cxl/pci: Handle truncated CDAT header

commit 34bafc747c54fb58c1908ec3116fa6137393e596 upstream.

cxl_cdat_get_length() only checks whether the DOE response size is
sufficient for the Table Access response header (1 dword), but not the
succeeding CDAT header (1 dword length plus other fields).

It thus returns whatever uninitialized memory happens to be on the stack
if a truncated DOE response with only 1 dword was received.  Fix it.

Fixes: c97006046c79 ("cxl/port: Read CDAT table")
Reported-by: Ming Li <ming4.li@intel.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Ming Li <ming4.li@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: stable@vger.kernel.org # v6.0+
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://lore.kernel.org/r/000e69cd163461c8b1bc2cf4155b6e25402c29c7.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index c17f3c066fa20ee5509bb23d43480b432351fcb7..a091f954dec4e7c115a50c9a50090fdc53a1e258 100644 (file)
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -531,7 +531,7 @@ static int cxl_cdat_get_length(struct device *dev,
                return rc;
        }
        wait_for_completion(&t.c);
-       if (t.task.rv < sizeof(__le32))
+       if (t.task.rv < 2 * sizeof(__le32))
                return -EIO;
 
        *length = le32_to_cpu(t.response_pl[1]);