From d200cf624c9247ab52b67d34d9e198262a23df31 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 23 Jul 2020 08:08:45 +0200
Subject: [PATCH] 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 <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/bpfilter/bpfilter_kern.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 78d561f2c54da..00540457e5f4d 100644
--- 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);
}