tree 32df8eca11e248b8ae89d869a89bbd12a853f377
parent 354b45fff90c3448c1eadabfad6ae7b8b8a2a237
author Clément Lecigne <clement.lecigne@netasq.com> 1234486749 -0800
committer David S. Miller <davem@davemloft.net> 1234486749 -0800

net: 4 bytes kernel memory disclosure in SO_BSDCOMPAT gsopt try #2

In function sock_getsockopt() located in net/core/sock.c, optval v.val
is not correctly initialized and directly returned in userland in case
we have SO_BSDCOMPAT option set.

This dummy code should trigger the bug:

int main(void)
{
	unsigned char buf[4] = { 0, 0, 0, 0 };
	int len;
	int sock;
	sock = socket(33, 2, 2);
	getsockopt(sock, 1, SO_BSDCOMPAT, &buf, &len);
	printf("%x%x%x%x\n", buf[0], buf[1], buf[2], buf[3]);
	close(sock);
}

Here is a patch that fix this bug by initalizing v.val just after its
declaration.

Signed-off-by: Clément Lecigne <clement.lecigne@netasq.com>
Signed-off-by: David S. Miller <davem@davemloft.net>