af_unix: Copy unix_mkname() into unix_find_(bsd|abstract)().

We should not call unix_mkname() before unix_find_other() and instead do
the same thing where necessary based on the address type:

  - terminating the address with '\0' in unix_find_bsd()
  - calculating the hash in unix_find_abstract().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index e2413a6..b97b694 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -239,19 +239,25 @@ static int unix_validate_addr(struct sockaddr_un *sunaddr, int addr_len)
        return 0;
 }
 
+static void unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len)
+{
+       /* This may look like an off by one error but it is a bit more
+        * subtle.  108 is the longest valid AF_UNIX path for a binding.
+        * sun_path[108] doesn't as such exist.  However in kernel space
+        * we are guaranteed that it is a valid memory location in our
+        * kernel address buffer because syscall functions always pass
+        * a pointer of struct sockaddr_storage which has a bigger buffer
+        * than 108.
+        */
+       ((char *)sunaddr)[addr_len] = 0;
+}
+
 static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
 {
        *hashp = 0;
 
        if (sunaddr->sun_path[0]) {
-               /*
-                * This may look like an off by one error but it is a bit more
-                * subtle. 108 is the longest valid AF_UNIX path for a binding.
-                * sun_path[108] doesn't as such exist.  However in kernel space
-                * we are guaranteed that it is a valid memory location in our
-                * kernel address buffer.
-                */
-               ((char *)sunaddr)[len] = 0;
+               unix_mkname_bsd(sunaddr, len);
                len = strlen(sunaddr->sun_path) +
                        offsetof(struct sockaddr_un, sun_path) + 1;
                return len;
@@ -958,13 +964,14 @@ static int unix_release(struct socket *sock)
 }
 
 static struct sock *unix_find_bsd(struct net *net, struct sockaddr_un *sunaddr,
-                                 int type)
+                                 int addr_len, int type)
 {
        struct inode *inode;
        struct path path;
        struct sock *sk;
        int err;
 
+       unix_mkname_bsd(sunaddr, addr_len);
        err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path);
        if (err)
                goto fail;
@@ -1002,9 +1009,9 @@ fail:
 
 static struct sock *unix_find_abstract(struct net *net,
                                       struct sockaddr_un *sunaddr,
-                                      int addr_len, int type,
-                                      unsigned int hash)
+                                      int addr_len, int type)
 {
+       unsigned int hash = unix_hash_fold(csum_partial(sunaddr, addr_len, 0));
        struct dentry *dentry;
        struct sock *sk;
 
@@ -1021,15 +1028,14 @@ static struct sock *unix_find_abstract(struct net *net,
 
 static struct sock *unix_find_other(struct net *net,
                                    struct sockaddr_un *sunaddr,
-                                   int addr_len, int type,
-                                   unsigned int hash)
+                                   int addr_len, int type)
 {
        struct sock *sk;
 
        if (sunaddr->sun_path[0])
-               sk = unix_find_bsd(net, sunaddr, type);
+               sk = unix_find_bsd(net, sunaddr, addr_len, type);
        else
-               sk = unix_find_abstract(net, sunaddr, addr_len, type, hash);
+               sk = unix_find_abstract(net, sunaddr, addr_len, type);
 
        return sk;
 }
@@ -1246,7 +1252,6 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
        struct net *net = sock_net(sk);
        struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
        struct sock *other;
-       unsigned int hash;
        int err;
 
        err = -EINVAL;
@@ -1258,11 +1263,6 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
                if (err)
                        goto out;
 
-               err = unix_mkname(sunaddr, alen, &hash);
-               if (err < 0)
-                       goto out;
-               alen = err;
-
                if (test_bit(SOCK_PASSCRED, &sock->flags) &&
                    !unix_sk(sk)->addr) {
                        err = unix_autobind(sk);
@@ -1271,7 +1271,7 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
                }
 
 restart:
-               other = unix_find_other(net, sunaddr, alen, sock->type, hash);
+               other = unix_find_other(net, sunaddr, alen, sock->type);
                if (IS_ERR(other)) {
                        err = PTR_ERR(other);
                        goto out;
@@ -1365,7 +1365,6 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
        struct sock *newsk = NULL;
        struct sock *other = NULL;
        struct sk_buff *skb = NULL;
-       unsigned int hash;
        int st;
        int err;
        long timeo;
@@ -1374,11 +1373,6 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
        if (err)
                goto out;
 
-       err = unix_mkname(sunaddr, addr_len, &hash);
-       if (err < 0)
-               goto out;
-       addr_len = err;
-
        if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr) {
                err = unix_autobind(sk);
                if (err)
@@ -1409,7 +1403,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 
 restart:
        /*  Find listening sock. */
-       other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash);
+       other = unix_find_other(net, sunaddr, addr_len, sk->sk_type);
        if (IS_ERR(other)) {
                err = PTR_ERR(other);
                other = NULL;
@@ -1807,9 +1801,7 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
        struct unix_sock *u = unix_sk(sk);
        DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
        struct sock *other = NULL;
-       int namelen = 0; /* fake GCC */
        int err;
-       unsigned int hash;
        struct sk_buff *skb;
        long timeo;
        struct scm_cookie scm;
@@ -1829,11 +1821,6 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
                err = unix_validate_addr(sunaddr, msg->msg_namelen);
                if (err)
                        goto out;
-
-               err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
-               if (err < 0)
-                       goto out;
-               namelen = err;
        } else {
                sunaddr = NULL;
                err = -ENOTCONN;
@@ -1886,8 +1873,8 @@ restart:
                if (sunaddr == NULL)
                        goto out_free;
 
-               other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
-                                       hash);
+               other = unix_find_other(net, sunaddr, msg->msg_namelen,
+                                       sk->sk_type);
                if (IS_ERR(other)) {
                        err = PTR_ERR(other);
                        other = NULL;