[PATCH] raw1394_read ignores __copy_to_user return value

[Jesper Juhl]

__copy_to_user can fail, and if it does something has gone wrong and we 
should act accordingly.

Currently the return value of __copy_to_user is not checked in 
raw1394_read which generates the warning below with gcc 3.4.1. 

  CC      drivers/ieee1394/raw1394.o
include/asm/uaccess.h: In function `raw1394_read':
drivers/ieee1394/raw1394.c:446: warning: ignoring return value of `__copy_to_user', declared with attribute warn_unused_result

Here's a patch to check the return value and return -EFAULT on failure.
I don't have hardware, so I've only compile tested this. Please review and 
consider applying.

Signed-off-by: Jesper Juhl <juhl-lkml@xxxxxx>

diff -up linux-2.6.9-rc2-bk5-orig/drivers/ieee1394/raw1394.c linux-2.6.9-rc2-bk5/drivers/ieee1394/raw1394.c
--- linux-2.6.9-rc2-bk5-orig/drivers/ieee1394/raw1394.c	2004-08-14 07:36:11.000000000 +0200
+++ linux-2.6.9-rc2-bk5/drivers/ieee1394/raw1394.c	2004-09-20 21:00:33.000000000 +0200
@@ -443,7 +443,10 @@ static ssize_t raw1394_read(struct file 
                         req->req.error = RAW1394_ERROR_MEMFAULT;
                 }
         }
-        __copy_to_user(buffer, &req->req, sizeof(req->req));
+        if (__copy_to_user(buffer, &req->req, sizeof(req->req))) {
+                free_pending_request(req);
+                return -EFAULT;
+        }
 
         free_pending_request(req);
         return sizeof(struct raw1394_request);


--
Jesper Juhl


PS. I'm only subscribed to linux-kernel, so please keep me on CC for 
replies from other lists.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/