[PATCH v6 0/4] crypto: AF_ALG: add AEAD and RNG support

From: Stephan Mueller
Date: Thu Dec 25 2014 - 17:03:44 EST


This patch set adds AEAD and RNG support to the AF_ALG interface
exported by the kernel crypto API. By extending AF_ALG with AEAD and RNG
support, all cipher types the kernel crypto API allows access to are
now accessible from userspace.

Both, AEAD and RNG implementations are stand-alone and do not depend
other AF_ALG interfaces (like hash or skcipher).

The AEAD implementation uses the same approach as provided with
skcipher by offering the following interfaces:

* sendmsg and recvmsg interfaces allowing multiple
invocations supporting a threaded user space. To support
multi-threaded user space, kernel-side buffering
is implemented similarly to skcipher.

* splice / vmsplice interfaces allowing a zero-copy

The RNG interface only implements the recvmsg interface as
zero-copy is not applicable.

The new AEAD and RNG interfaces are fully tested with the test application
provided at [1]. That test application exercises all newly added user space
interfaces. The testing covers:

* use of the sendmsg/recvmsg interface

* use of the splice / vmsplice interface

* invocation of all AF_ALG types (aead, rng, skcipher, hash)

* using all types of operation (encryption, decryption, keyed MD,
MD, random numbers, AEAD decryption with positive and negative
authentication verification)

* stress testing by running all tests for 30 minutes in an
endless loop

* test execution on 64 bit and 32 bit

[1] http://www.chronox.de/libkcapi.html

Changes v2:
* rebase to current cryptodev-2.6 tree
* use memzero_explicit to zeroize AEAD associated data
* use sizeof for determining length of AEAD associated data
* update algif_rng.c covering all suggestions from Daniel Borkmann
* addition of patch 9: add digestsize interface for hashes
* addition of patch to update documentation covering the userspace interface
* change numbers of getsockopt options: separate them from sendmsg interface

Changes v3:
* remove getsockopt interface
* AEAD: associated data is set prepended to the plain/ciphertext
* AEAD: allowing arbitrary associated data lengths
* remove setkey patch as protection was already in the existing code

Changes v4:
* stand-alone implementation of AEAD
* testing of all interfaces offered by AEAD
* stress testing of AEAD and RNG

Changes v5:
* AEAD: add outer while(size) loop in aead_sendmsg to ensure all data is
copied into the kernel (reporter Herbert Xu)
* AEAD: aead_sendmsg bug fix: change size -= len; to size -= plen;
* AF_ALG / AEAD: add aead_setauthsize and associated extension to
struct af_alg_type as well as alg_setsockopt (reporter Herbert Xu)
* RNG: rng_recvmsg: use 128 byte stack variable for output of RNG instead
of ctx->result (reporter Herbert Xu)
* RNG / AF_ALG: allow user space to seed RNG via setsockopt
* RNG: rng_recvmsg bug fix: use genlen as result variable for
crypto_rng_get_bytes as previously no negative errors were obtained
* AF_ALG: alg_setop: zeroize buffer before free

Changes v6:
* AEAD/RNG: port to 3.19-rc1 with the iov_iter handling
* RNG: use the setkey interface to obtain the seed and drop the patch adding
a separate reseeding interface
* extract the zeroization patch for alg_setkey into a stand-alone patch
* fix bug in aead_sufficient_data (reporter Herbert Xu)
* testing of all interfaces with test application provided with libkcapi version

Stephan Mueller (4):
crypto: AF_ALG: add AEAD support
crypto: AF_ALG: enable AEAD interface compilation
crypto: AF_ALG: add random number generator support
crypto: AF_ALG: enable RNG interface compilation

crypto/Kconfig | 18 ++
crypto/Makefile | 2 +
crypto/algif_aead.c | 651 ++++++++++++++++++++++++++++++++++++++++++++++++++++
crypto/algif_rng.c | 192 ++++++++++++++++
4 files changed, 863 insertions(+)
create mode 100644 crypto/algif_aead.c
create mode 100644 crypto/algif_rng.c


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