From: Dan Carpenter <[email protected]>

[ Upstream commit f84afbdd3a9e5e10633695677b95422572f920dc ]

The "cmd" comes from the user and it can be up to 255.  It it's more
than the number of bits in long, it results out of bounds read when we
check test_bit(cmd, &cmd_mask).  The highest valid value for "cmd" is
ND_CMD_CALL (10) so I added a compare against that.

Fixes: 62232e45f4a2 ("libnvdimm: control (ioctl) messages for nvdimm_bus and 
nvdimm devices")
Signed-off-by: Dan Carpenter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/nvdimm/bus.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index a8b5159685699..09087c38fabdc 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -1042,8 +1042,10 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, 
struct nvdimm *nvdimm,
                        return -EFAULT;
        }
 
-       if (!desc || (desc->out_num + desc->in_num == 0) ||
-                       !test_bit(cmd, &cmd_mask))
+       if (!desc ||
+           (desc->out_num + desc->in_num == 0) ||
+           cmd > ND_CMD_CALL ||
+           !test_bit(cmd, &cmd_mask))
                return -ENOTTY;
 
        /* fail write commands (when read-only) */
-- 
2.20.1
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