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| author | Yonghong Song <yonghong.song@linux.dev> | 2023-07-28 03:12:31 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-07-28 03:52:33 +0200 |
| commit | 4cd58e9af8b9d9fff6b7145e742abbfcda0af4af (patch) | |
| tree | 2b6a5c2980c745a2b0096f544a17b6d82bb0fc89 /kernel/bpf/verifier.c | |
| parent | bpf: Fix jit blinding with new sdiv/smov insns (diff) | |
| download | linux-4cd58e9af8b9d9fff6b7145e742abbfcda0af4af.tar.xz linux-4cd58e9af8b9d9fff6b7145e742abbfcda0af4af.zip | |
bpf: Support new 32bit offset jmp instruction
Add interpreter/jit/verifier support for 32bit offset jmp instruction.
If a conditional jmp instruction needs more than 16bit offset,
it can be simulated with a conditional jmp + a 32bit jmp insn.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011231.3716103-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | kernel/bpf/verifier.c | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c0aceedfcb9c..0b1ada93582b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2855,7 +2855,10 @@ static int check_subprogs(struct bpf_verifier_env *env) goto next; if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL) goto next; - off = i + insn[i].off + 1; + if (code == (BPF_JMP32 | BPF_JA)) + off = i + insn[i].imm + 1; + else + off = i + insn[i].off + 1; if (off < subprog_start || off >= subprog_end) { verbose(env, "jump out of range from insn %d to %d\n", i, off); return -EINVAL; @@ -2867,6 +2870,7 @@ next: * or unconditional jump back */ if (code != (BPF_JMP | BPF_EXIT) && + code != (BPF_JMP32 | BPF_JA) && code != (BPF_JMP | BPF_JA)) { verbose(env, "last insn is not an exit or jmp\n"); return -EINVAL; @@ -14792,7 +14796,7 @@ static int visit_func_call_insn(int t, struct bpf_insn *insns, static int visit_insn(int t, struct bpf_verifier_env *env) { struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t]; - int ret; + int ret, off; if (bpf_pseudo_func(insn)) return visit_func_call_insn(t, insns, env, true); @@ -14840,14 +14844,19 @@ static int visit_insn(int t, struct bpf_verifier_env *env) if (BPF_SRC(insn->code) != BPF_K) return -EINVAL; + if (BPF_CLASS(insn->code) == BPF_JMP) + off = insn->off; + else + off = insn->imm; + /* unconditional jump with single edge */ - ret = push_insn(t, t + insn->off + 1, FALLTHROUGH, env, + ret = push_insn(t, t + off + 1, FALLTHROUGH, env, true); if (ret) return ret; - mark_prune_point(env, t + insn->off + 1); - mark_jmp_point(env, t + insn->off + 1); + mark_prune_point(env, t + off + 1); + mark_jmp_point(env, t + off + 1); return ret; @@ -16643,15 +16652,18 @@ static int do_check(struct bpf_verifier_env *env) mark_reg_scratched(env, BPF_REG_0); } else if (opcode == BPF_JA) { if (BPF_SRC(insn->code) != BPF_K || - insn->imm != 0 || insn->src_reg != BPF_REG_0 || insn->dst_reg != BPF_REG_0 || - class == BPF_JMP32) { + (class == BPF_JMP && insn->imm != 0) || + (class == BPF_JMP32 && insn->off != 0)) { verbose(env, "BPF_JA uses reserved fields\n"); return -EINVAL; } - env->insn_idx += insn->off + 1; + if (class == BPF_JMP) + env->insn_idx += insn->off + 1; + else + env->insn_idx += insn->imm + 1; continue; } else if (opcode == BPF_EXIT) { @@ -17498,13 +17510,13 @@ static bool insn_is_cond_jump(u8 code) { u8 op; + op = BPF_OP(code); if (BPF_CLASS(code) == BPF_JMP32) - return true; + return op != BPF_JA; if (BPF_CLASS(code) != BPF_JMP) return false; - op = BPF_OP(code); return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL; } |