From mboxrd@z Thu Jan 1 00:00:00 1970 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 59016C3A5A7 for ; Tue, 6 Dec 2022 07:14:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234070AbiLFHOz (ORCPT ); Tue, 6 Dec 2022 02:14:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231530AbiLFHOr (ORCPT ); Tue, 6 Dec 2022 02:14:47 -0500 Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3451C14D04; Mon, 5 Dec 2022 23:14:47 -0800 (PST) Received: by mail-pl1-x62b.google.com with SMTP id jn7so13080223plb.13; Mon, 05 Dec 2022 23:14:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id:from :to:cc:subject:date:message-id:reply-to; bh=AwV+aQezPrqmBi+1p608TRrRU2Dd7rb+QPCbuqXm00Y=; b=Io1NM++sncn5eRES2/jZKZmNDFCuHxRqdNKbdkNpigNzh7SEoBIzImpXdIPsY+havC CZJhgEnmVdHYPoLotanDGcdPmMeW1NA1r4YBo4d8juIQSW5H0iGPrHKFLYWa/L1c0Kkw PmZvdPrdiTIhQogbicWB7Xr7P3iPZh3WJXQLwIEIz1DpERD8mbiTHFoAuMUZHVlj8y9Y WURfOT55kx/+dqp+wwdGjyTZZjFQelCGkul6W7AG4mLzQnG64wJtO62f/7v+KWUuD+2c xQWugvy/kzhVboqUEzoMRz/5Kc6FaXSp7J0EkteABUTP6CzWr3kyYC7Bee6IWugnH5/0 bhVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=AwV+aQezPrqmBi+1p608TRrRU2Dd7rb+QPCbuqXm00Y=; b=t7ep6CpNbv58f2UptR/3bHtPjYCuw10d0LneNRa4M+dWjqExHsVSoZT85AjuO0r+hb u1eo2OvFQysbpP+1inXbbsO/9QkjaVNyVSZX/a1qm/7WzcSskec7MhNX3elBTEDW+lur xjJnVRIovfX1o6n/BgY2DfOVWiOcwezbNO2oN8X0guGe6fok33Rx1vFDQudnvy+UE1IG qLM6giDHUnElAHtvvFD+vK1uCFmfCnyXqN9ZOXwOLNcUB/T3CxTwdAk9EfN+DOUkh7Vd e7Nv1hdjoPDn0ZZ7YKsIIUyV9gsApgQkgh1AQ84of/QPMy8NQQw6BSrvJPqA9bDp3lMU DZjg== X-Gm-Message-State: ANoB5pktTyErNvDo3hYaKjXNrOIlPPHogJju6oLOSDyabKXoAje6OSuW Mu+caOOWi58J1yO+nBlShjFIRyFYU8TBxQ== X-Google-Smtp-Source: AA0mqf5njaIFBPQ0FAuyk01o8a5QFgvF/4emMR4KG5ol+LRQkLvgFF0RC6vHDP2XDLJ9vRuYRSzhxQ== X-Received: by 2002:a17:902:d1d2:b0:189:d637:cc63 with SMTP id g18-20020a170902d1d200b00189d637cc63mr8638266plb.92.1670310886580; Mon, 05 Dec 2022 23:14:46 -0800 (PST) Received: from [192.168.1.5] ([180.171.235.177]) by smtp.gmail.com with ESMTPSA id m13-20020a170902f64d00b001891ea4d133sm11753590plg.12.2022.12.05.23.14.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 05 Dec 2022 23:14:45 -0800 (PST) Message-ID: <59dd6dba-cabf-bd80-dc1e-87da9cdd1671@gmail.com> Date: Tue, 6 Dec 2022 15:14:38 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.5.1 Subject: Re: [PATCH] bpftool: Fix memory leak in do_build_table_cb To: Daniel Borkmann , Quentin Monnet , Alexei Starovoitov , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , bpf@vger.kernel.org, linux-kernel@vger.kernel.org References: <20221205081300.561974-1-linmq006@gmail.com> <8d7ac47d-5d76-eaf1-7c1e-a4418d80dac5@iogearbox.net> Content-Language: en-US From: Miaoqian Lin In-Reply-To: <8d7ac47d-5d76-eaf1-7c1e-a4418d80dac5@iogearbox.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Daniel On 2022/12/6 4:05, Daniel Borkmann wrote: > On 12/5/22 9:13 AM, Miaoqian Lin wrote: >> strdup() allocates memory for path. We need to release the memory in >> the following error paths. Add free() to avoid memory leak. >> >> Fixes: 8f184732b60b ("bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects") >> Signed-off-by: Miaoqian Lin >> --- >>   tools/bpf/bpftool/common.c | 4 +++- >>   1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c >> index 0cdb4f711510..8a820356525e 100644 >> --- a/tools/bpf/bpftool/common.c >> +++ b/tools/bpf/bpftool/common.c >> @@ -499,9 +499,11 @@ static int do_build_table_cb(const char *fpath, const struct stat *sb, >>       if (err) { >>           p_err("failed to append entry to hashmap for ID %u, path '%s': %s", >>                 pinned_info.id, path, strerror(errno)); >> -        goto out_close; >> +        goto out_free; >>       } >>   +out_free: >> +    free(path); > > It would be ok if you were to add the free(path) into the err condition, but here you > also cause the !err to be freed which would trigger as UAF. See the hashmap_insert() > where just set the pointer entry->value = .. how was this tested before submission? > Thanks for your review. You're right. Sorry for the mistake, I meant to free it in the error path. I'll send v2 to fix this. I spotted it with static detection tool. >>   out_close: >>       close(fd); >>   out_ret: >> >