From 796caacfda1cea522bd0b442b37a6a9286500487 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 30 Dec 2015 11:47:53 +0800 Subject: crypto: af_alg - Disallow bind/setkey/... after accept(2) Each af_alg parent socket obtained by socket(2) corresponds to a tfm object once bind(2) has succeeded. An accept(2) call on that parent socket creates a context which then uses the tfm object. Therefore as long as any child sockets created by accept(2) exist the parent socket must not be modified or freed. This patch guarantees this by using locks and a reference count on the parent socket. Any attempt to modify the parent socket will fail with EBUSY. Cc: stable@vger.kernel.org Reported-by: Dmitry Vyukov Signed-off-by: Herbert Xu --- crypto/af_alg.c | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) (limited to 'crypto/af_alg.c') diff --git a/crypto/af_alg.c b/crypto/af_alg.c index a8e7aa3e..7b5b5926 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -125,6 +125,23 @@ int af_alg_release(struct socket *sock) } EXPORT_SYMBOL_GPL(af_alg_release); +void af_alg_release_parent(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + bool last; + + sk = ask->parent; + ask = alg_sk(sk); + + lock_sock(sk); + last = !--ask->refcnt; + release_sock(sk); + + if (last) + sock_put(sk); +} +EXPORT_SYMBOL_GPL(af_alg_release_parent); + static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) { const u32 forbidden = CRYPTO_ALG_INTERNAL; @@ -133,6 +150,7 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) struct sockaddr_alg *sa = (void *)uaddr; const struct af_alg_type *type; void *private; + int err; if (sock->state == SS_CONNECTED) return -EINVAL; @@ -160,16 +178,22 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) return PTR_ERR(private); } + err = -EBUSY; lock_sock(sk); + if (ask->refcnt) + goto unlock; swap(ask->type, type); swap(ask->private, private); + err = 0; + +unlock: release_sock(sk); alg_do_release(type, private); - return 0; + return err; } static int alg_setkey(struct sock *sk, char __user *ukey, @@ -202,11 +226,15 @@ static int alg_setsockopt(struct socket *sock, int level, int optname, struct sock *sk = sock->sk; struct alg_sock *ask = alg_sk(sk); const struct af_alg_type *type; - int err = -ENOPROTOOPT; + int err = -EBUSY; lock_sock(sk); + if (ask->refcnt) + goto unlock; + type = ask->type; + err = -ENOPROTOOPT; if (level != SOL_ALG || !type) goto unlock; @@ -264,7 +292,8 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) sk2->sk_family = PF_ALG; - sock_hold(sk); + if (!ask->refcnt++) + sock_hold(sk); alg_sk(sk2)->parent = sk; alg_sk(sk2)->type = type; -- cgit v1.2.3 From 21720b3ea4d374faaa77a1bf94a700515125301d Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 30 Dec 2015 20:24:17 +0800 Subject: crypto: af_alg - Fix socket double-free when accept fails When we fail an accept(2) call we will end up freeing the socket twice, once due to the direct sk_free call and once again through newsock. This patch fixes this by removing the sk_free call. Cc: stable@vger.kernel.org Reported-by: Dmitry Vyukov Signed-off-by: Herbert Xu --- crypto/af_alg.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'crypto/af_alg.c') diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 7b5b5926..eaf98e28 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -285,10 +285,8 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) security_sk_clone(sk, sk2); err = type->accept(ask->private, sk2); - if (err) { - sk_free(sk2); + if (err) goto unlock; - } sk2->sk_family = PF_ALG; -- cgit v1.2.3 From 51a3b513bb33b3dc43bb0f91d59b89bff758ced8 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 4 Jan 2016 13:35:18 +0900 Subject: crypto: af_alg - Add nokey compatibility path This patch adds a compatibility path to support old applications that do acept(2) before setkey. Cc: stable@vger.kernel.org Signed-off-by: Herbert Xu --- crypto/af_alg.