1 files changed, 129 insertions, 5 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index abfd57dd01e5..88c8edf67007 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -191,6 +191,7 @@ struct bpf_verifier_stack_elem {
 static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx);
 static int release_reference(struct bpf_verifier_env *env, int ref_obj_id);
 static void invalidate_non_owning_refs(struct bpf_verifier_env *env);
+static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env);
 static int ref_set_non_owning(struct bpf_verifier_env *env,
 			      struct bpf_reg_state *reg);
 
@@ -1642,6 +1643,16 @@ static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
 	reg->type &= ~PTR_MAYBE_NULL;
 }
 
+static void mark_reg_graph_node(struct bpf_reg_state *regs, u32 regno,
+				struct btf_field_graph_root *ds_head)
+{
+	__mark_reg_known_zero(&regs[regno]);
+	regs[regno].type = PTR_TO_BTF_ID | MEM_ALLOC;
+	regs[regno].btf = ds_head->btf;
+	regs[regno].btf_id = ds_head->value_btf_id;
+	regs[regno].off = ds_head->node_offset;
+}
+
 static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
 {
 	return type_is_pkt_pointer(reg->type);
@@ -6837,6 +6848,10 @@ skip_type_check:
 		meta->ret_btf_id = reg->btf_id;
 		break;
 	case ARG_PTR_TO_SPIN_LOCK:
+		if (in_rbtree_lock_required_cb(env)) {
+			verbose(env, "can't spin_{lock,unlock} in rbtree cb\n");
+			return -EACCES;
+		}
 		if (meta->func_id == BPF_FUNC_spin_lock) {
 			err = process_spin_lock(env, regno, true);
 			if (err)
@@ -7420,6 +7435,8 @@ static int set_callee_state(struct bpf_verifier_env *env,
 			    struct bpf_func_state *caller,
 			    struct bpf_func_state *callee, int insn_idx);
 
+static bool is_callback_calling_kfunc(u32 btf_id);
+
 static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 			     int *insn_idx, int subprog,
 			     set_callee_state_fn set_callee_state_cb)
@@ -7474,10 +7491,18 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 	 * interested in validating only BPF helpers that can call subprogs as
 	 * callbacks
 	 */
-	if (set_callee_state_cb != set_callee_state && !is_callback_calling_function(insn->imm)) {
-		verbose(env, "verifier bug: helper %s#%d is not marked as callback-calling\n",
-			func_id_name(insn->imm), insn->imm);
-		return -EFAULT;
+	if (set_callee_state_cb != set_callee_state) {
+		if (bpf_pseudo_kfunc_call(insn) &&
+		    !is_callback_calling_kfunc(insn->imm)) {
+			verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n",
+				func_id_name(insn->imm), insn->imm);
+			return -EFAULT;
+		} else if (!bpf_pseudo_kfunc_call(insn) &&
+			   !is_callback_calling_function(insn->imm)) { /* helper */
+			verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n",
+				func_id_name(insn->imm), insn->imm);
+			return -EFAULT;
+		}
 	}
 
 	if (insn->code == (BPF_JMP | BPF_CALL) &&
@@ -7742,6 +7767,63 @@ static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env,
 	return 0;
 }
 
+static int set_rbtree_add_callback_state(struct bpf_verifier_env *env,
+					 struct bpf_func_state *caller,
+					 struct bpf_func_state *callee,
+					 int insn_idx)
+{
+	/* void bpf_rbtree_add(struct bpf_rb_root *root, struct bpf_rb_node *node,
+	 *                     bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b));
+	 *
+	 * 'struct bpf_rb_node *node' arg to bpf_rbtree_add is the same PTR_TO_BTF_ID w/ offset
+	 * that 'less' callback args will be receiving. However, 'node' arg was release_reference'd
+	 * by this point, so look at 'root'
+	 */
+	struct btf_field *field;
+
+	field = reg_find_field_offset(&caller->regs[BPF_REG_1], caller->regs[BPF_REG_1].off,
+				      BPF_RB_ROOT);
+	if (!field || !field->graph_root.value_btf_id)
+		return -EFAULT;
+
+	mark_reg_graph_node(callee->regs, BPF_REG_1, &field->graph_root);
+	ref_set_non_owning(env, &callee->regs[BPF_REG_1]);
+	mark_reg_graph_node(callee->regs, BPF_REG_2, &field->graph_root);
+	ref_set_non_owning(env, &callee->regs[BPF_REG_2]);
+
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static bool is_rbtree_lock_required_kfunc(u32 btf_id);
+
+/* Are we currently verifying the callback for a rbtree helper that must
+ * be called with lock held? If so, no need to complain about unreleased
+ * lock
+ */
+static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env)
+{
+	struct bpf_verifier_state *state = env->cur_state;
+	struct bpf_insn *insn = env->prog->insnsi;
+	struct bpf_func_state *callee;
+	int kfunc_btf_id;
+
+	if (!state->curframe)
+		return false;
+
+	callee = state->frame[state->curframe];
+
+	if (!callee->in_callback_fn)
+		return false;
+
+	kfunc_btf_id = insn[callee->callsite].imm;
+	return is_rbtree_lock_required_kfunc(kfunc_btf_id);
+}
+
 static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
 {
 	struct bpf_verifier_state *state = env->cur_state;
@@ -8510,6 +8592,7 @@ struct bpf_kfunc_call_arg_meta {
 	bool r0_rdonly;
 	u32 ret_btf_id;
 	u64 r0_size;
+	u32 subprogno;
 	struct {
 		u64 value;
 		bool found;
@@ -8688,6 +8771,18 @@ static bool is_kfunc_arg_rbtree_node(const struct btf *btf, const struct btf_par
 	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_NODE_ID);
 }
 
