From d9f65018065ee1b161a85f54132193f248a45439 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Sat, 26 Sep 2009 20:50:25 +0200 Subject: [PATCH] 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 Signed-off-by: Len Brown --- drivers/acpi/proc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/acpi/proc.c b/drivers/acpi/proc.c index d0d550d22a6d..f8b6f555ba52 100644 --- 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; -- 2.20.1