[PATCH net 0/3] net/iucv: fixes 2018-09-05

[PATCH net 0/3] net/iucv: fixes 2018-09-05

[Julian Wiedmann]

Hi Dave,

please apply three straight-forward fixes for iucv. One that prevents
leaking the skb on malformed inbound packets, one to fix the error
handling on transmit error, and one to get rid of a compile warning.

Thanks,
Julian


Julian Wiedmann (3):
  net/af_iucv: drop inbound packets with invalid flags
  net/af_iucv: fix skb handling on HiperTransport xmit error
  net/iucv: declare iucv_path_table_empty() as static

 net/iucv/af_iucv.c | 38 +++++++++++++++++++++++++-------------
 net/iucv/iucv.c    |  2 +-
 2 files changed, 26 insertions(+), 14 deletions(-)

-- 
2.16.4

[PATCH net 1/3] net/af_iucv: drop inbound packets with invalid flags

[Julian Wiedmann]

Inbound packets may have any combination of flag bits set in their iucv
header. If we don't know how to handle a specific combination, drop the
skb instead of leaking it.

To clarify what error is returned in this case, replace the hard-coded
0 with the corresponding macro.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
---
 net/iucv/af_iucv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index a21d8ed0a325..01000c14417f 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -2155,8 +2155,8 @@ static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
 	struct sock *sk;
 	struct iucv_sock *iucv;
 	struct af_iucv_trans_hdr *trans_hdr;
+	int err = NET_RX_SUCCESS;
 	char nullstring[8];
-	int err = 0;
 
 	if (skb->len < (ETH_HLEN + sizeof(struct af_iucv_trans_hdr))) {
 		WARN_ONCE(1, "AF_IUCV too short skb, len=%d, min=%d",
@@ -2254,7 +2254,7 @@ static int afiucv_hs_rcv(struct sk_buff *skb, struct net_device *dev,
 		err = afiucv_hs_callback_rx(sk, skb);
 		break;
 	default:
-		;
+		kfree_skb(skb);
 	}
 
 	return err;
-- 
2.16.4

[PATCH net 2/3] net/af_iucv: fix skb handling on HiperTransport xmit error

[Julian Wiedmann]

When sending an skb, afiucv_hs_send() bails out on various error
conditions. But currently the caller has no way of telling whether the
skb was freed or not - resulting in potentially either
a) leaked skbs from iucv_send_ctrl(), or
b) double-free's from iucv_sock_sendmsg().

As dev_queue_xmit() will always consume the skb (even on error), be
consistent and also free the skb from all other error paths. This way
callers no longer need to care about managing the skb.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
---
 net/iucv/af_iucv.c | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 01000c14417f..e2f16a0173a9 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -351,20 +351,28 @@ static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock,
 		memcpy(&phs_hdr->iucv_hdr, imsg, sizeof(struct iucv_message));
 
 	skb->dev = iucv->hs_dev;
-	if (!skb->dev)
-		return -ENODEV;
-	if (!(skb->dev->flags & IFF_UP) || !netif_carrier_ok(skb->dev))
-		return -ENETDOWN;
+	if (!skb->dev) {
+		err = -ENODEV;
+		goto err_free;
+	}
+	if (!(skb->dev->flags & IFF_UP) || !netif_carrier_ok(skb->dev)) {
+		err = -ENETDOWN;
+		goto err_free;
+	}
 	if (skb->len > skb->dev->mtu) {
-		if (sock->sk_type == SOCK_SEQPACKET)
-			return -EMSGSIZE;
-		else
-			skb_trim(skb, skb->dev->mtu);
+		if (sock->sk_type == SOCK_SEQPACKET) {
+			err = -EMSGSIZE;
+			goto err_free;
+		}
+		skb_trim(skb, skb->dev->mtu);
 	}
 	skb->protocol = cpu_to_be16(ETH_P_AF_IUCV);
 	nskb = skb_clone(skb, GFP_ATOMIC);
-	if (!nskb)
-		return -ENOMEM;
+	if (!nskb) {
+		err = -ENOMEM;
+		goto err_free;
+	}
+
 	skb_queue_tail(&iucv->send_skb_q, nskb);
 	err = dev_queue_xmit(skb);
 	if (net_xmit_eval(err)) {
@@ -375,6 +383,10 @@ static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock,
 		WARN_ON(atomic_read(&iucv->msg_recv) < 0);
 	}
 	return net_xmit_eval(err);
+
+err_free:
+	kfree_skb(skb);
+	return err;
 }
 
 static struct sock *__iucv_get_sock_by_name(char *nm)
@@ -1167,7 +1179,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg,
 		err = afiucv_hs_send(&txmsg, sk, skb, 0);
 		if (err) {
 			atomic_dec(&iucv->msg_sent);
-			goto fail;
+			goto out;
 		}
 	} else { /* Classic VM IUCV transport */
 		skb_queue_tail(&iucv->send_skb_q, skb);
-- 
2.16.4

[PATCH net 3/3] net/iucv: declare iucv_path_table_empty() as static

[Julian Wiedmann]

Fixes a compile warning.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
---
 net/iucv/iucv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index 8f7ef167c45a..eb502c6290c2 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -1874,7 +1874,7 @@ static void iucv_pm_complete(struct device *dev)
  * Returns 0 if there are still iucv pathes defined
  *	   1 if there are no iucv pathes defined
  */
-int iucv_path_table_empty(void)
+static int iucv_path_table_empty(void)
 {
 	int i;
 
-- 
2.16.4

Re: [PATCH net 0/3] net/iucv: fixes 2018-09-05

[David Miller]

From: Julian Wiedmann <jwi@linux.ibm.com>
Date: Wed,  5 Sep 2018 16:55:09 +0200

> please apply three straight-forward fixes for iucv. One that prevents
> leaking the skb on malformed inbound packets, one to fix the error
> handling on transmit error, and one to get rid of a compile warning.

Series applied, thank you.