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Date: Sun, 29 Sep 2019 13:05:02 +0200
From: Amadeusz Sławiński <amade@...blr.net>
To: "David S . Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Cc: Amadeusz Sławiński <amade@...blr.net>
Subject: [RFC PATCH 2/2] net: tun: Fix incorrect memory access
This is equivalent commit to tap one, where we fix incorrect memory
access caused by sock_init_data being passed improper socket.
This happens due to the fact that if sock_init_data() is called with
sock argument being not NULL, it goes into path using SOCK_INODE macro.
SOCK_INODE itself is just a wrapper around
container_of(socket, struct socket_alloc, socket).
As can be seen from that flow sock_init_data, should be called with
sock, being part of struct socket_alloc, instead of being part of
struct tun_file.
Refactor code to follow flow similar in other places where sock is
allocated correctly.
Signed-off-by: Amadeusz Sławiński <amade@...blr.net>
---
drivers/net/tun.c | 92 +++++++++++++++++++++++++----------------------
1 file changed, 50 insertions(+), 42 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index aab0be40d443..60344794579c 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -159,7 +159,7 @@ struct tun_pcpu_stats {
*/
struct tun_file {
struct sock sk;
- struct socket socket;
+ struct socket *socket;
struct tun_struct __rcu *tun;
struct fasync_struct *fasync;
/* only used for fasnyc */
@@ -753,14 +753,14 @@ static void tun_detach_all(struct net_device *dev)
tfile = rtnl_dereference(tun->tfiles[i]);
BUG_ON(!tfile);
tun_napi_disable(tfile);
- tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
- tfile->socket.sk->sk_data_ready(tfile->socket.sk);
+ tfile->socket->sk->sk_shutdown = RCV_SHUTDOWN;
+ tfile->socket->sk->sk_data_ready(tfile->socket->sk);
RCU_INIT_POINTER(tfile->tun, NULL);
--tun->numqueues;
}
list_for_each_entry(tfile, &tun->disabled, next) {
- tfile->socket.sk->sk_shutdown = RCV_SHUTDOWN;
- tfile->socket.sk->sk_data_ready(tfile->socket.sk);
+ tfile->socket->sk->sk_shutdown = RCV_SHUTDOWN;
+ tfile->socket->sk->sk_data_ready(tfile->socket->sk);
RCU_INIT_POINTER(tfile->tun, NULL);
}
BUG_ON(tun->numqueues != 0);
@@ -794,7 +794,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
struct net_device *dev = tun->dev;
int err;
- err = security_tun_dev_attach(tfile->socket.sk, tun->security);
+ err = security_tun_dev_attach(tfile->socket->sk, tun->security);
if (err < 0)
goto out;
@@ -815,9 +815,9 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
/* Re-attach the filter to persist device */
if (!skip_filter && (tun->filter_attached == true)) {
- lock_sock(tfile->socket.sk);
- err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
- release_sock(tfile->socket.sk);
+ lock_sock(tfile->socket->sk);
+ err = sk_attach_filter(&tun->fprog, tfile->socket->sk);
+ release_sock(tfile->socket->sk);
if (!err)
goto out;
}
@@ -830,7 +830,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
}
tfile->queue_index = tun->numqueues;
- tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN;
+ tfile->socket->sk->sk_shutdown &= ~RCV_SHUTDOWN;
if (tfile->detached) {
/* Re-attach detached tfile, updating XDP queue_index */
@@ -1086,8 +1086,8 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
if (!check_filter(&tun->txflt, skb))
goto drop;
- if (tfile->socket.sk->sk_filter &&
- sk_filter(tfile->socket.sk, skb))
+ if (tfile->socket->sk->sk_filter &&
+ sk_filter(tfile->socket->sk, skb))
goto drop;
len = run_ebpf_filter(tun, skb, len);
@@ -1112,7 +1112,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
/* Notify and wake up reader process */
