From c29390c6dfeee0944ac6b5610ebbe403944378fc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 11 Mar 2015 18:42:02 -0700 Subject: [PATCH] xps: must clear sender_cpu before forwarding John reported that my previous commit added a regression on his router. This is because sender_cpu & napi_id share a common location, so get_xps_queue() can see garbage and perform an out of bound access. We need to make sure sender_cpu is cleared before doing the transmit, otherwise any NIC busy poll enabled (skb_mark_napi_id()) can trigger this bug. Signed-off-by: Eric Dumazet Reported-by: John Bisected-by: John Fixes: 2bd82484bb4c ("xps: fix xps for stacked devices") Signed-off-by: David S. Miller --- include/linux/skbuff.h | 7 +++++++ net/core/skbuff.c | 2 +- net/ipv4/ip_forward.c | 1 + net/ipv6/ip6_output.c | 1 + 4 files changed, 10 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 30007afe70b3..f54d6659713a 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -948,6 +948,13 @@ static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from) to->l4_hash = from->l4_hash; }; +static inline void skb_sender_cpu_clear(struct sk_buff *skb) +{ +#ifdef CONFIG_XPS + skb->sender_cpu = 0; +#endif +} + #ifdef NET_SKBUFF_DATA_USES_OFFSET static inline unsigned char *skb_end_pointer(const struct sk_buff *skb) { diff --git a/net/core/skbuff.c b/net/core/skbuff.c index f80507823531..434e78e5254d 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4173,7 +4173,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet) skb->ignore_df = 0; skb_dst_drop(skb); skb->mark = 0; - skb->sender_cpu = 0; + skb_sender_cpu_clear(skb); skb_init_secmark(skb); secpath_reset(skb); nf_reset(skb); diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c index 787b3c294ce6..d9bc28ac5d1b 100644 --- a/net/ipv4/ip_forward.c +++ b/net/ipv4/ip_forward.c @@ -67,6 +67,7 @@ static int ip_forward_finish(struct sk_buff *skb) if (unlikely(opt->optlen)) ip_forward_options(skb); + skb_sender_cpu_clear(skb); return dst_output(skb); } diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 0a04a37305d5..7e80b61b51ff 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -318,6 +318,7 @@ static int ip6_forward_proxy_check(struct sk_buff *skb) static inline int ip6_forward_finish(struct sk_buff *skb) { + skb_sender_cpu_clear(skb); return dst_output(skb); }