From: joeyli Subject: Re: [RFC V4 PATCH 00/15] Signature verification of hibernate snapshot Date: Thu, 26 Sep 2013 21:20:38 +0800 Message-ID: <1380201638.32302.90.camel__6502.82887877456$1380201697$gmane$org@linux-s257.site> References: <1380161957.32302.42.camel@linux-s257.site> <1380192218.32302.69.camel@linux-s257.site> <20130926120621.GA7537@amd.pavel.ucw.cz> <20130926122210.GA30225@suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Pavel Machek , Alan Stern , David Howells , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-pm@vger.kernel.org, linux-crypto@vger.kernel.org, opensuse-kernel@opensuse.org, "Rafael J. Wysocki" , Matthew Garrett , Len Brown , Josh Boyer , Matt Fleming , James Bottomley , Greg KH , JKosina@suse.com, Rusty Russell , Herbert Xu , "David S. Miller" , "H. Peter Anvin" , Michal Marek , Gary Lin , Vivek Goyal To: Vojtech Pavlik Return-path: In-Reply-To: <20130926122210.GA30225@suse.cz> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org =E6=96=BC =E5=9B=9B=EF=BC=8C2013-09-26 =E6=96=BC 14:22 +0200=EF=BC=8CVo= jtech Pavlik =E6=8F=90=E5=88=B0=EF=BC=9A > On Thu, Sep 26, 2013 at 02:06:21PM +0200, Pavel Machek wrote: >=20 > > > For the symmetric key solution, I will try HMAC (Hash Message > > > Authentication Code). It's already used in networking, hope the > > > performance is not too bad to a big image. > >=20 > > Kernel already supports crc32 of the hibernation image, you may wan= t > > to take a look how that is done. > >=20 > > Maybe you want to replace crc32 with cryptographics hash (sha1?) an= d > > then use only hash for more crypto? That way speed of whatever > crypto > > you do should not be an issue. >=20 > Well, yes, one could skip the CRC when the signing is enabled to gain > a > little speedup.=20 In current kernel, CRC is for check the integrity of LZO compressed image, the purpose is different to check the integrity of snapshot image. So, CRC will not in non-compress hibernate or userspace hibernate code path On the other hand, attacker can easily change the CRC code in the heade= r of LZO hibernate image. Thanks a lot! Joey Lee