From 017db8bc9a1d62710af99b0eec605ee1f0285277 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Fri, 8 Jan 2016 21:31:04 +0800 Subject: [PATCH] crypto: algif_hash - Require setkey before accept(2) commit 6de62f15b581f920ade22d758f4c338311c2f0d4 upstream. 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. Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/algif_hash.c | 201 +++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 193 insertions(+), 8 deletions(-) diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index b4c24fe..46637be 100644 --- 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) { @@ -235,22 +240,151 @@ 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; @@ -258,15 +392,40 @@ 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) @@ -286,7 +445,7 @@ 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); @@ -295,12 +454,38 @@ 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 }; -- 2.7.4