linux-kernel - Re: [RFC] swap image signature check upon resume

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 6 Dec 2007 22:46:48 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	bbpetkov@...oo.de
Cc:	Pavel Machek <pavel@...e.cz>, linux-kernel@...r.kernel.org
Subject: Re: [RFC] swap image signature check upon resume

On Thursday, 6 of December 2007, Borislav Petkov wrote:
> Hi Pavel,
> hi Rafael,
> 
> after a quick search i couldn't find anything dealing with the topic in the
> subject line so here we go:
> 
> One sometimes can mix up (and by one i mean me) the
> kernel images one boots after having suspended the machine previously. There can
> be at least two reasons for that:
> 
> 1. too many kernels in grub and having forgotten with which i suspended.
> 2. compile and install a new kernel and forget about it, suspend in the evening
> and then boot with the new kernel;
> 
> in both cases you end up staring at fsck since they filesystems haven't been unmounted,
> of course. Or at least see the warning message of some journal recovery whisk away.
> 
> In order to alleviate that, one could probably go, imho, and write in the swsusp_header
> the kernel version which suspended the machine (UTS_RELEASE) alongside
> SWSUSP_SIG and check that against the kernel version of the image just booting.
> If they match then all is well, if not, one could
> 
> a) issue a BIG FAT WARNING and reboot telling the user to select the proper
> image
> b) ask the user what to do:
> 	- proceed as if "noresume" has been entered on the kernel command line
> 	- reboot after issuing the kernel version which suspended the machine
> 	-
> c)...
> 
> In case you guys think something like that might be of use i can come up with a
> patch in the next coupla days...

Well, there's a patchset in the current mainline that allows you to use
arbitrary (sufficiently new) kernel to load the image and then restore the
image kernel.  So, you can hibernate 2.6.24-rc3 and use 2.6.24-rc2 to restore
it, for example.

I'm going to do that for i386 too.

Greetings,
Rafael
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/