libnvdimm: Fix security issue with DSM IOCTL.

Code attempts to prevent certain IOCTL DSM from being called
when device is opened read only.  This security feature can
be trivially overcome by changing the size portion of the
ioctl_command which isn't used.

Check only the _IOC_NR (i.e. the command).

Cc: <stable@vger.kernel.org>
Signed-off-by: Jerry Hoemann <jerry.hoemann@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Jerry Hoemann 2016-01-06 16:03:41 -07:00 коммит произвёл Dan Williams
Родитель 4dc0e7be88
Коммит 07accfa9d1
1 изменённых файлов: 4 добавлений и 4 удалений

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@ -547,10 +547,10 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
/* fail write commands (when read-only) */
if (read_only)
switch (ioctl_cmd) {
case ND_IOCTL_VENDOR:
case ND_IOCTL_SET_CONFIG_DATA:
case ND_IOCTL_ARS_START:
switch (cmd) {
case ND_CMD_VENDOR:
case ND_CMD_SET_CONFIG_DATA:
case ND_CMD_ARS_START:
dev_dbg(&nvdimm_bus->dev, "'%s' command while read-only.\n",
nvdimm ? nvdimm_cmd_name(cmd)
: nvdimm_bus_cmd_name(cmd));