Commit d9f65018 authored Sep 26, 2009 by Arjan van de Ven Committed by Len Brown Oct 03, 2009

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



The ACPI /proc write() code takes an unsigned length argument like any write()
function, but then assigned it to a *signed* integer called "len".
Only after this is a sanity check for len done to make it not larger than 4.

Due to the type change a len < 0 is in principle also possible; this patch
adds a check for this.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

parent 0efe5e32

drivers/acpi/proc.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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;