if (tfile->flags & TUN_FASYNC)
kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
- tfile->socket.sk->sk_data_ready(tfile->socket.sk);
+ tfile->socket->sk->sk_data_ready(tfile->socket->sk);
rcu_read_unlock();
return NETDEV_TX_OK;
@@ -1275,7 +1275,7 @@ static void __tun_xdp_flush_tfile(struct tun_file *tfile)
/* Notify and wake up reader process */
if (tfile->flags & TUN_FASYNC)
kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
- tfile->socket.sk->sk_data_ready(tfile->socket.sk);
+ tfile->socket->sk->sk_data_ready(tfile->socket->sk);
}
static int tun_xdp_xmit(struct net_device *dev, int n,
@@ -1415,7 +1415,7 @@ static void tun_net_init(struct net_device *dev)
static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
{
- struct sock *sk = tfile->socket.sk;
+ struct sock *sk = tfile->socket->sk;
return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
}
@@ -1433,7 +1433,7 @@ static __poll_t tun_chr_poll(struct file *file, poll_table *wait)
if (!tun)
return EPOLLERR;
- sk = tfile->socket.sk;
+ sk = tfile->socket->sk;
tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
@@ -1518,7 +1518,7 @@ static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,
size_t prepad, size_t len,
size_t linear, int noblock)
{
- struct sock *sk = tfile->socket.sk;
+ struct sock *sk = tfile->socket->sk;
struct sk_buff *skb;
int err;
@@ -1585,7 +1585,7 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
if ((tun->flags & TUN_TYPE_MASK) != IFF_TAP)
return false;
- if (tfile->socket.sk->sk_sndbuf != INT_MAX)
+ if (tfile->socket->sk->sk_sndbuf != INT_MAX)
return false;
if (!noblock)
@@ -1612,7 +1612,7 @@ static struct sk_buff *__tun_build_skb(struct tun_file *tfile,
skb_reserve(skb, pad);
skb_put(skb, len);
- skb_set_owner_w(skb, tfile->socket.sk);
+ skb_set_owner_w(skb, tfile->socket->sk);
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
@@ -2169,7 +2169,7 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
goto out;
}
- add_wait_queue(&tfile->socket.wq.wait, &wait);
+ add_wait_queue(&tfile->socket->wq.wait, &wait);
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
@@ -2180,7 +2180,7 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
error = -ERESTARTSYS;
break;
}
- if (tfile->socket.sk->sk_shutdown & RCV_SHUTDOWN) {
+ if (tfile->socket->sk->sk_shutdown & RCV_SHUTDOWN) {
error = -EFAULT;
break;
}
@@ -2189,7 +2189,7 @@ static void *tun_ring_recv(struct tun_file *tfile, int noblock, int *err)
}
__set_current_state(TASK_RUNNING);
- remove_wait_queue(&tfile->socket.wq.wait, &wait);
+ remove_wait_queue(&tfile->socket->wq.wait, &wait);
out:
*err = error;
@@ -2519,7 +2519,7 @@ static int tun_xdp_one(struct tun_struct *tun,
static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
{
int ret, i;
- struct tun_file *tfile = container_of(sock, struct tun_file, socket);
+ struct tun_file *tfile = container_of(sock->sk, struct tun_file, sk);
struct tun_struct *tun = tun_get(tfile);
struct tun_msg_ctl *ctl = m->msg_control;
struct xdp_buff *xdp;
@@ -2565,7 +2565,7 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len,
int flags)
{
- struct tun_file *tfile = container_of(sock, struct tun_file, socket);
+ struct tun_file *tfile = container_of(sock->sk, struct tun_file, sk);
struct tun_struct *tun = tun_get(tfile);
void *ptr = m->msg_control;
int ret;
@@ -2616,7 +2616,7 @@ static int tun_ptr_peek_len(void *ptr)
static int tun_peek_len(struct socket *sock)
{
- struct tun_file *tfile = container_of(sock, struct tun_file, socket);
+ struct tun_file *tfile = container_of(sock->sk, struct tun_file, sk);
struct tun_struct *tun;
