Messages in this thread | | | Date | Thu, 11 May 2023 15:17:11 +0200 | Subject | Re: [PATCH] scsi: Let scsi_execute_cmd() mark args->sshdr as invalid | From | Juergen Gross <> |
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On 11.05.23 15:10, Martin Wilck wrote: > 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@vger.kernel.org >> Fixes: 3949e2f04262 ("scsi: simplify scsi_execute_req_flags") >> Signed-off-by: Juergen Gross <jgross@suse.com> >> --- >> 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.
I fail to see why zeroing a single byte would be less efficient than zeroing a possibly unaligned 8-byte area.
Juergen [unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |