Patch "net: dsa: Ensure validity of dst->ds[0]" has been added to the 4.9-stable tree

Patch "net: dsa: Ensure validity of dst->ds[0]" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    net: dsa: Ensure validity of dst->ds[0]

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-dsa-ensure-validity-of-dst-ds.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Jan 12 21:37:26 CET 2017
From: Florian Fainelli <f.fainelli@gmail.com>
Date: Mon, 9 Jan 2017 11:58:34 -0800
Subject: net: dsa: Ensure validity of dst->ds[0]

From: Florian Fainelli <f.fainelli@gmail.com>


[ Upstream commit faf3a932fbeb77860226a8323eacb835edc98648 ]

It is perfectly possible to have non zero indexed switches being present
in a DSA switch tree, in such a case, we will be deferencing a NULL
pointer while dsa_cpu_port_ethtool_{setup,restore}. Be more defensive
and ensure that dst->ds[0] is valid before doing anything with it.

Fixes: 0c73c523cf73 ("net: dsa: Initialize CPU port ethtool ops per tree")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/dsa/dsa2.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -394,9 +394,11 @@ static int dsa_dst_apply(struct dsa_swit
 			return err;
 	}
 
-	err = dsa_cpu_port_ethtool_setup(dst->ds[0]);
-	if (err)
-		return err;
+	if (dst->ds[0]) {
+		err = dsa_cpu_port_ethtool_setup(dst->ds[0]);
+		if (err)
+			return err;
+	}
 
 	/* If we use a tagging format that doesn't have an ethertype
 	 * field, make sure that all packets from this point on get
@@ -433,7 +435,8 @@ static void dsa_dst_unapply(struct dsa_s
 		dsa_ds_unapply(dst, ds);
 	}
 
-	dsa_cpu_port_ethtool_restore(dst->ds[0]);
+	if (dst->ds[0])
+		dsa_cpu_port_ethtool_restore(dst->ds[0]);
 
 	pr_info("DSA: tree %d unapplied\n", dst->tree);
 	dst->applied = false;


Patches currently in stable-queue which might be from f.fainelli@gmail.com are

queue-4.9/net-dsa-ensure-validity-of-dst-ds.patch
queue-4.9/net-stmmac-fix-race-between-stmmac_drv_probe-and-stmmac_open.patch
queue-4.9/net-dsa-bcm_sf2-utilize-nested-mdio-read-write.patch
queue-4.9/net-dsa-bcm_sf2-do-not-clobber-b53_switch_ops.patch