[PATCH 01/24] bpfilter: reject kernel addresses

[Christoph Hellwig <hch@xxxxxx>]

When feeding addresses to userspace we can't support kernel addresses
that were fed under set_fs(KERNEL_DS) from bpf-cgroup.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 net/bpfilter/bpfilter_kern.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 2c31e82cb953af..977e9dad72ca4f 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -41,6 +41,11 @@ static int __bpfilter_process_sockopt(struct sock *sk, int 
optname,
        ssize_t n;
        int ret = -EFAULT;
 
+       if (uaccess_kernel()) {
+               pr_err("kernel access not supported\n");
+               return -EFAULT;
+       }
+
        req.is_set = is_set;
        req.pid = current->pid;
        req.cmd = optname;
-- 
2.27.0