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HID: uhid: make creating devices work on 64/32 systems

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Unfortunately UHID interface, as it was introduced, is broken with 32 bit
userspace running on 64 bit kernels as it uses a pointer in its userspace
facing API.

Fix it by checking if we are executing compat task and munge the request
appropriately.

Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Dmitry Torokhov 2013-02-18 11:26:11 +01:00 committed by Jiri Kosina
parent c284979aff
commit befde0226a
1 changed files with 92 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

95
drivers/hid/uhid.c
View file

@ -11,6 +11,7 @@
*/
#include <linux/atomic.h>
#include <linux/compat.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/hid.h>
@ -276,6 +277,94 @@ static struct hid_ll_driver uhid_hid_driver = {
.parse = uhid_hid_parse,
};
#ifdef CONFIG_COMPAT
/* Apparently we haven't stepped on these rakes enough times yet. */
struct uhid_create_req_compat {
__u8 name[128];
__u8 phys[64];
__u8 uniq[64];
compat_uptr_t rd_data;
__u16 rd_size;
__u16 bus;
__u32 vendor;
__u32 product;
__u32 version;
__u32 country;
} __attribute__((__packed__));
static int uhid_event_from_user(const char __user *buffer, size_t len,
struct uhid_event *event)
{
if (is_compat_task()) {
u32 type;
if (get_user(type, buffer))
return -EFAULT;
if (type == UHID_CREATE) {
/*
* This is our messed up request with compat pointer.
* It is largish (more than 256 bytes) so we better
* allocate it from the heap.
*/
struct uhid_create_req_compat *compat;
compat = kmalloc(sizeof(*compat), GFP_KERNEL);
if (!compat)
return -ENOMEM;
buffer += sizeof(type);
len -= sizeof(type);
if (copy_from_user(compat, buffer,
min(len, sizeof(*compat)))) {
kfree(compat);
return -EFAULT;
}
/* Shuffle the data over to proper structure */
event->type = type;
memcpy(event->u.create.name, compat->name,
sizeof(compat->name));
memcpy(event->u.create.phys, compat->phys,
sizeof(compat->phys));
memcpy(event->u.create.uniq, compat->uniq,
sizeof(compat->uniq));
event->u.create.rd_data = compat_ptr(compat->rd_data);
event->u.create.rd_size = compat->rd_size;
event->u.create.bus = compat->bus;
event->u.create.vendor = compat->vendor;
event->u.create.product = compat->product;
event->u.create.version = compat->version;
event->u.create.country = compat->country;
kfree(compat);
return 0;
}
/* All others can be copied directly */
}
if (copy_from_user(event, buffer, min(len, sizeof(*event))))
return -EFAULT;
return 0;
}
#else
static int uhid_event_from_user(const char __user *buffer, size_t len,
struct uhid_event *event)
{
if (copy_from_user(event, buffer, min(len, sizeof(*event))))
return -EFAULT;
return 0;
}
#endif
static int uhid_dev_create(struct uhid_device *uhid,
const struct uhid_event *ev)
{
@ -498,10 +587,10 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
len = min(count, sizeof(uhid->input_buf));
if (copy_from_user(&uhid->input_buf, buffer, len)) {
ret = -EFAULT;
ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
if (ret)
goto unlock;
}
switch (uhid->input_buf.type) {
case UHID_CREATE: