From 0f3adc288df8ba2ac2fea0a8e4890f9fb4cd075d Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Fri, 22 Mar 2019 09:53:59 +0800 Subject: [PATCH] bpf: track references based on is_acquire_func So far, the verifier only acquires reference tracking state for RET_PTR_TO_SOCKET_OR_NULL. Instead of extending this for every new return type which desires these semantics, acquire reference tracking state iff the called helper is an acquire function. Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 86f9cd5d1c4e..868a82ad5597 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3147,19 +3147,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn } else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) { mark_reg_known_zero(env, regs, BPF_REG_0); regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL; - if (is_acquire_function(func_id)) { - int id = acquire_reference_state(env, insn_idx); - - if (id < 0) - return id; - /* For mark_ptr_or_null_reg() */ - regs[BPF_REG_0].id = id; - /* For release_reference() */ - regs[BPF_REG_0].ref_obj_id = id; - } else { - /* For mark_ptr_or_null_reg() */ - regs[BPF_REG_0].id = ++env->id_gen; - } + regs[BPF_REG_0].id = ++env->id_gen; } else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) { mark_reg_known_zero(env, regs, BPF_REG_0); regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL; @@ -3170,9 +3158,19 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn return -EINVAL; } - if (is_ptr_cast_function(func_id)) + if (is_ptr_cast_function(func_id)) { /* For release_reference() */ regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id; + } else if (is_acquire_function(func_id)) { + int id = acquire_reference_state(env, insn_idx); + + if (id < 0) + return id; + /* For mark_ptr_or_null_reg() */ + regs[BPF_REG_0].id = id; + /* For release_reference() */ + regs[BPF_REG_0].ref_obj_id = id; + } do_refine_retval_range(regs, fn->ret_type, func_id, &meta); -- 2.30.2