* [patch 2/2] gru: cleanup gru_dump_context() a little
@ 2014-01-30 12:10 Dan Carpenter
2014-01-30 14:24 ` Dimitri Sivanich
0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2014-01-30 12:10 UTC (permalink / raw)
To: Dimitri Sivanich; +Cc: linux-kernel, kernel-janitors
"ret" is zero here so we can remove the "!ret" part of the condition.
"uhdr" is alread a __user pointer so we can remove the cast.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Btw, speaking of __user pointers there are some places where we
dereference them in this file. It's not a security problem because we
have already used copy_to_user() to successfully write to the pointer at
point. But if you have something like PAX which puts user pointers and
kernel pointers in a separate address space then this will cause
problems.
Run sparse to see the issue.
diff --git a/drivers/misc/sgi-gru/grukdump.c b/drivers/misc/sgi-gru/grukdump.c
index 2bef3f76032a..a3700a56b8ff 100644
--- a/drivers/misc/sgi-gru/grukdump.c
+++ b/drivers/misc/sgi-gru/grukdump.c
@@ -178,10 +178,10 @@ static int gru_dump_context(struct gru_state *gru, int ctxnum,
hdr.cbrcnt = cbrcnt;
hdr.dsrcnt = dsrcnt;
hdr.cch_locked = cch_locked;
- if (!ret && copy_to_user((void __user *)uhdr, &hdr, sizeof(hdr)))
- ret = -EFAULT;
+ if (copy_to_user(uhdr, &hdr, sizeof(hdr)))
+ return -EFAULT;
- return ret ? ret : bytes;
+ return bytes;
}
int gru_dump_chiplet_request(unsigned long arg)
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [patch 2/2] gru: cleanup gru_dump_context() a little
2014-01-30 12:10 [patch 2/2] gru: cleanup gru_dump_context() a little Dan Carpenter
@ 2014-01-30 14:24 ` Dimitri Sivanich
0 siblings, 0 replies; 2+ messages in thread
From: Dimitri Sivanich @ 2014-01-30 14:24 UTC (permalink / raw)
To: Dan Carpenter; +Cc: linux-kernel, kernel-janitors
Acked-by: Dimitri Sivanich <sivanich@sgi.com>
On Thu, Jan 30, 2014 at 03:10:48PM +0300, Dan Carpenter wrote:
> "ret" is zero here so we can remove the "!ret" part of the condition.
> "uhdr" is alread a __user pointer so we can remove the cast.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> Btw, speaking of __user pointers there are some places where we
> dereference them in this file. It's not a security problem because we
> have already used copy_to_user() to successfully write to the pointer at
> point. But if you have something like PAX which puts user pointers and
> kernel pointers in a separate address space then this will cause
> problems.
>
> Run sparse to see the issue.
>
> diff --git a/drivers/misc/sgi-gru/grukdump.c b/drivers/misc/sgi-gru/grukdump.c
> index 2bef3f76032a..a3700a56b8ff 100644
> --- a/drivers/misc/sgi-gru/grukdump.c
> +++ b/drivers/misc/sgi-gru/grukdump.c
> @@ -178,10 +178,10 @@ static int gru_dump_context(struct gru_state *gru, int ctxnum,
> hdr.cbrcnt = cbrcnt;
> hdr.dsrcnt = dsrcnt;
> hdr.cch_locked = cch_locked;
> - if (!ret && copy_to_user((void __user *)uhdr, &hdr, sizeof(hdr)))
> - ret = -EFAULT;
> + if (copy_to_user(uhdr, &hdr, sizeof(hdr)))
> + return -EFAULT;
>
> - return ret ? ret : bytes;
> + return bytes;
> }
>
> int gru_dump_chiplet_request(unsigned long arg)
^ permalink raw reply [flat|nested] 2+ messages in thread
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2014-01-30 12:10 [patch 2/2] gru: cleanup gru_dump_context() a little Dan Carpenter
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