kernel/linux.git/net/openvswitch/flow_netlink.c, branch v5.10.257

openvswitch: validate MPLS set/set_masked payload length

2026-04-18T08:31:04+00:00

[ Upstream commit 546b68ac893595877ffbd7751e5c55fd1c43ede6 ] validate_set() accepted OVS_KEY_ATTR_MPLS as variable-sized payload for SET/SET_MASKED actions. In action handling, OVS expects fixed-size MPLS key data (struct ovs_key_mpls). Use the already normalized key_len (masked case included) and reject non-matching MPLS action key sizes. Reject invalid MPLS action payload lengths early. Fixes: fbdcdd78da7c ("Change in Openvswitch to support MPLS label depth of 3 in ingress direction") Reported-by: Yifan Wu Reported-by: Juefei Pu Tested-by: Ao Zhou Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Signed-off-by: Yang Yang Reviewed-by: Ilya Maximets Link: https://patch.msgid.link/20260319080228.3423307-1-n05ec@lzu.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: openvswitch: fix middle attribute validation in push_nsh() action

2026-01-19T12:11:42+00:00

[ Upstream commit 5ace7ef87f059d68b5f50837ef3e8a1a4870c36e ] The push_nsh() action structure looks like this: OVS_ACTION_ATTR_PUSH_NSH(OVS_KEY_ATTR_NSH(OVS_NSH_KEY_ATTR_BASE,...)) The outermost OVS_ACTION_ATTR_PUSH_NSH attribute is OK'ed by the nla_for_each_nested() inside __ovs_nla_copy_actions(). The innermost OVS_NSH_KEY_ATTR_BASE/MD1/MD2 are OK'ed by the nla_for_each_nested() inside nsh_key_put_from_nlattr(). But nothing checks if the attribute in the middle is OK. We don't even check that this attribute is the OVS_KEY_ATTR_NSH. We just do a double unwrap with a pair of nla_data() calls - first time directly while calling validate_push_nsh() and the second time as part of the nla_for_each_nested() macro, which isn't safe, potentially causing invalid memory access if the size of this attribute is incorrect. The failure may not be noticed during validation due to larger netlink buffer, but cause trouble later during action execution where the buffer is allocated exactly to the size: BUG: KASAN: slab-out-of-bounds in nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch] Read of size 184 at addr ffff88816459a634 by task a.out/22624 CPU: 8 UID: 0 PID: 22624 6.18.0-rc7+ #115 PREEMPT(voluntary) Call Trace: dump_stack_lvl+0x51/0x70 print_address_description.constprop.0+0x2c/0x390 kasan_report+0xdd/0x110 kasan_check_range+0x35/0x1b0 __asan_memcpy+0x20/0x60 nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch] push_nsh+0x82/0x120 [openvswitch] do_execute_actions+0x1405/0x2840 [openvswitch] ovs_execute_actions+0xd5/0x3b0 [openvswitch] ovs_packet_cmd_execute+0x949/0xdb0 [openvswitch] genl_family_rcv_msg_doit+0x1d6/0x2b0 genl_family_rcv_msg+0x336/0x580 genl_rcv_msg+0x9f/0x130 netlink_rcv_skb+0x11f/0x370 genl_rcv+0x24/0x40 netlink_unicast+0x73e/0xaa0 netlink_sendmsg+0x744/0xbf0 __sys_sendto+0x3d6/0x450 do_syscall_64+0x79/0x2c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Let's add some checks that the attribute is properly sized and it's the only one attribute inside the action. Technically, there is no real reason for OVS_KEY_ATTR_NSH to be there, as we know that we're pushing an NSH header already, it just creates extra nesting, but that's how uAPI works today. So, keeping as it is. Fixes: b2d0f5d5dc53 ("openvswitch: enable NSH support") Reported-by: Junvy Yang Signed-off-by: Ilya Maximets Acked-by: Eelco Chaudron echaudro@redhat.com Reviewed-by: Aaron Conole Link: https://patch.msgid.link/20251204105334.900379-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: openvswitch: remove never-working support for setting nsh fields

