (input_end - input) - skipped_bytes; allocation_length = (size_t) (input_end - buffer_at_offset(input_buffer)) - skipped_bytes;
output = (unsigned char*)hooks->allocate(allocation_length + sizeof("")); output = (unsigned char*)hooks->allocate(allocation_length + sizeof(""));
if (output == NULL) if (output == NULL)
{ {
@ -721,6 +721,11 @@ static const unsigned char *parse_string(cJSON * const item, const unsigned char
else else
{ {
unsigned char sequence_length = 2; unsigned char sequence_length = 2;
if ((input_end - input_pointer) < 1)
{
goto fail;
}
switch (input_pointer[1]) switch (input_pointer[1])
{ {
case 'b': case 'b':
@ -768,7 +773,10 @@ static const unsigned char *parse_string(cJSON * const item, const unsigned char
item->type = cJSON_String; item->type = cJSON_String;
item->valuestring = (char*)output; item->valuestring = (char*)output;
return input_end + 1; input_buffer->offset = (size_t) (input_end - input_buffer->content);
input_buffer->offset++;
return buffer_at_offset(input_buffer);
fail: fail:
if (output != NULL) if (output != NULL)
@ -1141,14 +1149,7 @@ static const unsigned char *parse_value(cJSON * const item, parse_buffer * cons
/* string */ /* string */
if (can_access_at_index(input_buffer, 0) && (buffer_at_offset(input_buffer)[0] == '\"')) if (can_access_at_index(input_buffer, 0) && (buffer_at_offset(input_buffer)[0] == '\"'))
{ {
content_pointer = parse_string(item, buffer_at_offset(input_buffer), error_pointer, hooks); return content_pointer = parse_string(item, input_buffer, error_pointer, hooks);
if (content_pointer == NULL)
{
return NULL;
}
input_buffer->offset = (size_t)(content_pointer - input_buffer->content);
return buffer_at_offset(input_buffer);
} }
/* number */ /* number */
if (can_access_at_index(input_buffer, 0) && ((buffer_at_offset(input_buffer)[0] == '-') || ((buffer_at_offset(input_buffer)[0] >= '0') && (buffer_at_offset(input_buffer)[0] <= '9')))) if (can_access_at_index(input_buffer, 0) && ((buffer_at_offset(input_buffer)[0] == '-') || ((buffer_at_offset(input_buffer)[0] >= '0') && (buffer_at_offset(input_buffer)[0] <= '9'))))
@ -1422,7 +1423,6 @@ static const unsigned char *parse_object(cJSON * const item, parse_buffer * cons
{ {
cJSON *head = NULL; /* linked list head */ cJSON *head = NULL; /* linked list head */
cJSON *current_item = NULL; cJSON *current_item = NULL;
const unsigned char *content_pointer = NULL;
if (cannot_access_at_index(input_buffer, 0) || (buffer_at_offset(input_buffer)[0] != '{')) if (cannot_access_at_index(input_buffer, 0) || (buffer_at_offset(input_buffer)[0] != '{'))
{ {
@ -1474,12 +1474,10 @@ static const unsigned char *parse_object(cJSON * const item, parse_buffer * cons
/* parse the name of the child */ /* parse the name of the child */
input_buffer->offset++; input_buffer->offset++;
buffer_skip_whitespace(input_buffer); buffer_skip_whitespace(input_buffer);
content_pointer = parse_string(current_item, buffer_at_offset(input_buffer), error_pointer, hooks); if (parse_string(current_item, input_buffer, error_pointer, hooks) == NULL)
if (content_pointer == NULL)
{ {
goto fail; /* faile to parse name */ goto fail; /* faile to parse name */
} }
input_buffer->offset = (size_t)(content_pointer - input_buffer->content);
buffer_skip_whitespace(input_buffer); buffer_skip_whitespace(input_buffer);
/* swap valuestring and string, because we parsed the name */ /* swap valuestring and string, because we parsed the name */

View File

@ -47,16 +47,28 @@ static void assert_is_string(cJSON *string_item)
static void assert_parse_string(const char *string, const char *expected) static void assert_parse_string(const char *string, const char *expected)
{ {
TEST_ASSERT_NOT_NULL_MESSAGE(parse_string(item, (const unsigned char*)string, &error_pointer, &global_hooks), "Couldn't parse string."); parse_buffer buffer;
buffer.content = (const unsigned char*)string;
buffer.length = strlen(string) + sizeof("");
buffer.offset = 0;
TEST_ASSERT_NOT_NULL_MESSAGE(parse_string(item, &buffer, &error_pointer, &global_hooks), "Couldn't parse string.");
assert_is_string(item); assert_is_string(item);
TEST_ASSERT_EQUAL_STRING_MESSAGE(expected, item->valuestring, "The parsed result isn't as expected."); TEST_ASSERT_EQUAL_STRING_MESSAGE(expected, item->valuestring, "The parsed result isn't as expected.");
global_hooks.deallocate(item->valuestring); global_hooks.deallocate(item->valuestring);
item->valuestring = NULL; item->valuestring = NULL;
} }
#define assert_not_parse_string(string) \ static void assert_not_parse_string(const char * const string)
TEST_ASSERT_NULL_MESSAGE(parse_string(item, (const unsigned char*)string, &error_pointer, &global_hooks), "Malformed string should not be accepted");\ {
assert_is_invalid(item) parse_buffer buffer;
buffer.content = (const unsigned char*)string;
buffer.length = strlen(string) + sizeof("");
buffer.offset = 0;
TEST_ASSERT_NULL_MESSAGE(parse_string(item, &buffer, &error_pointer, &global_hooks), "Malformed string should not be accepted.");
assert_is_invalid(item);
}