bpfilter: reject kernel addresses

The bpfilter user mode helper processes the optval address using process_vm_readv. Don't send it kernel addresses fed under set_fs(KERNEL_DS) as that won't work. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: David S. Miller <[email protected]>
chewitt · Jul 24, 2020 · d200cf6 · d200cf6
1 parent c9ffebd
commit d200cf6
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
@@ -70,6 +70,10 @@ static int bpfilter_process_sockopt(struct sock *sk, int optname,
 		.addr		= (uintptr_t)optval,
 		.len		= optlen,
 	};
+	if (uaccess_kernel()) {
+		pr_err("kernel access not supported\n");
+		return -EFAULT;
+	}
 	return bpfilter_send_req(&req);
 }