Messages in this thread Patch in this message |  | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 03/24] ipv6: reset dst.expires value when clearing expire flag | Date | Mon, 18 Nov 2013 10:42:13 -0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Hannes Frederic Sowa <hannes@stressinduktion.org>
[ Upstream commit 01ba16d6ec85a1ec4669c75513a76b61ec53ee50 ]
On receiving a packet too big icmp error we update the expire value by calling rt6_update_expires. This function uses dst_set_expires which is implemented that it can only reduce the expiration value of the dst entry.
If we insert new routing non-expiry information into the ipv6 fib where we already have a matching rt6_info we only clear the RTF_EXPIRES flag in rt6i_flags and leave the dst.expires value as is.
When new mtu information arrives for that cached dst_entry we again call dst_set_expires. This time it won't update the dst.expire value because we left the dst.expire value intact from the last update. So dst_set_expires won't touch dst.expires.
Fix this by resetting dst.expires when clearing the RTF_EXPIRE flag. dst_set_expires checks for a zero expiration and updates the dst.expires.
In the past this (not updating dst.expires) was necessary because dst.expire was placed in a union with the dst_entry *from reference and rt6_clean_expires did assign NULL to it. This split happend in ecd9883724b78cc72ed92c98bcb1a46c764fff21 ("ipv6: fix race condition regarding dst->expires and dst->from").
Reported-by: Steinar H. Gunderson <sgunderson@bigfoot.com> Reported-by: Valentijn Sessink <valentyn@blub.net> Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Acked-by: Eric Dumazet <edumazet@google.com> Tested-by: Valentijn Sessink <valentyn@blub.net> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- include/net/ip6_fib.h | 1 + 1 file changed, 1 insertion(+)
--- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -165,6 +165,7 @@ static inline struct inet6_dev *ip6_dst_ static inline void rt6_clean_expires(struct rt6_info *rt) { rt->rt6i_flags &= ~RTF_EXPIRES; + rt->dst.expires = 0; } static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
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