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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        syzbot+1ddfb3357e1d7bb5b5d3@syzkaller.appspotmail.com,
        "Johannes Berg" <johannes.berg@intel.com>
Date:   Wed, 28 Feb 2018 15:20:18 +0000
Message-ID: <lsq.1519831218.970834889@decadent.org.uk>
Subject: [PATCH 3.16 207/254] cfg80211: check dev_set_name() return value
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3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@intel.com>

commit 59b179b48ce2a6076448a44531242ac2b3f6cef2 upstream.

syzbot reported a warning from rfkill_alloc(), and after a while
I think that the reason is that it was doing fault injection and
the dev_set_name() failed, leaving the name NULL, and we didn't
check the return value and got to rfkill_alloc() with a NULL name.
Since we really don't want a NULL name, we ought to check the
return value.

Fixes: fb28ad35906a ("net: struct device - replace bus_id with dev_name(), dev_set_name()")
Reported-by: syzbot+1ddfb3357e1d7bb5b5d3@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -315,6 +315,7 @@ struct wiphy *wiphy_new(const struct cfg
 
 	struct cfg80211_registered_device *rdev;
 	int alloc_size;
+	int rv;
 
 	WARN_ON(ops->add_key && (!ops->del_key || !ops->set_default_key));
 	WARN_ON(ops->auth && (!ops->assoc || !ops->deauth || !ops->disassoc));
@@ -346,7 +347,11 @@ struct wiphy *wiphy_new(const struct cfg
 	rdev->wiphy_idx--;
 
 	/* give it a proper name */
-	dev_set_name(&rdev->wiphy.dev, PHY_NAME "%d", rdev->wiphy_idx);
+	rv = dev_set_name(&rdev->wiphy.dev, PHY_NAME "%d", rdev->wiphy_idx);
+	if (rv < 0) {
+		kfree(rdev);
+		return NULL;
+	}
 
 	INIT_LIST_HEAD(&rdev->wdev_list);
 	INIT_LIST_HEAD(&rdev->beacon_registrations);