[CVE-2017-7487][PATCH T/Z] ipx: call ipxitf_put() in ioctl error path

[Po-Hsu Lin]

From: Dan Carpenter <dan.carpenter at oracle.com>

CVE-2017-7487

We should call ipxitf_put() if the copy_to_user() fails.

Reported-by: 李强 <liqiang6-s at 360.cn>
Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit ee0d8d8482345ff97a75a7d747efc309f13b0d80)
Signed-off-by: Po-Hsu Lin <po-hsu.lin at canonical.com>
---
 net/ipx/af_ipx.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/ipx/af_ipx.c b/net/ipx/af_ipx.c
index 6857ae4..654e39d 100644
--- a/net/ipx/af_ipx.c
+++ b/net/ipx/af_ipx.c
@@ -1183,11 +1183,10 @@ static int ipxitf_ioctl(unsigned int cmd, void __user *arg)
 		sipx->sipx_network	= ipxif->if_netnum;
 		memcpy(sipx->sipx_node, ipxif->if_node,
 			sizeof(sipx->sipx_node));
-		rc = -EFAULT;
+		rc = 0;
 		if (copy_to_user(arg, &ifr, sizeof(ifr)))
-			break;
+			rc = -EFAULT;
 		ipxitf_put(ipxif);
-		rc = 0;
 		break;
 	}
 	case SIOCAIPXITFCRT:
-- 
2.7.4