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From: Alexei Starovoitov <ast@fb.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Brendan Gregg <bgregg@netflix.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Wang Nan <wangnan0@huawei.com>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <kernel-team@fb.com>
Subject: [PATCH v3 net-next 1/6] bpf: support 8-byte metafield access
Date: Thu, 1 Sep 2016 18:37:21 -0700	[thread overview]
Message-ID: <1472780246-323814-2-git-send-email-ast@fb.com> (raw)
In-Reply-To: <1472780246-323814-1-git-send-email-ast@fb.com>

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 <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
---
 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

  reply	other threads:[~2016-09-02  1:37 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-02  1:37 [PATCH v3 net-next 0/6] perf, bpf: add support for bpf in sw/hw perf_events Alexei Starovoitov
2016-09-02  1:37 ` Alexei Starovoitov [this message]
2016-09-02  1:37 ` [PATCH v3 net-next 2/6] bpf: introduce BPF_PROG_TYPE_PERF_EVENT program type Alexei Starovoitov
2016-09-02  1:37 ` [PATCH v3 net-next 3/6] bpf: perf_event progs should only use preallocated maps Alexei Starovoitov
2016-09-02  1:37 ` [PATCH v3 net-next 4/6] perf, bpf: add perf events core support for BPF_PROG_TYPE_PERF_EVENT programs Alexei Starovoitov
2016-09-02  1:37 ` [PATCH v3 net-next 5/6] samples/bpf: add perf_event+bpf example Alexei Starovoitov
2016-09-02  1:37 ` [PATCH v3 net-next 6/6] samples/bpf: add sampleip example Alexei Starovoitov
2016-09-02  9:32 ` [PATCH v3 net-next 0/6] perf, bpf: add support for bpf in sw/hw perf_events Peter Zijlstra
2016-09-02 17:56 ` David Miller

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