Re: [PATCH] crypto: af_alg - Document the deprecation of AF_ALG

Re: [PATCH] crypto: af_alg - Document the deprecation of AF_ALG

[Bastien Nocera]

Hey,

Replying to this older patch.

On Wed, 2026-04-29 at 18:15 -0700, Eric Biggers wrote:
<snip>
> This isn't intended to change anything overnight.  After all, most Linux
> distros won't be able to disable the kconfig options quite yet, mainly
> because of iwd.  But this should create a bit more impetus for these
> userspace programs to be fixed, and the documentation update should also
> help prevent more users from appearing.

There are 2 other users that I know of: bluez, and the ell library
(used by iwd and bluez).

From what I could tell, bluetoothd uses AF_ALG for cryptography:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/shared/crypto.c
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/tools/mesh-gatt/crypto.c

It uses "ecb(aes)" and "cmac(aes)" as algorithms.

Finally, it also uses them both again:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/mesh/crypto.c
through ell:
https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/cipher.c

Because that's a question that also came up, bluetoothd also uses the
CAP_NET_ADMIN capability.

I'll let Luiz and Marcel take it over from here.

Cheers

Re: [PATCH] crypto: af_alg - Document the deprecation of AF_ALG

[Eric Biggers]

On Tue, Jun 23, 2026 at 02:44:28PM +0200, Bastien Nocera wrote:
> Hey,
> 
> Replying to this older patch.
> 
> On Wed, 2026-04-29 at 18:15 -0700, Eric Biggers wrote:
> <snip>
> > This isn't intended to change anything overnight.  After all, most Linux
> > distros won't be able to disable the kconfig options quite yet, mainly
> > because of iwd.  But this should create a bit more impetus for these
> > userspace programs to be fixed, and the documentation update should also
> > help prevent more users from appearing.
> 
> There are 2 other users that I know of: bluez, and the ell library
> (used by iwd and bluez).
>
> From what I could tell, bluetoothd uses AF_ALG for cryptography:
> https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/shared/crypto.c
> https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/tools/mesh-gatt/crypto.c
> 
> It uses "ecb(aes)" and "cmac(aes)" as algorithms.
> 
> Finally, it also uses them both again:
> https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/mesh/crypto.c
> through ell:
> https://git.kernel.org/pub/scm/libs/ell/ell.git/tree/ell/cipher.c
> 
> Because that's a question that also came up, bluetoothd also uses the
> CAP_NET_ADMIN capability.
> 
> I'll let Luiz and Marcel take it over from here.
> 

We're aware of that and are taking it into account in the allowlist:
https://lore.kernel.org/linux-crypto/20260622234803.6982-1-ebiggers@kernel.org/
If you have any feedback on the allowlist, please respond to that patch.

- Eric