diff options
| -rw-r--r-- | include/linux/bpf_verifier.h | 4 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 64 |
2 files changed, 26 insertions, 42 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 090aa26d1c98..b129e0aaee20 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -837,7 +837,9 @@ struct bpf_verifier_env { u64 scratched_stack_slots; u64 prev_log_pos, prev_insn_print_pos; /* buffer used to temporary hold constants as scalar registers */ - struct bpf_reg_state fake_reg[2]; + struct bpf_reg_state fake_reg[1]; + /* buffers used to save updated reg states while simulating branches */ + struct bpf_reg_state true_reg1, true_reg2, false_reg1, false_reg2; /* buffer used to generate temporary string representations, * e.g., in reg_type_str() to generate reg_type string */ diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 760cd137bf3f..15defae1d7ed 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -17253,10 +17253,6 @@ static void regs_refine_cond_op(struct bpf_reg_state *reg1, struct bpf_reg_state * but we don't support that right now. */ static int reg_set_min_max(struct bpf_verifier_env *env, - struct bpf_reg_state *true_reg1, - struct bpf_reg_state *true_reg2, - struct bpf_reg_state *false_reg1, - struct bpf_reg_state *false_reg2, u8 opcode, bool is_jmp32) { int err; @@ -17265,30 +17261,23 @@ static int reg_set_min_max(struct bpf_verifier_env *env, * variable offset from the compare (unless they were a pointer into * the same object, but we don't bother with that). */ - if (false_reg1->type != SCALAR_VALUE || false_reg2->type != SCALAR_VALUE) - return 0; - - /* We compute branch direction for same SCALAR_VALUE registers in - * is_scalar_branch_taken(). For unknown branch directions (e.g., BPF_JSET) - * on the same registers, we don't need to adjust the min/max values. - */ - if (false_reg1 == false_reg2) + if (env->false_reg1.type != SCALAR_VALUE || env->false_reg2.type != SCALAR_VALUE) return 0; /* fallthrough (FALSE) branch */ - regs_refine_cond_op(false_reg1, false_reg2, rev_opcode(opcode), is_jmp32); - reg_bounds_sync(false_reg1); - reg_bounds_sync(false_reg2); + regs_refine_cond_op(&env->false_reg1, &env->false_reg2, rev_opcode(opcode), is_jmp32); + reg_bounds_sync(&env->false_reg1); + reg_bounds_sync(&env->false_reg2); /* jump (TRUE) branch */ - regs_refine_cond_op(true_reg1, true_reg2, opcode, is_jmp32); - reg_bounds_sync(true_reg1); - reg_bounds_sync(true_reg2); - - err = reg_bounds_sanity_check(env, true_reg1, "true_reg1"); - err = err ?: reg_bounds_sanity_check(env, true_reg2, "true_reg2"); - err = err ?: reg_bounds_sanity_check(env, false_reg1, "false_reg1"); - err = err ?: reg_bounds_sanity_check(env, false_reg2, "false_reg2"); + regs_refine_cond_op(&env->true_reg1, &env->true_reg2, opcode, is_jmp32); + reg_bounds_sync(&env->true_reg1); + reg_bounds_sync(&env->true_reg2); + + err = reg_bounds_sanity_check(env, &env->true_reg1, "true_reg1"); + err = err ?: reg_bounds_sanity_check(env, &env->true_reg2, "true_reg2"); + err = err ?: reg_bounds_sanity_check(env, &env->false_reg1, "false_reg1"); + err = err ?: reg_bounds_sanity_check(env, &env->false_reg2, "false_reg2"); return err; } @@ -17672,6 +17661,10 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, } is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; + copy_register_state(&env->false_reg1, dst_reg); + copy_register_state(&env->false_reg2, src_reg); + copy_register_state(&env->true_reg1, dst_reg); + copy_register_state(&env->true_reg2, src_reg); pred = is_branch_taken(dst_reg, src_reg, opcode, is_jmp32); if (pred >= 0) { /* If we get here with a dst_reg pointer type it is because @@ -17736,27 +17729,16 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, return PTR_ERR(other_branch); other_branch_regs = other_branch->frame[other_branch->curframe]->regs; - if (BPF_SRC(insn->code) == BPF_X) { - err = reg_set_min_max(env, - &other_branch_regs[insn->dst_reg], - &other_branch_regs[insn->src_reg], - dst_reg, src_reg, opcode, is_jmp32); - } else /* BPF_SRC(insn->code) == BPF_K */ { - /* reg_set_min_max() can mangle the fake_reg. Make a copy - * so that these are two different memory locations. The - * src_reg is not used beyond here in context of K. - */ - memcpy(&env->fake_reg[1], &env->fake_reg[0], - sizeof(env->fake_reg[0])); - err = reg_set_min_max(env, - &other_branch_regs[insn->dst_reg], - &env->fake_reg[0], - dst_reg, &env->fake_reg[1], - opcode, is_jmp32); - } + err = reg_set_min_max(env, opcode, is_jmp32); if (err) return err; + copy_register_state(dst_reg, &env->false_reg1); + copy_register_state(src_reg, &env->false_reg2); + copy_register_state(&other_branch_regs[insn->dst_reg], &env->true_reg1); + if (BPF_SRC(insn->code) == BPF_X) + copy_register_state(&other_branch_regs[insn->src_reg], &env->true_reg2); + if (BPF_SRC(insn->code) == BPF_X && src_reg->type == SCALAR_VALUE && src_reg->id && !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) { |