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From: Alexei Starovoitov <ast@fb.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>, <netdev@vger.kernel.org>
Subject: [PATCH net] bpf/verifier: reject invalid LD_ABS | BPF_DW instruction
Date: Tue, 12 Apr 2016 10:26:19 -0700	[thread overview]
Message-ID: <1460481979-1771165-1-git-send-email-ast@fb.com> (raw)

verifier must check for reserved size bits in instruction opcode and
reject BPF_LD | BPF_ABS | BPF_DW and BPF_LD | BPF_IND | BPF_DW instructions,
otherwise interpreter will WARN_RATELIMIT on them during execution.

Fixes: ddd872bc3098 ("bpf: verifier: add checks for BPF_ABS | BPF_IND instructions")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
---
 kernel/bpf/verifier.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 2e08f8e9b771..618ef77c302a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1374,6 +1374,7 @@ static int check_ld_abs(struct verifier_env *env, struct bpf_insn *insn)
 	}
 
 	if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
+	    BPF_SIZE(insn->code) == BPF_DW ||
 	    (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
 		verbose("BPF_LD_ABS uses reserved fields\n");
 		return -EINVAL;
-- 
2.8.0

             reply	other threads:[~2016-04-12 17:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-12 17:26 Alexei Starovoitov [this message]
2016-04-14  5:32 ` [PATCH net] bpf/verifier: reject invalid LD_ABS | BPF_DW instruction David Miller

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