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authorDavide Caratti <dcaratti@redhat.com>2021-05-25 14:23:13 -0700
committerDavid S. Miller <davem@davemloft.net>2021-05-25 15:56:20 -0700
commitd58300c3185b78ab910092488126b97f0abe3ae2 (patch)
treec4f3cb3f50448f86525666eda4f15dcf0b1d374a
parent3ed0a585bfadb6bd7080f11184adbc9edcce7dbc (diff)
mptcp: validate 'id' when stopping the ADD_ADDR retransmit timer
when Linux receives an echo-ed ADD_ADDR, it checks the IP address against the list of "announced" addresses. In case of a positive match, the timer that handles retransmissions is stopped regardless of the 'Address Id' in the received packet: this behaviour does not comply with RFC8684 3.4.1. Fix it by validating the 'Address Id' in received echo-ed ADD_ADDRs. Tested using packetdrill, with the following captured output: unpatched kernel: Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0xfd2e62517888fe29,mptcp dss ack 3007449509], length 0 In <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 1 1.2.3.4,mptcp dss ack 3013740213], length 0 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0xfd2e62517888fe29,mptcp dss ack 3007449509], length 0 In <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 90 198.51.100.2,mptcp dss ack 3013740213], length 0 ^^^ retransmission is stopped here, but 'Address Id' is 90 patched kernel: Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0x1cf372d59e05f4b8,mptcp dss ack 3007449509], length 0 In <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 1 1.2.3.4,mptcp dss ack 1672384568], length 0 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0x1cf372d59e05f4b8,mptcp dss ack 3007449509], length 0 In <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 90 198.51.100.2,mptcp dss ack 1672384568], length 0 Out <...> Flags [.], ack 1, win 256, options [mptcp add-addr v1 id 1 198.51.100.2 hmac 0x1cf372d59e05f4b8,mptcp dss ack 3007449509], length 0 In <...> Flags [.], ack 1, win 257, options [mptcp add-addr v1-echo id 1 198.51.100.2,mptcp dss ack 1672384568], length 0 ^^^ retransmission is stopped here, only when both 'Address Id' and 'IP Address' match Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/mptcp/options.c2
-rw-r--r--net/mptcp/pm_netlink.c8
-rw-r--r--net/mptcp/protocol.h2
3 files changed, 6 insertions, 6 deletions
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 71c535f4e1ef..6b825fb3fa83 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1023,7 +1023,7 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
} else {
mptcp_pm_add_addr_echoed(msk, &mp_opt.addr);
- mptcp_pm_del_add_timer(msk, &mp_opt.addr);
+ mptcp_pm_del_add_timer(msk, &mp_opt.addr, true);
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
}
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 6ba040897738..2469e06a3a9d 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -346,18 +346,18 @@ out:
struct mptcp_pm_add_entry *
mptcp_pm_del_add_timer(struct mptcp_sock *msk,
- struct mptcp_addr_info *addr)
+ struct mptcp_addr_info *addr, bool check_id)
{
struct mptcp_pm_add_entry *entry;
struct sock *sk = (struct sock *)msk;
spin_lock_bh(&msk->pm.lock);
entry = mptcp_lookup_anno_list_by_saddr(msk, addr);
- if (entry)
+ if (entry && (!check_id || entry->addr.id == addr->id))
entry->retrans_times = ADD_ADDR_RETRANS_MAX;
spin_unlock_bh(&msk->pm.lock);
- if (entry)
+ if (entry && (!check_id || entry->addr.id == addr->id))
sk_stop_timer_sync(sk, &entry->add_timer);
return entry;
@@ -1064,7 +1064,7 @@ static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
{
struct mptcp_pm_add_entry *entry;
- entry = mptcp_pm_del_add_timer(msk, addr);
+ entry = mptcp_pm_del_add_timer(msk, addr, false);
if (entry) {
list_del(&entry->list);
kfree(entry);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 165c8b40b384..0c6f99c67345 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -672,7 +672,7 @@ void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
struct mptcp_pm_add_entry *
mptcp_pm_del_add_timer(struct mptcp_sock *msk,
- struct mptcp_addr_info *addr);
+ struct mptcp_addr_info *addr, bool check_id);
struct mptcp_pm_add_entry *
mptcp_lookup_anno_list_by_saddr(struct mptcp_sock *msk,
struct mptcp_addr_info *addr);