linux/net/netfilter, branch v6.2

Revert "netfilter: conntrack: fix bug in for_each_sctp_chunk"

2023-01-31T13:02:48Z

There is no bug. If sch->length == 0, this would result in an infinite loop, but first caller, do_basic_checks(), errors out in this case. After this change, packets with bogus zero-length chunks are no longer detected as invalid, so revert & add comment wrt. 0 length check. Fixes: 98ee00774525 ("netfilter: conntrack: fix bug in for_each_sctp_chunk") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: unify established states for SCTP paths

2023-01-24T08:52:52Z

An SCTP endpoint can start an association through a path and tear it down over another one. That means the initial path will not see the shutdown sequence, and the conntrack entry will remain in ESTABLISHED state for 5 days. By merging the HEARTBEAT_ACKED and ESTABLISHED states into one ESTABLISHED state, there remains no difference between a primary or secondary path. The timeout for the merged ESTABLISHED state is set to 210 seconds (hb_interval * max_path_retrans + rto_max). So, even if a path doesn't see the shutdown sequence, it will expire in a reasonable amount of time. With this change in place, there is now more than one state from which we can transition to ESTABLISHED, COOKIE_ECHOED and HEARTBEAT_SENT, so handle the setting of ASSURED bit whenever a state change has happened and the new state is ESTABLISHED. Removed the check for dir==REPLY since the transition to ESTABLISHED can happen only in the reply direction. Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") Signed-off-by: Sriram Yagnaraman Signed-off-by: Pablo Neira Ayuso

Revert "netfilter: conntrack: add sctp DATA_SENT state"

2023-01-24T08:52:32Z

This reverts commit (bff3d0534804: "netfilter: conntrack: add sctp DATA_SENT state") Using DATA/SACK to detect a new connection on secondary/alternate paths works only on new connections, while a HEARTBEAT is required on connection re-use. It is probably consistent to wait for HEARTBEAT to create a secondary connection in conntrack. Signed-off-by: Sriram Yagnaraman Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: fix bug in for_each_sctp_chunk

2023-01-24T08:52:31Z

skb_header_pointer() will return NULL if offset + sizeof(_sch) exceeds skb->len, so this offset < skb->len test is redundant. if sch->length == 0, this will end up in an infinite loop, add a check for sch->length > 0 Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") Suggested-by: Florian Westphal Signed-off-by: Sriram Yagnaraman Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: fix vtag checks for ABORT/SHUTDOWN_COMPLETE

2023-01-24T08:52:31Z

RFC 9260, Sec 8.5.1 states that for ABORT/SHUTDOWN_COMPLETE, the chunk MUST be accepted if the vtag of the packet matches its own tag and the T bit is not set OR if it is set to its peer's vtag and the T bit is set in chunk flags. Otherwise the packet MUST be silently dropped. Update vtag verification for ABORT/SHUTDOWN_COMPLETE based on the above description. Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") Signed-off-by: Sriram Yagnaraman Signed-off-by: Pablo Neira Ayuso

netfilter: nft_set_rbtree: skip elements in transaction from garbage collection

2023-01-23T20:38:33Z

Skip interference with an ongoing transaction, do not perform garbage collection on inactive elements. Reset annotated previous end interval if the expired element is marked as busy (control plane removed the element right before expiration). Fixes: 8d8540c4f5e0 ("netfilter: nft_set_rbtree: add timeout support") Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso

netfilter: nft_set_rbtree: Switch to node list walk for overlap detection

2023-01-23T20:36:38Z

...instead of a tree descent, which became overly complicated in an attempt to cover cases where expired or inactive elements would affect comparisons with the new element being inserted. Further, it turned out that it's probably impossible to cover all those cases, as inactive nodes might entirely hide subtrees consisting of a complete interval plus a node that makes the current insertion not overlap. To speed up the overlap check, descent the tree to find a greater element that is closer to the key value to insert. Then walk down the node list for overlap detection. Starting the overlap check from rb_first() unconditionally is slow, it takes 10 times longer due to the full linear traversal of the list. Moreover, perform garbage collection of expired elements when walking down the node list to avoid bogus overlap reports. For the insertion operation itself, this essentially reverts back to the implementation before commit 7c84d41416d8 ("netfilter: nft_set_rbtree: Detect partial overlaps on insertion"), except that cases of complete overlap are already handled in the overlap detection phase itself, which slightly simplifies the loop to find the insertion point. Based on initial patch from Stefano Brivio, including text from the original patch description too. Fixes: 7c84d41416d8 ("netfilter: nft_set_rbtree: Detect partial overlaps on insertion") Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: handle tcp challenge acks during connection reuse

2023-01-17T22:00:06Z

When a connection is re-used, following can happen: [ connection starts to close, fin sent in either direction ] > syn # initator quickly reuses connection < ack # peer sends a challenge ack > rst # rst, sequence number == ack_seq of previous challenge ack > syn # this syn is expected to pass Problem is that the rst will fail window validation, so it gets tagged as invalid. If ruleset drops such packets, we get repeated syn-retransmits until initator gives up or peer starts responding with syn/ack. Before the commit indicated in the "Fixes" tag below this used to work: The challenge-ack made conntrack re-init state based on the challenge ack itself, so the following rst would pass window validation. Add challenge-ack support: If we get ack for syn, record the ack_seq, and then check if the rst sequence number matches the last ack number seen in reverse direction. Fixes: c7aab4f17021 ("netfilter: nf_conntrack_tcp: re-init for syn packets only") Reported-by: Michal Tesar Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

netfilter: nft_payload: incorrect arithmetics when fetching VLAN header bits

2023-01-11T18:18:04Z

If the offset + length goes over the ethernet + vlan header, then the length is adjusted to copy the bytes that are within the boundaries of the vlan_ethhdr scratchpad area. The remaining bytes beyond ethernet + vlan header are copied directly from the skbuff data area. Fix incorrect arithmetic operator: subtract, not add, the size of the vlan header in case of double-tagged packets to adjust the length accordingly to address CVE-2023-0179. Reported-by: Davide Ornaghi Fixes: f6ae9f120dad ("netfilter: nft_payload: add C-VLAN support") Signed-off-by: Pablo Neira Ayuso

netfilter: ipset: Fix overflow before widen in the bitmap_ip_create() function.

2023-01-11T18:18:04Z

When first_ip is 0, last_ip is 0xFFFFFFFF, and netmask is 31, the value of an arithmetic expression 2 << (netmask - mask_bits - 1) is subject to overflow due to a failure casting operands to a larger data type before performing the arithmetic. Note that it's harmless since the value will be checked at the next step. Found by InfoTeCS on behalf of Linux Verification Center (linuxtesting.org) with SVACE. Fixes: b9fed748185a ("netfilter: ipset: Check and reject crazy /0 input parameters") Signed-off-by: Ilia.Gavrilov Reviewed-by: Simon Horman Signed-off-by: Pablo Neira Ayuso