kernel/linux.git/net, branch v5.4.201

tcp: drop the hash_32() part from the index calculation

2022-06-25T10:44:36+00:00

commit e8161345ddbb66e449abde10d2fdce93f867eba9 upstream. In commit 190cc82489f4 ("tcp: change source port randomizarion at connect() time"), the table_perturb[] array was introduced and an index was taken from the port_offset via hash_32(). But it turns out that hash_32() performs a multiplication while the input here comes from the output of SipHash in secure_seq, that is well distributed enough to avoid the need for yet another hash. Suggested-by: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau Signed-off-by: Jakub Kicinski Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

tcp: increase source port perturb table to 2^16

2022-06-25T10:44:36+00:00

commit 4c2c8f03a5ab7cb04ec64724d7d176d00bcc91e5 upstream. Moshe Kol, Amit Klein, and Yossi Gilad reported being able to accurately identify a client by forcing it to emit only 40 times more connections than there are entries in the table_perturb[] table. The previous two improvements consisting in resalting the secret every 10s and adding randomness to each port selection only slightly improved the situation, and the current value of 2^8 was too small as it's not very difficult to make a client emit 10k connections in less than 10 seconds. Thus we're increasing the perturb table from 2^8 to 2^16 so that the same precision now requires 2.6M connections, which is more difficult in this time frame and harder to hide as a background activity. The impact is that the table now uses 256 kB instead of 1 kB, which could mostly affect devices making frequent outgoing connections. However such components usually target a small set of destinations (load balancers, database clients, perf assessment tools), and in practice only a few entries will be visited, like before. A live test at 1 million connections per second showed no performance difference from the previous value. Reported-by: Moshe Kol Reported-by: Yossi Gilad Reported-by: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau Signed-off-by: Jakub Kicinski Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

tcp: dynamically allocate the perturb table used by source ports

2022-06-25T10:44:36+00:00

commit e9261476184be1abd486c9434164b2acbe0ed6c2 upstream. We'll need to further increase the size of this table and it's likely that at some point its size will not be suitable anymore for a static table. Let's allocate it on boot from inet_hashinfo2_init(), which is called from tcp_init(). Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau Signed-off-by: Jakub Kicinski Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

tcp: add small random increments to the source port

2022-06-25T10:44:36+00:00

commit ca7af0402550f9a0b3316d5f1c30904e42ed257d upstream. Here we're randomly adding between 0 and 7 random increments to the selected source port in order to add some noise in the source port selection that will make the next port less predictable. With the default port range of 32768-60999 this means a worst case reuse scenario of 14116/8=1764 connections between two consecutive uses of the same port, with an average of 14116/4.5=3137. This code was stressed at more than 800000 connections per second to a fixed target with all connections closed by the client using RSTs (worst condition) and only 2 connections failed among 13 billion, despite the hash being reseeded every 10 seconds, indicating a perfectly safe situation. Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau Signed-off-by: Jakub Kicinski Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

tcp: use different parts of the port_offset for index and offset

2022-06-25T10:44:35+00:00

commit 9e9b70ae923baf2b5e8a0ea4fd0c8451801ac526 upstream. Amit Klein suggests that we use different parts of port_offset for the table's index and the port offset so that there is no direct relation between them. Cc: Jason A. Donenfeld Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau Signed-off-by: Jakub Kicinski Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

tcp: add some entropy in __inet_hash_connect()

2022-06-25T10:44:35+00:00

commit c579bd1b4021c42ae247108f1e6f73dd3f08600c upstream. Even when implementing RFC 6056 3.3.4 (Algorithm 4: Double-Hash Port Selection Algorithm), a patient attacker could still be able to collect enough state from an otherwise idle host. Idea of this patch is to inject some noise, in the cases __inet_hash_connect() found a candidate in the first attempt. This noise should not significantly reduce the collision avoidance, and should be zero if connection table is already well used. Note that this is not implementing RFC 6056 3.3.5 because we think Algorithm 5 could hurt typical workloads. Signed-off-by: Eric Dumazet Cc: David Dworken Cc: Willem de Bruijn Signed-off-by: David S. Miller Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

