[PATCH] ISDN: check for userspace copy faults

Most of the ISDN ->readstat() implementations needed to check
copy_to_user() and put_user() return values.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/isdn/pcbit/drv.c b/drivers/isdn/pcbit/drv.c
index 94f2148..6ead5e1 100644
--- a/drivers/isdn/pcbit/drv.c
+++ b/drivers/isdn/pcbit/drv.c
@@ -725,23 +725,27 @@
 
 	if (stat_st < stat_end)
 	{
-		copy_to_user(buf, statbuf + stat_st, len);
+		if (copy_to_user(buf, statbuf + stat_st, len))
+			return -EFAULT;
 		stat_st += len;	   
 	}
 	else
 	{
 		if (len > STATBUF_LEN - stat_st)
 		{
-			copy_to_user(buf, statbuf + stat_st, 
-				       STATBUF_LEN - stat_st);
-			copy_to_user(buf, statbuf, 
-				       len - (STATBUF_LEN - stat_st));
+			if (copy_to_user(buf, statbuf + stat_st,
+				       STATBUF_LEN - stat_st))
+				return -EFAULT;
+			if (copy_to_user(buf, statbuf,
+				       len - (STATBUF_LEN - stat_st)))
+				return -EFAULT;
 
 			stat_st = len - (STATBUF_LEN - stat_st);
 		}
 		else
 		{
-			copy_to_user(buf, statbuf + stat_st, len);
+			if (copy_to_user(buf, statbuf + stat_st, len))
+				return -EFAULT;
 
 			stat_st += len;