| Message ID | 1246310665-31727-1-git-send-email-gwendal@google.com |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
On Mon, 29 Jun 2009 14:24:25 -0700 Gwendal Grignou <gwendal@google.com> wrote: > We can already send ATA specific commands using /dev/sd device files. > This patch allow to use /dev/sg device files as well. That seems a very very bad idea. The point of the filters is only to allow through commands that are safe for all users with read or write permission to use. Backdooring it with arbitary passthrough ATA12/ATA16 commands doesn't seem very wise. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Alan Cox wrote: > On Mon, 29 Jun 2009 14:24:25 -0700 > Gwendal Grignou <gwendal@google.com> wrote: > >> We can already send ATA specific commands using /dev/sd device files. >> This patch allow to use /dev/sg device files as well. > > That seems a very very bad idea. The point of the filters is only to > allow through commands that are safe for all users with read or write > permission to use. > > Backdooring it with arbitary passthrough ATA12/ATA16 commands doesn't > seem very wise. Indeed. This pretty much defeats the filter for all ATA commands, including ones that can brick your drive. Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Sorry for the noise: I thought I needed that change to send ATA passthrough commands as root. The change is indeed useless and dangerous. Gwendal. On Mon, Jun 29, 2009 at 4:26 PM, Jeff Garzik<jeff@garzik.org> wrote: > Alan Cox wrote: >> >> On Mon, 29 Jun 2009 14:24:25 -0700 >> Gwendal Grignou <gwendal@google.com> wrote: >> >>> We can already send ATA specific commands using /dev/sd device files. >>> This patch allow to use /dev/sg device files as well. >> >> That seems a very very bad idea. The point of the filters is only to >> allow through commands that are safe for all users with read or write >> permission to use. >> >> Backdooring it with arbitary passthrough ATA12/ATA16 commands doesn't >> seem very wise. > > Indeed. This pretty much defeats the filter for all ATA commands, including > ones that can brick your drive. > > Jeff > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Strange, my utilities and packages like smartmontools have been sending them through for at least three years. I presume this patch allows non-root users to send these commands. Might there be security implications if ATA WRITE commands are sent through? Non-root users would still need permissions on the sg device node (e.g. /dev/sg1). Doug Gilbert Gwendal Grignou wrote: > We can already send ATA specific commands using /dev/sd device files. > This patch allow to use /dev/sg device files as well. > > Signed-off-by: Gwendal Grignou <gwendal@google.com> > --- > block/scsi_ioctl.c | 6 ++++++ > 1 files changed, 6 insertions(+), 0 deletions(-) > > diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c > index 82a0ca2..93fa53e 100644 > --- a/block/scsi_ioctl.c > +++ b/block/scsi_ioctl.c > @@ -186,6 +186,12 @@ void blk_set_cmd_filter_defaults(struct blk_cmd_filter *filter) > __set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok); > __set_bit(GPCMD_SET_STREAMING, filter->write_ok); > __set_bit(GPCMD_SET_READ_AHEAD, filter->write_ok); > + > + /* ATA Passthrough */ > + __set_bit(ATA_12, filter->read_ok); > + __set_bit(ATA_12, filter->write_ok); > + __set_bit(ATA_16, filter->read_ok); > + __set_bit(ATA_16, filter->write_ok); > } > EXPORT_SYMBOL_GPL(blk_set_cmd_filter_defaults); > -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c index 82a0ca2..93fa53e 100644 --- a/block/scsi_ioctl.c +++ b/block/scsi_ioctl.c @@ -186,6 +186,12 @@ void blk_set_cmd_filter_defaults(struct blk_cmd_filter *filter) __set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok); __set_bit(GPCMD_SET_STREAMING, filter->write_ok); __set_bit(GPCMD_SET_READ_AHEAD, filter->write_ok); + + /* ATA Passthrough */ + __set_bit(ATA_12, filter->read_ok); + __set_bit(ATA_12, filter->write_ok); + __set_bit(ATA_16, filter->read_ok); + __set_bit(ATA_16, filter->write_ok); } EXPORT_SYMBOL_GPL(blk_set_cmd_filter_defaults);
We can already send ATA specific commands using /dev/sd device files. This patch allow to use /dev/sg device files as well. Signed-off-by: Gwendal Grignou <gwendal@google.com> --- block/scsi_ioctl.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-)