FORTIFY_SOURCE: enhanced memcpy protections.
Two changes:
1) Detect memory read overruns.
For example:
int main() {
char buf[10];
memcpy(buf, "abcde", sizeof(buf));
sprintf("%s\n", buf);
}
because "abcde" is only 6 bytes, copying 10 bytes from it is a bug.
This particular bug will be detected at compile time. Other similar
bugs may be detected at runtime.
2) Detect overlapping buffers on memcpy()
It is a bug to call memcpy() on buffers which overlap. For
example, the following code is buggy:
char buf3[0x800];
char *first_half = &buf3[0x400];
char *second_half = &buf3[1];
memset(buf3, 0, sizeof(buf3));
memcpy(first_half, second_half, 0x400);
printf("1: %s\n", buf3);
We now detect this at compile and run time.
Change-Id: I092bd89f11f18e08e8a9dda0ca903aaea8e06d91
3 files changed