* [PATCH] kernel: Return -EFAULT if copy_to_user() fails
@ 2021-03-01 11:28 Wang Qing
2021-03-01 11:32 ` Christian Brauner
0 siblings, 1 reply; 2+ messages in thread
From: Wang Qing @ 2021-03-01 11:28 UTC (permalink / raw)
To: Christian Brauner, Andrew Morton, Thomas Gleixner, Thomas Cedeno,
Nicolas Viennot, Michel Lespinasse, Rasmus Villemoes, Al Viro,
Gabriel Krisman Bertazi, linux-kernel
Cc: Wang Qing
The copy_to_user() function returns the number of bytes remaining to be
copied, but we want to return -EFAULT if the copy doesn't complete.
Signed-off-by: Wang Qing <wangqing@vivo.com>
---
kernel/sys.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sys.c b/kernel/sys.c
index 8bb46e5..d97a84a
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1247,7 +1247,7 @@ static int override_release(char __user *release, size_t len)
copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
ret = copy_to_user(release, buf, copy + 1);
}
- return ret;
+ return ret ? -EFAULT : 0;
}
SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] kernel: Return -EFAULT if copy_to_user() fails
2021-03-01 11:28 [PATCH] kernel: Return -EFAULT if copy_to_user() fails Wang Qing
@ 2021-03-01 11:32 ` Christian Brauner
0 siblings, 0 replies; 2+ messages in thread
From: Christian Brauner @ 2021-03-01 11:32 UTC (permalink / raw)
To: Wang Qing
Cc: Andrew Morton, Thomas Gleixner, Thomas Cedeno, Nicolas Viennot,
Michel Lespinasse, Rasmus Villemoes, Al Viro,
Gabriel Krisman Bertazi, linux-kernel
On Mon, Mar 01, 2021 at 07:28:11PM +0800, Wang Qing wrote:
> The copy_to_user() function returns the number of bytes remaining to be
> copied, but we want to return -EFAULT if the copy doesn't complete.
>
> Signed-off-by: Wang Qing <wangqing@vivo.com>
> ---
Hey Wang,
Thanks for the patch. It looks like override_release() is called in
three places and all three places return -EFAULT correctly. They simply
treat any as EFAULT. So not sure this change buys us anything.
Christian
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-03-01 11:28 [PATCH] kernel: Return -EFAULT if copy_to_user() fails Wang Qing
2021-03-01 11:32 ` Christian Brauner
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