ipv6: reset dst.expires value when clearing expire flag

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 <[email protected]>
Reported-by: Valentijn Sessink <[email protected]>
Cc: YOSHIFUJI Hideaki <[email protected]>
Acked-by: Eric Dumazet <[email protected]>
Tested-by: Valentijn Sessink <[email protected]>
Signed-off-by: Hannes Frederic Sowa <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions