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[118.158.218.50]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7a22ff1581dsm11484614b3a.12.2025.10.21.07.55.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Oct 2025 07:55:03 -0700 (PDT) From: Qianchang Zhao To: Namjae Jeon , Steve French Cc: Sergey Senozhatsky , Tom Talpey , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, Qianchang Zhao , stable@vger.kernel.org Subject: [PATCH] ksmbd: transport_ipc: validate payload size before reading handle Date: Tue, 21 Oct 2025 23:54:49 +0900 Message-Id: <20251021145449.473932-1-pioooooooooip@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <2025102125-petted-gristle-43a0@gregkh> References: <2025102125-petted-gristle-43a0@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" handle_response() dereferences the payload as a 4-byte handle without verifying that the declared payload size is at least 4 bytes. A malformed or truncated message from ksmbd.mountd can lead to a 4-byte read past the declared payload size. Validate the size before dereferencing. This is a minimal fix to guard the initial handle read. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and = tranport layers") Cc: stable@vger.kernel.org Reported-by: Qianchang Zhao Signed-off-by: Qianchang Zhao --- fs/smb/server/transport_ipc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index 46f87fd1ce1c..2028de4d3ddf 100644 --- a/fs/smb/server/transport_ipc.c +++ b/fs/smb/server/transport_ipc.c @@ -263,6 +263,10 @@ static void ipc_msg_handle_free(int handle) =20 static int handle_response(int type, void *payload, size_t sz) { + /* Prevent 4-byte read beyond declared payload size */ + if (sz < sizeof(unsigned int)) + return -EINVAL; + unsigned int handle =3D *(unsigned int *)payload; struct ipc_msg_table_entry *entry; int ret =3D 0; --=20 2.34.1