* [PATCH] libnvdimm: fix NULL pointer dereference
@ 2018-07-24 13:40 Gustavo A. R. Silva
2018-07-24 19:46 ` Keith Busch
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2018-07-24 13:40 UTC (permalink / raw)
To: Keith Busch, Dan Williams, Ross Zwisler, Vishal Verma, Dave Jiang
Cc: Gustavo A. R. Silva, linux-kernel, linux-nvdimm
ndd is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.
Fix this by moving the pointer dereference after ndd has been properly
null checked at line 554: if (!ndd)
Addresses-Coverity-ID: 1472020 ("Dereference before null check")
Fixes: 42218e643bd2 ("libnvdimm: Use max contiguous area for namespace size")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/nvdimm/dimm_devs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 9e977cb..1dc3125 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -546,7 +546,7 @@ resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
struct nd_mapping *nd_mapping)
{
struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
- struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+ struct nvdimm_bus *nvdimm_bus;
resource_size_t max = 0;
struct resource *res;
@@ -554,6 +554,8 @@ resource_size_t nd_pmem_max_contiguous_dpa(struct nd_region *nd_region,
if (!ndd)
return 0;
+ nvdimm_bus = walk_to_nvdimm_bus(ndd->dev);
+
if (reserve_free_pmem(nvdimm_bus, nd_mapping))
return 0;
for_each_dpa_resource(ndd, res) {
--
2.7.4
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] libnvdimm: fix NULL pointer dereference
2018-07-24 13:40 [PATCH] libnvdimm: fix NULL pointer dereference Gustavo A. R. Silva
@ 2018-07-24 19:46 ` Keith Busch
0 siblings, 0 replies; 2+ messages in thread
From: Keith Busch @ 2018-07-24 19:46 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: linux-nvdimm, linux-kernel, Ross Zwisler
On Tue, Jul 24, 2018 at 08:40:06AM -0500, Gustavo A. R. Silva wrote:
> ndd is being dereferenced before it is null checked, hence there is a
> potential null pointer dereference.
>
> Fix this by moving the pointer dereference after ndd has been properly
> null checked at line 554: if (!ndd)
I'll fold this into v4 of the patch since Vishal found an issue when a
DIMM has multiple regions.
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