From: Rusty Russell <rusty@rustcorp.com.au>
To: "Kasatkin\, Dmitry" <dmitry.kasatkin@intel.com>
Cc: David Howells <dhowells@redhat.com>,
zohar@linux.vnet.ibm.com, jmorris@namei.org,
keyrings@linux-nfs.org, linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC] module: signature infrastructure
Date: Wed, 05 Sep 2012 09:59:22 +0930 [thread overview]
Message-ID: <871uihl3bx.fsf@rustcorp.com.au> (raw)
In-Reply-To: <CALLzPKaA3MYncJD1X6B8f3p-R6FVA5-WDF-h6GGwdtinNpjqmw@mail.gmail.com>
"Kasatkin, Dmitry" <dmitry.kasatkin@intel.com> writes:
> Hi,
>
> Please read bellow...
>
> On Tue, Sep 4, 2012 at 8:55 AM, Rusty Russell <rusty@rustcorp.com.au> wrote:
>> OK, I took a look at the module.c parts of David and Dmitry's patchsets,
>> and didn't really like either, but I stole parts of David's to make
>> this.
>>
>> So, here's the module.c part of module signing. I hope you two got time
>> to discuss the signature format details? Mimi suggested a scheme where
>> the private key would never be saved on disk (even temporarily), but I
>> didn't see patches. Frankly it's something we can do later; let's aim
>> at getting the format right for the next merge window.
>
> In our patches key is stored on the disc in encrypted format...
Oh, I missed that twist. Thanks for the explanation.
On consideration, I prefer signing to be the final part of the "modules"
target rather than modules_install. I run the latter as root, and that
is wrong for doing any code generation.
>> + for (i = 0; i < *len - (sizeof(MODULE_SIG_STRING)-1); i++) {
>> + /* Our memcmp is dumb, speed it up a little. */
>> + if (((char *)mod)[i] != MODULE_SIG_STRING[0])
>> + continue;
>> + if (memcmp(mod, MODULE_SIG_STRING, strlen(MODULE_SIG_STRING)))
>
> should be (mod+i)?
Yes, indeed. Thanks, fixed.
>> + continue;
>> +
>> + sig = mod + i + strlen(MODULE_SIG_STRING);
>> + siglen = *len - i - strlen(MODULE_SIG_STRING);
>> + *len = i;
>> + break;
>> + }
>
> In general please clarify why do you need such parsing at all?
> Why not to have MODULE_SIG_STRING as a last octets of the module and
> have signature length field before?
> Then it is easy to get the signature and rest of the module?
> That will be super fast...
>
> Please clarify.
Ignore performance, it's just not an issue here. So the simplest code
wins.
And it's also simpler to sign a module this way.
(echo '~Module signature appended~'; gpg --sign ....) >> mod.ko
Cheers,
Rusty.
next prev parent reply other threads:[~2012-09-05 8:21 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-16 1:34 [PATCH 00/25] Crypto keys and module signing David Howells
2012-08-16 1:34 ` [PATCH 01/25] KEYS: Add payload preparsing opportunity prior to key instantiate or update David Howells
2012-08-16 1:34 ` [PATCH 02/25] MPILIB: Provide count_leading/trailing_zeros() based on arch functions David Howells
2012-09-10 7:13 ` Kasatkin, Dmitry
2012-09-13 5:14 ` James Morris
2012-09-13 14:09 ` Kasatkin, Dmitry
2012-08-16 1:34 ` [PATCH 03/25] KEYS: Create a key type that can be used for general cryptographic operations David Howells
2012-08-16 1:34 ` [PATCH 04/25] KEYS: Add signature verification facility David Howells
2012-08-16 1:35 ` [PATCH 05/25] KEYS: Asymmetric public-key algorithm crypto key subtype David Howells
2012-08-16 1:35 ` [PATCH 06/25] MPILIB: Reinstate mpi_cmp[_ui]() and export for RSA signature verification David Howells
2012-08-16 1:35 ` [PATCH 07/25] KEYS: RSA: Implement signature verification algorithm [PKCS#1 / RFC3447] David Howells
2012-08-16 1:35 ` [PATCH 08/25] KEYS: RSA: Fix signature verification for shorter signatures David Howells
2012-08-16 1:35 ` [PATCH 09/25] PGPLIB: PGP definitions (RFC 4880) David Howells
2012-08-16 1:36 ` [PATCH 10/25] PGPLIB: Basic packet parser David Howells
2012-08-16 1:36 ` [PATCH 11/25] PGPLIB: Signature parser David Howells
2012-08-16 1:36 ` [PATCH 12/25] KEYS: PGP data parser David Howells
2012-08-16 1:36 ` [PATCH 13/25] KEYS: PGP-based public key signature verification David Howells
2012-08-16 1:36 ` [PATCH 14/25] KEYS: PGP format signature parser David Howells
2012-08-16 1:36 ` [PATCH 15/25] KEYS: Provide PGP key description autogeneration David Howells
2012-08-16 1:37 ` [PATCH 16/25] KEYS: Provide a function to load keys from a PGP keyring blob David Howells
2012-08-16 1:37 ` [PATCH 17/25] MODSIGN: Provide gitignore and make clean rules for extra files David Howells
2012-08-16 1:37 ` [PATCH 18/25] MODSIGN: Provide Documentation and Kconfig options David Howells
2012-08-16 1:37 ` [PATCH 19/25] MODSIGN: Sign modules during the build process David Howells
2012-08-16 1:37 ` [PATCH 20/25] MODSIGN: Provide module signing public keys to the kernel David Howells
2012-08-31 14:33 ` Michal Marek
2012-08-16 1:38 ` [PATCH 21/25] MODSIGN: Module signature verification David Howells
2012-08-16 1:38 ` [PATCH 22/25] MODSIGN: Automatically generate module signing keys if missing David Howells
2012-08-16 1:38 ` [PATCH 23/25] MODSIGN: Panic the kernel if FIPS is enabled upon module signing failure David Howells
2012-08-16 1:38 ` [PATCH 24/25] MODSIGN: Allow modules to be signed with an unknown key unless enforcing David Howells
2012-08-16 1:38 ` [PATCH 25/25] MODSIGN: Fix documentation of signed-nokey behavior when not enforcing David Howells
2012-08-21 5:04 ` [PATCH 00/25] Crypto keys and module signing Rusty Russell
2012-08-22 10:50 ` David Howells
2012-08-22 11:52 ` Mimi Zohar
2012-08-22 16:07 ` Kasatkin, Dmitry
2012-09-04 5:55 ` [RFC] module: signature infrastructure Rusty Russell
2012-09-04 12:07 ` Kasatkin, Dmitry
2012-09-04 12:21 ` Kasatkin, Dmitry
2012-09-04 13:40 ` Mimi Zohar
2012-09-05 0:29 ` Rusty Russell [this message]
2012-09-05 13:34 ` Mimi Zohar
2012-09-06 2:05 ` Rusty Russell
2012-09-04 14:25 ` Lucas De Marchi
2012-09-04 15:04 ` Kasatkin, Dmitry
2012-09-05 0:19 ` Rusty Russell
2012-09-05 23:41 ` Lucas De Marchi
2012-09-06 7:55 ` Rusty Russell
2012-09-04 22:51 ` David Howells
2012-09-04 23:17 ` Kasatkin, Dmitry
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