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([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id y17sm6753309ejj.84.2020.12.11.03.46.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Dec 2020 03:46:03 -0800 (PST) Subject: Re: [PATCH] ide:atapi: check io_buffer_index in ide_atapi_cmd_reply_end To: Wenxiang Qian , P J P References: <20201118142745.112579-1-ppandit@redhat.com> <204751s9-11np-413q-q3pr-3o6os86078@erqung.pbz> <492170b8-8056-bd65-5150-62c6e89cb3f0@redhat.com> <933np1s-8p4p-o74p-rp94-517r98nop2o6@erqung.pbz> <87sg8o65ys.fsf@dusky.pond.sub.org> <212n55r-9n3q-8r4r-85p7-14n495r53s6n@erqung.pbz> From: Paolo Bonzini Message-ID: <9f02571c-5503-5734-b05b-9eaa7e5bcbb1@redhat.com> Date: Fri, 11 Dec 2020 12:46:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: QEMU Developers , John Snow , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , Markus Armbruster , Peter Maydell Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11/12/20 09:32, Wenxiang Qian wrote: > + The lba is set to -1 to avoid some code paths, to make PoC simpler. > > void ide_atapi_cmd_reply_end(IDEState *s) > { >     int byte_count_limit, size, ret; >     while (s->packet_transfer_size > 0) { > ..... >         if (s->lba != -1 && s->io_buffer_index >= s->cd_sector_size) { > <----- set lba to -1 to avoid this part >  ..... >         } >         if (s->elementary_transfer_size > 0) { > ...... >         } else { > ....... >             if (s->lba != -1) { <----- >                 if (size > (s->cd_sector_size - s->io_buffer_index)) >                     size = (s->cd_sector_size - s->io_buffer_index); > <----- >             } >         } > If the lba is not -1, I don't think bad things can happen on this path. Am I wrong? Paolo