On Wed, Oct 25, 2017 at 09:52:27AM -0700, Jonathan Basseri wrote: > If a socket has a valid dst cache, then xfrm_lookup_route will get > skipped. However, the cache is not invalidated when applying policy to a > socket (i.e. IPV6_XFRM_POLICY). The result is that new policies are > sometimes ignored on those sockets. (Note: This was broken for IPv4 and > IPv6 at different times.) > > This can be demonstrated like so, > 1. Create UDP socket. > 2. connect() the socket. > 3. Apply an outbound XFRM policy to the socket. (setsockopt) > 4. send() data on the socket. > > Packets will continue to be sent in the clear instead of matching an > xfrm or returning a no-match error (EAGAIN). This affects calls to > send() and not sendto(). > > Invalidating the sk_dst_cache is necessary to correctly apply xfrm > policies. Since we do this in xfrm_user_policy(), the sk_lock was > already acquired in either do_ip_setsockopt() or do_ipv6_setsockopt(), > and we may call __sk_dst_reset(). > > Performance impact should be negligible, since this code is only called > when changing xfrm policy, and only affects the socket in question. > > Fixes: 00bc0ef5880d ("ipv6: Skip XFRM lookup if dst_entry in socket cache is > valid") > Tested: https://android-review.googlesource.com/517555 > Tested: https://android-review.googlesource.com/418659 > Signed-off-by: Jonathan Basseri <misterik...@google.com>
Applied, thanks for your work Jonathan!