2025-12-06T21:08:20+00:00

[ Upstream commit dfe28c4167a9259fc0c372d9f9473e1ac95cff67 ] The validation of the set(nsh(...)) action is completely wrong. It runs through the nsh_key_put_from_nlattr() function that is the same function that validates NSH keys for the flow match and the push_nsh() action. However, the set(nsh(...)) has a very different memory layout. Nested attributes in there are doubled in size in case of the masked set(). That makes proper validation impossible. There is also confusion in the code between the 'masked' flag, that says that the nested attributes are doubled in size containing both the value and the mask, and the 'is_mask' that says that the value we're parsing is the mask. This is causing kernel crash on trying to write into mask part of the match with SW_FLOW_KEY_PUT() during validation, while validate_nsh() doesn't allocate any memory for it: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1c2383067 P4D 1c2383067 PUD 20b703067 PMD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 8 UID: 0 Kdump: loaded Not tainted 6.17.0-rc4+ #107 PREEMPT(voluntary) RIP: 0010:nsh_key_put_from_nlattr+0x19d/0x610 [openvswitch] Call Trace: validate_nsh+0x60/0x90 [openvswitch] validate_set.constprop.0+0x270/0x3c0 [openvswitch] __ovs_nla_copy_actions+0x477/0x860 [openvswitch] ovs_nla_copy_actions+0x8d/0x100 [openvswitch] ovs_packet_cmd_execute+0x1cc/0x310 [openvswitch] genl_family_rcv_msg_doit+0xdb/0x130 genl_family_rcv_msg+0x14b/0x220 genl_rcv_msg+0x47/0xa0 netlink_rcv_skb+0x53/0x100 genl_rcv+0x24/0x40 netlink_unicast+0x280/0x3b0 netlink_sendmsg+0x1f7/0x430 ____sys_sendmsg+0x36b/0x3a0 ___sys_sendmsg+0x87/0xd0 __sys_sendmsg+0x6d/0xd0 do_syscall_64+0x7b/0x2c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e The third issue with this process is that while trying to convert the non-masked set into masked one, validate_set() copies and doubles the size of the OVS_KEY_ATTR_NSH as if it didn't have any nested attributes. It should be copying each nested attribute and doubling them in size independently. And the process must be properly reversed during the conversion back from masked to a non-masked variant during the flow dump. In the end, the only two outcomes of trying to use this action are either validation failure or a kernel crash. And if somehow someone manages to install a flow with such an action, it will most definitely not do what it is supposed to, since all the keys and the masks are mixed up. Fixing all the issues is a complex task as it requires re-writing most of the validation code. Given that and the fact that this functionality never worked since introduction, let's just remove it altogether. It's better to re-introduce it later with a proper implementation instead of trying to fix it in stable releases. Fixes: b2d0f5d5dc53 ("openvswitch: enable NSH support") Reported-by: Junvy Yang Signed-off-by: Ilya Maximets Acked-by: Eelco Chaudron Reviewed-by: Aaron Conole Link: https://patch.msgid.link/20251112112246.95064-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: openvswitch: fix nested key length validation in the set() action

2025-05-02T05:41:00+00:00

[ Upstream commit 65d91192aa66f05710cfddf6a14b5a25ee554dba ] It's not safe to access nla_len(ovs_key) if the data is smaller than the netlink header. Check that the attribute is OK first. Fixes: ccb1352e76cf ("net: Add Open vSwitch kernel components.") Reported-by: syzbot+b07a9da40df1576b8048@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b07a9da40df1576b8048 Tested-by: syzbot+b07a9da40df1576b8048@syzkaller.appspotmail.com Signed-off-by: Ilya Maximets Reviewed-by: Eelco Chaudron Acked-by: Aaron Conole Link: https://patch.msgid.link/20250412104052.2073688-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: openvswitch: limit the number of recursions from action sets

