Commit 2ed46ce4 authored Aug 11, 2017 by Daniel Borkmann Committed by David S. Miller Aug 11, 2017

bpf: fix two missing target_size settings in bpf_convert_ctx_access



When CONFIG_NET_SCHED or CONFIG_NET_RX_BUSY_POLL is /not/ set and
we try a narrow __sk_buff load of tc_index or napi_id, respectively,
then verifier rightfully complains that it's misconfigured, because
we need to set target_size in each of the two cases. The rewrite
for the ctx access is just a dummy op, but needs to pass, so fix
this up.

Fixes: f96da094 ("bpf: simplify narrower ctx access")
Reported-by: Shubham Bansal <illusionist.neo@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent e4dde412

net/core/filter.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -3505,6 +3505,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
		bpf_target_off(struct sk_buff, tc_index, 2,
		target_size));
		#else
		*target_size = 2;
		if (type == BPF_WRITE)
		*insn++ = BPF_MOV64_REG(si->dst_reg, si->dst_reg);
		else
		@@ -3520,6 +3521,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
		*insn++ = BPF_JMP_IMM(BPF_JGE, si->dst_reg, MIN_NAPI_ID, 1);
		*insn++ = BPF_MOV64_IMM(si->dst_reg, 0);
		#else
		*target_size = 4;
		*insn++ = BPF_MOV64_IMM(si->dst_reg, 0);
		#endif
		break;

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