int ret = 0;
@@ -2799,7 +2799,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
tun->align = NET_SKB_PAD;
tun->filter_attached = false;
- tun->sndbuf = tfile->socket.sk->sk_sndbuf;
+ tun->sndbuf = tfile->socket->sk->sk_sndbuf;
tun->rx_batched = 0;
RCU_INIT_POINTER(tun->steering_prog, NULL);
@@ -2927,9 +2927,9 @@ static void tun_detach_filter(struct tun_struct *tun, int n)
for (i = 0; i < n; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
- lock_sock(tfile->socket.sk);
- sk_detach_filter(tfile->socket.sk);
- release_sock(tfile->socket.sk);
+ lock_sock(tfile->socket->sk);
+ sk_detach_filter(tfile->socket->sk);
+ release_sock(tfile->socket->sk);
}
tun->filter_attached = false;
@@ -2942,9 +2942,9 @@ static int tun_attach_filter(struct tun_struct *tun)
for (i = 0; i < tun->numqueues; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
- lock_sock(tfile->socket.sk);
- ret = sk_attach_filter(&tun->fprog, tfile->socket.sk);
- release_sock(tfile->socket.sk);
+ lock_sock(tfile->socket->sk);
+ ret = sk_attach_filter(&tun->fprog, tfile->socket->sk);
+ release_sock(tfile->socket->sk);
if (ret) {
tun_detach_filter(tun, i);
return ret;
@@ -2962,7 +2962,7 @@ static void tun_set_sndbuf(struct tun_struct *tun)
for (i = 0; i < tun->numqueues; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
- tfile->socket.sk->sk_sndbuf = tun->sndbuf;
+ tfile->socket->sk->sk_sndbuf = tun->sndbuf;
}
}
@@ -3109,7 +3109,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
if (tfile->detached)
ifr.ifr_flags |= IFF_DETACH_QUEUE;
- if (!tfile->socket.sk->sk_filter)
+ if (!tfile->socket->sk->sk_filter)
ifr.ifr_flags |= IFF_NOFILTER;
if (copy_to_user(argp, &ifr, ifreq_len))
@@ -3217,7 +3217,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
break;
case TUNGETSNDBUF:
- sndbuf = tfile->socket.sk->sk_sndbuf;
+ sndbuf = tfile->socket->sk->sk_sndbuf;
if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
ret = -EFAULT;
break;
@@ -3405,6 +3405,7 @@ static int tun_chr_fasync(int fd, struct file *file, int on)
static int tun_chr_open(struct inode *inode, struct file * file)
{
struct net *net = current->nsproxy->net_ns;
+ struct socket *sock;
struct tun_file *tfile;
DBG1(KERN_INFO, "tunX: tun_chr_open\n");
@@ -3413,7 +3414,16 @@ static int tun_chr_open(struct inode *inode, struct file * file)
&tun_proto, 0);
if (!tfile)
return -ENOMEM;
+
+ sock = sock_alloc();
+ if (!sock) {
+ sk_free(&tfile->sk);
+ return -ENOMEM;
+ }
+ tfile->socket = sock;
+
if (ptr_ring_init(&tfile->tx_ring, 0, GFP_KERNEL)) {
+ sock_release(tfile->socket);
sk_free(&tfile->sk);
return -ENOMEM;
}
@@ -3423,12 +3433,10 @@ static int tun_chr_open(struct inode *inode, struct file * file)
tfile->flags = 0;
tfile->ifindex = 0;
- init_waitqueue_head(&tfile->socket.wq.wait);
-
- tfile->socket.file = file;
- tfile->socket.ops = &tun_socket_ops;
+ sock->file = file;
+ sock->ops = &tun_socket_ops;
- sock_init_data(&tfile->socket, &tfile->sk);
+ sock_init_data(sock, &tfile->sk);
tfile->sk.sk_write_space = tun_sock_write_space;
tfile->sk.sk_sndbuf = INT_MAX;
@@ -3646,7 +3654,7 @@ static int tun_device_event(struct notifier_block *unused,
struct tun_file *tfile;
tfile = rtnl_dereference(tun->tfiles[i]);
- tfile->socket.sk->sk_write_space(tfile->socket.sk);
+ tfile->socket->sk->sk_write_space(tfile->socket->sk);
}
break;
default:
@@ -3713,7 +3721,7 @@ struct socket *tun_get_socket(struct file *file)
tfile = file->private_data;
if (!tfile)
return ERR_PTR(-EBADFD);
- return &tfile->socket;
+ return tfile->socket;
}
EXPORT_SYMBOL_GPL(tun_get_socket);
--
2.23.0
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