[PATCH 03/26] bpfilter: reject kernel addresses

Christoph Hellwig <[email protected]>
Newsgroups org.kernel.vger.dccp,dev.linux.lists.bridge,dev.linux.lists.mptcp,org.kernel.vger.bpf,org.kernel.vger.linux-bluetooth,org.kernel.vger.linux-can,org.kernel.vger.linux-crypto,org.kernel.vger.linux-hams,org.kernel.vger.linux-kernel,org.kernel.vger.linux-s390,org.kernel.vger.linux-sctp,org.kernel.vger.linux-wpan,org.kernel.vger.linux-x25,org.kernel.vger.lvs-devel,org.kernel.vger.netdev,org.kernel.vger.netfilter-devel
Message-ID <[email protected]>
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]>
---
 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 78d561f2c54da7..00540457e5f4d3 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);
 }
 
-- 
2.27.0
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