[PATCH] off-by-1 in kernel/power/main.c

[dean gaudet]

there's an off-by-1 in 2.6.16.9 (and 2.6.17-rc2) 
kernel/power/main.c:state_store() ... if your kernel just happens to have 
some non-zero data at pm_states[PM_SUSPEND_MAX] (i.e. one past the end of 
the array) then it'll let you write anything you want to /sys/power/state 
and in response the box will enter S5.

i randomly discovered this because i really wanted to put my box into S5 
(for wake on lan) and tried "echo off >/sys/power/state" and was quite 
happy that the box entered S5... happy until i compiled a different kernel 
and this S5 trick stopped working :)

anyhow, this begs the question, what is the correct way to get a box to 
shutdown into s5?  on a fc4 box i have here it does that happily, but 
ubuntu boxes don't seem to go into s5... and i couldn't figure out from 
fc4 patches if they'd changed anything in this area.  pointers 
appreciated.

btw i can whip up a patch making "off" a valid value for /sys/power/state 
...

-dean

Signed-off-by: dean gaudet <dean@xxxxxxxxxx>

--- linux/kernel/power/main.c.orig	2006-03-19 21:53:29.000000000 -0800
+++ linux/kernel/power/main.c	2006-04-21 20:54:12.000000000 -0700
@@ -272,7 +272,7 @@
 		if (*s && !strncmp(buf, *s, len))
 			break;
 	}
-	if (*s)
+	if (state < PM_SUSPEND_MAX && *s)
 		error = enter_state(state);
 	else
 		error = -EINVAL;
-
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