From patchwork Thu Oct 27 10:23:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: wangyufen X-Patchwork-Id: 13021878 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E04DFA373D for ; Thu, 27 Oct 2022 10:03:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235039AbiJ0KDd (ORCPT ); Thu, 27 Oct 2022 06:03:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234997AbiJ0KDO (ORCPT ); Thu, 27 Oct 2022 06:03:14 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD51D48CAC; Thu, 27 Oct 2022 03:02:59 -0700 (PDT) Received: from canpemm500010.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Myh3j1T3qzpVxx; Thu, 27 Oct 2022 17:59:29 +0800 (CST) Received: from localhost.localdomain (10.175.112.70) by canpemm500010.china.huawei.com (7.192.105.118) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 27 Oct 2022 18:02:55 +0800 From: Wang Yufen To: , CC: , , , , , , Subject: [PATCH net] bpf: Fix memory leaks in __check_func_call Date: Thu, 27 Oct 2022 18:23:33 +0800 Message-ID: <1666866213-4394-1-git-send-email-wangyufen@huawei.com> X-Mailer: git-send-email 1.8.3.1 MIME-Version: 1.0 X-Originating-IP: [10.175.112.70] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500010.china.huawei.com (7.192.105.118) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org kmemleak reports this issue: unreferenced object 0xffff88817139d000 (size 2048): comm "test_progs", pid 33246, jiffies 4307381979 (age 45851.820s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<0000000045f075f0>] kmalloc_trace+0x27/0xa0 [<0000000098b7c90a>] __check_func_call+0x316/0x1230 [<00000000b4c3c403>] check_helper_call+0x172e/0x4700 [<00000000aa3875b7>] do_check+0x21d8/0x45e0 [<000000001147357b>] do_check_common+0x767/0xaf0 [<00000000b5a595b4>] bpf_check+0x43e3/0x5bc0 [<0000000011e391b1>] bpf_prog_load+0xf26/0x1940 [<0000000007f765c0>] __sys_bpf+0xd2c/0x3650 [<00000000839815d6>] __x64_sys_bpf+0x75/0xc0 [<00000000946ee250>] do_syscall_64+0x3b/0x90 [<0000000000506b7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd The root case here is: In function prepare_func_exit(), the callee is not released in the abnormal scenario after "state->curframe--;". In addition, function __check_func_call() has a similar problem. In the abnormal scenario before "state->curframe++;", the callee is alse not released. Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") Fixes: fd978bf7fd31 ("bpf: Add reference tracking to verifier") Signed-off-by: Wang Yufen --- kernel/bpf/verifier.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 014ee09..bff8477 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6736,11 +6736,11 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn /* Transfer references to the callee */ err = copy_reference_state(callee, caller); if (err) - return err; + goto err; err = set_callee_state_cb(env, caller, callee, *insn_idx); if (err) - return err; + goto err; clear_caller_saved_regs(env, caller->regs); @@ -6757,6 +6757,10 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn print_verifier_state(env, callee, true); } return 0; + +err: + kfree(callee); + return err; } int map_set_for_each_callback_args(struct bpf_verifier_env *env, @@ -6954,7 +6958,7 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) struct bpf_verifier_state *state = env->cur_state; struct bpf_func_state *caller, *callee; struct bpf_reg_state *r0; - int err; + int ret; callee = state->frame[state->curframe]; r0 = &callee->regs[BPF_REG_0]; @@ -6977,11 +6981,13 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) if (r0->type != SCALAR_VALUE) { verbose(env, "R0 not a scalar value\n"); - return -EACCES; + ret = -EACCES; + goto out; } if (!tnum_in(range, r0->var_off)) { verbose_invalid_scalar(env, r0, &range, "callback return", "R0"); - return -EINVAL; + ret = -EINVAL; + goto out; } } else { /* return to the caller whatever r0 had in the callee */ @@ -6995,9 +7001,9 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) */ if (!callee->in_callback_fn) { /* Transfer references to the caller */ - err = copy_reference_state(caller, callee); - if (err) - return err; + ret = copy_reference_state(caller, callee); + if (ret) + goto out; } *insn_idx = callee->callsite + 1; @@ -7008,9 +7014,10 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) print_verifier_state(env, caller, true); } /* clear everything in the callee */ +out: free_func_state(callee); state->frame[state->curframe + 1] = NULL; - return 0; + return ret; } static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,