[PATCH 4.9 097/130] nfit: fix unchecked dereference in acpi_nfit_ctl

Greg Kroah-Hartman
2018-08-23T08:10:59Z

From: Dave Jiang <dave.jiang@intel.com>

[ Upstream commit ee6581ceba7f8314b81b2f2a81f1cf3f67c679e2 ]

Incremental patch to fix the unchecked dereference in acpi_nfit_ctl.
Reported by Dan Carpenter:

"acpi/nfit: fix cmd_rc for acpi_nfit_ctl to
always return a value" from Jun 28, 2018, leads to the following
Smatch complaint:

drivers/acpi/nfit/core.c:578 acpi_nfit_ctl()
warn: variable dereferenced before check 'cmd_rc' (see line 411)

drivers/acpi/nfit/core.c
410
411 *cmd_rc = -EINVAL;
^^^^^^^^^^^^^^^^^^
Patch adds unchecked dereference.

Fixes: c1985cefd844 ("acpi/nfit: fix cmd_rc for acpi_nfit_ctl to always return a value")

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/acpi/nfit/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -201,7 +201,8 @@ int acpi_nfit_ctl(struct nvdimm_bus_desc
const u8 *uuid;
int rc, i;

- *cmd_rc = -EINVAL;
+ if (cmd_rc)
+ *cmd_rc = -EINVAL;
func = cmd;
if (cmd == ND_CMD_CALL) {
call_pkg = buf;
@@ -289,7 +290,8 @@ int acpi_nfit_ctl(struct nvdimm_bus_desc
* If we return an error (like elsewhere) then caller wouldn't
* be able to rely upon data returned to make calculation.
*/
- *cmd_rc = 0;
+ if (cmd_rc)
+ *cmd_rc = 0;
return 0;
}