2024-02-23T07:42:23+00:00

[ Upstream commit 6e2f90d31fe09f2b852de25125ca875aabd81367 ] The ovs module allows for some actions to recursively contain an action list for complex scenarios, such as sampling, checking lengths, etc. When these actions are copied into the internal flow table, they are evaluated to validate that such actions make sense, and these calls happen recursively. The ovs-vswitchd userspace won't emit more than 16 recursion levels deep. However, the module has no such limit and will happily accept limits larger than 16 levels nested. Prevent this by tracking the number of recursions happening and manually limiting it to 16 levels nested. The initial implementation of the sample action would track this depth and prevent more than 3 levels of recursion, but this was removed to support the clone use case, rather than limited at the current userspace limit. Fixes: 798c166173ff ("openvswitch: Optimize sample action for the clone use cases") Signed-off-by: Aaron Conole Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20240207132416.1488485-2-aconole@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

openvswitch: fix OOB access in reserve_sfa_size()

2022-04-27T11:53:55+00:00

commit cefa91b2332d7009bc0be5d951d6cbbf349f90f8 upstream. Given a sufficiently large number of actions, while copying and reserving memory for a new action of a new flow, if next_offset is greater than MAX_ACTIONS_BUFSIZE, the function reserve_sfa_size() does not return -EMSGSIZE as expected, but it allocates MAX_ACTIONS_BUFSIZE bytes increasing actions_len by req_size. This can then lead to an OOB write access, especially when further actions need to be copied. Fix it by rearranging the flow action size check. KASAN splat below: ================================================================== BUG: KASAN: slab-out-of-bounds in reserve_sfa_size+0x1ba/0x380 [openvswitch] Write of size 65360 at addr ffff888147e4001c by task handler15/836 CPU: 1 PID: 836 Comm: handler15 Not tainted 5.18.0-rc1+ #27 ... Call Trace: dump_stack_lvl+0x45/0x5a print_report.cold+0x5e/0x5db ? __lock_text_start+0x8/0x8 ? reserve_sfa_size+0x1ba/0x380 [openvswitch] kasan_report+0xb5/0x130 ? reserve_sfa_size+0x1ba/0x380 [openvswitch] kasan_check_range+0xf5/0x1d0 memcpy+0x39/0x60 reserve_sfa_size+0x1ba/0x380 [openvswitch] __add_action+0x24/0x120 [openvswitch] ovs_nla_add_action+0xe/0x20 [openvswitch] ovs_ct_copy_action+0x29d/0x1130 [openvswitch] ? __kernel_text_address+0xe/0x30 ? unwind_get_return_address+0x56/0xa0 ? create_prof_cpu_mask+0x20/0x20 ? ovs_ct_verify+0xf0/0xf0 [openvswitch] ? prep_compound_page+0x198/0x2a0 ? __kasan_check_byte+0x10/0x40 ? kasan_unpoison+0x40/0x70 ? ksize+0x44/0x60 ? reserve_sfa_size+0x75/0x380 [openvswitch] __ovs_nla_copy_actions+0xc26/0x2070 [openvswitch] ? __zone_watermark_ok+0x420/0x420 ? validate_set.constprop.0+0xc90/0xc90 [openvswitch] ? __alloc_pages+0x1a9/0x3e0 ? __alloc_pages_slowpath.constprop.0+0x1da0/0x1da0 ? unwind_next_frame+0x991/0x1e40 ? __mod_node_page_state+0x99/0x120 ? __mod_lruvec_page_state+0x2e3/0x470 ? __kasan_kmalloc_large+0x90/0xe0 ovs_nla_copy_actions+0x1b4/0x2c0 [openvswitch] ovs_flow_cmd_new+0x3cd/0xb10 [openvswitch] ... Cc: stable@vger.kernel.org Fixes: f28cd2af22a0 ("openvswitch: fix flow actions reallocation") Signed-off-by: Paolo Valerio Acked-by: Eelco Chaudron Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: openvswitch: fix leak of nested actions

2022-04-13T19:01:06+00:00

[ Upstream commit 1f30fb9166d4f15a1aa19449b9da871fe0ed4796 ] 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 Signed-off-by: Sasha Levin

net: openvswitch: don't send internal clone attribute to the userspace.

