crypto: algif_aead - Require setkey before accept(2)

Some cipher implementations will crash if you try to use them
without calling setkey first.  This patch adds a check so that
the accept(2) call will fail with -ENOKEY if setkey hasn't been
done on the socket yet.

Fixes: 400c40cf78da ("crypto: algif - add AEAD support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 5a805375865731f4cc7e94790362c208dd58d05b..e0d55ea2f0ebaee18d3ed148a9168348c45d7c84 100644 (file)
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -44,6 +44,11 @@ struct aead_async_req {
        char iv[];
 };
 
+struct aead_tfm {
+       struct crypto_aead *aead;
+       bool has_key;
+};
+
 struct aead_ctx {
        struct aead_sg_list tsgl;
        struct aead_async_rsgl first_rsgl;
@@ -723,24 +728,146 @@ static struct proto_ops algif_aead_ops = {
        .poll           =       aead_poll,
 };
 
+static int aead_check_key(struct socket *sock)
+{
+       int err = 0;
+       struct sock *psk;
+       struct alg_sock *pask;
+       struct aead_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 aead_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
+                                 size_t size)
+{
+       int err;
+
+       err = aead_check_key(sock);
+       if (err)
+               return err;
+
+       return aead_sendmsg(sock, msg, size);
+}
+
+static ssize_t aead_sendpage_nokey(struct socket *sock, struct page *page,
+                                      int offset, size_t size, int flags)
+{
+       int err;
+
+       err = aead_check_key(sock);
+       if (err)
+               return err;
+
+       return aead_sendpage(sock, page, offset, size, flags);
+}
+
+static int aead_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
+                                 size_t ignored, int flags)
+{
+       int err;
+
+       err = aead_check_key(sock);
+       if (err)
+               return err;
+
+       return aead_recvmsg(sock, msg, ignored, flags);
+}
+
+static struct proto_ops algif_aead_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        =       aead_sendmsg_nokey,
+       .sendpage       =       aead_sendpage_nokey,
+       .recvmsg        =       aead_recvmsg_nokey,
+       .poll           =       aead_poll,
+};
+
 static void *aead_bind(const char *name, u32 type, u32 mask)
 {
-       return crypto_alloc_aead(name, type, mask);
+       struct aead_tfm *tfm;
+       struct crypto_aead *aead;
+
+       tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
+       if (!tfm)
+               return ERR_PTR(-ENOMEM);
+
+       aead = crypto_alloc_aead(name, type, mask);
+       if (IS_ERR(aead)) {
+               kfree(tfm);
+               return ERR_CAST(aead);
+       }
+
+       tfm->aead = aead;
+
+       return tfm;
 }
 
 static void aead_release(void *private)
 {
-       crypto_free_aead(private);
+       struct aead_tfm *tfm = private;
+
+       crypto_free_aead(tfm->aead);
+       kfree(tfm);
 }
 
 static int aead_setauthsize(void *private, unsigned int authsize)
 {
-       return crypto_aead_setauthsize(private, authsize);
+       struct aead_tfm *tfm = private;
+
+       return crypto_aead_setauthsize(tfm->aead, authsize);
 }
 
 static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
 {
-       return crypto_aead_setkey(private, key, keylen);
+       struct aead_tfm *tfm = private;
+       int err;
+
+       err = crypto_aead_setkey(tfm->aead, key, keylen);
+       tfm->has_key = !err;
+
+       return err;
 }
 
 static void aead_sock_destruct(struct sock *sk)
@@ -757,12 +884,14 @@ static void aead_sock_destruct(struct sock *sk)
        af_alg_release_parent(sk);
 }
 
-static int aead_accept_parent(void *private, struct sock *sk)
+static int aead_accept_parent_nokey(void *private, struct sock *sk)
 {
        struct aead_ctx *ctx;
        struct alg_sock *ask = alg_sk(sk);
-       unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
-       unsigned int ivlen = crypto_aead_ivsize(private);
+       struct aead_tfm *tfm = private;
+       struct crypto_aead *aead = tfm->aead;
+       unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(aead);
+       unsigned int ivlen = crypto_aead_ivsize(aead);
 
        ctx = sock_kmalloc(sk, len, GFP_KERNEL);
        if (!ctx)
@@ -789,7 +918,7 @@ static int aead_accept_parent(void *private, struct sock *sk)
 
        ask->private = ctx;
 
-       aead_request_set_tfm(&ctx->aead_req, private);
+       aead_request_set_tfm(&ctx->aead_req, aead);
        aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
                                  af_alg_complete, &ctx->completion);
 
@@ -798,13 +927,25 @@ static int aead_accept_parent(void *private, struct sock *sk)
        return 0;
 }
 
+static int aead_accept_parent(void *private, struct sock *sk)
+{
+       struct aead_tfm *tfm = private;
+
+       if (!tfm->has_key)
+               return -ENOKEY;
+
+       return aead_accept_parent_nokey(private, sk);
+}
+
 static const struct af_alg_type algif_type_aead = {
        .bind           =       aead_bind,
        .release        =       aead_release,
        .setkey         =       aead_setkey,
        .setauthsize    =       aead_setauthsize,
        .accept         =       aead_accept_parent,
+       .accept_nokey   =       aead_accept_parent_nokey,
        .ops            =       &algif_aead_ops,
+       .ops_nokey      =       &algif_aead_ops_nokey,
        .name           =       "aead",
        .owner          =       THIS_MODULE
 };