Re: [PATCH] put_user() on struct is not nice

From: Rusty Russell
Date: Tue Sep 25 2007 - 22:06:49 EST


On Wed, 2007-09-26 at 01:54 +0100, Al Viro wrote:
> use copy_to_user() instead...

Thanks Al, Jes sent me the same fix which I have queued for for 2.6.24:

From: Jes Sorensen <jes@xxxxxxx>

Use copy_to_user() when copying a struct timespec to the guest -
put_user() cannot handle two long's in one go on a 64bit arch.

Signed-off-by: Jes Sorensen <jes@xxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
---
drivers/lguest/hypercalls.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

===================================================================
--- linux-2.6.23-rc4.orig/drivers/lguest/hypercalls.c
+++ linux-2.6.23-rc4/drivers/lguest/hypercalls.c
@@ -243,6 +243,6 @@ void write_timestamp(struct lguest *lg)
{
struct timespec now;
ktime_get_real_ts(&now);
- if (put_user(now, &lg->lguest_data->time))
+ if (copy_to_user(&lg->lguest_data->time, &now, sizeof(struct timespec)))
kill_guest(lg, "Writing timestamp");
}


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