int extra = (strlen(current->value) - strlen(current->key));
char *next;
for (next = bufcopy;
- (next = strcasestr(bufcopy + (next - bufcopy), current->key)) != NULL;
+ next < (bufcopy + stbuf.st_size) &&
+ (next = strcasestr(next, current->key)) != NULL;
next += strlen(current->key)) {
*next = '_';
extra_bytes += extra;