ACPI: Fix bound checks for copy_from_user in the acpi /proc code

[linux-2.6.git] / drivers / acpi / proc.c

diff --git a/drivers/acpi/proc.c b/drivers/acpi/proc.c
index d0d550d22a6d43a14ccecec6658e9fb2773d6b70..f8b6f555ba52ba328d43efca6c5926831a663d06 100644 (file)
--- a/drivers/acpi/proc.c
+++ b/drivers/acpi/proc.c
@@ -398,6 +398,8 @@ acpi_system_write_wakeup_device(struct file *file,
 
        if (len > 4)
                len = 4;
+       if (len < 0)
+               return -EFAULT;
 
        if (copy_from_user(strbuf, buffer, len))
                return -EFAULT;