diff options
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/btf.c | 32 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 52 |
2 files changed, 72 insertions, 12 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index cf46694cb266..57f5fd5af2f9 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5686,11 +5686,13 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, bool ptr_to_mem_ok) { struct bpf_verifier_log *log = &env->log; + u32 i, nargs, ref_id, ref_obj_id = 0; bool is_kfunc = btf_is_kernel(btf); const char *func_name, *ref_tname; const struct btf_type *t, *ref_t; const struct btf_param *args; - u32 i, nargs, ref_id; + int ref_regno = 0; + bool rel = false; t = btf_type_by_id(btf, func_id); if (!t || !btf_type_is_func(t)) { @@ -5768,6 +5770,16 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, if (reg->type == PTR_TO_BTF_ID) { reg_btf = reg->btf; reg_ref_id = reg->btf_id; + /* Ensure only one argument is referenced PTR_TO_BTF_ID */ + if (reg->ref_obj_id) { + if (ref_obj_id) { + bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", + regno, reg->ref_obj_id, ref_obj_id); + return -EFAULT; + } + ref_regno = regno; + ref_obj_id = reg->ref_obj_id; + } } else { reg_btf = btf_vmlinux; reg_ref_id = *reg2btf_ids[reg->type]; @@ -5838,7 +5850,23 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, } } - return 0; + /* Either both are set, or neither */ + WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno)); + if (is_kfunc) { + rel = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog), + BTF_KFUNC_TYPE_RELEASE, func_id); + /* We already made sure ref_obj_id is set only for one argument */ + if (rel && !ref_obj_id) { + bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n", + func_name); + return -EINVAL; + } + /* Allow (!rel && ref_obj_id), so that passing such referenced PTR_TO_BTF_ID to + * other kfuncs works + */ + } + /* returns argument register number > 0 in case of reference release kfunc */ + return rel ? ref_regno : 0; } /* Compare BTF of a function with given bpf_reg_state. diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 2b186185b6b2..8c5a46d41f28 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -452,7 +452,8 @@ static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type) { return base_type(type) == PTR_TO_SOCKET || base_type(type) == PTR_TO_TCP_SOCK || - base_type(type) == PTR_TO_MEM; + base_type(type) == PTR_TO_MEM || + base_type(type) == PTR_TO_BTF_ID; } static bool type_is_rdonly_mem(u32 type) @@ -3493,11 +3494,6 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno, #define MAX_PACKET_OFF 0xffff -static enum bpf_prog_type resolve_prog_type(struct bpf_prog *prog) -{ - return prog->aux->dst_prog ? prog->aux->dst_prog->type : prog->type; -} - static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, const struct bpf_call_arg_meta *meta, enum bpf_access_type t) @@ -6845,15 +6841,17 @@ static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno, } } -static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn) +static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, + int *insn_idx_p) { const struct btf_type *t, *func, *func_proto, *ptr_type; struct bpf_reg_state *regs = cur_regs(env); const char *func_name, *ptr_type_name; u32 i, nargs, func_id, ptr_type_id; + int err, insn_idx = *insn_idx_p; const struct btf_param *args; struct btf *desc_btf; - int err; + bool acq; /* skip for now, but return error when we find this in fixup_kfunc_call */ if (!insn->imm) @@ -6875,16 +6873,36 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EACCES; } + acq = btf_kfunc_id_set_contains(desc_btf, resolve_prog_type(env->prog), + BTF_KFUNC_TYPE_ACQUIRE, func_id); + /* Check the arguments */ err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs); - if (err) + if (err < 0) return err; + /* In case of release function, we get register number of refcounted + * PTR_TO_BTF_ID back from btf_check_kfunc_arg_match, do the release now + */ + if (err) { + err = release_reference(env, regs[err].ref_obj_id); + if (err) { + verbose(env, "kfunc %s#%d reference has not been acquired before\n", + func_name, func_id); + return err; + } + } for (i = 0; i < CALLER_SAVED_REGS; i++) mark_reg_not_init(env, regs, caller_saved[i]); /* Check return type */ t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL); + + if (acq && !btf_type_is_ptr(t)) { + verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n"); + return -EINVAL; + } + if (btf_type_is_scalar(t)) { mark_reg_unknown(env, regs, BPF_REG_0); mark_btf_func_reg_size(env, BPF_REG_0, t->size); @@ -6903,7 +6921,21 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn) regs[BPF_REG_0].btf = desc_btf; regs[BPF_REG_0].type = PTR_TO_BTF_ID; regs[BPF_REG_0].btf_id = ptr_type_id; + if (btf_kfunc_id_set_contains(desc_btf, resolve_prog_type(env->prog), + BTF_KFUNC_TYPE_RET_NULL, func_id)) { + regs[BPF_REG_0].type |= PTR_MAYBE_NULL; + /* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */ + regs[BPF_REG_0].id = ++env->id_gen; + } mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *)); + if (acq) { + int id = acquire_reference_state(env, insn_idx); + + if (id < 0) + return id; + regs[BPF_REG_0].id = id; + regs[BPF_REG_0].ref_obj_id = id; + } } /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */ nargs = btf_type_vlen(func_proto); @@ -11548,7 +11580,7 @@ static int do_check(struct bpf_verifier_env *env) if (insn->src_reg == BPF_PSEUDO_CALL) err = check_func_call(env, insn, &env->insn_idx); else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) - err = check_kfunc_call(env, insn); + err = check_kfunc_call(env, insn, &env->insn_idx); else err = check_helper_call(env, insn, &env->insn_idx); if (err) |