From 7fe94612dd4cfcd35fe0ec87745fb31ad2be71f8 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Thu, 8 Oct 2020 16:13:24 +0800 Subject: xfrm: interface: fix the priorities for ipip and ipv6 tunnels As Nicolas noticed in his case, when xfrm_interface module is installed the standard IP tunnels will break in receiving packets. This is caused by the IP tunnel handlers with a higher priority in xfrm interface processing incoming packets by xfrm_input(), which would drop the packets and return 0 instead when anything wrong happens. Rather than changing xfrm_input(), this patch is to adjust the priority for the IP tunnel handlers in xfrm interface, so that the packets would go to xfrmi's later than the others', as the others' would not drop the packets when the handlers couldn't process them. Note that IPCOMP also defines its own IPIP tunnel handler and it calls xfrm_input() as well, so we must make its priority lower than xfrmi's, which means having xfrmi loaded would still break IPCOMP. We may seek another way to fix it in xfrm_input() in the future. Reported-by: Nicolas Dichtel Tested-by: Nicolas Dichtel Fixes: da9bbf0598c9 ("xfrm: interface: support IPIP and IPIP6 tunnels processing with .cb_handler") FIxes: d7b360c2869f ("xfrm: interface: support IP6IP6 and IP6IP tunnels processing with .cb_handler") Signed-off-by: Xin Long Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_interface.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'net/xfrm') diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c index a8f66112c52b..0bb7963b9f6b 100644 --- a/net/xfrm/xfrm_interface.c +++ b/net/xfrm/xfrm_interface.c @@ -830,14 +830,14 @@ static struct xfrm6_tunnel xfrmi_ipv6_handler __read_mostly = { .handler = xfrmi6_rcv_tunnel, .cb_handler = xfrmi_rcv_cb, .err_handler = xfrmi6_err, - .priority = -1, + .priority = 2, }; static struct xfrm6_tunnel xfrmi_ip6ip_handler __read_mostly = { .handler = xfrmi6_rcv_tunnel, .cb_handler = xfrmi_rcv_cb, .err_handler = xfrmi6_err, - .priority = -1, + .priority = 2, }; #endif @@ -875,14 +875,14 @@ static struct xfrm_tunnel xfrmi_ipip_handler __read_mostly = { .handler = xfrmi4_rcv_tunnel, .cb_handler = xfrmi_rcv_cb, .err_handler = xfrmi4_err, - .priority = -1, + .priority = 3, }; static struct xfrm_tunnel xfrmi_ipip6_handler __read_mostly = { .handler = xfrmi4_rcv_tunnel, .cb_handler = xfrmi_rcv_cb, .err_handler = xfrmi4_err, - .priority = -1, + .priority = 2, }; #endif -- cgit v1.2.3 From a779d91314ca7208b7feb3ad817b62904397c56d Mon Sep 17 00:00:00 2001 From: zhuoliang zhang Date: Fri, 23 Oct 2020 09:05:35 +0200 Subject: net: xfrm: fix a race condition during allocing spi we found that the following race condition exists in xfrm_alloc_userspi flow: user thread state_hash_work thread ---- ---- xfrm_alloc_userspi() __find_acq_core() /*alloc new xfrm_state:x*/ xfrm_state_alloc() /*schedule state_hash_work thread*/ xfrm_hash_grow_check() xfrm_hash_resize() xfrm_alloc_spi /*hold lock*/ x->id.spi = htonl(spi) spin_lock_bh(&net->xfrm.xfrm_state_lock) /*waiting lock release*/ xfrm_hash_transfer() spin_lock_bh(&net->xfrm.xfrm_state_lock) /*add x into hlist:net->xfrm.state_byspi*/ hlist_add_head_rcu(&x->byspi) spin_unlock_bh(&net->xfrm.xfrm_state_lock) /*add x into hlist:net->xfrm.state_byspi 2 times*/ hlist_add_head_rcu(&x->byspi) 1. a new state x is alloced in xfrm_state_alloc() and added into the bydst hlist in __find_acq_core() on the LHS; 2. on the RHS, state_hash_work thread travels the old bydst and tranfers every xfrm_state (include x) into the new bydst hlist and new byspi hlist; 3. user thread on the LHS gets the lock and adds x into the new byspi hlist again. So the same xfrm_state (x) is added into the same list_hash (net->xfrm.state_byspi) 2 times that makes the list_hash become an inifite loop. To fix the race, x->id.spi = htonl(spi) in the xfrm_alloc_spi() is moved to the back of spin_lock_bh, sothat state_hash_work thread no longer add x which id.spi is zero into the hash_list. Fixes: f034b5d4efdf ("[XFRM]: Dynamic xfrm_state hash table sizing.") Signed-off-by: zhuoliang zhang Acked-by: Herbert Xu Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_state.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'net/xfrm') diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index efc89a92961d..ee6ac32bb06d 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2004,6 +2004,7 @@ int xfrm_alloc_spi(struct xfrm_state *x, u32 low, u32 high) int err = -ENOENT; __be32 minspi = htonl(low); __be32 maxspi = htonl(high); + __be32 newspi = 0; u32 mark = x->mark.v & x->mark.m; spin_lock_bh(&x->lock); @@ -2022,21 +2023,22 @@ int xfrm_alloc_spi(struct xfrm_state *x, u32 low, u32 high) xfrm_state_put(x0); goto unlock; } - x->id.spi = minspi; + newspi = minspi; } else { u32 spi = 0; for (h = 0; h < high-low+1; h++) { spi = low + prandom_u32()%(high-low+1); x0 = xfrm_state_lookup(net, mark, &x->id.daddr, htonl(spi), x->id.proto, x->props.family); if (x0 == NULL) { - x->id.spi = htonl(spi); + newspi = htonl(spi); break; } xfrm_state_put(x0); } } - if (x->id.spi) { + if (newspi) { spin_lock_bh(&net->xfrm.xfrm_state_lock); + x->id.spi = newspi; h = xfrm_spi_hash(net, &x->id.daddr, x->id.spi, x->id.proto, x->props.family); hlist_add_head_rcu(&x->byspi, net->xfrm.state_byspi + h); spin_unlock_bh(&net->xfrm.xfrm_state_lock); -- cgit v1.2.3