From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: [PATCH v2 net-next 1/6] bpf: support 8-byte metafield access Date: Wed, 31 Aug 2016 14:50:38 -0700 Message-ID: <1472680243-1326608-2-git-send-email-ast@fb.com> References: <1472680243-1326608-1-git-send-email-ast@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Peter Zijlstra , Brendan Gregg , Daniel Borkmann , Arnaldo Carvalho de Melo , Wang Nan , , , To: "David S . Miller" Return-path: In-Reply-To: <1472680243-1326608-1-git-send-email-ast@fb.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org The verifier supported only 4-byte metafields in struct __sk_buff and struct xdp_md. The metafields in upcoming struct bpf_perf_event are 8-byte to match register width in struct pt_regs. Teach verifier to recognize 8-byte metafield access. The patch doesn't affect safety of sockets and xdp programs. They check for 4-byte only ctx access before these conditions are hit. Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann --- kernel/bpf/verifier.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index abb61f3f6900..c1c9e441f0f5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2333,7 +2333,8 @@ static int do_check(struct verifier_env *env) if (err) return err; - if (BPF_SIZE(insn->code) != BPF_W) { + if (BPF_SIZE(insn->code) != BPF_W && + BPF_SIZE(insn->code) != BPF_DW) { insn_idx++; continue; } @@ -2642,9 +2643,11 @@ static int convert_ctx_accesses(struct verifier_env *env) for (i = 0; i < insn_cnt; i++, insn++) { u32 insn_delta, cnt; - if (insn->code == (BPF_LDX | BPF_MEM | BPF_W)) + if (insn->code == (BPF_LDX | BPF_MEM | BPF_W) || + insn->code == (BPF_LDX | BPF_MEM | BPF_DW)) type = BPF_READ; - else if (insn->code == (BPF_STX | BPF_MEM | BPF_W)) + else if (insn->code == (BPF_STX | BPF_MEM | BPF_W) || + insn->code == (BPF_STX | BPF_MEM | BPF_DW)) type = BPF_WRITE; else continue; -- 2.8.0