+static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf,
+				  const struct btf_param *arg)
+{
+	const struct btf_type *t;
+
+	t = btf_type_resolve_func_ptr(btf, arg->type, NULL);
+	if (!t)
+		return false;
+
+	return true;
+}
+
 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
 static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
 					const struct btf *btf,
@@ -8747,6 +8842,7 @@ enum kfunc_ptr_arg_type {
 	KF_ARG_PTR_TO_BTF_ID,	     /* Also covers reg2btf_ids conversions */
 	KF_ARG_PTR_TO_MEM,
 	KF_ARG_PTR_TO_MEM_SIZE,	     /* Size derived from next argument, skip it */
+	KF_ARG_PTR_TO_CALLBACK,
 	KF_ARG_PTR_TO_RB_ROOT,
 	KF_ARG_PTR_TO_RB_NODE,
 };
@@ -8871,6 +8967,9 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
 		return KF_ARG_PTR_TO_BTF_ID;
 	}
 
+	if (is_kfunc_arg_callback(env, meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_CALLBACK;
+
 	if (argno + 1 < nargs && is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1]))
 		arg_mem_size = true;
 
@@ -9130,6 +9229,16 @@ static bool is_bpf_graph_api_kfunc(u32 btf_id)
 	return is_bpf_list_api_kfunc(btf_id) || is_bpf_rbtree_api_kfunc(btf_id);
 }
 
+static bool is_callback_calling_kfunc(u32 btf_id)
+{
+	return btf_id == special_kfunc_list[KF_bpf_rbtree_add];
+}
+
+static bool is_rbtree_lock_required_kfunc(u32 btf_id)
+{
+	return is_bpf_rbtree_api_kfunc(btf_id);
+}
+
 static bool check_kfunc_is_graph_root_api(struct bpf_verifier_env *env,
 					  enum btf_field_type head_field_type,
 					  u32 kfunc_btf_id)
@@ -9468,6 +9577,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
 		case KF_ARG_PTR_TO_RB_NODE:
 		case KF_ARG_PTR_TO_MEM:
 		case KF_ARG_PTR_TO_MEM_SIZE:
+		case KF_ARG_PTR_TO_CALLBACK:
 			/* Trusted by default */
 			break;
 		default:
@@ -9619,6 +9729,9 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
 			/* Skip next '__sz' argument */
 			i++;
 			break;
+		case KF_ARG_PTR_TO_CALLBACK:
+			meta->subprogno = reg->subprogno;
+			break;
 		}
 	}
 
@@ -9753,6 +9866,16 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 		}
 	}
 
+	if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add]) {
+		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
+					set_rbtree_add_callback_state);
+		if (err) {
+			verbose(env, "kfunc %s#%d failed callback verification\n",
+				func_name, func_id);
+			return err;
+		}
+	}
+
 	for (i = 0; i < CALLER_SAVED_REGS; i++)
 		mark_reg_not_init(env, regs, caller_saved[i]);
 
@@ -14621,7 +14744,8 @@ static int do_check(struct bpf_verifier_env *env)
 					return -EINVAL;
 				}
 
-				if (env->cur_state->active_lock.ptr) {
+				if (env->cur_state->active_lock.ptr &&
+				    !in_rbtree_lock_required_cb(env)) {
 					verbose(env, "bpf_spin_unlock is missing\n");
 					return -EINVAL;
 				}