[patch 9/9] compat_ioctl: fix compat_fd_ioctl pointer access

[Arnd Bergmann <arnd@arndb.de>]

[-- Attachment #1: compat-floppy-ioctl-pointer.diff --]
[-- Type: text/plain, Size: 896 bytes --]

As found by sparse, a user space pointer is assigned to a kernel
data structure while calling other code with set_fs(KERNEL_DS),
which could lead to leaking kernel data if that pointer is
ever accessed.

I could not find any place in the floppy drivers that actually
uses that pointer, but assigning it to an empty string is
a safer choice and gets rid of the sparse warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Index: linux-2.6/block/compat_ioctl.c
===================================================================
--- linux-2.6.orig/block/compat_ioctl.c
+++ linux-2.6/block/compat_ioctl.c
@@ -349,7 +349,7 @@ static int compat_fd_ioctl(struct inode 
 		err |= __get_user(f->spec1, &uf->spec1);
 		err |= __get_user(f->fmt_gap, &uf->fmt_gap);
 		err |= __get_user(name, &uf->name);
-		f->name = compat_ptr(name);
+		f->name = "";
 		if (err) {
 			err = -EFAULT;
 			goto out;

--