3.16.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>
commit 9fc12023d6f51551d6ca9ed7e02ecc19d79caf17 upstream.
Remove BUG_ON() from fib_compute_spec_dst routine and check
in_dev pointer during flowi4 data structure initialization.
fib_compute_spec_dst routine can be run concurrently with device removal
where ip_ptr net_device pointer is set to NULL. This can happen
if userspace enables pkt info on UDP rx socket and the device
is removed while traffic is flowing
Fixes: 35ebf65e851c ("ipv4: Create and use fib_compute_spec_dst() helper")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -209,19 +209,20 @@ __be32 fib_compute_spec_dst(struct sk_bu
return ip_hdr(skb)->daddr;
in_dev = __in_dev_get_rcu(dev);
- BUG_ON(!in_dev);
net = dev_net(dev);
scope = RT_SCOPE_UNIVERSE;
if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
+ bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
+
fl4.flowi4_oif = 0;
fl4.flowi4_iif = LOOPBACK_IFINDEX;
fl4.daddr = ip_hdr(skb)->saddr;
fl4.saddr = 0;
fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
fl4.flowi4_scope = scope;
- fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
+ fl4.flowi4_mark = vmark ? skb->mark : 0;
if (!fib_lookup(net, &fl4, &res))
return FIB_RES_PREFSRC(net, res);
} else {
