5.10-stable review patch. If anyone has any objections, please let me know.
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From: Davide Caratti dcaratti@redhat.com
commit d58300c3185b78ab910092488126b97f0abe3ae2 upstream.
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 Stable-dep-of: b4cd80b03389 ("mptcp: pm: Fix uaf in __timer_delete_sync") [ Conflicts in options.c, because some features are missing in this version, e.g. commit 557963c383e8 ("mptcp: move to next addr when subflow creation fail") and commit f7dafee18538 ("mptcp: use mptcp_addr_info in mptcp_options_received"). ] Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/options.c | 2 +- net/mptcp/pm_netlink.c | 8 ++++---- net/mptcp/protocol.h | 2 +- 3 files changed, 6 insertions(+), 6 deletions(-)
--- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -915,7 +915,7 @@ void mptcp_incoming_options(struct sock mptcp_pm_add_addr_received(msk, &addr); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); } else { - mptcp_pm_del_add_timer(msk, &addr); + mptcp_pm_del_add_timer(msk, &addr, true); MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); } mp_opt.add_addr = 0; --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -249,18 +249,18 @@ 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; @@ -764,7 +764,7 @@ static bool remove_anno_list_by_saddr(st { 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); --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -450,7 +450,7 @@ void mptcp_pm_rm_addr_received(struct mp void mptcp_pm_free_anno_list(struct mptcp_sock *msk); 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);