From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: [PATCH net-next] bpf: fix verifier memory leaks Date: Wed, 1 Nov 2017 00:08:04 -0700 Message-ID: <20171101070804.1848191-1-ast@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Daniel Borkmann , Edward Cree , Jakub Kicinski , , To: "David S . Miller" Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:42014 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716AbdKAHIG (ORCPT ); Wed, 1 Nov 2017 03:08:06 -0400 Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vA173UHT025264 for ; Wed, 1 Nov 2017 00:08:05 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2dy4rasbxp-2 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 01 Nov 2017 00:08:05 -0700 Sender: netdev-owner@vger.kernel.org List-ID: fix verifier memory leaks Fixes: 638f5b90d460 ("bpf: reduce verifier memory consumption") Signed-off-by: Alexei Starovoitov --- while re-reviewing my own code noticed few memory leaks. Sorry rushed the rewrite stack[0] into *stack too fast. Used kasan only and didn't test it with kmemleak. Now kmemleak+kasan are clean. --- kernel/bpf/verifier.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5f26f7ad124f..2bb6d6aa7085 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -341,10 +341,12 @@ 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); - kfree(state); + if (free_self) + kfree(state); } /* copy verifier state from src to dst growing dst stack space @@ -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: -- 2.9.5