[PATCH stable 4.20 01/10] bpf: move {prev_, }insn_idx into verifier env

[ commit c08435ec7f2bc8f4109401f696fd55159b4b40cb upstream ]

Move prev_insn_idx and insn_idx from the do_check() function into the verifier environment, so they can be read inside the various helper functions for handling the instructions. It's easier to put this into the environment rather than changing all call-sites only to pass it along. insn_idx is useful in particular since this later on allows to hold state in env->insn_aux_data[env->insn_idx].

Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net --- include/linux/bpf_verifier.h | 2 + kernel/bpf/verifier.c | 74 ++++++++++++++++++------------------ 2 files changed, 39 insertions(+), 37 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index d93e89761a8b..b01edd2aaa7b 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -210,6 +210,8 @@ struct bpf_subprog_info { * one verifier_env per bpf_check() call */ struct bpf_verifier_env { + u32 insn_idx; + u32 prev_insn_idx; struct bpf_prog *prog; /* eBPF program being verified */ const struct bpf_verifier_ops *ops; struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 51ba84d4d34a..88b57c518620 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5172,7 +5172,6 @@ static int do_check(struct bpf_verifier_env *env) struct bpf_insn *insns = env->prog->insnsi; struct bpf_reg_state *regs; int insn_cnt = env->prog->len, i; - int insn_idx, prev_insn_idx = 0; int insn_processed = 0; bool do_print_state = false;

@@ -5190,19 +5189,19 @@ static int do_check(struct bpf_verifier_env *env) BPF_MAIN_FUNC /* callsite */, 0 /* frameno */, 0 /* subprogno, zero == main subprog */); - insn_idx = 0; + for (;;) { struct bpf_insn *insn; u8 class; int err;

- if (insn_idx >= insn_cnt) { + if (env->insn_idx >= insn_cnt) { verbose(env, "invalid insn idx %d insn_cnt %d\n", - insn_idx, insn_cnt); + env->insn_idx, insn_cnt); return -EFAULT; }

- insn = &insns[insn_idx]; + insn = &insns[env->insn_idx]; class = BPF_CLASS(insn->code);

if (++insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) { @@ -5212,7 +5211,7 @@ static int do_check(struct bpf_verifier_env *env) return -E2BIG; }

- err = is_state_visited(env, insn_idx); + err = is_state_visited(env, env->insn_idx); if (err < 0) return err; if (err == 1) { @@ -5220,9 +5219,9 @@ static int do_check(struct bpf_verifier_env *env) if (env->log.level) { if (do_print_state) verbose(env, "\nfrom %d to %d: safe\n", - prev_insn_idx, insn_idx); + env->prev_insn_idx, env->insn_idx); else - verbose(env, "%d: safe\n", insn_idx); + verbose(env, "%d: safe\n", env->insn_idx); } goto process_bpf_exit; } @@ -5235,10 +5234,10 @@ static int do_check(struct bpf_verifier_env *env)

if (env->log.level > 1 || (env->log.level && do_print_state)) { if (env->log.level > 1) - verbose(env, "%d:", insn_idx); + verbose(env, "%d:", env->insn_idx); else verbose(env, "\nfrom %d to %d:", - prev_insn_idx, insn_idx); + env->prev_insn_idx, env->insn_idx); print_verifier_state(env, state->frame[state->curframe]); do_print_state = false; } @@ -5249,19 +5248,19 @@ static int do_check(struct bpf_verifier_env *env) .private_data = env, };

- verbose(env, "%d: ", insn_idx); + verbose(env, "%d: ", env->insn_idx); print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); }

if (bpf_prog_is_dev_bound(env->prog->aux)) { - err = bpf_prog_offload_verify_insn(env, insn_idx, - prev_insn_idx); + err = bpf_prog_offload_verify_insn(env, env->insn_idx, + env->prev_insn_idx); if (err) return err; }

regs = cur_regs(env); - env->insn_aux_data[insn_idx].seen = true; + env->insn_aux_data[env->insn_idx].seen = true;

if (class == BPF_ALU || class == BPF_ALU64) { err = check_alu_op(env, insn); @@ -5287,13 +5286,13 @@ static int do_check(struct bpf_verifier_env *env) /* check that memory (src_reg + off) is readable, * the state of dst_reg will be updated by this func */ - err = check_mem_access(env, insn_idx, insn->src_reg, insn->off, - BPF_SIZE(insn->code), BPF_READ, - insn->dst_reg, false); + err = check_mem_access(env, env->insn_idx, insn->src_reg, + insn->off, BPF_SIZE(insn->code), + BPF_READ, insn->dst_reg, false); if (err) return err;

