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Commit 1969db47 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

bpf: fix verifier memory leaks 



fix verifier memory leaks

Fixes: 638f5b90 ("bpf: reduce verifier memory consumption")
Signed-off-by: default avatarAlexei Starovoitov <ast@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4bfbe53f

kernel/bpf/verifier.c

+18 −9
Original line number Diff line number Diff line
@@ -341,9 +341,11 @@ static int realloc_verifier_state(struct bpf_verifier_state *state, int size, 
	return 0;

}



static void free_verifier_state(struct bpf_verifier_state *state)

static void free_verifier_state(struct bpf_verifier_state *state,

				bool free_self)

{

	kfree(state->stack);

	if (free_self)

		kfree(state);

}
@@ -382,6 +384,7 @@ static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, 
	if (prev_insn_idx)

		*prev_insn_idx = head->prev_insn_idx;

	elem = head->next;

	free_verifier_state(&head->st, false);

	kfree(head);

	env->head = elem;

	env->stack_size--;
@@ -399,14 +402,14 @@ static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, 
	if (!elem)

		goto err;



	err = copy_verifier_state(&elem->st, cur);

	if (err)

		return NULL;

	elem->insn_idx = insn_idx;

	elem->prev_insn_idx = prev_insn_idx;

	elem->next = env->head;

	env->head = elem;

	env->stack_size++;

	err = copy_verifier_state(&elem->st, cur);

	if (err)

		goto err;

	if (env->stack_size > BPF_COMPLEXITY_LIMIT_STACK) {

		verbose(env, "BPF program is too complex\n");

		goto err;
@@ -3641,7 +3644,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) 
	struct bpf_verifier_state_list *new_sl;

	struct bpf_verifier_state_list *sl;

	struct bpf_verifier_state *cur = env->cur_state;

	int i;

	int i, err;



	sl = env->explored_states[insn_idx];

	if (!sl)
@@ -3679,7 +3682,12 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) 
		return -ENOMEM;



	/* add new state to the head of linked list */

	copy_verifier_state(&new_sl->state, cur);

	err = copy_verifier_state(&new_sl->state, cur);

	if (err) {

		free_verifier_state(&new_sl->state, false);

		kfree(new_sl);

		return err;

	}

	new_sl->next = env->explored_states[insn_idx];

	env->explored_states[insn_idx] = new_sl;

	/* connect new state to parentage chain */
@@ -4424,6 +4432,7 @@ static void free_states(struct bpf_verifier_env *env) 
		if (sl)

			while (sl != STATE_LIST_MARK) {

				sln = sl->next;

				free_verifier_state(&sl->state, false);

				kfree(sl);

				sl = sln;

			}
@@ -4494,7 +4503,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) 
	env->allow_ptr_leaks = capable(CAP_SYS_ADMIN);



	ret = do_check(env);

	free_verifier_state(env->cur_state);

	free_verifier_state(env->cur_state, true);

	env->cur_state = NULL;



skip_full_check:
@@ -4601,7 +4610,7 @@ int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, 
	env->allow_ptr_leaks = capable(CAP_SYS_ADMIN);



	ret = do_check(env);

	free_verifier_state(env->cur_state);

	free_verifier_state(env->cur_state, true);

	env->cur_state = NULL;



skip_full_check: