From: Tadeusz Struk Subject: [PATCH v3 5/7] crypto: algif_akcipher - add ops_nokey Date: Tue, 29 Mar 2016 17:57:21 -0700 Message-ID: <20160330005721.25410.1864.stgit@tstruk-mobl1> References: <20160330005649.25410.70508.stgit@tstruk-mobl1> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: tadeusz.struk@intel.com, smueller@chronox.de, linux-api@vger.kernel.org, marcel@holtmann.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, dwmw2@infradead.org, davem@davemloft.net To: herbert@gondor.apana.org.au Return-path: In-Reply-To: <20160330005649.25410.70508.stgit@tstruk-mobl1> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Similar to algif_skcipher and algif_hash, algif_akcipher needs to prevent user space from using the interface in an improper way. This patch adds nokey ops handlers, which do just that. Signed-off-by: Tadeusz Struk --- crypto/algif_akcipher.c | 159 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 152 insertions(+), 7 deletions(-) diff --git a/crypto/algif_akcipher.c b/crypto/algif_akcipher.c index 6342b6e..e00793d 100644 --- a/crypto/algif_akcipher.c +++ b/crypto/algif_akcipher.c @@ -27,6 +27,11 @@ struct akcipher_sg_list { struct scatterlist sg[ALG_MAX_PAGES]; }; +struct akcipher_tfm { + struct crypto_akcipher *akcipher; + bool has_key; +}; + struct akcipher_ctx { struct akcipher_sg_list tsgl; struct af_alg_sgl rsgl[ALG_MAX_PAGES]; @@ -450,25 +455,151 @@ static struct proto_ops algif_akcipher_ops = { .poll = akcipher_poll, }; +static int akcipher_check_key(struct socket *sock) +{ + int err = 0; + struct sock *psk; + struct alg_sock *pask; + struct akcipher_tfm *tfm; + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + + lock_sock(sk); + if (ask->refcnt) + goto unlock_child; + + psk = ask->parent; + pask = alg_sk(ask->parent); + tfm = pask->private; + + err = -ENOKEY; + lock_sock_nested(psk, SINGLE_DEPTH_NESTING); + if (!tfm->has_key) + goto unlock; + + if (!pask->refcnt++) + sock_hold(psk); + + ask->refcnt = 1; + sock_put(psk); + + err = 0; + +unlock: + release_sock(psk); +unlock_child: + release_sock(sk); + + return err; +} + +static int akcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg, + size_t size) +{ + int err; + + err = akcipher_check_key(sock); + if (err) + return err; + + return akcipher_sendmsg(sock, msg, size); +} + +static ssize_t akcipher_sendpage_nokey(struct socket *sock, struct page *page, + int offset, size_t size, int flags) +{ + int err; + + err = akcipher_check_key(sock); + if (err) + return err; + + return akcipher_sendpage(sock, page, offset, size, flags); +} + +static int akcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg, + size_t ignored, int flags) +{ + int err; + + err = akcipher_check_key(sock); + if (err) + return err; + + return akcipher_recvmsg(sock, msg, ignored, flags); +} + +static struct proto_ops algif_akcipher_ops_nokey = { + .family = PF_ALG, + + .connect = sock_no_connect, + .socketpair = sock_no_socketpair, + .getname = sock_no_getname, + .ioctl = sock_no_ioctl, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .getsockopt = sock_no_getsockopt, + .mmap = sock_no_mmap, + .bind = sock_no_bind, + .accept = sock_no_accept, + .setsockopt = sock_no_setsockopt, + + .release = af_alg_release, + .sendmsg = akcipher_sendmsg_nokey, + .sendpage = akcipher_sendpage_nokey, + .recvmsg = akcipher_recvmsg_nokey, + .poll = akcipher_poll, +}; + static void *akcipher_bind(const char *name, u32 type, u32 mask) { - return crypto_alloc_akcipher(name, type, mask); + struct akcipher_tfm *tfm; + struct crypto_akcipher *akcipher; + + tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); + if (!tfm) + return ERR_PTR(-ENOMEM); + + akcipher = crypto_alloc_akcipher(name, type, mask); + if (IS_ERR(akcipher)) { + kfree(tfm); + return ERR_CAST(akcipher); + } + + tfm->akcipher = akcipher; + return tfm; } static void akcipher_release(void *private) { - crypto_free_akcipher(private); + struct akcipher_tfm *tfm = private; + struct crypto_akcipher *akcipher = tfm->akcipher; + + crypto_free_akcipher(akcipher); + kfree(tfm); } static int akcipher_setprivkey(void *private, const u8 *key, unsigned int keylen) { - return crypto_akcipher_set_priv_key(private, key, keylen); + struct akcipher_tfm *tfm = private; + struct crypto_akcipher *akcipher = tfm->akcipher; + int err; + + err = crypto_akcipher_set_priv_key(akcipher, key, keylen); + tfm->has_key = !err; + return err; } static int akcipher_setpubkey(void *private, const u8 *key, unsigned int keylen) { - return crypto_akcipher_set_pub_key(private, key, keylen); + struct akcipher_tfm *tfm = private; + struct crypto_akcipher *akcipher = tfm->akcipher; + int err; + + err = crypto_akcipher_set_pub_key(akcipher, key, keylen); + tfm->has_key = !err; + return err; } static void akcipher_sock_destruct(struct sock *sk) @@ -481,11 +612,13 @@ static void akcipher_sock_destruct(struct sock *sk) af_alg_release_parent(sk); } -static int akcipher_accept_parent(void *private, struct sock *sk) +static int akcipher_accept_parent_nokey(void *private, struct sock *sk) { struct akcipher_ctx *ctx; struct alg_sock *ask = alg_sk(sk); - unsigned int len = sizeof(*ctx) + crypto_akcipher_reqsize(private); + struct akcipher_tfm *tfm = private; + struct crypto_akcipher *akcipher = tfm->akcipher; + unsigned int len = sizeof(*ctx) + crypto_akcipher_reqsize(akcipher); ctx = sock_kmalloc(sk, len, GFP_KERNEL); if (!ctx) @@ -503,7 +636,7 @@ static int akcipher_accept_parent(void *private, struct sock *sk) ask->private = ctx; - akcipher_request_set_tfm(&ctx->req, private); + akcipher_request_set_tfm(&ctx->req, akcipher); akcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, af_alg_complete, &ctx->completion); @@ -512,13 +645,25 @@ static int akcipher_accept_parent(void *private, struct sock *sk) return 0; } +static int akcipher_accept_parent(void *private, struct sock *sk) +{ + struct akcipher_tfm *tfm = private; + + if (!tfm->has_key) + return -ENOKEY; + + return akcipher_accept_parent_nokey(private, sk); +} + static const struct af_alg_type algif_type_akcipher = { .bind = akcipher_bind, .release = akcipher_release, .setkey = akcipher_setprivkey, .setpubkey = akcipher_setpubkey, .accept = akcipher_accept_parent, + .accept_nokey = akcipher_accept_parent_nokey, .ops = &algif_akcipher_ops, + .ops_nokey = &algif_akcipher_ops_nokey, .name = "akcipher", .owner = THIS_MODULE };