From dca2307ed6250e7be6993e165570fa4097903a58 Mon Sep 17 00:00:00 2001
From: Arend Van Spriel <arend.vanspriel@broadcom.com>
Date: Sat, 24 Jun 2017 22:08:27 +0100
Subject: [PATCH] brcmfmac: fix double free upon register_netdevice() failure
Git-commit: dca2307ed6250e7be6993e165570fa4097903a58
Patch-mainline: v4.13-rc1
References: bsc#1051510

The function brcmf_net_attach() can only fail when register_netdevice()
fails. When this happens register_netdevice() calls priv_destructor, ie.
brcmf_cfg80211_free_netdev() freeing the vif instance. Also upon this
failure brcmf_net_attach() calls free_netdev(). However, callers are also
doing cleanup resulting in double free. In some places they need netdev
private space as it holds parameters to communicate with the device. So
we want to do the cleanup only in callers of brcmf_net_attach() by making
the following changes:

 - set priv_destructor after register_netdevice() succeeds.
 - remove call to free_netdev() in brcmf_net_attach().
 - call free_netdev() in brcmf_net_detach() for unregistered netdev.
 - add free_netdev() if brcmf_net_attach() fails for a created interface.

Fixes: cf124db566e6 ("net: Fix inconsistent teardown and release of private netdev state.")
Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c |    1 +
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c     |    5 ++---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c      |    1 +
 3 files changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -625,6 +625,7 @@ struct wireless_dev *brcmf_ap_add_vif(st
 	err = brcmf_net_attach(ifp, true);
 	if (err) {
 		brcmf_err("Registering netdevice failed\n");
+		free_netdev(ifp->ndev);
 		goto fail;
 	}
 
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
@@ -484,13 +484,13 @@ int brcmf_net_attach(struct brcmf_if *if
 		goto fail;
 	}
 
+	ndev->priv_destructor = brcmf_cfg80211_free_netdev;
 	brcmf_dbg(INFO, "%s: Broadcom Dongle Host Driver\n", ndev->name);
 	return 0;
 
 fail:
 	drvr->iflist[ifp->bsscfgidx] = NULL;
 	ndev->netdev_ops = NULL;
-	free_netdev(ndev);
 	return -EBADE;
 }
 
@@ -503,6 +503,7 @@ static void brcmf_net_detach(struct net_
 			unregister_netdev(ndev);
 	} else {
 		brcmf_cfg80211_free_netdev(ndev);
+		free_netdev(ndev);
 	}
 }
 
@@ -579,7 +580,6 @@ static int brcmf_net_p2p_attach(struct b
 fail:
 	ifp->drvr->iflist[ifp->bsscfgidx] = NULL;
 	ndev->netdev_ops = NULL;
-	free_netdev(ndev);
 	return -EBADE;
 }
 
@@ -625,7 +625,6 @@ struct brcmf_if *brcmf_add_if(struct brc
 			return ERR_PTR(-ENOMEM);
 
 		ndev->needs_free_netdev = true;
-		ndev->priv_destructor = brcmf_cfg80211_free_netdev;
 		ifp = netdev_priv(ndev);
 		ifp->ndev = ndev;
 		/* store mapping ifidx to bsscfgidx */
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
@@ -2208,6 +2208,7 @@ struct wireless_dev *brcmf_p2p_add_vif(s
 	err = brcmf_net_attach(ifp, true);
 	if (err) {
 		brcmf_err("Registering netdevice failed\n");
+		free_netdev(ifp->ndev);
 		goto fail;
 	}