crypto: algif_hash - Require setkey before accept(2)

[ Upstream commit 6de62f15b581f920ade22d758f4c338311c2f0d4 ]

Hash implementations that require a key may crash if you use
them without setting a key.  This patch adds the necessary checks
so that if you do attempt to use them without a key that we return
-ENOKEY instead of proceeding.

This patch also adds a compatibility path to support old applications
that do acept(2) before setkey.

Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 1396ad0..b3df979 100644 (file)
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -34,6 +34,11 @@ struct hash_ctx {
        struct ahash_request req;
 };
 
+struct algif_hash_tfm {
+       struct crypto_ahash *hash;
+       bool has_key;
+};
+
 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
                        size_t ignored)
 {
@@ -227,22 +232,151 @@ static struct proto_ops algif_hash_ops = {
        .accept         =       hash_accept,
 };
 
+static int hash_check_key(struct socket *sock)
+{
+       int err;
+       struct sock *psk;
+       struct alg_sock *pask;
+       struct algif_hash_tfm *tfm;
+       struct sock *sk = sock->sk;
+       struct alg_sock *ask = alg_sk(sk);
+
+       if (ask->refcnt)
+               return 0;
+
+       psk = ask->parent;
+       pask = alg_sk(ask->parent);
+       tfm = pask->private;
+
+       err = -ENOKEY;
+       lock_sock(psk);
+       if (!tfm->has_key)
+               goto unlock;
+
+       if (!pask->refcnt++)
+               sock_hold(psk);
+
+       ask->refcnt = 1;
+       sock_put(psk);
+
+       err = 0;
+
+unlock:
+       release_sock(psk);
+
+       return err;
+}
+
+static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
+                             size_t size)
+{
+       int err;
+
+       err = hash_check_key(sock);
+       if (err)
+               return err;
+
+       return hash_sendmsg(sock, msg, size);
+}
+
+static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page,
+                                  int offset, size_t size, int flags)
+{
+       int err;
+
+       err = hash_check_key(sock);
+       if (err)
+               return err;
+
+       return hash_sendpage(sock, page, offset, size, flags);
+}
+
+static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
+                             size_t ignored, int flags)
+{
+       int err;
+
+       err = hash_check_key(sock);
+       if (err)
+               return err;
+
+       return hash_recvmsg(sock, msg, ignored, flags);
+}
+
+static int hash_accept_nokey(struct socket *sock, struct socket *newsock,
+                            int flags)
+{
+       int err;
+
+       err = hash_check_key(sock);
+       if (err)
+               return err;
+
+       return hash_accept(sock, newsock, flags);
+}
+
+static struct proto_ops algif_hash_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,
+       .setsockopt     =       sock_no_setsockopt,
+       .poll           =       sock_no_poll,
+
+       .release        =       af_alg_release,
+       .sendmsg        =       hash_sendmsg_nokey,
+       .sendpage       =       hash_sendpage_nokey,
+       .recvmsg        =       hash_recvmsg_nokey,
+       .accept         =       hash_accept_nokey,
+};
+
 static void *hash_bind(const char *name, u32 type, u32 mask)
 {
-       return crypto_alloc_ahash(name, type, mask);
+       struct algif_hash_tfm *tfm;
+       struct crypto_ahash *hash;
+
+       tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
+       if (!tfm)
+               return ERR_PTR(-ENOMEM);
+
+       hash = crypto_alloc_ahash(name, type, mask);
+       if (IS_ERR(hash)) {
+               kfree(tfm);
+               return ERR_CAST(hash);
+       }
+
+       tfm->hash = hash;
+
+       return tfm;
 }
 
 static void hash_release(void *private)
 {
-       crypto_free_ahash(private);
+       struct algif_hash_tfm *tfm = private;
+
+       crypto_free_ahash(tfm->hash);
+       kfree(tfm);
 }
 
 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
 {
-       return crypto_ahash_setkey(private, key, keylen);
+       struct algif_hash_tfm *tfm = private;
+       int err;
+
+       err = crypto_ahash_setkey(tfm->hash, key, keylen);
+       tfm->has_key = !err;
+
+       return err;
 }
 
-static void hash_sock_destruct(struct sock *sk)
+static void hash_sock_destruct_common(struct sock *sk)
 {
        struct alg_sock *ask = alg_sk(sk);
        struct hash_ctx *ctx = ask->private;
@@ -250,15 +384,40 @@ static void hash_sock_destruct(struct sock *sk)
        sock_kzfree_s(sk, ctx->result,
                      crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
        sock_kfree_s(sk, ctx, ctx->len);
+}
+
+static void hash_sock_destruct(struct sock *sk)
+{
+       hash_sock_destruct_common(sk);
        af_alg_release_parent(sk);
 }
 
-static int hash_accept_parent(void *private, struct sock *sk)
+static void hash_release_parent_nokey(struct sock *sk)
+{
+       struct alg_sock *ask = alg_sk(sk);
+
+       if (!ask->refcnt) {
+               sock_put(ask->parent);
+               return;
+       }
+
+       af_alg_release_parent(sk);
+}
+
+static void hash_sock_destruct_nokey(struct sock *sk)
+{
+       hash_sock_destruct_common(sk);
+       hash_release_parent_nokey(sk);
+}
+
+static int hash_accept_parent_common(void *private, struct sock *sk)
 {
        struct hash_ctx *ctx;
        struct alg_sock *ask = alg_sk(sk);
-       unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(private);
-       unsigned ds = crypto_ahash_digestsize(private);
+       struct algif_hash_tfm *tfm = private;
+       struct crypto_ahash *hash = tfm->hash;
+       unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash);
+       unsigned ds = crypto_ahash_digestsize(hash);
 
        ctx = sock_kmalloc(sk, len, GFP_KERNEL);
        if (!ctx)
@@ -278,7 +437,7 @@ static int hash_accept_parent(void *private, struct sock *sk)
 
        ask->private = ctx;
 
-       ahash_request_set_tfm(&ctx->req, private);
+       ahash_request_set_tfm(&ctx->req, hash);
        ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
                                   af_alg_complete, &ctx->completion);
 
@@ -287,12 +446,38 @@ static int hash_accept_parent(void *private, struct sock *sk)
        return 0;
 }
 
+static int hash_accept_parent(void *private, struct sock *sk)
+{
+       struct algif_hash_tfm *tfm = private;
+
+       if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash))
+               return -ENOKEY;
+
+       return hash_accept_parent_common(private, sk);
+}
+
+static int hash_accept_parent_nokey(void *private, struct sock *sk)
+{
+       int err;
+
+       err = hash_accept_parent_common(private, sk);
+       if (err)
+               goto out;
+
+       sk->sk_destruct = hash_sock_destruct_nokey;
+
+out:
+       return err;
+}
+
 static const struct af_alg_type algif_type_hash = {
        .bind           =       hash_bind,
        .release        =       hash_release,
        .setkey         =       hash_setkey,
        .accept         =       hash_accept_parent,
+       .accept_nokey   =       hash_accept_parent_nokey,
        .ops            =       &algif_hash_ops,
+       .ops_nokey      =       &algif_hash_ops_nokey,
        .name           =       "hash",
        .owner          =       THIS_MODULE
 };