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path: root/net/netfilter/nft_inner.c
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2025-05-23netfilter: nft_inner: Use nested-BH locking for nft_pcpu_tun_ctxSebastian Andrzej Siewior
nft_pcpu_tun_ctx is a per-CPU variable and relies on disabled BH for its locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT this data structure requires explicit locking. Make a struct with a nft_inner_tun_ctx member (original nft_pcpu_tun_ctx) and a local_lock_t and use local_lock_nested_bh() for locking. This change adds only lockdep coverage and does not alter the functional behaviour for !PREEMPT_RT. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2024-12-03netfilter: nft_inner: incorrect percpu area handling under softirqPablo Neira Ayuso
Softirq can interrupt ongoing packet from process context that is walking over the percpu area that contains inner header offsets. Disable bh and perform three checks before restoring the percpu inner header offsets to validate that the percpu area is valid for this skbuff: 1) If the NFT_PKTINFO_INNER_FULL flag is set on, then this skbuff has already been parsed before for inner header fetching to register. 2) Validate that the percpu area refers to this skbuff using the skbuff pointer as a cookie. If there is a cookie mismatch, then this skbuff needs to be parsed again. 3) Finally, validate if the percpu area refers to this tunnel type. Only after these three checks the percpu area is restored to a on-stack copy and bh is enabled again. After inner header fetching, the on-stack copy is stored back to the percpu area. Fixes: 3a07327d10a0 ("netfilter: nft_inner: support for inner tunnel header matching") Reported-by: syzbot+84d0441b9860f0d63285@syzkaller.appspotmail.com Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2023-10-12nf_tables: fix NULL pointer dereference in nft_inner_init()Xingyuan Mo
We should check whether the NFTA_INNER_NUM netlink attribute is present before accessing it, otherwise a null pointer deference error will occur. Call Trace: dump_stack_lvl+0x4f/0x90 print_report+0x3f0/0x620 kasan_report+0xcd/0x110 __asan_load4+0x84/0xa0 nft_inner_init+0x128/0x2e0 nf_tables_newrule+0x813/0x1230 nfnetlink_rcv_batch+0xec3/0x1170 nfnetlink_rcv+0x1e4/0x220 netlink_unicast+0x34e/0x4b0 netlink_sendmsg+0x45c/0x7e0 __sys_sendto+0x355/0x370 __x64_sys_sendto+0x84/0xa0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Fixes: 3a07327d10a0 ("netfilter: nft_inner: support for inner tunnel header matching") Signed-off-by: Xingyuan Mo <hdthky0@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de>
2022-11-15netfilter: nf_tables: Introduce NFT_MSG_GETRULE_RESETPhil Sutter
Analogous to NFT_MSG_GETOBJ_RESET, but for rules: Reset stateful expressions like counters or quotas. The latter two are the only consumers, adjust their 'dump' callbacks to respect the parameter introduced earlier. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-11-15netfilter: nf_tables: Extend nft_expr_ops::dump callback parametersPhil Sutter
Add a 'reset' flag just like with nft_object_ops::dump. This will be useful to reset "anonymous stateful objects", e.g. simple rule counters. No functional change intended. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-11-01netfilter: nft_inner: fix return value check in nft_inner_parse_l2l3()Peng Wu
In nft_inner_parse_l2l3(), the return value of skb_header_pointer() is 'veth' instead of 'eth' when case 'htons(ETH_P_8021Q)' and fix it. Fixes: 3a07327d10a0 ("netfilter: nft_inner: support for inner tunnel header matching") Signed-off-by: Peng Wu <wupeng58@huawei.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-10-25netfilter: nft_inner: set tunnel offset to GRE header offsetPablo Neira Ayuso
Set inner tunnel offset to the GRE header, this is redundant to existing transport header offset, but this normalizes the handling of the tunnel header regardless its location in the layering. GRE version 0 is overloaded with RFCs, the type decorator in the inner expression might also be useful to interpret matching fields from the netlink delinearize path in userspace. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-10-25netfilter: nft_inner: add geneve supportPablo Neira Ayuso
Geneve tunnel header may contain options, parse geneve header and update offset to point to the link layer header according to the opt_len field. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-10-25netfilter: nft_meta: add inner match supportPablo Neira Ayuso
Add support for inner meta matching on: - NFT_META_PROTOCOL: to match on the ethertype, this can be used regardless tunnel protocol provides no link layer header, in that case nft_inner sets on the ethertype based on the IP header version field. - NFT_META_L4PROTO: to match on the layer 4 protocol. These meta expression are usually autogenerated as dependencies by userspace nftables. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-10-25netfilter: nft_inner: add percpu inner contextPablo Neira Ayuso
Add NFT_PKTINFO_INNER_FULL flag to annotate that inner offsets are available. Store nft_inner_tun_ctx object in percpu area to cache existing inner offsets for this skbuff. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-10-25netfilter: nft_inner: support for inner tunnel header matchingPablo Neira Ayuso
This new expression allows you to match on the inner headers that are encapsulated by any of the existing tunneling protocols. This expression parses the inner packet to set the link, network and transport offsets, so the existing expressions (with a few updates) can be reused to match on the inner headers. The inner expression supports for different tunnel combinations such as: - ethernet frame over IPv4/IPv6 packet, eg. VxLAN. - IPv4/IPv6 packet over IPv4/IPv6 packet, eg. IPIP. - IPv4/IPv6 packet over IPv4/IPv6 + transport header, eg. GRE. - transport header (ESP or SCTP) over transport header (usually UDP) The following fields are used to describe the tunnel protocol: - flags, which describe how to parse the inner headers: NFT_PAYLOAD_CTX_INNER_TUN, the tunnel provides its own header. NFT_PAYLOAD_CTX_INNER_ETHER, the ethernet frame is available as inner header. NFT_PAYLOAD_CTX_INNER_NH, the network header is available as inner header. NFT_PAYLOAD_CTX_INNER_TH, the transport header is available as inner header. For example, VxLAN sets on all of these flags. While GRE only sets on NFT_PAYLOAD_CTX_INNER_NH and NFT_PAYLOAD_CTX_INNER_TH. Then, ESP over UDP only sets on NFT_PAYLOAD_CTX_INNER_TH. The tunnel description is composed of the following attributes: - header size: in case the tunnel comes with its own header, eg. VxLAN. - type: this provides a hint to userspace on how to delinearize the rule. This is useful for VxLAN and Geneve since they run over UDP, since transport does not provide a hint. This is also useful in case hardware offload is ever supported. The type is not currently interpreted by the kernel. - expression: currently only payload supported. Follow up patch adds also inner meta support which is required by autogenerated dependencies. The exthdr expression should be supported too at some point. There is a new inner_ops operation that needs to be set on to allow to use an existing expression from the inner expression. This patch adds a new NFT_PAYLOAD_TUN_HEADER base which allows to match on the tunnel header fields, eg. vxlan vni. The payload expression is embedded into nft_inner private area and this private data area is passed to the payload inner eval function via direct call. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>