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([2001:b07:6468:f312:bb8c:429c:6de1:f4ec]) by smtp.gmail.com with ESMTPSA id p21sm5606425wmc.28.2020.10.08.00.03.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 Oct 2020 00:03:24 -0700 (PDT) Subject: Re: [PATCH v3 02/16] fuzz: Add general virtual-device fuzzer To: Alexander Bulekov , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= References: <20200921022506.873303-1-alxndr@bu.edu> <20200921022506.873303-3-alxndr@bu.edu> <63ca7622-557b-4217-f15e-ee9b024fbd77@redhat.com> <20200921143405.3taiymgzwvscxsry@mozz.bu.edu> From: Paolo Bonzini Message-ID: <74511624-33ed-ff5d-62c2-f9b2b632b39a@redhat.com> Date: Thu, 8 Oct 2020 09:03:21 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200921143405.3taiymgzwvscxsry@mozz.bu.edu> 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 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/08 02:56:27 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.742, 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: Laurent Vivier , Thomas Huth , qemu-devel@nongnu.org, darren.kenny@oracle.com, bsd@redhat.com, stefanha@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 21/09/20 16:34, Alexander Bulekov wrote: >> Can you fuzz writing "FUZZ" in memory? Like: >> OP_WRITE(0x100000, "UsingLibFUZZerString")? > No.. Hopefully that's not a huge problem. > Instead of always looking for a separator, can you: 1) skip over it if you find it naturally at the end of a command (that is, "FUZZ" is like a comment command) 2) actively search for it only if you stumble upon an unrecognized command? In that case, if you have AbcFUZZD0x100000UsingLibFUZZerFUZZ The first and third instances would be ignored, while the second would be part of the input. On the other hand if you have bcFUZZD0x100000UsingLibFUZZerFUZZ "b" is an invalid command and therefore you'd skip directly to "D". Paolo