Commit 85d31dd0 authored Nov 06, 2019 by Martin KaFai Lau Committed by Alexei Starovoitov Nov 06, 2019

bpf: Account for insn->off when doing bpf_probe_read_kernel



In the bpf interpreter mode, bpf_probe_read_kernel is used to read
from PTR_TO_BTF_ID's kernel object.  It currently missed considering
the insn->off.  This patch fixes it.

Fixes: 2a02759e ("bpf: Add support for BTF pointers to interpreter")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191107014640.384083-1-kafai@fb.com

parent ed578021

kernel/bpf/core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1569,7 +1569,7 @@ out:
		#undef LDST
		#define LDX_PROBE(SIZEOP, SIZE) \
		LDX_PROBE_MEM_##SIZEOP: \
		bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) SRC); \
		bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) (SRC + insn->off)); \
		CONT;
		LDX_PROBE(B, 1)
		LDX_PROBE(H, 2)

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