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 <herbert@gondor.apana.org.au>

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index e7cb8367771df9b47582d193b3bec366b6f0e8ea..f5e18c2a48527bb3f5bbdc5202b37577689710b3 100644 (file)
--- 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;