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Mon, 06 Jul 2026 10:13:57 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7eb544fcb1csm12057174a34.23.2026.07.06.10.13.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Jul 2026 10:13:56 -0700 (PDT) Message-ID: Date: Mon, 6 Jul 2026 11:13:55 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1] io_uring: fix dangling iovec after provided-buffer bundle grow failure To: Hao-Yu Yang Cc: linux-kernel@vger.kernel.org, io-uring@vger.kernel.org References: <20260705234534.768138-1-naup96721@gmail.com> <0a370728-f8be-4aaa-bbc6-276376adc5ce@kernel.dk> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/6/26 11:01 AM, Hao-Yu Yang wrote: > Sorry, i forgot to cc others mail > > I discovered and wrote the PoC myself. Trigger way is > send1: Submit an IORING_OP_SEND request with four valid > provided buffers. The system will allocate and cache an > iovec array (of size 4) for this request and store the > pointer in kmsg->vec.iovec. > > send2: Submit a second send request with 8, and I set > the fourth passed-in address to point to an invalid address. > Now kmsg still hold old iovec, but old iovec object have > been freed. > > So this will lead dangling pointer. Side note: please don't top post, linux mailing lists always reply under the text for better readability. Top posting turns any kind of threaded conversation into both a mess, and it's also wasteful. Great thanks! Want to turn this into a liburing test case? Then we can include it there as well, and it'd catch both UAF and memory leaks when run. -- Jens Axboe