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[PATCH 3.2 73/87] crypto: algif_hash - Require setkey before accept(2)

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3.2.77-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Herbert Xu <herbert@gondor.apana.org.au>

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 <herbert@gondor.apana.org.au>
[bwh: Backported to 3.2:
 - Add struct kiocb * parameter to {recv,send}msg ops
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 crypto/algif_hash.c | 201 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 193 insertions(+), 8 deletions(-)

--- 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 kiocb *unused, struct socket *sock,
 			struct msghdr *msg, size_t ignored)
 {
@@ -246,22 +251,151 @@ 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 kiocb *unused, struct socket *sock,
+			      struct msghdr *msg, size_t size)
+{
+	int err;
+
+	err = hash_check_key(sock);
+	if (err)
+		return err;
+
+	return hash_sendmsg(unused, 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 kiocb *unused, 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(unused, 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;
@@ -269,15 +403,40 @@ static void hash_sock_destruct(struct so
 	sock_kfree_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)
@@ -297,7 +456,7 @@ static int hash_accept_parent(void *priv
 
 	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);
 
@@ -306,12 +465,38 @@ static int hash_accept_parent(void *priv
 	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
 };

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[PATCH 3.2 00/87] 3.2.77-rc1 review Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 79/87] crypto: af_alg - Forbid bind(2) when nokey  child sockets are present Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 17/87] asix: silence log message from oversize packet Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 73/87] crypto: algif_hash - Require setkey before  accept(2) Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 18/87] futex: Drop refcount if requeue_pi() acquired  the rtmutex Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 60/87] crypto: af_alg - Fix socket double-free when  accept fails Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 72/87] crypto: hash - Add crypto_ahash_has_setkey Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 70/87] crypto: af_alg - Add nokey compatibility path Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 57/87] ALSA: timer: Harden slave timer list handling Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 61/87] ALSA: hrtimer: Fix stall by hrtimer_cancel() Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 82/87] crypto: algif_skcipher - Load TX SG list after  waiting Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 11/87] rtlwifi: fix memory leak for USB device Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 64/87] ALSA: control: Avoid kernel warnings from tlv  ioctl with numid 0 Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 01/87] [media] gspca: ov534/topro: prevent a division by 0 Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:20 +0100
  [PATCH 3.2 08/87] mtd: nand: fix ONFI parameter page layout Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 80/87] crypto: algif_hash - Fix race condition in  hash_check_key Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 04/87] SCSI: initio: remove duplicate module device table Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 87/87] [media] usbvision: fix crash on detecting  device with invalid configuration Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 15/87] powerpc: Make value-returning atomics fully ordered Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 10/87] xhci: refuse loading if nousb is used Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 05/87] KVM: x86: expose MSR_TSC_AUX to userspace Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 86/87] [media] usbvision fix overflow of interfaces array Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 85/87] [media] usbvision: fix leak of usb_dev on  failure paths in  usbvision_probe() Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 07/87] ath9k_htc: check for underflow in  ath9k_htc_rx_msg() Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 13/87] wlcore/wl12xx: spi: fix oops on firmware load Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 14/87] EDAC: Robustify workqueues destruction Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 19/87] ALSA: fm801: propagate TUNER_ONLY bit when  autodetected Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 84/87] [media] usbvision-video: fix memory leak of  alt_max_pkt_size Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 12/87] wlcore: SPI - fix spi transfer_list Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 16/87] powerpc: Make {cmp}xchg* and their atomic_  versions fully ordered Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 78/87] crypto: algif_skcipher - Remove custom release  parent function Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  [PATCH 3.2 03/87] [media] rc: allow rc modules to be loaded if  rc-main is not a module Ben Hutchings <ben@decadent.org.uk> - 2016-02-09 01:30 +0100
  Re: [PATCH 3.2 00/87] 3.2.77-rc1 review Guenter Roeck <linux@roeck-us.net> - 2016-02-09 05:00 +0100
    Re: [PATCH 3.2 00/87] 3.2.77-rc1 review Ben Hutchings <ben@decadent.org.uk> - 2016-02-10 02:10 +0100

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