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[61.239.74.230]) by smtp.gmail.com with ESMTPSA id t9-20020a170902bc4900b001d3aafd228dsm397249plz.75.2023.12.20.18.14.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 20 Dec 2023 18:14:17 -0800 (PST) Message-ID: Date: Thu, 21 Dec 2023 10:14:09 +0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] net: sched: em_text: fix possible memory leak in em_text_destroy() To: Jamal Hadi Salim Cc: xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, tgraf@suug.ch, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20231220030838.11751-1-hbh25y@gmail.com> Content-Language: en-US From: Hangyu Hua In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 21/12/2023 00:05, Jamal Hadi Salim wrote: > On Wed, Dec 20, 2023 at 6:55 AM Jamal Hadi Salim wrote: >> >> Hi Hangyu, >> While the fix looks correct - can you please describe how you came >> across this issue? Was it a tool or by inspection? Do you have a text >> case that triggered something etc, etc. I discovered this accidentally when I used gdb to debug a program that uses em_text. And I think putting the code in the commit log will will make it too bulky. >> >> On Tue, Dec 19, 2023 at 10:09 PM Hangyu Hua wrote: >>> >>> m->data needs to be freed when em_text_destroy is called. >>> >>> Fixes: d675c989ed2d ("[PKT_SCHED]: Packet classification based on textsearch (ematch)") >>> Signed-off-by: Hangyu Hua >>> --- >>> net/sched/em_text.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/net/sched/em_text.c b/net/sched/em_text.c >>> index 6f3c1fb2fb44..b9d5d4dca2c9 100644 >>> --- a/net/sched/em_text.c >>> +++ b/net/sched/em_text.c >>> @@ -97,8 +97,10 @@ static int em_text_change(struct net *net, void *data, int len, >>> >>> static void em_text_destroy(struct tcf_ematch *m) >>> { >>> - if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) >>> + if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) { >>> textsearch_destroy(EM_TEXT_PRIV(m)->config); >>> + kfree(m->data); >>> + } >>> } >>> >> > > the bot just complained about needing a cast, use this: > struct text_match * I see. I will send a v2 later. Thanks, Hangyu > > cheers, > jamal >> Acked-by: Jamal Hadi Salim >> >> cheers, >> jamal >> >>> static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m) >>> -- >>> 2.34.1 >>>