Similarly to the previous patch fixing the flow_dissector ctx accesses, nf_is_valid_access also doesn't check that ctx accesses are aligned. Contrary to flow_dissector programs, netfilter programs don't have context conversion. The unaligned ctx accesses are therefore allowed by the verifier. Fixes: fd9c663b9ad6 ("bpf: minimal support for programs hooked into netfilter framework") Signed-off-by: Paul Chaignon --- net/netfilter/nf_bpf_link.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c index 3e4fb9ddcd36..46e667a50d98 100644 --- a/net/netfilter/nf_bpf_link.c +++ b/net/netfilter/nf_bpf_link.c @@ -296,6 +296,9 @@ static bool nf_is_valid_access(int off, int size, enum bpf_access_type type, if (off < 0 || off >= sizeof(struct bpf_nf_ctx)) return false; + if (off % size != 0) + return false; + if (type == BPF_WRITE) return false; -- 2.43.0