...
| Code Block |
|---|
struct buffer {
size_t size;
char buffer[50];
};
...
void func(struct buffer *buf) {
/* assuming sizeof(size_t) is 4, this equals 54 */
struct buffer *buf_cpy = malloc((sizeof(size_t)+(sizeof(char)*50)));
if (buf_cpy == NULL) {
/* Handle malloc() error */
}
...
/* with padding, sizeof(struct buffer) may be greater than 54, causing in a small buffer overflow */
memcpy(buf_cpy, buf, sizeof(struct buffer));
}
|
Compliant Solution
Structure padding should be accounted for when working with structuresAccounting for structure padding prevents these types of errors.
| Code Block |
|---|
struct buffer {
size_t size;
char buffer[50];
};
...
void func(struct buffer *buf) {
struct buffer *buf_cpy = malloc((sizeof(struct buffer));
if (buf_cpy == NULL) {
/* Handle malloc() error */
}
...
memcpy(buf_cpy, buf, sizeof(struct buffer));
}
|