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'crypto/af_alg.c') diff --git a/crypto/af_alg.c b/crypto/af_alg.c index eaf98e28..6566d2eb 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -76,6 +76,8 @@ int af_alg_register_type(const struct af_alg_type *type) goto unlock; type->ops->owner = THIS_MODULE; + if (type->ops_nokey) + type->ops_nokey->owner = THIS_MODULE; node->type = type; list_add(&node->list, &alg_types); err = 0; @@ -267,6 +269,7 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) const struct af_alg_type *type; struct sock *sk2; int err; + bool nokey; lock_sock(sk); type = ask->type; @@ -285,12 +288,17 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) security_sk_clone(sk, sk2); err = type->accept(ask->private, sk2); + + nokey = err == -ENOKEY; + if (nokey && type->accept_nokey) + err = type->accept_nokey(ask->private, sk2); + if (err) goto unlock; sk2->sk_family = PF_ALG; - if (!ask->refcnt++) + if (nokey || !ask->refcnt++) sock_hold(sk); alg_sk(sk2)->parent = sk; alg_sk(sk2)->type = type; @@ -298,6 +306,9 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) newsock->ops = type->ops; newsock->state = SS_CONNECTED; + if (nokey) + newsock->ops = type->ops_nokey; + err = 0; unlock: -- cgit v1.2.3 From e8ae341ff042e81d49f021aeb53a51a7dbb68e72 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 13 Jan 2016 14:59:03 +0800 Subject: crypto: af_alg - Allow af_af_alg_release_parent to be called on nokey path This patch allows af_alg_release_parent to be called even for nokey sockets. Cc: stable@vger.kernel.org Signed-off-by: Herbert Xu --- crypto/af_alg.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'crypto/af_alg.c') diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 6566d2eb..e7cb8367 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -133,6 +133,12 @@ void af_alg_release_parent(struct sock *sk) bool last; sk = ask->parent; + + if (ask->nokey_refcnt && !ask->refcnt) { + sock_put(sk); + return; + } + ask = alg_sk(sk); lock_sock(sk); @@ -268,8 +274,8 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) struct alg_sock *ask = alg_sk(sk); const struct af_alg_type *type; struct sock *sk2; + unsigned int nokey; int err; - bool nokey; lock_sock(sk); type = ask->type; @@ -302,6 +308,7 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) sock_hold(sk); alg_sk(sk2)->parent = sk; alg_sk(sk2)->type = type; + alg_sk(sk2)->nokey_refcnt = nokey; newsock->ops = type->ops; newsock->state = SS_CONNECTED; -- cgit v1.2.3 From 366f8f5f4b55065dd49a82a5ad1239d3ca570cbc Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 13 Jan 2016 15:03:32 +0800 Subject: crypto: af_alg - Forbid bind(2) when nokey child sockets are present This patch forbids the calling of bind(2) when there are child sockets created by accept(2) in existence, even if they are created on the nokey path. This is needed as those child sockets have references to the tfm object which bind(2) will destroy. Cc: stable@vger.kernel.org Signed-off-by: Herbert Xu --- crypto/af_alg.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'crypto/af_alg.c') diff --git a/crypto/af_alg.c b/crypto/af_alg.c index e7cb8367..f5e18c2a 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -130,19 +130,16 @@ EXPORT_SYMBOL_GPL(af_alg_release); void af_alg_release_parent(struct sock *sk) { struct alg_sock *ask = alg_sk(sk); - bool last; + unsigned int nokey = ask->nokey_refcnt; + bool last = nokey && !ask->refcnt; sk = ask->parent; - - if (ask->nokey_refcnt && !ask->refcnt) { - sock_put(sk); - return; - } - ask = alg_sk(sk); lock_sock(sk); - last = !--ask->refcnt; + ask->nokey_refcnt -= nokey; + if (!last) + last = !--ask->refcnt; release_sock(sk); if (last) @@ -188,7 +185,7 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) err = -EBUSY; lock_sock(sk); - if (ask->refcnt) + if (ask->refcnt | ask->nokey_refcnt) goto unlock; swap(ask->type, type); @@ -306,6 +303,7 @@ int af_alg_accept(struct sock *sk, struct socket *newsock) if (nokey || !ask->refcnt++) sock_hold(sk); + ask->nokey_refcnt += nokey; alg_sk(sk2)->parent = sk; alg_sk(sk2)->type = type; alg_sk(sk2)->nokey_refcnt = nokey; -- cgit v1.2.3