tools/testing/nvdimm: Fix the array size for dimm devices.

KASAN reports following global out of bounds access while
nfit_test is being loaded. The out of bound access happens
the following reference to dimm_fail_cmd_flags[dimm]. 'dimm' is
over than the index value, NUM_DCR (==5).

  static int override_return_code(int dimm, unsigned int func, int rc)
  {
          if ((1 << func) & dimm_fail_cmd_flags[dimm]) {

dimm_fail_cmd_flags[] definition:
  static unsigned long dimm_fail_cmd_flags[NUM_DCR];

'dimm' is the return value of get_dimm(), and get_dimm() returns
the index of handle[] array. The handle[] has 7 index. Let's use
ARRAY_SIZE(handle) as the array size.

KASAN report:

==================================================================
BUG: KASAN: global-out-of-bounds in nfit_test_ctl+0x47bb/0x55b0 [nfit_test]
Read of size 8 at addr ffffffffc10cbbe8 by task kworker/u41:0/8
...
Call Trace:
 dump_stack+0xea/0x1b0
 ? dump_stack_print_info.cold.0+0x1b/0x1b
 ? kmsg_dump_rewind_nolock+0xd9/0xd9
 print_address_description+0x65/0x22e
 ? nfit_test_ctl+0x47bb/0x55b0 [nfit_test]
 kasan_report.cold.6+0x92/0x1a6
 nfit_test_ctl+0x47bb/0x55b0 [nfit_test]
...
The buggy address belongs to the variable:
 dimm_fail_cmd_flags+0x28/0xffffffffffffa440 [nfit_test]
==================================================================

Fixes: 39611e8 ("tools/testing/nvdimm: Make DSM failure code injection...")
Signed-off-by: Masayoshi Mizuma <[email protected]>
Signed-off-by: Dan Williams <[email protected]>

Author: mmizuma

tools/testing/nvdimm/test/nfit.c

@@ -140,8 +140,8 @@ static u32 handle[] = {
 	[6] = NFIT_DIMM_HANDLE(1, 0, 0, 0, 1),
 };
 
-static unsigned long dimm_fail_cmd_flags[NUM_DCR];
-static int dimm_fail_cmd_code[NUM_DCR];
+static unsigned long dimm_fail_cmd_flags[ARRAY_SIZE(handle)];
+static int dimm_fail_cmd_code[ARRAY_SIZE(handle)];
 
 static const struct nd_intel_smart smart_def = {
 	.flags = ND_INTEL_SMART_HEALTH_VALID
@@ -205,7 +205,7 @@ struct nfit_test {
 		unsigned long deadline;
 		spinlock_t lock;
 	} ars_state;
-	struct device *dimm_dev[NUM_DCR];
+	struct device *dimm_dev[ARRAY_SIZE(handle)];
 	struct nd_intel_smart *smart;
 	struct nd_intel_smart_threshold *smart_threshold;
 	struct badrange badrange;
@@ -2680,7 +2680,7 @@ static int nfit_test_probe(struct platform_device *pdev)
 		u32 nfit_handle = __to_nfit_memdev(nfit_mem)->device_handle;
 		int i;
 
-		for (i = 0; i < NUM_DCR; i++)
+		for (i = 0; i < ARRAY_SIZE(handle); i++)
 			if (nfit_handle == handle[i])
 				dev_set_drvdata(nfit_test->dimm_dev[i],
 						nfit_mem);