2022-04-13T19:01:06+00:00

[ Upstream commit 3f2a3050b4a3e7f32fc0ea3c9b0183090ae00522 ] 'OVS_CLONE_ATTR_EXEC' is an internal attribute that is used for performance optimization inside the kernel. It's added by the kernel while parsing user-provided actions and should not be sent during the flow dump as it's not part of the uAPI. The issue doesn't cause any significant problems to the ovs-vswitchd process, because reported actions are not really used in the application lifecycle and only supposed to be shown to a human via ovs-dpctl flow dump. However, the action list is still incorrect and causes the following error if the user wants to look at the datapath flows: # ovs-dpctl add-dp system@ovs-system # ovs-dpctl add-flow "" "clone(ct(commit),0)" # ovs-dpctl dump-flows , packets:0, bytes:0, used:never, actions:clone(bad length 4, expected -1 for: action0(01 00 00 00), ct(commit),0) With the fix: # ovs-dpctl dump-flows , packets:0, bytes:0, used:never, actions:clone(ct(commit),0) Additionally fixed an incorrect attribute name in the comment. Fixes: b233504033db ("openvswitch: kernel datapath clone action") Signed-off-by: Ilya Maximets Acked-by: Aaron Conole Link: https://lore.kernel.org/r/20220404104150.2865736-1-i.maximets@ovn.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

openvswitch: Fixed nd target mask field in the flow dump.

2022-04-08T12:40:44+00:00

commit f19c44452b58a84d95e209b847f5495d91c9983a upstream. IPv6 nd target mask was not getting populated in flow dump. In the function __ovs_nla_put_key the icmp code mask field was checked instead of icmp code key field to classify the flow as neighbour discovery. ufid:bdfbe3e5-60c2-43b0-a5ff-dfcac1c37328, recirc_id(0),dp_hash(0/0), skb_priority(0/0),in_port(ovs-nm1),skb_mark(0/0),ct_state(0/0), ct_zone(0/0),ct_mark(0/0),ct_label(0/0), eth(src=00:00:00:00:00:00/00:00:00:00:00:00, dst=00:00:00:00:00:00/00:00:00:00:00:00), eth_type(0x86dd), ipv6(src=::/::,dst=::/::,label=0/0,proto=58,tclass=0/0,hlimit=0/0,frag=no), icmpv6(type=135,code=0), nd(target=2001::2/::, sll=00:00:00:00:00:00/00:00:00:00:00:00, tll=00:00:00:00:00:00/00:00:00:00:00:00), packets:10, bytes:860, used:0.504s, dp:ovs, actions:ovs-nm2 Fixes: e64457191a25 (openvswitch: Restructure datapath.c and flow.c) Signed-off-by: Martin Varghese Link: https://lore.kernel.org/r/20220328054148.3057-1-martinvarghesenokia@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

openvswitch: fix error return code in validate_and_copy_dec_ttl()

2020-12-04T23:43:14+00:00

Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Changing 'return start' to 'return action_start' can fix this bug. Fixes: 69929d4c49e1 ("net: openvswitch: fix TTL decrement action netlink message format") Reported-by: Hulk Robot Signed-off-by: Wang Hai Reviewed-by: Eelco Chaudron Link: https://lore.kernel.org/r/20201204114314.1596-1-wanghai38@huawei.com Signed-off-by: Jakub Kicinski