net: openvswitch: fix leak of nested actions

2022-06-22T12:11:24+00:00

commit 1f30fb9166d4f15a1aa19449b9da871fe0ed4796 upstream. While parsing user-provided actions, openvswitch module may dynamically allocate memory and store pointers in the internal copy of the actions. So this memory has to be freed while destroying the actions. Currently there are only two such actions: ct() and set(). However, there are many actions that can hold nested lists of actions and ovs_nla_free_flow_actions() just jumps over them leaking the memory. For example, removal of the flow with the following actions will lead to a leak of the memory allocated by nf_ct_tmpl_alloc(): actions:clone(ct(commit),0) Non-freed set() action may also leak the 'dst' structure for the tunnel info including device references. Under certain conditions with a high rate of flow rotation that may cause significant memory leak problem (2MB per second in reporter's case). The problem is also hard to mitigate, because the user doesn't have direct control over the datapath flows generated by OVS. Fix that by iterating over all the nested actions and freeing everything that needs to be freed recursively. New build time assertion should protect us from this problem if new actions will be added in the future. Unfortunately, openvswitch module doesn't use NLA_F_NESTED, so all attributes has to be explicitly checked. sample() and clone() actions are mixing extra attributes into the user-provided action list. That prevents some code generalization too. Fixes: 34ae932a4036 ("openvswitch: Make tunnel set action attach a metadata dst") Link: https://mail.openvswitch.org/pipermail/ovs-dev/2022-March/392922.html Reported-by: Stéphane Graber Signed-off-by: Ilya Maximets Acked-by: Aaron Conole Signed-off-by: David S. Miller [Backport for 5.4: Removed handling of OVS_ACTION_ATTR_DEC_TTL as it doesn't exist in this version. BUILD_BUG_ON condition adjusted accordingly.] Signed-off-by: Greg Kroah-Hartman

net: openvswitch: fix misuse of the cached connection on tuple changes

2022-06-22T12:11:24+00:00

commit 2061ecfdf2350994e5b61c43e50e98a7a70e95ee upstream. If packet headers changed, the cached nfct is no longer relevant for the packet and attempt to re-use it leads to the incorrect packet classification. This issue is causing broken connectivity in OpenStack deployments with OVS/OVN due to hairpin traffic being unexpectedly dropped. The setup has datapath flows with several conntrack actions and tuple changes between them: actions:ct(commit,zone=8,mark=0/0x1,nat(src)), set(eth(src=00:00:00:00:00:01,dst=00:00:00:00:00:06)), set(ipv4(src=172.18.2.10,dst=192.168.100.6,ttl=62)), ct(zone=8),recirc(0x4) After the first ct() action the packet headers are almost fully re-written. The next ct() tries to re-use the existing nfct entry and marks the packet as invalid, so it gets dropped later in the pipeline. Clearing the cached conntrack entry whenever packet tuple is changed to avoid the issue. The flow key should not be cleared though, because we should still be able to match on the ct_state if the recirculation happens after the tuple change but before the next ct() action. Cc: stable@vger.kernel.org Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action") Reported-by: Frode Nordahl Link: https://mail.openvswitch.org/pipermail/ovs-discuss/2022-May/051829.html Link: https://bugs.launchpad.net/ubuntu/+source/ovn/+bug/1967856 Signed-off-by: Ilya Maximets Link: https://lore.kernel.org/r/20220606221140.488984-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski [Backport to 5.10: minor rebase in ovs_ct_clear function. This version also applicable to and tested on 5.4 and 4.19.] Signed-off-by: Greg Kroah-Hartman

net/sched: act_police: more accurate MTU policing

2022-06-22T12:11:24+00:00

commit 4ddc844eb81da59bfb816d8d52089aba4e59e269 upstream. in current Linux, MTU policing does not take into account that packets at the TC ingress have the L2 header pulled. Thus, the same TC police action (with the same value of tcfp_mtu) behaves differently for ingress/egress. In addition, the full GSO size is compared to tcfp_mtu: as a consequence, the policer drops GSO packets even when individual segments have the L2 + L3 + L4 + payload length below the configured valued of tcfp_mtu. Improve the accuracy of MTU policing as follows: - account for mac_len for non-GSO packets at TC ingress. - compare MTU threshold with the segmented size for GSO packets. Also, add a kselftest that verifies the correct behavior. Signed-off-by: Davide Caratti Reviewed-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller [dcaratti: fix conflicts due to lack of the following commits: - commit 2ffe0395288a ("net/sched: act_police: add support for packet-per-second policing") - commit afe231d32eb5 ("selftests: forwarding: Add tc-police tests") - commit 53b61f29367d ("selftests: forwarding: Add tc-police tests for packets per second")] Link: https://lore.kernel.org/netdev/876d597a0ff55f6ba786f73c5a9fd9eb8d597a03.1644514748.git.dcaratti@redhat.com Signed-off-by: Greg Kroah-Hartman

ipv6: Fix signed integer overflow in l2tp_ip6_sendmsg

2022-06-22T12:11:21+00:00

[ Upstream commit f638a84afef3dfe10554c51820c16e39a278c915 ] When len >= INT_MAX - transhdrlen, ulen = len + transhdrlen will be overflow. To fix, we can follow what udpv6 does and subtract the transhdrlen from the max. Signed-off-by: Wang Yufen Link: https://lore.kernel.org/r/20220607120028.845916-2-wangyufen@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin