libnvdimm: Fix security issue with DSM IOCTL.

commit 07accfa9d1a8bac8262f6d24a94a54d2d1f35149 upstream.

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).

Signed-off-by: Jerry Hoemann <jerry.hoemann@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 7e2c43f701bc451463c5273ed3a5a1e49f6be15f..496b9b662dc6efd4e2dd8bc76f96183dd4e45c7e 100644 (file)
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -513,10 +513,10 @@ 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));