- prev_src_type = &env->insn_aux_data[insn_idx].ptr_type; + prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type;

if (*prev_src_type == NOT_INIT) { /* saw a valid insn @@ -5318,10 +5317,10 @@ static int do_check(struct bpf_verifier_env *env) enum bpf_reg_type *prev_dst_type, dst_reg_type;

if (BPF_MODE(insn->code) == BPF_XADD) { - err = check_xadd(env, insn_idx, insn); + err = check_xadd(env, env->insn_idx, insn); if (err) return err; - insn_idx++; + env->insn_idx++; continue; }

@@ -5337,13 +5336,13 @@ static int do_check(struct bpf_verifier_env *env) dst_reg_type = regs[insn->dst_reg].type;

/* check that memory (dst_reg + off) is writeable */ - err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, - BPF_SIZE(insn->code), BPF_WRITE, - insn->src_reg, false); + err = check_mem_access(env, env->insn_idx, insn->dst_reg, + insn->off, BPF_SIZE(insn->code), + BPF_WRITE, insn->src_reg, false); if (err) return err;

- prev_dst_type = &env->insn_aux_data[insn_idx].ptr_type; + prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type;

if (*prev_dst_type == NOT_INIT) { *prev_dst_type = dst_reg_type; @@ -5371,9 +5370,9 @@ static int do_check(struct bpf_verifier_env *env) }

/* check that memory (dst_reg + off) is writeable */ - err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, - BPF_SIZE(insn->code), BPF_WRITE, - -1, false); + err = check_mem_access(env, env->insn_idx, insn->dst_reg, + insn->off, BPF_SIZE(insn->code), + BPF_WRITE, -1, false); if (err) return err;

@@ -5391,9 +5390,9 @@ static int do_check(struct bpf_verifier_env *env) }

if (insn->src_reg == BPF_PSEUDO_CALL) - err = check_func_call(env, insn, &insn_idx); + err = check_func_call(env, insn, &env->insn_idx); else - err = check_helper_call(env, insn->imm, insn_idx); + err = check_helper_call(env, insn->imm, env->insn_idx); if (err) return err;

@@ -5406,7 +5405,7 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; }

- insn_idx += insn->off + 1; + env->insn_idx += insn->off + 1; continue;

} else if (opcode == BPF_EXIT) { @@ -5420,8 +5419,8 @@ static int do_check(struct bpf_verifier_env *env)

if (state->curframe) { /* exit from nested function */ - prev_insn_idx = insn_idx; - err = prepare_func_exit(env, &insn_idx); + env->prev_insn_idx = env->insn_idx; + err = prepare_func_exit(env, &env->insn_idx); if (err) return err; do_print_state = true; @@ -5451,7 +5450,8 @@ static int do_check(struct bpf_verifier_env *env) if (err) return err; process_bpf_exit: - err = pop_stack(env, &prev_insn_idx, &insn_idx); + err = pop_stack(env, &env->prev_insn_idx, + &env->insn_idx); if (err < 0) { if (err != -ENOENT) return err; @@ -5461,7 +5461,7 @@ static int do_check(struct bpf_verifier_env *env) continue; } } else { - err = check_cond_jmp_op(env, insn, &insn_idx); + err = check_cond_jmp_op(env, insn, &env->insn_idx); if (err) return err; } @@ -5478,8 +5478,8 @@ static int do_check(struct bpf_verifier_env *env) if (err) return err;

- insn_idx++; - env->insn_aux_data[insn_idx].seen = true; + env->insn_idx++; + env->insn_aux_data[env->insn_idx].seen = true; } else { verbose(env, "invalid BPF_LD mode\n"); return -EINVAL; @@ -5489,7 +5489,7 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; }

- insn_idx++; + env->insn_idx++; }

verbose(env, "processed %d insns (limit %d), stack depth ",