On Thu, 2023-05-11 at 14:34 +0200, Juergen Gross wrote:
> Some callers of scsi_execute_cmd() (like e.g. sd_spinup_disk()) are
> passing an uninitialized struct sshdr and don't look at the return
> value of scsi_execute_cmd() before looking at the contents of that
> struct.
>
> This can result in false positives when looking for specific error
> conditions.
>
> In order to fix that let scsi_execute_cmd() zero sshdr-
> >response_code,
> resulting in scsi_sense_valid() returning false.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 3949e2f04262 ("scsi: simplify scsi_execute_req_flags")
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> ---
> I'm not aware of any real error having happened due to this problem,
> but I thought it should be fixed anyway.
> I _think_ 3949e2f04262 was introducing the problem, but I'm not 100%
> sure it is really the commit to be blamed.
> ---
> drivers/scsi/scsi_lib.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
One nitpick below, otherwise it looks good to me.
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index b7c569a42aa4..923336620bff 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -209,11 +209,17 @@ int scsi_execute_cmd(struct scsi_device *sdev,
> const unsigned char *cmd,
> struct scsi_cmnd *scmd;
> int ret;
>
> - if (!args)
> + if (!args) {
> args = &default_args;
> - else if (WARN_ON_ONCE(args->sense &&
> - args->sense_len !=
> SCSI_SENSE_BUFFERSIZE))
> - return -EINVAL;
> + } else {
> + /* Mark sense data to be invalid. */
> + if (args->sshdr)
> + args->sshdr->response_code = 0;
We know for certain that sizeof(*sshdr) is 8 bytes, and will most
probably remain so. Thus
memset(sshdr, 0, sizeof(*sshdr))
would result in more efficient code.
Martin
