From: Andrii Nakryiko <andriin@fb.com>
Date: Fri, 12 Jun 2020 17:21:15 -0700
Subject: bpf: Undo internal BPF_PROBE_MEM in BPF insns dump
Patch-mainline: v5.8-rc1
Git-commit: 29fcb05bbf1a7008900bb9bee347bdbfc7171036
References: bsc#1155518
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: 2a02759ef5f8 ("bpf: Add support for BTF pointers to interpreter")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200613002115.1632142-1-andriin@fb.com
Acked-by: Gary Lin <glin@suse.com>
---
kernel/bpf/syscall.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2415,6 +2415,7 @@ static struct bpf_insn *bpf_insn_prepare
struct bpf_insn *insns;
u32 off, type;
u64 imm;
+ u8 code;
int i;
insns = kmemdup(prog->insnsi, bpf_prog_insn_size(prog),
@@ -2423,21 +2424,27 @@ static struct bpf_insn *bpf_insn_prepare
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;