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* [PATCH] libnvdimm, pmem: fix a possible OOB access when read and write pmem
@ 2019-04-04  2:58 Li RongQing
  2019-04-04 16:54 ` Ira Weiny
  2019-04-05 15:43 ` Jeff Moyer
  0 siblings, 2 replies; 3+ messages in thread
From: Li RongQing @ 2019-04-04  2:58 UTC (permalink / raw)
  To: dan.j.williams, vishal.l.verma, dave.jiang, keith.busch,
	ira.weiny, linux-nvdimm

If offset is not zero and length is bigger than PAGE_SIZE,
this will cause to out of boundary access to a page memory

Fixes: 98cc093cba1e "(block, THP: make block_device_operations.rw_page support THP)"
Co-developed-by: Liang ZhiCheng <liangzhicheng@baidu.com>
Signed-off-by: Liang ZhiCheng <liangzhicheng@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 drivers/nvdimm/pmem.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index bc2f700feef8..0279eb1da3ef 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -113,13 +113,13 @@ static void write_pmem(void *pmem_addr, struct page *page,
 
 	while (len) {
 		mem = kmap_atomic(page);
-		chunk = min_t(unsigned int, len, PAGE_SIZE);
+		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
 		memcpy_flushcache(pmem_addr, mem + off, chunk);
 		kunmap_atomic(mem);
 		len -= chunk;
 		off = 0;
 		page++;
-		pmem_addr += PAGE_SIZE;
+		pmem_addr += chunk;
 	}
 }
 
@@ -132,7 +132,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
 
 	while (len) {
 		mem = kmap_atomic(page);
-		chunk = min_t(unsigned int, len, PAGE_SIZE);
+		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
 		rem = memcpy_mcsafe(mem + off, pmem_addr, chunk);
 		kunmap_atomic(mem);
 		if (rem)
@@ -140,7 +140,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
 		len -= chunk;
 		off = 0;
 		page++;
-		pmem_addr += PAGE_SIZE;
+		pmem_addr += chunk;
 	}
 	return BLK_STS_OK;
 }
-- 
2.16.2

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Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] libnvdimm, pmem: fix a possible OOB access when read and write pmem
  2019-04-04  2:58 [PATCH] libnvdimm, pmem: fix a possible OOB access when read and write pmem Li RongQing
@ 2019-04-04 16:54 ` Ira Weiny
  2019-04-05 15:43 ` Jeff Moyer
  1 sibling, 0 replies; 3+ messages in thread
From: Ira Weiny @ 2019-04-04 16:54 UTC (permalink / raw)
  To: Li RongQing; +Cc: linux-nvdimm

On Thu, Apr 04, 2019 at 10:58:01AM +0800, Li RongQing wrote:
> If offset is not zero and length is bigger than PAGE_SIZE,
> this will cause to out of boundary access to a page memory
> 
> Fixes: 98cc093cba1e "(block, THP: make block_device_operations.rw_page support THP)"
> Co-developed-by: Liang ZhiCheng <liangzhicheng@baidu.com>
> Signed-off-by: Liang ZhiCheng <liangzhicheng@baidu.com>
> Signed-off-by: Li RongQing <lirongqing@baidu.com>

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> ---
>  drivers/nvdimm/pmem.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index bc2f700feef8..0279eb1da3ef 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -113,13 +113,13 @@ static void write_pmem(void *pmem_addr, struct page *page,
>  
>  	while (len) {
>  		mem = kmap_atomic(page);
> -		chunk = min_t(unsigned int, len, PAGE_SIZE);
> +		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
>  		memcpy_flushcache(pmem_addr, mem + off, chunk);
>  		kunmap_atomic(mem);
>  		len -= chunk;
>  		off = 0;
>  		page++;
> -		pmem_addr += PAGE_SIZE;
> +		pmem_addr += chunk;
>  	}
>  }
>  
> @@ -132,7 +132,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
>  
>  	while (len) {
>  		mem = kmap_atomic(page);
> -		chunk = min_t(unsigned int, len, PAGE_SIZE);
> +		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
>  		rem = memcpy_mcsafe(mem + off, pmem_addr, chunk);
>  		kunmap_atomic(mem);
>  		if (rem)
> @@ -140,7 +140,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
>  		len -= chunk;
>  		off = 0;
>  		page++;
> -		pmem_addr += PAGE_SIZE;
> +		pmem_addr += chunk;
>  	}
>  	return BLK_STS_OK;
>  }
> -- 
> 2.16.2
> 
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Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] libnvdimm, pmem: fix a possible OOB access when read and write pmem
  2019-04-04  2:58 [PATCH] libnvdimm, pmem: fix a possible OOB access when read and write pmem Li RongQing
  2019-04-04 16:54 ` Ira Weiny
@ 2019-04-05 15:43 ` Jeff Moyer
  1 sibling, 0 replies; 3+ messages in thread
From: Jeff Moyer @ 2019-04-05 15:43 UTC (permalink / raw)
  To: Li RongQing; +Cc: linux-nvdimm

Li RongQing <lirongqing@baidu.com> writes:

> If offset is not zero and length is bigger than PAGE_SIZE,
> this will cause to out of boundary access to a page memory

Agreed, though I don't think this can be triggered in practice.

> Fixes: 98cc093cba1e "(block, THP: make block_device_operations.rw_page support THP)"
> Co-developed-by: Liang ZhiCheng <liangzhicheng@baidu.com>
> Signed-off-by: Liang ZhiCheng <liangzhicheng@baidu.com>
> Signed-off-by: Li RongQing <lirongqing@baidu.com>

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>


> ---
>  drivers/nvdimm/pmem.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index bc2f700feef8..0279eb1da3ef 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -113,13 +113,13 @@ static void write_pmem(void *pmem_addr, struct page *page,
>  
>  	while (len) {
>  		mem = kmap_atomic(page);
> -		chunk = min_t(unsigned int, len, PAGE_SIZE);
> +		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
>  		memcpy_flushcache(pmem_addr, mem + off, chunk);
>  		kunmap_atomic(mem);
>  		len -= chunk;
>  		off = 0;
>  		page++;
> -		pmem_addr += PAGE_SIZE;
> +		pmem_addr += chunk;
>  	}
>  }
>  
> @@ -132,7 +132,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
>  
>  	while (len) {
>  		mem = kmap_atomic(page);
> -		chunk = min_t(unsigned int, len, PAGE_SIZE);
> +		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
>  		rem = memcpy_mcsafe(mem + off, pmem_addr, chunk);
>  		kunmap_atomic(mem);
>  		if (rem)
> @@ -140,7 +140,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
>  		len -= chunk;
>  		off = 0;
>  		page++;
> -		pmem_addr += PAGE_SIZE;
> +		pmem_addr += chunk;
>  	}
>  	return BLK_STS_OK;
>  }
_______________________________________________
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Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-04-05 15:43 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2019-04-04  2:58 [PATCH] libnvdimm, pmem: fix a possible OOB access when read and write pmem Li RongQing
2019-04-04 16:54 ` Ira Weiny
2019-04-05 15:43 ` Jeff Moyer

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