* [PATCH] libnvdimm: Fix dereference of pointer ndns before it is null checked
@ 2020-09-15 7:06 Jing Xiangfeng
0 siblings, 0 replies; 2+ messages in thread
From: Jing Xiangfeng @ 2020-09-15 7:06 UTC (permalink / raw)
To: dan.j.williams, vishal.l.verma, dave.jiang, ira.weiny
Cc: linux-nvdimm, linux-kernel, jingxiangfeng
In current code, the pointer ndns is being dereferenced on the
initialization of pointer parent_uuid before ndns is null check. This
could lead to a potential null pointer dereference. Fix this by
dereferencing ndns after ndns has been null pointer sanity checked.
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
---
drivers/nvdimm/pfn_devs.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 3e11ef8d3f5b..c443994f81f3 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -452,7 +452,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
unsigned long align, start_pad;
struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
struct nd_namespace_common *ndns = nd_pfn->ndns;
- const u8 *parent_uuid = nd_dev_to_uuid(&ndns->dev);
+ const u8 *parent_uuid;
if (!pfn_sb || !ndns)
return -ENODEV;
@@ -472,6 +472,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
return -ENODEV;
pfn_sb->checksum = cpu_to_le64(checksum);
+ parent_uuid = nd_dev_to_uuid(&ndns->dev);
if (memcmp(pfn_sb->parent_uuid, parent_uuid, 16) != 0)
return -ENODEV;
--
2.17.1
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* Re: [PATCH] libnvdimm: Fix dereference of pointer ndns before it is null checked
@ 2020-09-15 12:45 Markus Elfring
0 siblings, 0 replies; 2+ messages in thread
From: Markus Elfring @ 2020-09-15 12:45 UTC (permalink / raw)
To: Jing Xiangfeng, linux-nvdimm; +Cc: linux-kernel, kernel-janitors, Zhen Lei
> … Fix this by
I suggest to replace this information by the tag “Fixes”.
> dereferencing ndns after ndns has been null pointer sanity checked.
Would an other imperative wording become helpful for the change description?
Regards,
Markus
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