diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a231223d985b..c2762b56e604 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1543,6 +1543,17 @@ static void release_reference_state(struct bpf_verifier_state *state, int idx) return; } +static bool find_reference_state(struct bpf_verifier_state *state, int ptr_id) +{ + int i; + + for (i = 0; i < state->acquired_refs; i++) + if (state->refs[i].id == ptr_id) + return true; + + return false; +} + static int release_lock_state(struct bpf_verifier_state *state, int type, int id, void *ptr) { int i; @@ -5981,7 +5992,8 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, /* check access to 'struct bpf_context' fields. Supports fixed offsets only */ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, enum bpf_access_type t, enum bpf_reg_type *reg_type, - struct btf **btf, u32 *btf_id, bool *is_retval, bool is_ldsx) + struct btf **btf, u32 *btf_id, bool *is_retval, bool is_ldsx, + u32 *ref_obj_id) { struct bpf_insn_access_aux info = { .reg_type = *reg_type, @@ -6003,8 +6015,16 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, *is_retval = info.is_retval; if (base_type(*reg_type) == PTR_TO_BTF_ID) { + if (info.ref_obj_id && + !find_reference_state(env->cur_state, info.ref_obj_id)) { + verbose(env, "invalid bpf_context access off=%d. Reference may already be released\n", + off); + return -EACCES; + } + *btf = info.btf; *btf_id = info.btf_id; + *ref_obj_id = info.ref_obj_id; } else { env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; } @@ -7367,7 +7387,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn struct bpf_retval_range range; enum bpf_reg_type reg_type = SCALAR_VALUE; struct btf *btf = NULL; - u32 btf_id = 0; + u32 btf_id = 0, ref_obj_id = 0; if (t == BPF_WRITE && value_regno >= 0 && is_pointer_value(env, value_regno)) { @@ -7380,7 +7400,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn return err; err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, - &btf_id, &is_retval, is_ldsx); + &btf_id, &is_retval, is_ldsx, &ref_obj_id); if (err) verbose_linfo(env, insn_idx, "; "); if (!err && t == BPF_READ && value_regno >= 0) { @@ -7411,6 +7431,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (base_type(reg_type) == PTR_TO_BTF_ID) { regs[value_regno].btf = btf; regs[value_regno].btf_id = btf_id; + regs[value_regno].ref_obj_id = ref_obj_id; } } regs[value_regno].type = reg_type; @@ -22176,6 +22197,7 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) { bool pop_log = !(env->log.level & BPF_LOG_LEVEL2); struct bpf_subprog_info *sub = subprog_info(env, subprog); + struct bpf_prog_aux *aux = env->prog->aux; struct bpf_verifier_state *state; struct bpf_reg_state *regs; int ret, i; @@ -22283,6 +22305,13 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) mark_reg_known_zero(env, regs, BPF_REG_1); } + /* Acquire references for struct_ops program arguments tagged with "__ref" */ + if (!subprog && env->prog->type == BPF_PROG_TYPE_STRUCT_OPS) { + for (i = 0; i < aux->ctx_arg_info_size; i++) + aux->ctx_arg_info[i].ref_obj_id = aux->ctx_arg_info[i].refcounted ? + acquire_reference(env, 0) : 0; + } + ret = do_check(env); out: /* check for NULL is necessary, since cur_state can be freed inside |