Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

2cfa46da · Linus Torvalds <[email protected]> · 2020-06-29 10:06:26 -07:00

Pull crypto fixes from Herbert Xu:
 "This fixes two race conditions, one in padata and one in af_alg"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  padata: upgrade smp_mb__after_atomic to smp_mb in padata_do_serial
  crypto: af_alg - fix use-after-free in af_alg_accept() due to bh_lock_sock()

Commit: 2cfa46dadd203eef88cc70131df7a81ebc34b8ff
Parents: b6509f6a · e04ec0de

Merge commit. Changes below are compared with the first parent: b6509f6a.

Changes

6 files changed · +24 −37

File	Status	Add	Del	Content
crypto/af_alg.c	modified	+11	−15	View file
crypto/algif_aead.c	modified	+3	−6	View file
crypto/algif_hash.c	modified	+3	−6	View file
crypto/algif_skcipher.c	modified	+3	−6	View file
include/crypto/if_alg.h	modified	+2	−2	View file
kernel/padata.c	modified	+2	−2	View file

crypto/af_alg.c

View file

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index b1cd353..28fc323 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -128,21 +128,15 @@ EXPORT_SYMBOL_GPL(af_alg_release);
 void af_alg_release_parent(struct sock *sk)
 {
 	struct alg_sock *ask = alg_sk(sk);
-	unsigned int nokey = ask->nokey_refcnt;
-	bool last = nokey && !ask->refcnt;
+	unsigned int nokey = atomic_read(&ask->nokey_refcnt);
 
 	sk = ask->parent;
 	ask = alg_sk(sk);
 
-	local_bh_disable();
-	bh_lock_sock(sk);
-	ask->nokey_refcnt -= nokey;
-	if (!last)
-		last = !--ask->refcnt;
-	bh_unlock_sock(sk);
-	local_bh_enable();
+	if (nokey)
+		atomic_dec(&ask->nokey_refcnt);
 
-	if (last)
+	if (atomic_dec_and_test(&ask->refcnt))
 		sock_put(sk);
 }
 EXPORT_SYMBOL_GPL(af_alg_release_parent);
@@ -187,7 +181,7 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 
 	err = -EBUSY;
 	lock_sock(sk);
-	if (ask->refcnt | ask->nokey_refcnt)
+	if (atomic_read(&ask->refcnt))
 		goto unlock;
 
 	swap(ask->type, type);
@@ -236,7 +230,7 @@ static int alg_setsockopt(struct socket *sock, int level, int optname,
 	int err = -EBUSY;
 
 	lock_sock(sk);
-	if (ask->refcnt)
+	if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt))
 		goto unlock;
 
 	type = ask->type;
@@ -301,12 +295,14 @@ int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
 	if (err)
 		goto unlock;
 
-	if (nokey || !ask->refcnt++)
+	if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
 		sock_hold(sk);
-	ask->nokey_refcnt += nokey;
+	if (nokey) {
+		atomic_inc(&ask->nokey_refcnt);
+		atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
+	}
 	alg_sk(sk2)->parent = sk;
 	alg_sk(sk2)->type = type;
-	alg_sk(sk2)->nokey_refcnt = nokey;
 
 	newsock->ops = type->ops;
 	newsock->state = SS_CONNECTED;

crypto/algif_aead.c

View file

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index eb1910b..0ae000a 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -384,7 +384,7 @@ static int aead_check_key(struct socket *sock)
 	struct alg_sock *ask = alg_sk(sk);
 
 	lock_sock(sk);
-	if (ask->refcnt)
+	if (!atomic_read(&ask->nokey_refcnt))
 		goto unlock_child;
 
 	psk = ask->parent;
@@ -396,11 +396,8 @@ static int aead_check_key(struct socket *sock)
 	if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
 		goto unlock;
 
-	if (!pask->refcnt++)
-		sock_hold(psk);
-
-	ask->refcnt = 1;
-	sock_put(psk);
+	atomic_dec(&pask->nokey_refcnt);
+	atomic_set(&ask->nokey_refcnt, 0);
 
 	err = 0;
 

crypto/algif_hash.c

View file

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index da1ffa4..e71727c 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -301,7 +301,7 @@ static int hash_check_key(struct socket *sock)
 	struct alg_sock *ask = alg_sk(sk);
 
 	lock_sock(sk);
-	if (ask->refcnt)
+	if (!atomic_read(&ask->nokey_refcnt))
 		goto unlock_child;
 
 	psk = ask->parent;
@@ -313,11 +313,8 @@ static int hash_check_key(struct socket *sock)
 	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		goto unlock;
 
-	if (!pask->refcnt++)
-		sock_hold(psk);
-
-	ask->refcnt = 1;
-	sock_put(psk);
+	atomic_dec(&pask->nokey_refcnt);
+	atomic_set(&ask->nokey_refcnt, 0);
 
 	err = 0;
 

crypto/algif_skcipher.c

View file

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 4c3bdff..ec5567c 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -211,7 +211,7 @@ static int skcipher_check_key(struct socket *sock)
 	struct alg_sock *ask = alg_sk(sk);
 
 	lock_sock(sk);
-	if (ask->refcnt)
+	if (!atomic_read(&ask->nokey_refcnt))
 		goto unlock_child;
 
 	psk = ask->parent;
@@ -223,11 +223,8 @@ static int skcipher_check_key(struct socket *sock)
 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		goto unlock;
 
-	if (!pask->refcnt++)
-		sock_hold(psk);
-
-	ask->refcnt = 1;
-	sock_put(psk);
+	atomic_dec(&pask->nokey_refcnt);
+	atomic_set(&ask->nokey_refcnt, 0);
 
 	err = 0;
 

include/crypto/if_alg.h

View file

diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 56527c8..088c1de 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -29,8 +29,8 @@ struct alg_sock {
 
 	struct sock *parent;
 
-	unsigned int refcnt;
-	unsigned int nokey_refcnt;
+	atomic_t refcnt;
+	atomic_t nokey_refcnt;
 
 	const struct af_alg_type *type;
 	void *private;

kernel/padata.c

View file

diff --git a/kernel/padata.c b/kernel/padata.c
index 29fc5d8..4373f7a 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -335,7 +335,7 @@ static void padata_reorder(struct parallel_data *pd)
 	 *
 	 * Ensure reorder queue is read after pd->lock is dropped so we see
 	 * new objects from another task in padata_do_serial.  Pairs with
-	 * smp_mb__after_atomic in padata_do_serial.
+	 * smp_mb in padata_do_serial.
 	 */
 	smp_mb();
 
@@ -418,7 +418,7 @@ void padata_do_serial(struct padata_priv *padata)
 	 * with the trylock of pd->lock in padata_reorder.  Pairs with smp_mb
 	 * in padata_reorder.
 	 */
-	smp_mb__after_atomic();
+	smp_mb();
 
 	padata_reorder(pd);
 }