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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+1ddfb3357e1d7bb5b5d3@syzkaller.appspotmail.com,
        Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 4.4 003/193] cfg80211: check dev_set_name() return value
Date:   Fri, 23 Feb 2018 19:23:56 +0100
Message-Id: <20180223170326.555798015@linuxfoundation.org>
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4.4-stable 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/wireless/core.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -390,6 +390,8 @@ struct wiphy *wiphy_new_nm(const struct
 		if (rv)
 			goto use_default_name;
 	} else {
+		int rv;
+
 use_default_name:
 		/* NOTE:  This is *probably* safe w/out holding rtnl because of
 		 * the restrictions on phy names.  Probably this call could
@@ -397,7 +399,11 @@ use_default_name:
 		 * phyX.  But, might should add some locking and check return
 		 * value, and use a different name if this one exists?
 		 */
-		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);