net/flow_dissector: correctly cap nhoff and thoff in case of BPF
authorStanislav Fomichev <sdf@google.com>
Thu, 6 Dec 2018 04:40:48 +0000 (20:40 -0800)
committerAlexei Starovoitov <ast@kernel.org>
Fri, 7 Dec 2018 21:38:29 +0000 (13:38 -0800)
commitec3d837aac5dca7cb8a69c9f101690c182da79c4
treeb4943b459ce0aa731a75f27543b536fc8ba070bd
parent13e56ec2cc9860aa22e01ffc7a3160f35a96b728
net/flow_dissector: correctly cap nhoff and thoff in case of BPF

We want to make sure that the following condition holds:
0 <= nhoff <= thoff <= skb->len

BPF program can set out-of-bounds nhoff and thoff, which is dangerous, see
recent commit d0c081b49137 ("flow_dissector: properly cap thoff field")'.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
net/core/flow_dissector.c