Commit 29fcb05b authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
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bpf: Undo internal BPF_PROBE_MEM in BPF insns dump 



BPF_PROBE_MEM is kernel-internal implmementation details. When dumping BPF
instructions to user-space, it needs to be replaced back with BPF_MEM mode.

Fixes: 2a02759e ("bpf: Add support for BTF pointers to interpreter")
Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200613002115.1632142-1-andriin@fb.com
parent caf62492

kernel/bpf/syscall.c

+12 −5
Original line number Diff line number Diff line
@@ -3158,6 +3158,7 @@ static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog) 
	struct bpf_insn *insns;

	u32 off, type;

	u64 imm;

	u8 code;

	int i;



	insns = kmemdup(prog->insnsi, bpf_prog_insn_size(prog),
@@ -3166,21 +3167,27 @@ static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog) 
		return insns;



	for (i = 0; i < prog->len; i++) {

		if (insns[i].code == (BPF_JMP | BPF_TAIL_CALL)) {

		code = insns[i].code;



		if (code == (BPF_JMP | BPF_TAIL_CALL)) {

			insns[i].code = BPF_JMP | BPF_CALL;

			insns[i].imm = BPF_FUNC_tail_call;

			/* fall-through */

		}

		if (insns[i].code == (BPF_JMP | BPF_CALL) ||

		    insns[i].code == (BPF_JMP | BPF_CALL_ARGS)) {

			if (insns[i].code == (BPF_JMP | BPF_CALL_ARGS))

		if (code == (BPF_JMP | BPF_CALL) ||

		    code == (BPF_JMP | BPF_CALL_ARGS)) {

			if (code == (BPF_JMP | BPF_CALL_ARGS))

				insns[i].code = BPF_JMP | BPF_CALL;

			if (!bpf_dump_raw_ok())

				insns[i].imm = 0;

			continue;

		}

		if (BPF_CLASS(code) == BPF_LDX && BPF_MODE(code) == BPF_PROBE_MEM) {

			insns[i].code = BPF_LDX | BPF_SIZE(code) | BPF_MEM;

			continue;

		}



		if (insns[i].code != (BPF_LD | BPF_IMM | BPF_DW))

		if (code != (BPF_LD | BPF_IMM | BPF_DW))

			continue;



		imm = ((u64)insns[i + 1].imm << 32) | (u32)insns[i].imm;

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