HID: uhid: make creating devices work on 64/32 systems
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>
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 714cd8c..fc307e04 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -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 @@
.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 @@
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: