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[98.227.24.213]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-90e9f0d998dsm27152966d6.9.2026.09.02.14.29.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Sep 2026 14:29:38 -0700 (PDT) Message-ID: Date: Wed, 2 Sep 2026 16:29:36 -0500 Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: sorenson@redhat.com Subject: Re: [PATCH v3 0/2] smb: client: fix out-of-bounds reads in CIFSSMBRead() To: Diego Oliva , Paulo Alcantara , Namjae Jeon Cc: Ronnie Sahlberg , Shyam Prasad N , Tom Talpey , Bharath SM , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org References: <20260902104207.1820332-1-diego@bynar.io> From: Frank Sorenson Content-Language: en-US In-Reply-To: <20260902104207.1820332-1-diego@bynar.io> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Diego, On 9/2/26 5:42 AM, Diego Oliva wrote: > CIFSSMBRead() parses the server's READ_RSP without validating either > the length of the response or the DataOffset it carries. A malicious > or compromised SMB1 server can exploit either to read past the end of > the receive buffer, leaking adjacent kernel heap into the caller's > read buffer or oopsing on unmapped memory. SMB1 is not negotiated by > default; reaching this code requires an explicit vers=1.0 mount. > > Patch 1 rejects responses too short to contain a whole READ_RSP, so > the header fields can be dereferenced safely. Patch 2 ejects a > DataOffset/DataLength pair that falls outside the received response. Your patch 2 checks that data_offset + data_length fit: + } else if ((size_t)data_offset + data_length > rsp_iov.iov_len) { but I think you may also need a lower-bound check to make sure data_offset is at least sizeof(READ_RSP): +               } else if (data_offset < sizeof(READ_RSP)) { otherwise, the data would overlap the response header itself. Frank -- Frank Sorenson sorenson@redhat.com Principal Software Maintenance Engineer, filesystems Red Hat